Bunomys chrysocomus ( Hoffmann, 1887 )

Musser, Guy G., 2014, A Systematic Review Of Sulawesi Bunomys (Muridae, Murinae) With The Description Of Two New Species, Bulletin of the American Museum of Natural History 2014 (392), pp. 1-313 : 58-106

Bunomys chrysocomus ( Hoffmann, 1887)

Mus chrysocomus Hoffmann, 1887: 17 .

Rattus nigellus Miller and Hollister, 1921a: 72 . Rattus rallus Miller and Hollister, 1921a: 73 . Rattus brevimolaris Tate and Archbold, 1935a: 7 . Bunomys caelistis koka Tate and Archbold, 1935b: 1 .

HOLOTYPE: SNSD B 612 , the skin and skull of an adult male (original numbers are

TABLE 17 Results of Discriminant-Function Analysis Comparing Samples of Bunomys chysocomus , B. coelestis , B. prolatus , B. torajae n. sp., B. fratrorum , B. andrewsi , B. penitus , and B. karokophilus n. sp. Correlations (loadings) of 16 cranial and 2 dental log-transformed variables are based on 660 specimens; see figure 20.

1707 for the skin and 1727 for the skull) obtained by F. von Faber in 1876. External, cranial, and dental measurements, along with other data, are listed in table 18.

Until the advent of World War II, the holotype was in the collection at the Staatliches Naturhistorische Sammlungen Dresden, Museum für Tierkunde. It was apparently lost or misplaced for some time after the War (see Musser, 1970: 14), but fortunately has been found ( Feiler, 1999: 409) and was loaned to me by A. Feiler, the retired curator of the mammal collection at Dresden.

The stuffed skin is intact (fig. 23), but parts of the pelage are discolored. The dorsal coat is dark brownish gray and has a slight rusty sheen due to color alteration: bands of the overhairs that are normally brown in recently collected specimens have altered to rust or yellowish brown. The appendages are dark brown, which is unusual, and are likely discolored. The dark brown ears are bent and fragile. The ventral coat is brownish buff and its color is not sharply demarcated from that of the upperparts. Except for the slight chromatic alteration of the dorsal coat and appendages, pelage color of the holotype falls within the range of variation present in the large series of B. chrysocomus I collected during the 1970s in the forests around Sadaunta, Danau Lindu, and Gunung Kanino (localities 7–33 in the gazetteer). Compared with a series of B. chrysocomus collected by C.H.S. Watts during the 1980s in the northeastern peninsula (localities 3 and 4 in the gazetteer), the holotype has a paler dorsal coat with rusty highlights (dark brownish gray with scatter of buff through the coat in the fresher specimens) and a duller ventral coat that appears soiled (contrasted to bright, buffy brown venters).

The skull is incomplete (fig. 24). Most of the left zygomatic arch, the entire occipital region, and pieces from the roof of the mesopterygoid region are missing, and the basioccipital is cracked. The mandible is intact, as are the upper and lower incisors and maxillary and mandibular molar rows (fig. 25).

TYPE LOCALITY: Amurang (01 ° 11 9 N, 124 ° 35 9 E), locality 1 in the gazetteer and on the map in figure 22, the northeastern arm of Sulawesi, Propinsi Sulawesi Utara, Indonesia. Hoffmann (1887: 17) indicated the region of ‘‘Minahassa, Nord Celébes’’ to be the origin of the holotype and that is notated on the original skin tags. Feiler (1999: 409; and in a letter to me [quoted in Musser, 1970: 15]) narrowed the locality to Amurang, a town on the coastal plain near sea level. Minahassa is an expansive administrative region within the province of Sulawesi Utara (northern Sulawesi) between 0.8 ° – 1.8 ° N and 124.3 ° – 125.3 ° E on the northeastern peninsula of the island (coordinates are from Fooden, 1969: 134; also see the map in Whitten et al., 1987: xiv). Amurang is unlikely the actual collection site of the holotype because no other specimens to which reliable elevational data are attached have been encountered in coastal plain habitats (see below). F. von Faber, who presented the holotype to the Dresden Museum, stayed at Amurang during 1876 while he collected birds in the broader Minahassa region ( Meyer and Wiglesworth, 1898: 7). The holotype was probably obtained beyond the coastal plain at a higher elevation somewhere in ‘‘Minahassa.’’

EMENDED DIAGNOSIS: Among the smallest in physical size ( LHB 5 97–180 mm, WT 5 55–175 g, ONL 5 35.8–41.1 mm) of the Sulawesian species in Bunomys and further characterized by the following combination of traits: (1) a long muzzle, small eyes, and long external pinnae; (2) dark brown to brownish gray upperparts speckled with buff, grayish white underparts with some individuals washed with buffy, ochraceous, or rusty hues, dorsal surfaces of feet range from grayish white to brownish gray; (3) front claws moderetly long and robust; (4) tail averages shorter than length of head and body (85 % – 98 %), brown or grayish brown on the dorsal surface, white, mottled brown, or brown along the ventral surface (5) white tail tip infrequent (20 % of 396 specimens in 13 samples) and when present is short relative to tail length (mean 5 5.5 %, range 5 1 % –25 %); (6) testes large relative to body size (22 %); (7) sperm head long, thin, asymmetrical and falciform in outline, tail long; (8) skull gracile with a moderately long and narrow rostrum, wide upright or backward sloping zygomatic plate, bony palate projecting slightly beyond posterior margins of third molars, and large ectotympanic bulla relative to skull size; (9) molars small relative to size of skull and mandible; (10) cusp t3 occurs infrequently on second upper molar (17 %) and third upper molar (5 %); (11) anterior labial cusplets on first lower molar present in about half of sample, posterior labial cusplets typically present on first and second lower molars; (12) anterolabial cusp present on second lower molar in 90 % of sample and on third lower molar in 65 % of sample; and (13) karyotype, 2N 5 42, FNa 5 56, FNt 5 58.

GEOGRAPHIC AND ELEVATIONAL DISTRI- BUTIONS: Collection localities appear as a spotty pattern compared to Sulawesi’s land area (fig. 22), but the scatter suggests B. chrysocomus to range throughout much of the island wherever lowland and montane evergreen rainforest formations persist. All samples of B. chrysocomus describe an altitudinal range from 250 m (in the Bogani Nani Wartabone National Park on the northern arm) to 2200 m (on Pegunungan Latimojong at the southern margin of the west-central mountain block). Modern specimens with reliable provenence data have not been collected in habitats below 250 m, strongly suggesting B. chrysocomus to be a denizen of forested hills, mountains, and intermontane valleys. The only sample from a coastal plain (0–100 m) consists of subfossil fragments from a cave on the southwestern peninsula; whether the specimens were obtained by mammalian or avian predators near the cave or at higher elevations is unknown.

The species is either uncommon or infrequently encountered by collectors in the northern peninsula and the few records from there are in the zone of tropical lowland evergreen rain forest. Besides the holotype, obtained somewhere in the Minahassa Region, three individuals come from Langgon at 700–800 m (locality 2 in the gazetteer and map in fig. 22) and 10 were taken at 250 and 300 m in the Bogani Nani Wartabone National Park (localities 3 and 4), where it appears to be relatively abundant. The northeastern peninsula of Sulawesi has been a focus for collecting mammals and birds since the 1800s, and why B. chrysocomus is not represented in museum collections by large samples from more localities is inexplicable.

H.C. Raven, who collected birds and mammals for the Smithsonian Institution, was one of the more successful of the early mammal trappers to have worked in the northeastern arm of Sulawesi, and his results are illustrative. He arrived in Menado in January of 1916 and remained in the northeast until the end of August with the intention of beginning his survey at the extreme end of the peninsula and working west toward Gorontalo ( Miller, 1917: 29). Raven collected in primary forest habitats in lowlands and mountains where he garnered large samples of B. fratrorum (see gazetteer for that species) along with other species of murines, but never encountered B. chrysocomus . After August, he moved south to where the northern peninsula joins the central body of the island, planning to use either Palu or Parigi as a base and working north from there until he had surveyed all of the northern peninsula. His stations were scat- tered from west of Gorontalo in the north to the base of the peninsula in the south, and it is only there, at Bumbarujaba (locality 5), that he came upon B. chrysocomus .

Except for a specimen from the Mamasa area, seven specimens from Pegunungan Latimojong, and four individuals obtained on Gunung Balease, all three places in Sulawesi’s west-central mountain block, most of the material I have studied came from highlands south of the Palu Valley in the northern part of the west-central region. Small samples are from south of the Palu Valley at Bakubakulu (600 m) in the Puro Valley, Gunung Lehio (1880–2185 m), and Gimpu. The bulk of the material was collected on my transect extending from 320 m along the Sungai Oha Kecil to 1555 m on Gunung Kanino, which includes the range from tropical lowland evergreen rain forest to lower montane forest. Apart from these localities are vast stretches of forested hills, mountains, and valleys unsurveyed for small mammals, so the actual distribution of B. chrysocomus throughout the west-central region remains to be discovered.

Available samples of B. chrysocomus from the core of Sulawesi come only from the west-central region (see the map in fig. 22), which suggests to me that the range of the species does not extend into coastal lowland habitats and that its absence from mountains east of the west-central mountain block (generally between Danau Poso and the coast rimming Telok Tolo) may reflect the lack of adequate surveys for small nonvolant mammals there. East of Danau Poso lie mountainous terrain (Pegunungan Pompangeo, for example) that has yet to enjoy surveys for small mammals. There seems no reason why B. chrysocomus does not occur in these eastern highlands—providing, of course, that

TABLE 19 Descriptive Statistics for Measurements (mm) of Lengths of Head and Body, Tail, Hind Foot, and Weight (g), Derived from Samples of Bunomys chrysocomus , B. coelestis , B. prolatus , and B. torajae , n. sp. Mean ± 1 SD, observed range (in parentheses), and size of sample are provided. Mean values were used to compute LT/LHB. Specimens measured are listed in footnotes.

forest has not been removed—because the species has been taken on the slopes of Gunung Tambusisi to the northeast at the western margin of the eastern peninsula.

Trapping efforts bolster the hypothesis that B. chrysocomus is absent from very low elevations. Along my transect in the northern part of the west-central mountain block, I did not encounter the species below 320 m —only B. andrewsi was caught at lower elevations (see fig. 103 and the gazetteer for B. andrewsi and map in fig. 50). Nor did I collect B. chrysocomus in the northern part of the eastern portion of the central core at Kuala Navusu and Sungai Tolewonu, lowlands and ridges just back of the northeastern coast (see the map in fig. 5). I trapped only B. andrewsi at Kuala Navusu (31–122 m), but did not encounter either species of Bunomys at Sungai Tolewonu (136–366 m). Farther south in the eastern coastal lowlands, H.C. Raven collected a large sample of B. andrewsi from the forest by Pinedapa at 31 m but no B. chrysocomus .

The eastern peninsula of Sulawesi is another region receiving little exploration for small mammals, and the range of B. chrysocomus throughout that area is unknown. My only sample comes from 1372– 1829 m on the flanks of Gunung Tambusisi, located at the southwestern margin of the peninsula. Mammal surveys in the eastern arm have been few, and sampling macaques has been the focus of most research trips. One exception is a collection of rodents and bats made by Luis Ruedas in 1998 from lowlands in the eastern Poso and Banggai districts of the peninsula, and another is a collection made by Jake Esselstyn and Anang Achmadi from Gunung Tompotika at the eastern end of the peninsula, neither of which contained examples of B. chrysocomus . What species occur at middle and high elevations along the mountainous backbone of the eastern peninsula has yet to be determined.

Tropical lowland evergreen rain forest to lower montane forest is the broad habitat range in which samples of B. chrysocomus have been obtained from the southeastern peninsular arm of the island. A specimen from Pulau Buton, the small sample from Lalolei at 300 m, and the material from Pegunungan Mekongga collected at 1500 and 2000 m embody the material I have included in this report, nearly all obtained by G. Heinrich in the 1930s. Additional specimens of B. chrysocomus from the Mekongga highlands are reported by Mortelliti et al. (2012).

Three subfossil fragments from cave deposits in the Maros region (below 100 m), about 40 km northeast of Ujung Pandang, provide the only record of B. chrysocomus from the southwestern peninsula (table 27). The species apparently lived in forest habitats at low and moderately high elevations because montane forests between 1800 and 2500 m on Gunung Lompobatang, south of the caves, support populations of B. coelestis , the mountain counterpart of B. chrysocomus in this region. Much of the lowlands in the southwestern peninsula are deforested and converted to agriculture ( Whitten et al., 1987: 93, 102; Bernard and De Koninck, 1996: 3), but low forest cover still exists in limestone regions, especially in the Maros hills (personal obs.; Whitten et al., 1987), which are difficult to traverse and have never been surveyed for small mammals, and possibly B. chrysocomus still lives in those places.

SYMPATRY WITH OTHER BUNOMYS: Througout Sulawesi, B. chrysocomus is broadly sympatric with all the other species of Bunomys (tables 6, 20; also see gazetteers), but samples documenting its occurrence at the same locality and taken in the same trapline are few. Among the two other species in the B. chrysocomus group, B. prolatus and B chrysocomus have been collected on the slopes of Gunung Tambusisi. The eight known specimens of B. prolatus were trapped on a ridge at 1830 m in upper montane forest. One B. chrysocomus was taken ‘‘just below the same ridge, at about the same altitude (6000 ft) but a few meters downslope, and on the same day (March 9) as were four examples of B. prolatus . Six specimens of B. chrysocomus were collected at 4500 and 4700 ft during the same period, March 6–27, 1980 ’’ (Musser, 1991: 6). Samples of both species are small— whether the altitudinal ranges of each narrowly overlap or the two are truely altitudinally parapatric can only be determined by future elevational surveys on Gunung Tambusisi.

No modern samples of B. chrysocomus are available from the lower slopes of Gunung Lompobatang at the tip of the southwestern arm of Sulawesi. It is represented there only by subfossil fragments collected on the western coastal plain. Its original altitudinal distribution on the volcano and throughout the southwestern peninsula in general is unknown. Forests above 1800 m contain B. coelestis , the montane relative of B. chrysocomus .

On the northeastern peninsular arm of Sulawesi, B. chrysocomus and the largerbodied B. fratrorum are recorded at two localities (see gazetteers). One is Rurukan, but the samples were obtained during different years and the actual collection sites are unknown. The second place is in the Bogani Nani Wartabone National Park, 1 km north of Gunung Mogogonipa at 250 m. There during August 2–8, 1985, C. Watts collected two B. chrysocomus and three B. fratrorum . Thus, in this northeastern arm the two species are regionally sympatric and apparently syntopic at one collection site.

Bunomys chrysocomus and B. andrewsi have been recorded from the same places in four regions of Sulawesi. Both species come from the PuroValley at Bakubakulu, 600 m, in the northern portion of the west-central mountain block, where on July 30, 1973, NAMRU-2 personnel trapped two B. chrysocomus and two B. andrewsi .

I collected the two species along a portion of my transect that extended from the Sungai Oha Kecil at 290 m to the Sungai Sadaunta at 675 m in the valley of the Sungai Miu. At 457 m on the Oha Kecil, both species were taken in the same trapline on the same days during August, 16 and 17, 1974; along the Sungai Sadaunta at 675 m, both species were collected in the same trapline on February 10 and 12, 1974 (at the latter locality an example of B. andrewsi [AMNH 224107] was trapped

TABLE 20

Summary of Elevational Relationships between Bunomys chrysocomus and Other Species of Bunomys Derived from Voucher Specimens

in a runway beneath a rotting tree trunk laying in shrubby understory of streamside forest; during the next night a B. chrysocomus [AMNH 224108] was trapped in the same spot). Bunomys andrewsi was rare in this overlap zone, but B. chrysocomus was relatively abundant (see the elevational distribution of specimens in fig. 103).

Bunomys chrysocomus and B. andrewsi are sympatric, but may not be syntopic, on Gunung Balease in the southeastern portion of the west-central mountain block (table 20). During 2010, four examples of B. chrysocomus were caught between 980 m and 1240 m, a range through the upper limit of tropical lowland evergreen rain forest and into lower montane rain forest, on October 25, 28, and 29, and Nov 1. Downslope between 830 m and 925 m, 18 specimens of B. andrewsi were trapped in tropical lowland evergreen rain forest during the period, October 18–29. No B. chrysocomus were encountered below 980 m and no B. andrewsi above 925 m (elevational data was kindly provided by J.L. Patton and K.C. Rowe).

Finally, B. chrysocomus and B. andrewsi are represented by subfossil fragments extracted from sediments at Ulu Leang I, a cave in the Maros region on the western coastal plain of the southwestern peninsula. The pieces may have been originally packaged in owl pellets or scat from the civet, Macrogalidia . If so, we know nothing of the ranges of these predators or habitats in which they hunted and cannot now determine whether the two species of Bunomys lived together on the coastal plain or came from different elevations.

Except for the few places of syntopy, the ranges of B. chrysocomus and B. andrewsi are generally mutually exclusive. Places yielding large samples of B. andrewsi —such as Pinedapa, Kuala Navusu, Gunung Balease, and the coastal plain west of Pegunungan Mekongga—are either devoid of B. chrysocomus , the species is rarely encountered, or its microhabitat in those places was never or inadequately sampled. The interplay of environmental factors related to elevation and competition for food (insects, oligochete earthworms, snails, and some fruit form the diet of both species, judged by my field observations and examination of stomach contents; see table 13) may partly explain the checkerboard pattern. Reliable altitudinal measurements indicate that modern samples of B. chrysocomus have yet to be encountered below 250 m. In more or less continuous intact forest, which characterized the landscape along my transect in the west-central region, I collected B. chrysocomus from 320 m at Sungai Oha Kecil to 1555 m on Gunung Kanino. Elsewhere in the central core of Sulawesi, the species occurs in montane forests up to 2200 m. With a few exceptions, most collection sites for B. andrewsi are below 600 m, and many between 30 and 300 m; 1000–1600 m seems to bracket the upper limit of its elevational range. In primary forest at Pinedapa, H.C. Raven collected 22 B. andrewsi during about a month, but no B. chrysocomus . At 30 m, that place is likely too low and the environmental conditions unsuitable for B. chrysocomus . West of Pinedapa, in the Malakosa region, I worked along the Kuala Navusu for three months and the nearby Sungai Tolewonu for another two months and caught B. andrewsi between 30 and 122 m in the Navusu area but no B. chrysocomus . Work in the Tolewonu drainage extended from 137 m to 366 m, but neither one of the species was encountered in forest seemingly no different than that covering the Navusu drainage basin.

Samples from four mountains provide records of syntopy between B. chrysocomus and the montane B. penitus . During June 13– 14, 1930, G. Heinrich collected both species at 2200 m on Pegunungan Latimojong, the highlands on the northern margin of the southwestern peninsula. His survey on Pegunungan Mekongga in the southeastern arm of the island garnered both species from 1500 m during January 3–13, 1932, and from 2000 m during December 18–30, 1931.

Samples of the two species come from Gunung Lehio, just northwest of Gimpu. Above 1800 m, H.C. Raven collected B. chrysocomus on January 13 and 16, 1917, and B. penitus a few days later, during January 18–21.

From the end of October to the last part of November, 1973, I trapped five B. chrysoco- mus and 60 B. penitus in lower montane rain forest between 1265 and 1555 m on the slopes and top of Gunung Kanino, a high ridge leading to the higher Gunung Nokilalaki; during one night, an example of each species was taken in the same runway beneath a rotting, moss-covered tree trunk on the forest floor (fig. 32). Below 1265 m, B. chrysocomus ranges down through tropical lowland evergreen rain forest to 320 m along my Sungai Miu–Danau Lindu–Gunung Nokilalaki transect, and occurs with B. andrewsi and B. karokophilus , n. sp.; above 1555 m, B. penitus was the only Bunomys encountered during the period in which I trapped, and was common in lower and upper montane rainforest formations, all the way to the summit of Gunung Nokilalaki.

Bunomys chrysocomus and B. karokophilus , n. sp., are sympatric and syntopic in distribution. I trapped examples of each species along my transect between 823 and 1006 m in the streamside forest along the Sungai Sadaunta (both were taken at 823 m in the same trapline on September 25 and 28, 1974; and at 854 m on October 1, 1974); at Tomado, 1000 m (taken in same trapline on July 26 and 27, and August 2–4, 10, and 14, 1973); and at 1150 m near the Sungai Tokararu (both were caught in the same trapline on October 8, 1973).

DESCRIPTION: Hoffman (1887: 17) joined chryso, from the Greek meaning ‘‘gold,’’ to the Latin coma, referring to ‘‘hair’’ of the head, to produce chrysocomus , the combination meaning ‘‘golden haired,’’ which emphasized, in Hoffmann’s eyes, the ‘‘gold-yellow’’ luster highlighting the dark brown dorsal coat of the new rat presented to the Dresden Museum by F. von Faber. His description follows (translated by E. Brothers; the original German version is provided in appendix 1):

This rat from north Celebes is yet another that is just a bit smaller than our own house rat; its coloring tallies so well with Mus rattus that at first glance, one might think that it was a juvenile of that species. The fundamental distinction is in the nature of the skull and of the pelt. Craniology: The rear of the skull is damaged, so I present here the range from bony nasal tips to the back edge of the parietals; this distance amounts to 3.4 cm. The rostrum is very pointy; this is because the nasals are long and the front end of the rostrum is very narrow; at the other end the zygomatic plate is shifted back, while its forward edge is oblique, rising toward the back. Behind that lies the rudimentary upper base of the zygomatic arch, and thus also the site of the smallest width of the skull between the orbital concavities, more distant from the nose-tip than in all other rats [Hoffmann’s description of chrysocomus was one of six accounts describing Indo-Australian species of murines]. This distance amounts to 2.07 cm; in a M. rattus of the same size it is only 1.75 cm. The parietals have the breadth of the aforementioned M. rattus , measuring 1.09 cm at the anterior suture. This forms a twice broken line, of which the front middle part is straight. The lateral parts both rise anteriorly. The orbital ridges are extremely slightly developed, yet can be discerned up to the occipitals. The interparietal is very small, its width approximately 3/5 the width of both parietals. The incisive foramina terminate about 1 mm anterior to the bases of the first molars. The bony palate terminates just behind the last molars. The molar tooth row is 0.66 cm long; the teeth themselves are wide, extend farther back and are taller than those of M. rattus . The distance between toothrows is 0.34 cm at the front, and both toothrows diverge, so that the distance between them is 0.41 cm at the back. The osseous bullae are 0.68 cm long. In the mandible the roots of the incisors travel outward and exactly under the forward projection of the crown; the condyle and the angular process are very weak. In general, the upper teeth, as well as those of the mandible, are comparable to those of Mus decumanus . A significant characteristic is that the inner cusp of both first upper teeth are displaced backward relative to M. decumanus . The shape of the small lateral cusp of the mandible is similar to that of M. rattus , only it is a bit smaller in general and those of the first lamella of the third tooth lie more to the inside of the top of the front surface of the lamella. External Characteristics: Head and body measure 17 K cm, tail 12 K cm long with about 190 scale rows. Forefoot including underarm 4 cm, hind foot 3.2 cm long. Sole of the hind foot small, callosities rather long, with a point at the back, one at the base of the middle toe, one under the first toe, and two under the fifth toe; in the center of the sole there is a small wide projecting callosity. The fur is long, thick, very soft and smooth lying. The back has a beautiful light brown color, a little darker than that of Mus rattus , with a gold-yellow luster; at the base it becomes a

brown, nearly black color, which in most other rats and mice is not as prominent, but is here a bit more pervasive. The blackish color disappears at the sides; it merges with the lighter brown in a somewhat stronger tone, uniting to supplant it with a brownish to pure neutral gray color, which however is not as extensive as the dark color of the back–-rather it is very constrained. The underside of the body is pale yellow, paler at the back than at the front and not sharply set off from the color of the flanks. The light gray color of the bases of the hairs often asserts itself. The specimen before me presents on its underside several irregularly scattered rust-brown patches with yellow edges. The head is brown like the back, fading a bit to pale yellow at the front and sides. Fore and hind feet are dark gray-brown, and covered with whitish glossy little hairs. The very fine woolly hair is, at the midline of the back, colored dark neutral gray in the lower 2/3, the upper portion is slightly more than a third and almost completely dark brown-black, with only the outermost tip, approximately K – 1mm, a light brown. For the great length of the woolly hairs (between 1.6 and 1.8 cm) the tips are very conspicuous, thereby explaining the overall color of the back fur. Entirely spiny hairs are absent in this mouse. The bristly hairs [guard hairs] are difficult to separate from the woolly hairs. They are small in number, and distinguish themselves only in that they are completely straight and in the front part [of the dorsum] the outermost tips are colored dark brown-black. In the remaining areas they are very similar to the woolly hairs; their lengths are barely different, such that no bristle-hairs greater than 1.9 cm in length are encountered. Toward the flanks the woolly hairs become lighter next to the very dark part and mix to gray. On the other hand the light brown tips become more prominent and extensive. The bristly hairs gradually diminish altogether. The roughly 12 K cm long tail contains about 190 scale rows, between them stand quite a lot of dark little hairs, which are of uniform length over the entire tail.

A compact body and moderately long head, relatively short tail, dark brown, lustrous fur, and medium body size (LHB 5 97–180 mm, LT 5 90–180 mm, LHF 5 31–40 mm, LE 5 17–28 mm, W 5 55–175 g, ONL 5 35.8–41.1 mm) describes Bunomys chrysocomus (see the rendition of B. chrysocomus presented in fig. 6), which among members of the B. chrysocomus group is physically similar to B. coelestis , but smaller than B. prolatus and B. torajae , n. sp. (tables 7, 19). The dorsal coat is dense, smooth, and soft to the touch; it is 12– 15 mm long over the back on rats from lowlands, but reaches 20 mm on those from middle and high elevations. Dark brown with buffy speckling (produced by the combination of dark brown and buffy bands of the overhairs) describes the typical coloration of the dorsal coat covering most of the the head and body; sides of the body are paler, a grayish brown (because the brown and buffy bands are reduced in lengths or absent, more of the gray bases of the underhairs and overhairs dominate). A few individuals exhibit a darker coat, brownish black with only slight speckling. Because guard hairs and overhairs are about the same length, the surface of the coat is smooth, and the glistening guard hairs impart sheen to the fur. The rhinarium and sides of the muzzle are brown.

Fur covering the underparts of the head and body is also soft and dense, but shorter (8–10 mm long) than the dorsal fur, which is the usual pattern in murids. The contrast in color between upperparts and underparts is evident but not sharply marked. Grayish white (bases of the hairs are gray, tips are unpigmented), gray tinged with pale buff (tips of the hairs are pale buff), or dark gray washed or saturated with buff or ochraceous (hairs with long gray bands and short buffy or ochraceous tips) illustrate the predominant variation in color within the samples, although grayish white is most common; chestnut overlays the chin, neck, and chest in some specimens, pigmentation similar to that seen in many examples of B. andrewsi . In the west-central mountain block, deeply pigmented underparts (buffy gray or ochraceous-gray) predominate in samples from lower montane forest (Gunung Kanino and Gunung Balease) but are seen in only a few specimens from tropical lowland evergreen rain forest.

In life, the ears (external pinnae) feel and appear rubbery to me; they seem to be naked but are sparsely covered by short hairs. Their color is variable, ranging from shiny gray through dark gray, dark grayish brown, and grayish black to blackish gray. The stiff dried ears of stuffed museum skins lack the rubbery texture of the live animal and have dried to a dark brown.

Averaging shorter than the combined length of head and body (LT/LHB 5 85 % – 98 %), the tail’s dorsal surface is some shade of brown, the ventral surface ranges from white to brownish; a white tail tip is infrequent (20 % of 396 specimens in 13 samples; table 8) and when present is short relative to tail length (mean 5 5.5 %, range 5 1 % –25 %). The following color patterns (ignoring any white tip) are present in any large sample of B. chrysocomus : (1) mottled brown on the dorsal surface, white for the full length of the ventral surface (a rare bicolored variant); (2) dark brownish gray along the dorsal surface, white below but very lightly speckled—still appears sharply bicolor, dark above and whitish below; (3) dark grayish brown or dark brown on dorsal surface, white on ventral surface and moderately to densely speckled grayish brown—no clear demarcation between dorsal and ventral surfaces; (4) densely speckled grayish brown on dorsal surface, slightly less speckled on ventral surface—appears grayish brown all over; (5) dark brown above, slightly paler below—appears monocolored.

Carpal and metacarpal along with tarsal and metatarsal surfaces vary in color, ranging from grayish white (skin is unpigmented and covered with short gray and silvery hairs), through whitish brown (sparsely covered with brown hairs) to brownish white and then dark brown (denser cover of brown hairs). Digits of front and hind feet are typically unpigmented and sparsely covered with short silvery hairs; in some individuals, the bases of the digits are gray, in a few others the digits are white and sparsely covered with brown hairs. The moderately long front claws are not concealed by ungual tufts, but thin tufts of silvery hairs lay over the hind claws. Palmar and plantar surfaces are typically unpigmented except for near the heel and over the tubercles, which are gray; specimens from Gunung Balease have dark brown palmar and plantar regions, the darkest I have seen.

Females exhibit the number of teats usual for all Sulawesian species of Bunomys —four, arranged in two inguinal pairs. Males have large testes relative to body size, as measured by lengths (table 9) and weights ( Breed and Taylor, 2000). Gross and ultrastructural spermatozoal descriptions are provided by Breed and Musser (1991) and Breed (2004).

Juveniles have a distinctly different pelage than that of adults. It is shorter, has a velvety texture, and is very dark compared with the brownish adults—brownish black with a flat tone (lacking the glossy sheen of the adult fur). Underparts are dark grayish white. Coloration of ears, feet, and tail ranges through the same patterns seen in any large series of adults.

The small gracile cranium and mandible of B. chrysocomus is depicted in figures 16 and 37–39. Their conformation and internal structure epitomizes the description of the Bunomys skull provided in the introduction to the morphological characteristics of the genus. Noteworthy features of the cranium are its wide interorbit, deep and boxy braincase, moderately long and tapered rostrum, low postorbital ridging, sloping anterior edge of the zygomatic plate in most specimens, relatively short incisive foramina, short projection of the bony palate past posterior faces of the third molars, and relatively large bullar capsules. Each dentary is gracile and somewhat elongate, especially that slim portion of the ramus between incisor and first molar (diastema).

Molars are small relative to size of the cranium and mandible, and the occlusal patterns of cusps (figs. 12, 25) mirror the general patterns already described for the genus. I point out here only the frequencies of certain cusps and cusplets. Cusp t3 occurs on the second upper molar in only 17 % of the sample, and on the third upper molar in only 5 % of all specimens examined (table 10). About half of all specimens surveyed support an anterior labial cusplet on the first lower molar, and posterior labial cusplets are typically present on the first and second lower molars; an anterolabial cusp is present on the second lower molar in 90 % of the sample and on the third lower molar in 65 % of all specimens surveyed (table 11).

KARYOTYPE: 2N 5 42, FNa 5 56 and FNt 5 58, comprised of seven pairs of metacentric chromosomes, one pair of subtelocentrics, and 12 pairs of acrocentrics; the sex chromosomes are acrocentrics (fig. 13, table 12).

COMPARISONS: In its morphology, Bunomys chrysocomus most closely resembles the other members of the B. chrysocomus group— B. coelestis , B. prolatus , and B. torajae , n. sp. —and is compared with them in those three respective accounts. Bunomys chrysocomus is also contrasted with each of the species in the B. fratrorum group in the accounts of B. fratrorum , B. andrewsi , B. penitus , and B. karokophilus , n. sp.

GEOGRAPHIC VARIATION: Morphological variation among available samples is estimated primarily from characters of dry museum skins along with qualitative and morphometric traits of the skull and dentition. In traits related to general body size, relative lengths of hind feet and tail, as well as fur and skin pigmentation, adult examples of B. chrysocomus , to my eyes, look similar whatever the geographic provenance of the specimen. I did not detect any noteworthy variation among population samples in dimensions of head and body, tail, hind foot, and ear; in texture and coloration of fur; in color of feet and ears; or in pigmentation patterns on the tail. In any large sample (the 146 from Sungai Oha Kecil and Sungai Sadaunta, for example), the range in chromatic tones of body fur and the range of patterns formed by brown and unpigmented regions of the tail is greater than the range of variation in these features I saw among most other geographic samples.

Some specimens are darker than most others. The four adults from Gunung Balease and the rats from Gunung Kanino have darker dorsal and ventral coats, feet, and tails than is typical of the individuals comprising most samples.

My assessment of variation in color of the fur, skin, and pattern of the tail revealed by its dorsal and ventral pigmentation is not quantified and derives from simple observation of skins. Coloration of the distal portion of the tail is an exception and I quantified the frequencies of a white tip and its length in samples (table 8). The results did not reveal a pattern among the samples that bore significant concordance with their geographic origins.

Lengths of head and body, tail, hind foot, and ear are statistically summarized by sample but I did not treat the data in any rigorous comparative way for several reasons. Samples are uneven in composition of adult classes (young to old). Except for the material from my transect most samples are small (table 19). And there is always the problem of comparing measurements obtained by different collectors. Was length of head and body measured separately from length of tail? Was the tail measured on the dorsal side from the rump to the tip or ventrally from the anus to the tip? Did the collector include or omit claws in obtaining values for length of hind foot? Is length of pinna (if obtained; H.C. Raven, for example, did not measure the ear) measured from notch to crown or from base of the pinna to crown?

Morphometric variation in cranial and dental variables among the population samples does exist (tables 21, 22), detectable not so much by side-to-side comparison of skulls of comparable age classes, but by multivariate analyses, and I relied on those results to reveal possible patterns of variation in morphometric traits over Sulawesi’s landscape. Intersample geographic variation is less apparent in the ordination of specimen scores for all population samples of B. chrysocomus projected on first and second principal components (fig. 26). Scores representing the two large samples from my transect (Sungai Oha Kecil + Sungai Sadaunta, Danau Lindu + Gunung Kanino) are diffused along the lengths of both axes, and that cloud also embraces nearly all scores representing the other eight population samples, including scores for the holotypes of nigellus , rallus , koka, and brevimolaris (fig. 26, upper graph) as well as chrysocomus itself (fig. 26, lower graph). The positive and high loadings for most variables on the first component, along with significant correlations among all of them (table 23), point to size as primarily responsible for the spread of scores along the first axis with covariation in overall size of skull (occipitonasal length and zygomatic breadth), interorbit, rostrum (length and breadth), zygomatic plate, and palatal region (length of diastema, breadth of incisive foramina, length and breadth of bony palate, postpalatal length, and breadth of mesopterygoid fossa) being the most influential (r 5 0.43–0.78 for upper graph). Covari- ation among other variables (size of the braincase, lengths of incisive foramina and ectotympanic bulla) exert moderate force in the dispersion of scores, and size of molars express the smallest loadings and the least pressure. After full eruption the molars do not increase in dimensions and the braincase reaches nearly full size early in ontogeny, so the dispersion of scores along the first axis partly signals variation in the facial skeleton due to different stages of postweaning growth within adults (young to old) as well as some variation associated with geographic origin of the samples.

Plotted results of discriminant-function analysis provide a sharper resolution of geographic variation in morphometric traits among samples. Individual specimen scores projected on first and second canonical variates form two slightly overlapping constellations in the scatter plot that include holotypes of brevimolaris , koka, nigellus , and rallus (fig. 27, upper graph) and the plot incorporating those holotypes as well as that for chrysocomus (fig. 27, lower graph). The largest and densest cluster of scores in the right half of both scatter plots represents the 188 specimens from my transect in the northern part of the west-central mountain block (Sunga Oha Kecil + Sungai Sadaunta combined with Danau Lindu + Gunung Kanino), the rat from Bakubakulu just north of my transect, and the three individuals from Gimpu, south of the transect and also in the west-central region. Specimens from along the transect were collected at sites in mostly unbroken forest extending from Sungai Oha Kecil at 320 m to Gunung Kanino at 1524 m, an elevational range embracing habitats in tropical lowland evergreen rain forest and lower montane forest. It is not surprising that their scores form a single cluster, and one that also embraces scores of the specimen from Bakubakulu and the three from Gimpu.

Slightly separated from the dense cluster of points representing specimens from the westcentral region are those scores for samples from the northern peninsula (Bogani Nani Wartabone National Park); Bumbarujaba, near the southern end of the northern peninsula; Gunung Tambusisi, at the western margin of the eastern peninsula; part of the

TABLE 21

Descriptive Statistics for Cranial and Dental Measurements (mm) Derived from Population Samples of Bunomys chrysocomus

Mean ± 1 SD and observed range (in parentheses) are listed. Compare with statistics summarized in table 22.

sample from Gunung Balease on the eastern margin of the west-central mountain block; Pegunungan Mekongga in the southeastern peninsula, and Lalolei in lowlands adjacent to the Mekongga highlands. The position of scores along the first canonical variate representing these samples reflects their slightly larger braincase and bulla; longer diastema, incisive foramina, and molar row; and narrower rostrum, zygomatic plate, and mesopterygoid fossa (see moderate to large positive and negative loadings in table 24) compared with those samples from the westcentral mountain block, distinctions reflected in univariate summary statistics (tables 21, 22).

The association of four of these five population samples relative to the four from the west-central region in the scatter plot is also portrayed in the clustering pattern based on Mahalanobis distances squared as a measure of phenetic resemblance (fig. 28).

TABLE 22

Descriptive Statistics for Cranial and Dental Measurements (mm) Derived from Population Samples of Bunomys chrysocomus from the West-Central Region a

Mean ± 1 SD and observed range (in parentheses) are listed. Compare with statistics summarized in table 21.

Samples from the northern peninsula, Bumbarujaba, Gunung Tambusisi, and Pegunungan Mekongga form a cluster separate from that containing the samples from Danau Lindu + Gunung Kanino, Sungai Oha Kecil + Sungai Sadaunta, Bakubakulu, and Gimpu. This pattern of phenetic relationships among population samples also appears in the cluster diagrams where samples of all phenetic members of the B. chrysocomus group are compared (fig. 49) as well as the phenetic alliances among all species of Bunomys diagrammed in figure 21. The two clusters for B. chrysocomus describe a distributional pattern in which one group of samples is from a region extending from the northern peninsula onto the western end of the eastern peninsula and ending on the southeastern peninsula (population samples are from thenorthern peninsula, Bumbaru-

TABLE 23 Results of Principal Components Analysis of All Population Samples of B. chrysocomus Upper graph: correlations (loadings) of 16 cranial and two dental log-transformed variables are based on 232 specimens; includes all holotypes ( Rattus nigellus , R. rallus , R. brevimolaris , and Bunomys coelestis koka ) except Mus chrysocomus . Lower graph: correlations (loadings) of 12 cranial and two dental log-transformed variables are based on 233 specimens; includes the holotype of Mus chrysocomus (its skull is incomplete); see figure 26.

jaba, Gunung Tambusisi, and Pegunungan Mekongga), and the other samples are from mountains and valleys in the west-central region (Danau Lindu + Gunung Kanino, Sungai Oha Kecil + Sungai Sadaunta, Bakubakulu, and Gimpu).

Samples from Laolei and Gunung Balaese, not mentioned above, deserve highlighting. The three Laolei animals are from lowlands (300 m) adjacent to Pegunungan Mekongga. Their individual scores in the canonical variate ordinations group with those representing specimens in samples from the northern peninsula, Bumbarujaba, Gunung Tambusisi, and Pegunungan Mekongga (fig. 27). Close association with Pegunungan Mekongga should be expected considering the near geographic proximity of Lalolei to that highland region, but in the Mahalanobis diagram, the sample forms an independent link to both that cluster and the one containing samples from the west-central region (figs. 28, 49). In different iterations of the Mahalanobis diagram where small samples of B. chrysocomus were subtracted or samples of other species of Bunomys were added (not illustrated here), the Lalolei sample either remains isolated or links with the group of population samples containing Pegunungan Mekongga. A larger sample from the lowlands adjacent to the Mekongga massif is needed to obtain a better estimate of the population mean and more reliable assessment of its phenetic affinity to other population samples.

Results of the multivariate analyses of cranial and dental variables described above suggest some interruption of gene flow between populations in the west-central region and those on the northern and southeastern peninsulas (geographic variation within a single species) but not complete genetic isolation (two species very similar in morphological attributes). In this context, the samples from Gunung Balease and Bakubakulu provide insights. Gunung Balease lies on the eastern margin of the west-central mountain block (locality 43 on the map in fig. 22). Collecting efforts there during October, 2010, produced four adult B. chrysocomus , but only three have intact skulls and these three form the population sample used in the multivariate analyses (see table 2). Mitochondrial cytochrome- b sequences were obtained from three specimens and analyzed in Jim Patton’s laboratory. One rat was collected at Bakubakulu (locality 6 on the map in fig. 22) in the Puro Valley, which is just north of my transect; no DNA sequences are available for it.

In the canonical variate ordinations (fig. 27), scores for two of the animals from Gunung Balease cluster with scores representing the northern and eastern population samples (northern peninsula, Bumbarujaba, Gunung Tambusisi, Pegunungan Mekongga, and Lalolei), but the third score falls in the constellation formed by points identifying samples from the west-central mountain block (Sungai Oha Kecil + Sungai Sadaunta, Danau Lindu + Gunung Kanino, Bakuba- kulu, and Gimpu). In the Mahalanobis distance (squared) cluster, the sample from Gunung Balease either links with the sample from Pegunungan Mekongga (figs. 21, 28) or is independent, without a discrete link to either of the two primary clusters of population samples (fig. 49) depending on what species are used in the analyses.

TABLE 24 Results of Discriminant-Function Analysis of All Population Samples of B. chrysocomus Upper graph: correlations (loadings) of 16 cranial and two dental log-transformed variables are based on 232 specimens; includes all holotypes ( Rattus nigellus , R. rallus , R. brevimolaris , and Bunomys coelestis koka ) except Mus chrysocomus . Lower graph: correlations (loadings) of 12 cranial and two dental log-transformed variables are based on 233 specimens; includes the holotype of Mus chrysocomus (its skull is incomplete); see figure 27.

Both principal-components and canonical variate ordinations place the score for the specimen from Bakubakulu in the heart of the cloud of scores representing the samples from the west-central mountain block (figs. 26, 27). In the Mahalanobis cluster diagrams, no matter the composition of the species, the specimen always links with the sample from Sungai Oha Kecil + Sungai Sadaunta (figs. 21, 28, 49). This placement is significant in that Bakubakulu (01 ° 07 9 S, 120 ° 00 9 E) is not far from Tangoa (01 ° 10 9 S, 120 ° 05 9 E), also in the Puro Valley , where Chris Watts collected specimens and preserved tissues from which DNA sequences could be extracted. Attached to the Tangoa specimen is a cytochrome- b sequence available from GenBank ( ABTC 65755 ; I have not seen the voucher or any of Watts’s material from the Puro Valley ), and I am assuming it could easily represent cytochrome- b sequences for the population of B. chrysocomus in the Puro Valley, including the sample from Bakubakulu .

Placements of the scores for three specimens from Gunung Balease and the animal from Bakubakulu in multivariate space are summarized in the lower canonical-variate scatter plot in figure 28. The left cloud contains scores for the northern and eastern population samples combined, the right assemblage represents combined samples from the west-central region. The two constellations marginally overlap, the sample from Gunung Balease overlaps each large cluster, and the score for the Bakubakulu rat is nestled among those for the animals collected in the west-central region. The molecular distance between the cytochromeb sequence from the Tangoa animal (which I use as a stand-in for the Bakubakulu rat, that is, drawn from the same population) and those from Gunung Balease is about 1 % (the molecular trees were provided by Jim Patton and Kevin Rowe), ‘‘which is well within what might be viewed as a ‘typical’ intraspecific range’’ (J.L. Patton, in litt., 2011; see also Baker and Bradley, 2006). The meager genetic data combined with the larger set of information revealing morphometric variation among samples suggests that samples available to me represent a single species. There are homogeneous populations in some areas (the west-central mountain block, for example) that are somewhat different in their genetic and morphometric attributes from populations in other regions of the island, but the geographic variation seems to be contained within B. chrysocomus . This is a reasonable hypothesis but certainly one that requires testing by analyzing DNA sequences from multiple genes (mitochondrial and nuclear) derived from far more geographic samples, and also looking at variation in cranial and dental variables in large samples from currently unsampled geographic regions. Expansive stretches of the island have not been surveyed for the species: most of the northern peninsula, the Pompango mountains east of Danau Poso, the entire eastern peninsula, most of the west-central mountain block south of the Danau Lindu area, and the remnants of forest on the southwestern arm require focused survey efforts. Current samples are unequal in size (available series of specimens from Bogani Nani Wartabone National Park, Bumbarujaba, Gunung Tambusisi, Pegunungan Mekongga, and Lalolei are small, ranging from 3 to 11 specimens for a total of 37) and univariate mean differences among all the population samples are not great (tables 21 and 22). Available samples are unequal in composition of adult age categories and future inquiries into patterns of geographic variation should be based on comparisons among similar adult age classes.

Of course, analyses of gene sequences in samples from the same regions from which my samples were obtained, and analysis of morphometric traits in samples from regions where specimens are now not available, may produce a different pattern of phenetic and genetic alliance among regional populations that is not revealed by my present analyses.

From my study of variation in cranial and dental variables emerged another pattern of phenetic relationships among some of the population samples that are instructive within the context of contrasting samples from montane habitats in different regions of Sulawesi. Are montane populations in different areas isolated by stretches of lowland forest closely related to one another or is a particular population in montane forest more closely related to the population inhabiting the adjacent lowlands covered by tropical lowland evergreen rain forest? My analyses points to a closer tie (phenetically and presumably genetically) between highland and immediately adjacent lowland populations than among distant montane regions, at least in comparison between samples from the core of the island and those from the southeastern peninsula. In the west-central region, the specimens from along my transect come from lowlands and middle elevations along the Sungai Oha Kecil, Sungai Sadaunta, and in the valley of Danau Lindu in tropical lowland evergreen forest, and from higher elevations on nearby Gunung Kanino in lower montane forest. Scores for these specimens are tightly packed in mutilvariate space as reflected by first and second canonical variates and phenetic clustering based on squared Mahalanobis distances among centroids (figs. 27, 28), which suggests uninhibited gene flow between the lowland to middle-elevation populations (Sungai Oha Kecil, Sungai Sadaunta, and Danau Lindu) and the one in the adjacent highlands (Gunung Kanino).

None of the scores for the specimens in ‘‘Danau Lindu + Gunung Kanino’’ are close to the scores representing the sample from Pegunungan Mekongga on the southeastern peninsula. In the canonical-variate ordinations, scores for individuals from that mountain range fall closer to the points representing the sample from Lalolei, located in the lowlands south of Pegunungan Mekongga. The samples from the southeastern peninsula are small and none come from a transect linking samples from lowland tropical evergreen rain forest with montane forest habitats on the Mekongga range, but the analysis suggests a stronger phenetic (and inferentially genetic) link between lowland and highland populations on the southeastern arm than between the Pegunungan Mekongga population and those in montane habitats of the west-central region.

In this context of montane samples one other small group of specimens deserves attention. The highest point from which a sample of B. chrysocomus has been collected is 2200 m on Pegunungan Latimojong, the highlands forming the southern margin of the west-central mountain block. That series is not included in the multivariate analyses of cranial and dental measurements. Of the seven specimens available to me, one is an old adult, two are adults, one is a young adult, another is a very young adult (in fresh adult coat), and two are juveniles. I could obtain a complete set of measurements from only one of the young adult skulls (table 22); two from the other adults are in fragments and one skull is missing. The juvenile skulls and that from the very young adult, although complete, are too young to include in the multivariate analyses. Values for cranial and dental measurements from the intact young adult skull fall within the range of variation seen in the other geographic samples of B. chrysocomus from the mountain block (tables 21, 22). Crown lengths of maxillary molar rows and breadths of first upper molars, which could be measured in five of the seven skulls, range from 6.1 to 6.2 mm and 2.0 to 2.1 mm, respectively, also well within the range of variation for these two variables in the other three population samples from the west-central region. Dorsal and ventral coats of the five adults are long (15–20 mm), and browner than in most other population samples, but with a sheen and silky texture resembling most other examples of B. chrysocomus .

In summary, geographic variation in qualitative traits associated with the skull and molars, or with any aspects of fur traits (texture, thickness, and coloration), tail pattern, or dimensions of combined head and body, ears, feet, or tail is not readily apparent or lost within the variation seen in any large single sample. By contrast, intersample variation in measured dimensions of crania and molars is present, as shown by discriminant-function analyses. Revealed are two primary sets of samples: one is from the west-central mountain block, the other contains samples from the northern peninsula, western margin of the eastern peninsula, and the southeastern arm of the island. Absolute and proportional differences among univariate means responsible for the geographic patterns are modest and usually undetectable by visually comparing skulls and dentitions (using specimens of relative comparable age). The degree of difference between the two geographic clusters in Mahalanobis distance units is far less than the magnitude separating the morphologically similar and montane B. coelestis , B. prolatus , and B. torajae , n. sp., from the population samples representing B. chrysocomus (fig. 49).

NATURAL HISTORY: Information present- ed here is organized under habitat, diet, burrows, nests, development of young, testes and sperm, and forest pathways.

Habitat: Bunomys chrysocomus was commonly encountered along the transect area extending from Sungai Oha Kecil to Gunung Kanino in forest formations embracing environs in tropical lowland evergreen rain forest (figs. 29–31, 96–98) and lower montane forest (figs. 32, 79) through the eleva- tional range from 320 m to 1555 m (fig. 103). More specimens of B. chrysocomus (323 examples) were collected than any other murid, all but five were taken in lowland tropical evergreen rainforest habitats, and those five were trapped in lower montane forest (fig. 103). Only Paruromys dominator (306 specimens) came close to the dominance of B. chrysocomus along the transect line, followed by Rattus hoffmanni (201 examples) and Rattus facetus (161 specimens).

Nocturnal and terrestrial, all but two specimens were caught on the ground. The exceptions are one taken on a woody vine about 2 ft above ground, another on a vine 3 ft above ground; both places were easily accessible from ground level.

Examples of the microhabitats in which we trapped B. chrysocomus are described in table 25 (the descriptions are selected to cover the range of habitats trapped and not to document where every rat was trapped). Mean ambient air temperatures ranged from 61.1 ° to 80.9 ° F in the lowland forest from Sungai Oha Kecil (290 m) to Sungai Tokararu (1150 m), with high relative humidity; 58.4 ° to 68.9 ° F and comparable relative humidity characterized lower montane forest on Gunung Kanino (table 3).

Mature tropical lowland evergreen rainforest habitats where we encountered most of the B. chrysocomus along the transect is floristically species rich. While our floristic survey was not exhaustive, we either collected samples of or identified approximately 350 species of trees (canopy species, emergents, and understory trees), nine species of solitary palms (in Areca , Pinanga , Pigafetta , Arenga , Caryota , and Licuala ), a dozen species of rattan ( Calamus Korthalsia , and Daemonorops ), half a dozen species of terrestrial pandans ( Pandanus ) and climbing pandans ( Freycinetia ), several kinds of gingers, a few lilies, two species of native bananas ( Musa ), dozens of shrubs, two kinds of bamboo, and some woody and herbaceous vines.

Most B. chrysocomus were encountered in steep and wet hillside forest, on forested terraces bordering streams and rivers, along streams at the waters edge, and occasionally on decaying tree trunks and limbs spanning streams (figs. 29, 30).

TABLE 25

Selected Examples of Microhabitats at Trap Sites in Which Some of the Specimens of Bunomys chryscomus Were Collected on My Transect in Central Sulawesi, 1973–1974

Descriptions of the collection sites are summarized from my field journals (in Mammalogy Archives at AMNH). See habitats in figures 29–32.

Place and date Microhabitat

Sungai Oha Primary tropical lowland evergreen rain forest (320–488 m)

Kecil Streamside or just above stream at base of steep hillside

(July 30– On ground 1–3 ft above stream alongside partly cut bank in understory—very damp, good cover of

Sept 5, 1974) shrubs, ground blanketed by debris and leaf litter.

Ground at base of cut bank among large, open roots of strangler fig growing 10 ft higher on bank. B. chrysocomus also taken nearby on ground under roots of small tree growing from undercut bank away from stream, undergrowth densely shrubby.

On damp ground beneath overturned rotting base of a large tree that was laying downslope and over the stream; good runways, very damp; dense streamside vegetative cover.

Alongside rotting tangle of trunk and limbs on steep rocky slope just above stream, all covered, including the trunk and limbs, by dense streamside vegetation; 5 ft away a limb from this tangle lay across the stream and on it I caught three B. andrewsi .

On wet, decaying trunk (not mossy) across stream (two other B. chrysocomus and a Maxomys muschenbroekii were taken at same spot); on nearby terrace caught B. chrysocomus at base of rocks Above stream in moss-covered cleft 5 ft from ground in damp, moss-encrusted rock cliff face; other B. chrysocomus were trapped nearby on ground in dense low shrubbery above stream in upper streamside forest—no special rock, trunk or other cover, just dense undergrowth.

Open ground beneath base of decaying trunk where upturned roots are resting on the ground, on very steep, short steamside forest; three other B. chrysocomus were taken at same spot.

On steep, wet upper streamside slope; trap set at base of boulder that is part of a jumble of rocks densely covered with understory shrubs and vines; many cavities among large and small rocks; probably washed by water during high runoffs, but used by rats when stream is lower and not flooding.

In runway beneath roots on cut bank above stream; one Rattus hoffmanni , Rattus facetus , and another B. chrysocomus were caught in same spot.

On ground at end of huge, wet, rotting trunk laying in dense shrubby understory of streamside forest; adjacent slopes are steep.

On wet ground beneath pile of rotting limbs draped over tree roots on stream terrace, very dark and damp—upper streamside forest.

Sungai Sadaunta Primary tropical lowland evergreen rain forest (762–1037 m)

Steep hillside forest

(Feb 5–March On forest floor beneath dense undergrowth.

8, 1974) On ground among tall roots of large Ficus on steep hillside; caught other B. chrysocomus here.

On gound inside base of trunk remnant of huge tree decaying on ground—only skeleton of outer trunk remains. On leaf litter alongside rocks, underbrush is dense, patch of ferns and shrubs, probably regenerating vegetative cover over landslip or clearing made by old treefall.

On ground beneath base of decaying trunk lying down hillside; caught other B. chrysocomus here.

On wet, leaf-littered forest floor in open part of understory below large pangi ( Pangium edule ) and torode ( Pterospermum celebicum ) trees, no undergrowth here, only open space in understory.

Trap set in runway under and alongside root of tall strangler fig, this and an adjacent strangler fig are well developed and enclose living canopy tree host.

On ground beneath decaying trunk bridging damp, leaf-littered ravine in forest on hillside terrace above stream. On steep hillside beneath tangle of rotten branches and twigs that are part of an old treefall.

Terrace above stream near camp

On damp ground at end of rotting limb in thick shrubbery on terrace above a small tributary of Sungai Sadaunta.

On ground among rocks covered with a dense undergrowth of epiphytes, small shrubs, moss, and ferns.

In wet and damp forest above gully joining main stream; understory of saplings, gingers, shrubs, palms ( Caryota , Pinanga , Areca ), and much rattan; caught another B. chrysocomus on the forest floor here.

TABLE 25

(Continued)

Place and date Microhabitat

On wet ground in front of large angular opening into rock pile; caught several B. chrysocomus here. On leaf litter in open space in understory; Maxomys muschenbroekii was taken nearby.

On wet ground beneath jumble of rotting, wet limbs on steep hillside in dense underbrush above terrace. B. chrysocomus was also trapped nearby on damp ground at base of moss and fern-covered rocks in dense cover of shrubs and ferns on stream terrace.

On ground in front of burrow entrance at base of medium-sized tree (bole 1–1.5 ft diameter near ground) at junction of hillside and terrace above stream, between short buttress roots (2 ft high, 1 ft from bole); leaf litter and debris has accumulated and been nearly incorporated with earth; burrow entrance 2 in. wide in one of these alcoves; typical hillside forest understory.

On wet ground beneath tangled understory of rattan and shrubs on terrace of small tributary to Sungai Sadaunta, undergrowth is thick, mostly tall shrubs, tall gingers, and rattan, along with woody and monocot vines, good cover for small mammals, very wet, much leaf litter.

On leaf litter in open place in very steep hillside, relatively dry (drier than along stream), good forest, about 50 ft above stream.

On wet ground beneath rotten, moss-covered trunk leaning from cut bank to ground. High (15 ft) terrace above stream; dense underbrush of shrubs and ferns; ground muddy, rocky, eroded but still partly covered with leaf litter.

Mixture of primary forest, disturbed forest, coffee grove, and garden near house (675 m) Intact primary forest

Rats were taken on ground in underbrush alongside dry creek; under rocks in open understory of streamside forest; runway among roots of giant strangler fig; beneath rotting trunk in shrubby understory of streamside forest; on ground beneath rotting roots and stump in understory of steamside forest; along earth bank beneath overhang in shrubby understory; on ground under rotting trunk of huge tree, nearly covered by shrubby and viney understory; on ground beneath boulder in boulder-strewn streamside forest.

On large woody vine growing from steep hillside and into canopy from where it hangs down 2–3 ft from ground; two traps were placed back to back, rat caught in trap with opening facing ground.

Trap above ground on tree (8–10 ft diameter) that grows from steep slope and out through the understory (of saplings, small trees, thin shrubs, rataan, leafy and woody vines) in a low arc, so it forms a long (40 ft) limb platform in the understory above the ground; two Rattus facetus also taken here.

Slightly thinned forest along stream

B. chrysocomus was caught on clear ground underneath boulder in dense undergrowth; runway along rocks beneath dense undergrowth; damp ground underneath limbs next to creek; at base of rocks in dense undergrowth; on top of trunk and vine about 1 ft off ground in understory; on leaf litter at base of young tree in understory of forest; on ground under boulder and roots; base of emergent strangler fig.

Three feet above ground on thick woody vines at base of giant canopy carmel-barked tree—the vines twirl and twist from the crown down the trunk of the tree to a mass of loops on the ground around the base of the tree; caught one Rattus facetus in same spot and another B. chrysocomus on ground beneath the tangle of woody vines.

Two chrysocomus 4 feet off ground on top of large rotten stump covered with vines.

Coffee grove

B. chrysocomus were encountered among interstices of rocks next to stream; in scub adjacent to coffee trees; runway along rocks and tree limbs in dense undergrowth beneath coffee trees; on ground beneath roots of large emergent strangler fig shading coffee trees; beneath decaying trunk lying in dense undergrowth next to newly planted coffee grove; along base of rocks in dense undergrowth between coffee grove and stream.

Disturbed habitat

Two B. chrysocomus in a garden between a house and dense scrub (caught one Rattus tanezumi here); two B. chrysocomus in cut-over forest next to a house.

TABLE 25

(Continued)

Place and date Microhabitat

Tomado Deep intact forest, slightly disturbed areas, coffee grove (1000 m).

Intact primary forest

(July 21– Several B. chrysocomus trapped on ground beneath understory in deep forest; runway beneath rotting

September trunk covered with moss and vines; beneath moss-covered jumble of large branches and smaller

11, 1973; limbs from old tree-fall; on moss-covered rotting trunk (1 ft diam) lying across stream 6 ft from

Jan 15–21, water surface; open ground underneath tangle of rattan on steep slope (caught Taeromys celebensis

1974; May in same spot, Maxomys hellwaldii and Rattus hoffmanni nearby on terrace).

12–28, 1974) Stream and meadow

In dense scrub alongside stream, and dense scrub on other side adjacent to meadow; on ground beneath shrubs, ferns, and vines bordering forest on one side and large meadow on the other.

Slightly thinned forest

On ground in undergrowth of slightly thinned forest; among roots of large strangler fig; alongside large trunk lying on ground; beneath tree trunk and tangle of rattan and shrubs.

Coffee grove

Beneath trunk lying in scrub next to coffee grove; caught Rattus hoffmanni on top of trunk.

Sungai Tokararu Primary tropical lowland evergreen rain forest (1150 m)

(September 12– On matted leaves, twigs, and soil deep beneath jumble of rotting tree limbs in clearing caused by huge treefall;

October 11, caught Taeromys celebensis two other B. chrysocomus , and two Rattus hoffmanni in same spot.

1973) On wet leaf litter beneath huge (house-size) jumble of decaying branches, larger limbs and trunks of old treefall.

Rats taken beneath rotting stump and nearby under moss-covered decaying trunk on ground.

On top of moss-covered rotting trunk in open understory of forest.

On large limb 3 ft from ground, part of a large, old treefall; caught Rattus facetus in same spot and Taeromys callitrichus on ground next to the trunk.

On large, moss-covered woody vine 1 ft from forest floor; vine drapes down from canopy through understory. In runway alongside high walllike root of huge emergent strangler fig; vines and shrubs grow around the base of the tree and over the roots, leaf and rotting twigs form a deep carpet and fill spaces between the high shouldered roots; five other B. chrysocomus were taken here along with a Rattus hoffmanni . On ground at base of emergent strangler fig; within the interstices of same tree and about 10 ft from ground caught two Paruromys dominator .

On ground in hollow base of huge emergent strangler fig; trapped three B. chrysocomus .

In runway alongside decaying, moss-covered trunk lying on forest floor; two Paruromys dominator were caught in same spot.

At base of tree on leaf litter in open part of the forest understory.

Gunung Kanino Primary forest: upper band of lowland evergreen rain forest -lower montane forest (1190–1555m; lower montane begins about 1285 m)

(October On leaf litter of forest floor at base of small tree in understory.

5–November Runway along clump of exposed roots on steep slope in dense understory consisting of rattan, shrubs,

20, 1973) woody and herbaceous vines, some covered with moss.

On ground among roots at base of small tree on steep slope; understory dense, forest like at 1150 m; two Rattus hoffmanni also taken here.

Beneath decaying, moss-covered trunk on leaf-carpeted forest floor near large strangler fig; relatively open understory in tall forest.

In runway beneath roots, vines, rotting limbs, leaf and stem litter, and rattan rosettes in very dense understory on hillside forest; Taeromys hamatus caught just above this spot; this is part of dense second-growth between 1220 and 1311 m that is covering an old landslip and tree-fall area; undisturbed tropical lowland forest just below and lower montane forest above; on either side of this regrowth the transition between intact lowland and lower montane formations is sharp.

On forest floor in tunnel-like runway beneath dense tangle of rattan fronds, tree branches, and woody and herbaceous vines in open part of forest.

In runway beneath decaying moss-covered trunk lying on ground in chestnut forest; caught Bunomys penitus and Rattus hoffmanni in same spot (see figure 32).

Vegetation bordering streams the size Sadaunta and its tributary Pormina at about 700 m (fig. 31) form good examples of bank and terrace habitats. The waterways may be open in spots but usually have a broken or partial canopy shading them. A low partial or complete canopy over the stream is provided by half a dozen species of understory figs (which include Ficus lepicarpa , F. minahassae , F. adenosperma , F. obscura , F. nervosa , F. geocarpa among others) that line the banks. These figs are the most common small tree along the streams and a few of them also grow back on terraces and hillsides. Their crowns, coming from each side of the stream sometimes intertwine over it and in places are connected by looping and coiling woody vines. Growing up through the figs as tall emergents are Wanga palms ( Pigaffetta filaris ), some Lekotu ( Duabanga moluccana ), the common Leutu ( Pometia pinnata ), and scattered Leda ( Eucalyptus deglupta ). At spots, the Wanga palms are dense enough to form a high canopy. Beneath the Wanga palms and tall trees are scattered ground and tree ferns; the palms Korthalsia celebica , Arenga undulatifolia , Areca vestiaria , Caryotis mitis , and the occasional Pinanga sp. ; bananas (two species of Musa ) that form groves in forest openings; the understory tree Semecarpus sp. ; dense shrubs mixed with tall waist-high ground ferns, gingers, Pandanus sp. , and a variety of broad-leaved monocots. Decaying wet tree trunks and limbs clutter the banks, here and there bridging the stream.

Mature forest at the level where Sungai Pormina joins the Sungai Sadaunta, about 700 m, is comprised of many species of large and old trees, some forming the high canopy, others emerging above it, and is characteristic of lowland and middle elevation forest along the transect. On the higher terraces back of the streams and base of the steep hills, for example, Dysoxylum densiflorum , Magnolia vrieseana (with boles 6 ft in diameter at waist level), Ficus magnifolia (4 ft diameter near base), Ficus cordatula , Octomeles sumatrana , Pterospermum celebicum , Aglia argentia , Canarium sp. , and Palaquium obovatum are some of the common big trees, along with scattered strangler figs ( Ficus sp. ). Commonly encountered understory trees are Dillenia serrata , Pangium edule , Macaranga sp. , Siphonodon sp. , and the laurels Litsea and Alseodaphne . Most of the terrace species extend onto the hillsides, but there the most common high-canopy former is usually Mussaendopsis beccariana . Scattered oaks ( Lithocarpus sp. ), walnut ( Engelhardtia serrata ), Calophyllum sp. , the occasional ebony ( Diospyros macrophylla ), old strangler and solitary figs also contribute to the canopy. Recognizable understory trees are Nauclea puberla , Timonius koordersii , Pouteria maclayana , Elaeocarpus sp. , nutmegs ( Knema , Myristica ), Artocarpus sp. , and Cinnamomum sp. The sugar palm Arenga pinnata is scattered through the forest as are the palms Areca vestiaria , Pinanga sp. , and Caryota sp. Here and there are clumps of pandans and groves of Casurina in open spots.

Bunomys chrysocomus , although commonly found in wet and shaded parts of the forest, is also one of the few murids found in the drier steep hillside forest and ridgetops well away from streams. For example, we set a trapline in steep hillside forest away from any streams or wet ravines from 763 to 1068 m above one of our camps and caught 40 B. chrysocomus and three Paruromys dominator . Other murid species were in these hillside forests but only in damper situations along small tributary brooks and the sides of wet ravines.

Most of the B. chrysocomus came from intact primary forest, but we did trap a few in other habitats. One was scrubby secondary growth on landslips and clearings made by tree-falls in intact old-growth forest. An example was a place on a high terrace along the Sungai Sadaunta where the mature forest was interrupted by a 40–50 ft square area covered by regenerating growth 10–20 ft high concealing a fallen canopy tree, now shattered into decaying limbs and trunk partly covered with moss. Low ground shrubs, bananas, clumps of ginger, dense thickets of ground ferns and spiny rattan rosettes, young solitary palms and pandans, tree seedlings and saplings, all threaded by herbaceous and woody vines, are typical elements of this secondary growth.

Another was a patch in tall mature forest near the village of Tomado where the understory had been thinned by villagers to plant coffee trees. Huge, tall canopy and emergent trees were left from the old-growth forest to shade the coffee. Among the most prominent of these were strangler and nonstrangler figs ( Ficus sp. ), Uru ( Magnolia vrieseana ), Kume ( Palaquium obtusifolium ), Torode ( Pterospermum celebicum ), Benoa ( Octomeles sumatrana ), Lekotu ( Duabanga moluccana ), and Tahiti ( Dysoxylum densiflorum ).

A third place was scrubby ecotone between high forest and meadow or garden (table 25).

Diet: Bunomys chrysocomus consumes invertebrates, small vertebrates, and some fruit, but not fungi (table 13). At several camps I kept a few adults captive (each for 3–4 weeks) and offered them a variety of foods gathered from the forests. Invertebrates and vertebrates were the items most voraciously consumed. All were very selective about fruits, accepting only a very few of the wide range offered. Below I present the foods eaten by B. chrysocomus drawn from my observations of captive animals and study of contents extracted from stomachs.

Earthworms (oligochaetes) —A rat aggressively yanked an earthworm from my fingers with its incisors before transferring the worm to its front feet. The rat placed one end of the worm in its mouth, cutting it into segments and pulled the worm through its paws until entirely consumed (the remains of earth- worms in most of the stomachs surveyed consisted of short unchewed pieces); the action is to pull, bite off a piece, chew it, swallow, then bite off another segment. No attempt was made to seek the anterior end of the worm (specialized Sulawesi murid vermivores such as Echiothrix manipulate the earthworm so it could ingest the anterior portion first and hold the body tight so most of the gastrointestinal contents are forced out of the worm’s anus onto the ground; see Musser and Durden, 2014), which resulted in the worm’s gastrointestinal contents covering the muzzle and front feet.

All sizes of earthworms were offered and accepted. I had been feeding one captive male small earthworms (2–3 inches long) and one day placed a very large worm (6 inches long, about 3/ 8 inches in diameter) in the cage. He promptly jumped on the worm but could not initally subdue it, attacking one end and then the other. Repeated attacks caused the worm to eject a clear fluid 8–12 inches into the air from pores along its body. At first irritated, the rat left the worm, cleaned its muzzle, but quickly renewed its attack. Finally he sank his incisors into the last 2 inches of the worm and managed to separate and eat that short segment. Although captive rats ate large earthworms, I found only segments of small worms in stomachs. Smaller earthworms are likely more commonly taken and can be eaten quickly with less exposure of the rat to predators. Earthworms averaging 2 inches long and 1/ 8 inch in diameter were consumed in 3 to 14 seconds by captive rats; worms 4– 5 inches long and 1/8 to 3/ 16 inches diameter were completely ingested by the rats after 57 to 145 seconds. One rat used 5 minutes to eat a 6 inch long earthworm that it first had to bite into several pieces.

Snails —Managing snails followed a typical behavior by all captive B. chrysocomus . Each snail was grabbed with the incisors and transferred to the front feet. The rat usually used 30–60 seconds to turn the shell over and over, trying several spots with the incisors, all the while sniffing the shell. Eventually it began biting off pieces from around the aperature until enough shell had been removed to expose the snail’s body; sometimes the rat turned the shell and bit into the side, removing bits of shell until the enclosed body was exposed. Once accessible, the rat pulled away a bit of the flesh, ingested it, bit away more shell, pulled and ingested more of the tissue, and proceeded in this manner until the entire snail was consumed. After the snail’s body was extracted the remainder of the shell was discarded. Sometimes after removing just a few pieces of shell, a rat managed to extract the entire snail. The shell fragments were not ingested, and I never found pieces in the stomachs I surveyed; I did find an operculum along with the partly digested remains of the snail in a few stomachs.

Most of the snails accepted by the rats were small, K to 1 inch in diameter and a quarter of an inch thick. I often encountered empty shells this size and some up to 1.5 inches in diameter lying among the leaf litter and debris on stream banks and terraces; all were breached.

Insects and other arthropods —Moths, cicadids, grasshoppers, katydids, crickets, praying mantises, cockroaches, and wasps were provided and all consumed by captive adult rats. Each rat used its incisors to pull the insect from my fingers, transfered it to the front feet and manipulated it until the head was up. It then bit the insect’s head and proceeded to voraciously consume head, thorax, and abdomen—wings and legs were discarded. Only heads of the wasps were eaten. Larger insects, such as praying mantises, were propped against the cage floor and consumed beginning with the head.

One particular rat never seemed satisfied with the number of insects provided. One morning I gave it 12 large crickets (up to 2 in. long), which were quickly dispatched and eaten; afterward it kept probing the mesh with its muzzle seeking more. Another rat ate 17 cockroach nymphs (1–1.5 in. long, half an inch wide) at one feeding, consuming one after the other, averaging 90 seconds per nymph. A different rat ate five large katydids (3–4 in. long) in one evening, taking 6– 8 minutes to consume each insect. The head, thorax, abdomen, and thicker portions of the hind legs were ingested, wings and other legs were discarded.

A juvenile given small grasshoppers and crickets ate them in much the same way as did the adult rats. Often, however, the young rat fumbled about trying to catch and dispatch a grasshopper by the head in which case the insect would escape and hop about the cage with the little rat in hot pursuit. Once caught and eventually killed the grasshopper was eaten beginning at the head and finishing with the abdomen; only wings and legs were discarded, the typical feeding behavior of adult rats.

Contents of the stomachs I surveyed record additional kinds of insects and other arthropods consumed by B. chrysocomus : macrolepidopteran caterpillars, rhinotermitid termites, adult and larval beetles, ants, spiders, and geophilomorph centipedes (table 13).

Other invertebrates —I offered small freshwater crabs found near streams to B. chrysocomus —all were ignored.

Vertebrates —I gave small frogs and a small lizard to the captive adult B. chrysocomus . One rat was satisfied with three small frogs (1 to 1.5 inches long) at any single feeding bout. The rat grabbed the head, bit it, which immobilized the frog, then turned the frog around and began eating the legs. Both legs were usually eaten first, sometimes the body, but the head was discarded. Sometimes the rat would begin chewing on the head, stop and turn to the legs, ignoring the head. A different rat consumed all but a few foot bones of a frog 2.5 inches long. A juvenile rat seemed less familiar with frogs and those placed in its cage often escaped. Once the frog was subdued, the rat chewed on the hind legs without any attempt to first bite the head to immobilize the frog.

Small frogs are likely one of the most common small vertebrates encountered in the wet forests along streams and sheltered hillsides, the habitats where B. chrysocomus was commonly trapped. It was in those places that I collected the frogs fed to the rats.

In another rat’s cage I placed a small lizard (head and body 2 in. long, tail about 4 in. long). The rat immediately pounced on the lizard, bit the head, and consumed the entire animal, proceeding from head to tip of the tail, leaving nothing.

Fruit —I offered captive rats a variety of fruits. Those from the following species of canopy and understory trees were rejected: Chisocheton, Garcina , Planchonella , Knema , Aglia , Palaquium , Magnolia , Myristica, Eleocarpus , Siphonodon , Lithocarpus , and some Ficus . Fruit from several species of woody vines were consistently rejected as well as fruits from three species of common understory palms, Areca vestiaria , Pinanga ceasia , and Pinanga sp.

Only a few fruits were eaten by the rats. Two species of wild bananas ( Musa ) occur in tropical lowland evergreen rain forest throughout my transect area; the white, sticky pulp of both species was readily accepted and consumed by all captive B. chrysocomus ; the skin along with the large and hard seeds were rejected. Pulp surrounding seeds of fruit from the canopy tree Himantandra belgraveana was eaten, as were small red berries from an understory shrub, and large and small figs from different species of understory Ficus . Remains of fig were the most common fruit found in contents of stomachs. Fruit from the wanga palm Pigafetta filaris was always accepted. The rats neatly removed the scaly covering, ate the transparent jellylike pulp and discarded the single hard black seed. One rat ate the gelatinous pulp that encloses the seeds of a ginger.

Stomachs examined rarely contained only fruit. The content of stomachs from two rats trapped at Tomado is illustrative. One full stomach contained remains of a fig with large seeds and seeds from another kind of fruit; several moderately large cursorial beetle lavae, pieces of a cockroach numph, and one geophilomorph centipede were mixed with the masticated fruit. Another stomach was distended with reddish-brown fruit pulp, remains from two kinds of figs, a fruit with hard orange oblong seeds, and a different fruit with small striped seeds; one wellchewed earthworm, fragments of a young cockroach instar, and remains of a few rhinotermitid soldiers constituted the invertebrate remains.

Stomachs from two rats illustrate contents consisting of primarily invertebrates and little fruit. An animal from Tomado had a stomach packed with rhinotermitid soldiers and workers, and also held remains of a few small adult beetles, a cockroach nymph, geophilomorph centipede, and pulp from figs. The stomach from a rat trapped on the Sungai Sadaunta was distended with remains of arthropods: many rhinotermitid termites and small adult beetles, pieces of larger adult beetles, two kinds of small beetle larvae, one geophilomorph centipede, one macrolepidopteran caterpillar, orthopterans, several cockroach nymphs, and a few ants; a bit of tanorange pulp and some small pieces of tough rind comprised the meager remains of fruit.

Fungi —I offered captive rats samples of the two kinds of shelf or ear fungi so readily consumed by Bunomys karokophilus , n. sp. (see that account), the purplish Auricularia delicata and white A. fuscosuccinea . Both were consistently rejected. Offerings of capand-stem fungi were also ignored.

Overview— Bunomys chrysocomus is an aggressive, quick and agile predator of arthropods, earthworms, snails, and small vertebrates. Any insect or frog loose in a cage was immediately chased and caught in a blur of movement; usually a rat grabbed the prey with its incisors, occasionally pinning it to the cage floor with its front feet. The animals are also adept at nosing through leaf litter and debris on the forest floor. I watched a released male nose about in the leaf litter until only half the body was visible, and occasionally dig, then nose about again, dig, and when he located something stop and eat. Most of the work was done with his head and nose, pushing into the litter and sniffing about, sometimes digging or pulling back debris with the front feet. He also ambled over the litter, sometimes making quick jumps of a foot or so. Bunomys chrysocomus has access to prey living on the surface of the forest floor (leaf litter, exposed soil surface); within the leaf litter and ground debris; in decaying trunks and limbs of treefalls; on the surface of green leaves attached to stems and branches freshly detached from trees during storms and lying on the forest floor; and on the basal stems of forbs, shrubs, trees, and palms. See the account of B. andrewsi for an inventory of the range of invertebrates and small vertebrates found in these places.

The contents of a stomach from a rat trapped at Tomado summarize the range of foods ingested by B. chrysocomus . The distended stomach contained pulp and skin from an unidentified fruit; several earthworms chopped into segments (contents of the gastrointestinal tract present within each segment, unlike remains found in stomachs of Echiothrix in which the worm segments are hollow); several ants; at least one cockroach nymph; one ‘‘hairy spider’’ (long hairy legs and part of thorax); at least four kinds of beetle larvae (one small with rows of markings and ‘‘proleg’’ type feet, many that are small and intact [5–8 mm long], a few small legless larvae, and thoracic remains from long-legged cursorial larvae); several large margarodid scale insects; small adult staphylinid beetle; skin fragments from a macrolepidopteran caterpillar; and a few rhinotermitid workers. The combination of invertebrates would have been found in leaf litter, decaying wood, beneath rocks, and in soil beneath moss and decaying wood.

I insert a final statement about the reaction by captives to food. All the captive adult B. chrysocomus (as well as the examples of B. andrewsi , B. penitus , and B. karokophilus , n. sp.) unambiguously either accepted or reject- ed different foods I offered. Of those rejected, particular items were especially distasteful to the rats (some fruits and fungi) and their first response was to run about the cage rubbing their lips and chin on pieces of wood, leaves, or even the cage floor. Then a rat would use its tongue to moisten its palms to clean the lips and chin.

Burrows, nests, and young: Bunomys chrysocomus nests in burrows below ground. I have seen burrow openings in the alcove between buttresses of a tree growing on the terrace of a stream; runways and entrances to burrows along a 6 inch high tree root growing above ground; and under jumbles of rocks lying on a stream terrace just above water level. At about 8:00 A.M. on a ridge terrace at about 1000 m I saw an adult B. chrysocomus with two young running around the base of a tree. They heard me. The adult female stopped by a raised root and sat there. The two young ran, each in a different direction, about 2 ft from the root and froze, looking at me. Eventually the juveniles ran off into the undercover and the adult disappeared down a burrow beneath the root. At another time I captured a rat in a live trap that had been placed on the mud and leaves just above a stream; when released, it peered out of the trap, finally ambled away, then slowly ran uphill about 4 ft to disappear into a burrow beneath a pile of small rocks partially covered with soil and vegetation.

My notes recording construction of nests are summarized here. I placed dry leaves in a small cage with an adult male caught along the Sungai Sadaunta. He arranged these into a globular nest with a deep cup-shaped depression in which he slept. None of the leaves were folded or cut, simply arranged to form the nest. Another rat kept in a small cage on the ground reached between the mesh to pull in pieces of dry stems and leaves of grass and sedges, small forbs, and plant debris. The green, growing plants would be pulled through the mesh, cut and placed on the growing pile of vegetation on which it slept in a depression during the day. At night the rat shoved the debris around with its nose, often burrowing into the pile, and occasionally flushing an insect, which it quickly pounced on and ate.

One captive female kept constructing a nest using dry leaves in much the same way as described above. After about a week, she gave birth to two young. Their growth and interactions with the mother are summarized in table 26. One or two young is standard for B. chrysocomus and all the other species of Bunomys for which I have data covering litter size.

Testes and sperm: Body and testes weights (mass) along with sperm size was derived from two B. chrysocomus by Breed and Taylor (2000) and employed in an investigation of murines designed ‘‘to test the hypothesis that differences in relative testes mass, and perhaps sperm size, relate to interspecific differences in the amount of intermale sperm competition and in breeding systems.’’

Forest pathways: Along my transect in the west-central region and in the Malakosa area, we always set traps on decaying tree trunks and limbs, and palm trunks bridging streams, creeks, and ravines. Traps were also placed on leafy limbs growing across streams. Squirrels used these live bridges as well as rotting and wet trunks and limbs spanning streams, but we caught rats only on the latter, not on the live limbs. By using the trunks and limbs, rats can

TABLE 26

Ontogenetic Development from Nestling to Juvenile Stages of Young in Litter of Bunomys chrysocomus Captured at Sungai Oha Kecil in Sulawesi’s West-Central Region, August–September, 1974

Date Developmental progression of young

Aug. 20 Two pups born, each 30 mm long, naked, unpigmented (pink), eyes sealed, little puffy outgrowths for ears, tiny claws, digits webbed, mouth sealed except for pinhole opening. Both squeal when uncovered and detached from mother’s teats; easily crawl over leaf litter; nest a depression in pile of dry leaves.

Aug. 21 Pups a few millimeters longer, but have increased in bulk; eyes still shut, digits remain webbed, back and top of head pale gray; silver mustacial vibrissae 3 mm long. Mother modified nest, surrounded herself with dry leaves, is more wary and watches over young more intensely; she will leave nest to grab an insect, but then rushes back and consumes it in the nest.

Aug. 22 Pups 38 mm long, eyes gray and still shut; ears gray, still sealed on one pup, the external pinnae erect on the other; top of back and neck gray; digits beginning to separate distally. Pups pull themselves over the nest with front feet, hind legs still weak; both emit loud squeaks.

Aug. 23 Both pups 42 mm long; solid gray over the back and head; external pinnae gray and erect on both pups; ankles gray, but remainder of feet unpigmented. Bodies covered with fine fuzz. Digits still fused for L their lengths. Eyes still shut.

Aug. 24 Pups about 50 mm long; heads and back solid gray; dorsal surface of tail pale gray; pinnae, forearms, heel, and instep are gray. Eyes still closed. Pups crawl but can almost stand on all legs and move about.

Aug. 25 Pups a bit fatter, more darkly pigmented. Vocalizations beginning to have tone and timber of adult rather than the squeaks and squeals when younger.

Aug. 26 Pups appear strong and bulky, still about 50 mm long; no longer resemble inflated bag with short appendages, but are taking on form of a young rat. Fur thick but still fuzzy, growing towards midline where it is forming a ridge; upperparts of head and body intense solid dark gray, dorsal surface of tail gray, ventral surface unpigmented; pinnae, legs, and plantar surfaces gray. Claws long and conspicuous; digits fully separated; mustachial region prominent. Eyes still shut. Mouths open and pups often yawn. Pups crawl about and burrow into the leaf litter. When left by the mother pups lay together in nest with minor vocalizing.

Aug. 27 Pelage thicker, black and gray hairs give speckled appearance; basic adult outline of pelage covering evident. Eyes still closed. Pups yawn frequently. Periodically, mother grooms back of each pup by vibrating her incisors over the back.

Aug. 28 Pups fatter. Fur covering thicker, forming high middorsal ridge where tips of hairs meet as they grow from each side of body. Tops of ears gray but still appear naked. Pups able to stand for nearly a minute.

Mother occasionally drags them from nest until they become disengaged from the teats. Then she returns to the nest, grabs the pup’s skin on head or back with her incisors, pulls it back into the nest, then grooms each pup and tucks it beneath her body.

Aug. 29 Pups 65–75 mm long; pelage thicker, upperparts gray and speckled black; underparts grayish white. Eyes remain shut, but membrane gone.

Aug. 30 Pelager thicker and darker; pups actually look like small furry mice. Eyes still shut. Mother extremely protective and responsive to pups, grooms them frequently, licking them over head and body, around genitals and anus, and over feet and tail. Between lickings, she changes into her vibrating motion, going over the body with her incisors, then returns to licking.

Aug. 31– Pups stronger, tails longer; feet, ears, and head larger. Pelage thicker, upperparts darker. Eyes still shut. Both

Sept. 1 walk clumsily around cage, scream less when left alone. One pup can scratch itself with its hind foot.

Mother protective, leaves nest only to accept insects, then rushes back and eats them at nest.

Sept. 3 Nestlings about 75 mm long; now covered in thicker juvenile pelage. Young are aggressive, strong, and spend more time sleeping than before. Eyes still shut. Pups are large enough now that mother has to lie on her side so they can nurse.

Sept. 4 Young exploring cage; when they bump into the mother they don’t try to nurse but amble off erratically in another direction. They stand but still tremble, move erratically, plunging ahead quickly only to topple when they reach their goal; clearly coordination still developing. Grooming behavior much like that of mother: lick front feet, wash their face, scratch with hind feet and lick digits after scratching. Eyes still closed. Vocalizations resemble adult sounds but still higher-pitched.

Sept. 5 Eyes still closed. Pups move about quicker, less erratically; vocalizations becoming more like adult; now yell when mother steps on them, but not when she leaves the nest.

Sept. 6 Eyes have opened. Pups can stand without the body trembling, the tail held straight out with the distal half moving up and down. Both are better coordinated, although they often still fall over when grooming.

TABLE 26

(Continued)

Date Developmental progression of young

Sept. 9 Both young in full, fluffy juvenile pelage. Both still suckling, both run quickly about in the cage and only occasionally stumble or vibrate their tails.

Sept. 12 Young very active and have achieved full body coordination. They run around in the cage, burrow beneath the dry leaves and debris, and occasionally squeeze through the mesh and run around outside the cage. Both are still nursing, but sometimes will grab a piece of cockroach with their front feet, sit back and take tentative bites, only to then discard the piece. Pelage is thick and fluffy, darker and grayer than the adult, the banded hairs pale buffy yellow rather than buffy brown. Ears are shiny dark gray; feet pigmented as in the adult; tail solid tan on the dorsal surface and unpigmented below, covered with tiny silver hairs.

Mother still grooms young by licking fur and biting the skin; she turns each over and licks the genital region.

Sept. 14 Still nursing, but active in cage. One squeezed through mesh in the afternoon but returned during the night.

Sept. 16 Young very active, run around the cage chasing cockroach nymphs. They grab the nymph then sit back like the adult and hold the insect with their front feet and start to eat it, head first; still slow and awkward handling the nymph. Beginning to compete with the mother for cockroaches, although cannot quite handle a living, adult cockroach, but will accept a dead or live nymph from my fingers. The young still nurse between bouts of chewing on nymphs.

Sept. 19 Both still nursing, and actively bother the mother as she eats. Young can consume cockroach nymphs much quicker than on previous days. Each night both young leave the cage, wander around in the tent and outside of it, then return to the cage. Mother devours small earthworms in seconds, but young show no interest in either earthworms or snails.

Sept. 23 One young left cage night of 22nd and did not return; other young left next night without returning; mother released same evening. Young were still nursing but also eating insects and aggressively competing with mother for food. Both had shiny, dark gray ears and were in full juvenile pelage that was soft, fluffy, and thick—a pale bluish gray and contrasting with the stiffer, brown adult coat.

scamper across streams and narrow rivers without getting wet. Wet fur is life threatening. Mist and fine droplets of water adhering to the end of the hairs can be shaken off without compromising the insulative capacity of the coat—the fur between hair tips and skin remains dry. If the rats accidentally fall into water or are forced to run through shallow parts of the stream the fur may become soaked and difficult to dry in an environment where the relative humidity is between 90 % and 100 %.

We saw firsthand the importance of keeping fur dry when occasional intense storms knocked over tents and cages in which we kept some B. chrysocomus . The rats were soaked, appeared to be stunned and made no attempt to dry their fur until hours later when the coat had partially dried. Then each rat tried to fluff the fur, but most of the coat remained matted and difficult to groom. Rats taken in live traps unprotected from nightly rains were sickly when we found them in the morning and did not recover.

Rats might scramble over rocks jutting above the water surface in shallow streams. We placed traps on such exposed rats but invariably caught only toads—no rats. This type of potential crossing is useless when the stream floods during heavy rains, which was usual during the time I worked in forests along the transect. Dead trunks and limbs connecting higher stream terraces usually were higher than flood level.

ECTOPARASITES, PSEUDOSCORPIONS, AND ENDOPARASITES: Sucking lice, fleas, ticks, chiggers, and mites are the groups of ectoparasites utilizing Bunomys chrysocomus as a host (table 14). Of the two species of sucking lice (Anoplura), Hoplopleura chrysocomi has been found only on Bunomys chrysocomus ( Durden, 1990) , but Polyplax wallacei also parasitizes Bunomys fratrorum and a species of Taeromys ( Durden, 1987; Durden and Musser, 1991, 1992).

Six species of fleas ( Siphonaptera ) in five genera are recorded from Bunomys chrysocomus . In addition to B. chrysocomus , Sigmactenus alticola pilosus (Leptopsyllidae) also infests 14 other species of endemic Sulawesi murine rodents ( Bunomys penitus , B. prolatus , and B. karokophilus , n. sp.; Margaretamys elegans ; Maxomys hellwaldii , M. wattsi , and Maxomys sp. ; Melasmothrix naso and Tateomys rhinogradoides ; Paruromys dominator ; Taeromys celebensis and Taeromys sp. ; Rattus hoffmanni and R. facetus [recorded as R. marmosurus ]), and the nonnative Rattus exulans ( Durden and Beaucournu, 2000) . Besides Bunomys chrysocomus , five endemic Sulawesi murids ( Rattus hoffmanni ; Bunomys penitus and B. karokophilus , n. sp.; Maxomys sp. ; Paruromys dominator ) and two nonnative rats ( Rattus exulans and R. nitidus ) are also hosts for Stivalius franciscae ( Stivaliidae ; Beaucournu and Durden, 2001). Gymnomeropsylla bunomydis (Pygiopsyllidae) parasitizes the Sulawesi endemic rat Maxomys wattsi as well as Bunomys chrysocomus . ( Durden and Beaucournu, 2002). Nestivalius sulawesiensis (Pygiopsyllidae) is recorded from Bunomys chrysocomus and from Bunomys fratrorum , Maxomys hellwaldii and M. musschenbroekii , and Rattus facetus and R. hoffmanni ( Mardon and Durden, 2003) . Finally, Musserella , n. gen., species # 1 and # 4 ( Pygiopsyllidae ) resides not only on Bunomys chrysocomus , but also parasitizes eight other Sulawesi endemic murids ( Bunomys penitus and B. fratrorum , Rattus hoffmanni and R. facetus , Paruromys dominator , Maxomys hellwaldii and M. muschenbroekii , and Taeromys celebensis ) and the nonnative Rattus exulans and R. tanazumi (Durden, in litt., 2008).

Bunomys chrysocomus is host to immature stages (larvae and nymphs) of species in three genera of ticks ( Acari : Ixodoidea): Amblyomma sp. , Dermacentor atrosignatus and Dermacentor sp. , and Haemaphysalis psalistos and Haemaphysalis sp. ( Durden et al., 2008). Collectively, in addition to B. chrysocomus , members of these three tick genera have been collected from a suite of other mammal hosts living in Sulawesi: immature stages from shrews (the endemic Crocidura sp. and Crocidura elongata , and the commensal Suncus murinus ), two species of bat ( Nyctimene minutus and Rousettus celebensis ), three endemic squirrels ( Rubrisciurus rubriventer , Hyosciurus heinrichi , and H. ileile ), 12 species of endemic murid rodents ( Bunomys fratrorum and B. andrewsi ; Margaretamys beccari ; Echiothrix centrosa ; Maxomys hellwaldii , M. musschenbroekii , and M. wattsi ; Parur- omys dominator ; Taeromys sp. ; Rattus hoffmanni , R. xanthurus , and R. facetus [recorded as R. marmosurus ]), four nonnative murines ( Mus musculus ; Rattus tanezumi [recorded as R. rattus ], R. argentiventer , and R. exulans ), and adults from pigs (Sus celebensis and Babyrousa babyrussa , both endemics, and the domestic Sus scrofa), rusa ( Rusa timorensis , nonnative), water buffalo ( Bubalus bubalis , nonnative), humans, and domestic dog (nonnative) ( Durden et al., 2008; Musser and Durden, 2014).

Two species of chiggers ( Acari : Trombiculidae ) are known to parasitize Bunomys chrysocomus . Walchiella oudemansi also parasitizes Bunomys fratrorum and the nonnative Rattus exulans ( Goff and Durden, 1987; Whitaker and Durden, 1987). Leptotrombidium deliense has also been recorded from the endemic rats Bunomys fratrorum , Maxomys musschenbroekii , Paruromys dominator , Rattus hoffmanni , and Rattus xanthurus . Phoretic deutonymphs of one species of mite ( Acari : Histiostomatidae ), Histiostoma sp. , have also been recorded as being attached to laelapid mites ( Laelaps spp. ) parasitizing Maxomys hellwaldii , M. musschenbroekii , and Rattus hoffmanni ( Whitaker and Durden, 1987) ; as noted above, Laelaps sp. have also been recorded from B. chrysocomus (L.A. Durden, personal commun.).

The pseudoscorpion, Megachernes sp. , has been found on Bunomys chrysocomus (W.B. Muchmore, in litt., 1986).

A trematode ( Trematoda) and nematodes (Nematoda) constitute the endoparasitic records. The human blood fluke, Schistosoma japonicum (Strigeidida, Schistosomatidae ), is a trematode that requires in its life cycle an oncomelanid snail as intermediate host, and a mammal as the definitive or reservoir host. In the valley of Danau Lindu, humans, along with their dogs and domestic livestock, are reservoirs for the parasite as are the native murid rodents Bunomys chrysocomus , Rattus facetus [recorded as R. marmosurus ], Rattus hoffmanni , and Taeromys celebensis , and the nonnative Rattus exulans ( Sudomo and Carney, 1974; W.P. Carney, in litt., 1974; see also Clarke et al., 1974; I identified the hosts).

Several reports record nematodes parasitizing ‘‘ Bunomys chrysocomus ’’ and ‘‘ Bunomys prolatus , ’’ but identifications of the hosts have to be verified (I have not seen the specimens). Specimens from Kabubaten Donggala identified as ‘‘ Bunomys chrysocomus ’’ and series from Lore Lindu said to be ‘‘ B. prolatus ’’ were found to be parasitized by the nematode, Syphacia rifaii (Oxyurida, Oxyuridae ), which is presumed to infect only species of Bunomys ( Dewi and Hasegawa, 2010) . The sample of ‘‘ B. chrysocomus ’’ was collected at Kampong Simoro, Gunung Watu (01 ° 15 9 45.8 0 S, 119 ° 58 9 40.9 0 E), 559 m (K. Dewi, in litt., 2012), which lay in the northwestern portion of Lore Lindu not far south of Bakubakulu in Puro Valley, (01 ° 07 9 S, 120 ° 00 9 E), 600 m, where B. chrysocomus and B. andrewsi occur together (table 20). In this region, the two species are closely similar in physical size and color of fur, and the host specimens could be either B. chrysocomus or B. andrewsi . The other host sample, ‘‘ B. prolatus , ’’ does not reside in the Lore Lindu region and those specimens are likely misidentified B. chrysocomus (see my account of B. prolatus ).

‘‘ Bunomys chrysocomus ’’ and ‘‘ Bunomys prolatus ’’ from Lore Lindu have also been reported as hosts for the nematodes Subulura andersoni ( Ascaridida , Subuluridae ), Heterakis spumosa ( Ascaridida , Ascarididae ), and Syphacia muris (5 S. rifaii , see Dewi and Hasegawa, 2010); ‘‘ Bunomys chrysocomus ’’ from Lore Lindu is host to Protospirura muris ( Spirurida , Spiruridae ) and Trichurus muris (Trichurida, Trichuridae ); and ‘‘ Bunomys prolatus ’’ hosts Molinacuaria indonesiensis ( Spirurida , Acuariidae ) ( Purwaningsih and Dewi, 2007). Again, Bunomys prolatus has been found only on Gunung Tambusisi at the western margin of the eastern peninsula and does not occur in Lore Lindu and I suspect the voucher specimens represent B. chrysocomus . The hosts identified as ‘‘ Bunomys chrysocomus ’’ are either B. chrysocomus or B. andrewsi , which in Lore Lindu are very similar in their external traits.

Finally, Dewi (2008, 2011) reported the nematodes Subulura andersoni , Heterakis spumosa , Syphacia rifaii , and Gongylonema neoplasticum ( Spirurida , Gonglonematidae) were found in ‘‘ Bunomys chrysocomus ’’ collected at Pakuli, a village in the valley of Sungai Miu at 110 m (01 ° 14 9 S, 119 ° 56 9 E; see locality 7 in the gazetteer for Bunomys andrewsi ). But 250 m is the lowest B. chrysocomus has been collected anyplace in Sulawesi where surveys for small mammals have been conducted (table 6), and 320 m is the lowest point in the valley of Sungai Miu where B. chrysocomus was encountered (see gazetteer for B. chrysocomus ). The only accurately identified Bunomys from Pakuli represent B. andrewsi (see that account), and that may be the host species for the nematodes reported by Dewi.

SYNONYMS: Information about holotypes of the four taxa that are associated with Bunomys chrysocomus and reasons why the name attached to a particular holotype is a synonym is summarized below.

Rattus nigellus Miller and Hollister, 1921a: 72 . HOLOTYPE: USNM 218140 (skin and skull; measurements are listed in table 18), an adult male collected November 8, 1916, by H.C. Raven (original number 2936). TYPE LOCALITY: Indonesia, Propinsi Sulawesi Tengah, Bumbarujaba (00 ° 43 9 S, 120 ° 04 9 E), 915 m (locality 5 in gazetteer and the map in fig. 22).

Of the four names I synonymize with chrysocomus , two of them were proposed by Miller and Hollister. The first, Rattus nigellus, Miller and Hollister (1921a: 72) diagnosed as:

a small dark member of the chrysocomus group with long, soft pelage. Flanks as dark as back, median area of underparts cinnamon drab. Flecking of upperparts brown, not yellowish; wrist and heel blackish; toes whitish. Tail short, almost entirely blackish, with only a slight indication in a few specimens of light color on underside. Skull smaller than that of Rattus adspersus .

The authors remarked of nigellus that ‘‘this small species is related to R. adspersus rather than to R. chrysocomus of northern Celebes. It is easily distinguished from adspersus by its lesser external measurements; longer, softer pelage; and small skull.’’ Twelve specimens were identified as nigellus , 11 from Bumbarujaba, the type locality, and one from Labuan Sore. I located three additional examples of nigellus that Raven had trapped at Bumbarujaba (see locality 5 in the gazetteer); the individual from Labuan Sore (USNM 218138) is an example of what Miller and Hollister (1921a: 71) described, on a page preceeding their description of nigellus , as Rattus adspersus (5 B. andrewsi ; see that account).

I understand why Miller and Hollister thought the specimens from Bumbarujaba represented an undescribed species. The authors had never examined the holotype of chrysocomus and Raven did not encounter it in northern Sulawesi. He trapped 176 specimens of a Bunomys at Teteamoet, Kuala Prang, Gunung Klabat, and Temboan on the northeastern peninsula of the island (see the gazetteer for B. fratrorum and the map in fig. 50), which were subsequently identified by Miller and Hollister as B. chrysocomus . All, however, are examples of the largerbodied B. fratrorum . Fur coloration and tail patterning as well as small size of skull and molars typical of the specimens from Bumbarujaba are strikingly unlike comparable traits in Raven’s series from the northeast peninsula, which have somewhat paler fur, different tail patterns, and significantly great- er external (compare the values in tables 19 and 41) as well as cranial and dental dimensions (table 42). And specimens in the sample from Bumbarujaba, although appreciably smaller in body size and cranial and dental dimensions than adspersus , as Miller and Hollister noted, closely resemble the larger-bodied adspersus in fur coloration and tail patterning. Without examples of true chrysocomus at hand for comparison, coupled with their misidentification of Raven’s material from the northeast peninsula as chrysocomus, Miller and Hollister correctly noted that the specimens from Bumbarujaba were appreciably different not only from Raven’s peninsular samples but from the central Sulawesian adspersus , and looked on them as representing an undescribed species.

In their cranial and dental measurements and proportions, Miller and Hollister’s sample of nigellus clusters with population samples from the northern peninsula, Gunung Tambusisi, and the southeastern peninsula (see Geographic Variation).

Rattus rallus Miller and Hollister, 1921a: 73 . HOLOTYPE: USNM 219595 (skin and skull; measurements are listed in table 18), an adult female collected September 7, 1917, by H.C. Raven (original number 3233). TYPE LOCALITY: Indonesia, Propinsi Sulawesi Tengah, Gimpu (01 ° 36 9 S, 119 ° 53 9 E), 400 m (locality 35 in gazetteer and the map in fig. 22).

Rattus rallus , the second species to be named in the same publication as nigellus , was diagnosed by Miller and Hollister (1921a: 73–74) as:

A member of the chrysocomus group resembling Rattus nigellus , but smaller, with shorter hind foot, and much smaller teeth. Tail dark above, light below. Skull with flatter, less arched braincase, longer rostrum, and smaller auditory bullae. This species differs conspicuously from the other member of the chrysocomus group inhabiting the same district ( Rattus penitus ), and externally resembles very closely Rattus nigellus from northern Middle Celbes. From R. nigellus it is chiefly distinguished by the smaller foot, more sharply bicolored tail; more slender skull with less inflated braincase; and smaller teeth. Two specimens out of the eight examined have the tip of the tail for 12 mm. whitish.

Miller and Hollister assigned eight specimens to rallus : two from Gimpu, four from the valley of Danau Lindu, and two from Gunung Lehio. They overlooked an additional example collected by H.C. Raven from Gimpu that is represented by only a skull (see the gazetteer).

The holotype of rallus along with two additional specimens from Gimpu, the type locality, form one of the 10 population samples used in my multivariate analysis (table 2). In the scatter plots defined by first and second principal components and first and second canonical variates (upper and and lower graphs in figs. 26 and 27), scores representing the three specimens of rallus fall within or near the large cloud of points for specimens in the two population samples from along my transect in the west-central mountain block (Sungai Oha Kecil + Sungai Sadaunta and Danau Lindu + Gunung Kanino) and the animal from Bakubakulu just north of my transect. Scores for the seven specimens from Bumbarujaba, the type locality of nigellus , lay at the edge and to the left of the large west-central constellation. Among the variables influencing the position of the seven nigellus along the first canonical axis is their slightly higher braincase and larger bullae compared with the specimens of rallus from Gimpu (see Geographic Variation) and highlights two of the traits Miller and Hollister used to distinguish rallus from nigellus : ‘‘less arched braincase’’ and ‘‘smaller auditory bullae’’ (higher braincase and larger bullae in nigellus ). Scores for nigellus from Bumbarujaba are more closely positioned near those for samples from the northern peninsula, Gunung Tambusisi at the western margin of the eastern peninsula, and Pegunungan Mekongga on the southeastern peninsula than to the points representing rallus from Gimpu, which is also reflected by the cluster configuration in the diagram of Mahalanobis distance as a phenetic measure of resemblance (fig. 28).

These multivariate analytical results described above pertain only to cranial and dental variables. The range of variation in fur coloration, color and pattern of the tail, ears, and feet, along with dimensions of the combined head and body, tail, and hind feet typical of the series of nigellus fall within that range of variation seen in the large sample obtained from my transect, which also embraces the range of variation in these external traits present among the three specimens of rallus . Miller and Hollister thought the smaller foot and more sharply bicolored tail of rallus distinguished it from nigellus , but neither trait is diagnostic. Length of hind foot varies within any large sample (table 19), and the extremes of a sharply bicolored tail and a monocolored tail connected by intermediate patterns is also usual in large samples (see the range of patterns enumerated in the description of B. chrysocomus ).

There appears to be detectable geographic variation in cranial and dental variables among population samples of B. chrysocomus , which is reflected in the different spatial distribution of scores for the samples of nigellus and rallus in the discriminant-function ordinations, and the observations recorded by Miller and Hollister. The population samples defined here form two clusters, one from the west-central region, and the other from peninsulas east of there. Should analyses of DNA sequences and morphometric data from future samples demonstrate the populations living in the valleys and mountains in the west-central region to be genetically isolated from populations occurring elsewhere on Sulawesi, rallus would be the name to apply to the west-central form.

Rattus brevimolaris Tate and Archbold, 1935a: 7 . HOLOTYPE: AMNH 101055 (skin and skull; measurements are listed in table 18), an adult female collected January 6, 1932, by G. Heinrich (original number 891). TYPE LOCALITY: Indonesia, Propinsi Sulawesi Tenggara (southeastern peninsula of Sulawesi), Lalolei (03 ° 57 9 S, 122 ° 03 9 E), 300 m (locality 38 in gazetteer and the map in fig. 22).

Tate and Archbold proposed the two other scientific names that turn out to be synonyms of B. chrysocomus , one as a species of Rattus , the other as a subspecies of Bunomys coelestis . Rattus brevimolaris was characterized by Tate and Archbold (1935a: 7) as ‘‘A rather small member of the chrysocomus group with somewhat thin pelage, a skull with small palatal foramina, narrowly point- ed anteriorly and quite small molars.’’ The holotype was described as follows:

Pelage of type rather thin, thinner than that of andrewsi , approximating the condition in the larger sized inferior. Dorsal color, as in allied forms, near natal brown, but not uniformly so because of dulling effect of gray under-color. Ventral color dirty buff, becoming clay color on breast and russet just anterior to scrotum. No clear line of demarcation along sides. Feet dull grayish-white. Tail short, white beneath.

Skull small and delicate, the palatal foramina well pointed in front, only slightly exceeding length of tooth row (110 per cent); bulla large to medium (in type 7.0 mm., in another specimen, female, only 6.1 mm.). Molars quite small....

Besides the type, 3 males and 3 females, all topotypes [see specimens listed under locality 38 in gazetteer] have been studied. At first sight this species looks like andrewsi . The latter, however, has crown of m 1 at least 3.8 × 2.2. When the type of chrysocomus is restudied it may be found that our brevimolaris will fit in with it. Meanwhile, we consider the closests allies of brevimolaris to be nigellus and rallus .

Tate and Archbold had never examined the holotype of Mus chrysocomus , but they correctly assessed the taxonomic affinities of brevimolaris (which Tate [1936: 554] repeated in his survey of ‘‘Some Muridae of the Indo- Australian Region’’: brevimolaris ‘‘is intermediate in size and locality between inferior of the Mengkoka Mts. and andrewsi of Buton Island, southeast of Celebes. Its nearest relatives, however, on account of its small skull and teeth, should be sought in nigellus and rallus of Middle Celebes.’’). Sody (1941: 317), who had actually examined the holotype of chrysocomus , noted that tail coloration was the only difference he could find between brevimolaris (known to Sody by the specimen listed in the gazetteer from locality 39 [Pulau Buton], the original description by Tate and Archbold, and two AMNH specimens from Lalolei that had been sent to Bogor [MZB 4074 and 4075, both with incomplete skulls]) and the holotype of chrysocomus . The tail of the latter is monocolor, those of brevimolaris bicolored; these extremes, however, are found within any large sample of B. chrysocomus collected from a single locality. The slightly higher braincase possessed by the holotype of brevimolaris , and the other two specimens from Lalolei (where the type was also collected), is one of several cranial variables that are responsible for clustering the scores representing the Lalolei specimens closely with those for the sample from Pegunungan Mekongga and more broadly with scores for the samples from the northeastern end of the northern peninsula, Bumbarujaba at the base of the northern peninsula, and Gunung Tambusisi at the western margin of the eastern peninsula as reflected in the ordination bounded by first and second canonical variates (fig. 27; see Geographic Variation).

Bunomys caelestis koka Tate and Archbold, 1935b: 1 . HOLOTYPE: AMNH 101236 (skin and skull; measurements are listed in table 18), an adult female collected January 11, 1932, by G. Heinrich (original number 753). TYPE LOCALITY: Indonesia, Propinsi Sulawesi Tenggara (southeastern peninsula of Sulawesi), Pegunungan Mekongga (03 ° 35 9 S, 121 ° 15 9 E), Tanke Salokko , 1500 m (locality 37 in gazetteer and the map in fig. 22).

Tate and Archbold (1935b: 1) characterized ‘‘ Bunomys caelestis koka ’’ as ‘‘Smaller than true caelistis and with smaller hind foot, shorter claws, and shorter nasal bones …,’’ and provided the following description:

Pelage soft and fine, dorsally fuscous-based, tipped with Mars brown which pales to Prout’s brown on sides. Under parts with bases of hairs fuscous, their tips tawny, the tawny becoming pale russet on chest and throat. Hands and feet with backs light fuscous, digits flesh-colored. Tail fuscous above, flesh-colored beneath. Ears light fuscous. Claws, though decidedly more elongate than those of the R. chrysocomus rats (of which we consider Bunomys a derivative), shorter than those of B. c. caelistis .

Skull with the long rostrum and full occipital region of Bunomys . Zygomatic plate sloping; palatal foramina short; bullae moderate in length; back of palate level with back of m 3; molar teeth small. No inflation of muzzle (which, however, probably occurs as a manifestation of age and growth).

The authors described and provided measurements for only the holotype; that specimen is one from a series of 21 collected by G. Heinrich from Pegunungan Mekongga (see locality 37 in the gazetteer).

The holotype and other specimens of koka do contrast with examples of Bunomys coelestis , which is known only by voucher samples from Gunung Lompobatang on the southwestern peninsula of Sulawesi (fig. 22), in the way that Tate and Archbold characterized koka. Those differences are part of the suite of phenetic external and and morphometric traits that distinguish examples of B. chrysocomus from specimens of B. coelestis (see Comparisons in the account of B. coelestis ).

Coloration of the tail is an example of a chromatic trait linking koka with B. chrysocomus and not B. coelestis . Typically, specimens of B. coelestis have a sharply bicolored tail: from base to tip, the dorsal surface is dark brown and the ventral surface white (unpigmented). Dorsal surfaces of the tails are dark brown in the sample of koka, but the ventral surfaces range from all white (tail bicolored) to all brown (tail monocolored), and a range of brown speckling between those extremes, variation that is typical of the ventral tail pigmentation found in any large sample of B. chrysocomus .

Results of multivariate analyses of cranial and dental variables cement the identity of koka with B. chrysocomus rather than B. coelestis . In the discriminant-function analy- sis of population samples for B. chrysocomus , the points representing specimens of koka overlap those of the three scores for brevimolaris from the lowlands adjacent to the Mekongga highlands and nigellus from the southern tip of the northern peninsula (fig. 27). Furthermore, in a canonical variate ordination where the sample of B. coelestis from Gunung Lompobatang is compared with all 10 population samples of B. chrysocomus , the specimen scores for koka fall within the cluster of scores representing B. chrysocomus and well outside the cloud of points for B. coelestis (fig. 42). Clustering based on Mahalinobis distance (squared) also aligns the sample of koka (from Pegunungan Mekongga) with the rest of the population samples of B. chrysocomus , not with the sample of B. coelestis (figs. 21, 49).

Although originally described as a subspecies of B. coelestis , the specimens identified as koka from Pegunungan Mekongga are actually examples of B. chrysocomus and are phenetically more similar in their cranial and dental dimensions to brevimolaris of the nearby lowlands than to other geographic samples of B. chrysocomus .

SUBFOSSILS: Two right dentary fragments (fig. 33) and an isolated right lower incisor (tables 27, 28) were found in sediments excavated from Ulu Leang I, a cave in the Maros region on the coastal plain of the southwestern peninsula (locality 42 in the gazetteer and map in fig. 22; also mapped by Simons and Bulbeck, 2004: 168).

Excavations in the cave were described by Glover (1976), who provided me with 10,000–3500 years B.P. as the age of the dated sediments (Glover, in litt., 1989; Bulbeck, 2004, reported 9500–3470 years B.P.). More precise dates associated with the particular site (‘‘Trench J’’) at which the pieces were uncovered are unavailable.

Two other species of Bunomys occur on the southwestern peninsula: B. coelestis inhabits mountain forest on Gunung Lompobatang and B. andrewsi has been collected at lower elevations on the flank of the volcano and is represented in the lowlands by subfossils (see accounts of those species).

I compared the two jaw fragments with dentaries in samples of the three species. No modern samples of B. chrysocomus exist from the southwestern peninsula, so I first compared the subfossils with specimens of B. chrysocomus from the west-central region. Shape of the dentary fragments and sizes of the molars remaining in those pieces qualitatively and quantitatively closely resemble dentaries and molars in the sample of modern B. chrysocomus (table 28).

Bunomys coelestis is a close montane relative of B. chrysocomus , so my second set of comparisons set the subfossils against the sample of B. coelestis from Gunung Lompobatang to test the possibility that the subfossils actually represent a lowland sample of B. coelestis . In side-by-side comparisons of specimens of comparable age (judged by degree of molar wear), the fragmentary ramus of each subfossil is qualitatively more robust and the portion anterior to the first molar is shorter than the gracile B. coelistis with its more delicate ramus and elongate incisor sheath; the ramal remnants fit better with the morphology characteristic of B. chrysocomus .

Sizes of the molars associated with the fragments are more typical of the range of variation seen in B. chrysocomus than in B. coelestis (table 28). These qualitative observations of molar size were quantitatively verified by results from principal-components analyses that associate the subfossils with the sample of B. chrysosomus and not B. coelestis (fig. 34). In both ordinations containing specimen scores projected onto first and second principal components, size of molars is primarily responsible for the separation of scores for B. chrysocomus (right side of each graph) from the constellation representing B. coelestis with smaller molars (table 29).

The curvature of the subfossil incisor, the third subfossil fragment from Ulu Liang I, along with its width and shape of wear facet, matches examples of B. chrysocomus .

The two dentary fragments and lone incisor are not lowland samples of the montane B. coelestis .

Finally, I contrasted the two dentary fragments from Ulu Leang I with dentaries of B. andrewsi from Lombasang on the flanks of Gunung Lompobatang, and included the subfossil fragment of that species found in Batu Ejaya II. Compared with B. chrysocomus , examples of B. andrewsi are physically larger (see external measurements seen in tables 19 and 41, and cranial and dental measurements in table 42), and this size distinction is reflected in the dentaries. Bunomys andrewsi typically has more robust dentaries, a longer toothrow, and wider molars (tables 28, 42). Inspected side by side, the dentary fragments and molars from Ulu Liang I are smaller than those elements in the series of specimens from Lombasang, and this difference is quantitatively reinforced by results of principal-components analyses. Specimen scores projected on first and second axes (fig. 35) form two clusters along the first component, those for B. chrysocomus on the left and B. andrewsi on the right, a function of the larger molars in the latter (table 30).

The subfossil from Batu Ejaya II is associated with the aggregation of points representing the sample from Lombasang ( B. andrewsi ), and the two subfossils from Ulu Leang I nest with the cluster of scores denoting B. chrysocomus .

The three subfossil fragments from Ulu Liang I are the only representatives of B. chrysocomus found to date in lowlands of the southwestern peninsula. I would like to see more complete specimens but until any are

TABLE 27

Subfossil Bunomys chrysocomus from the Southwestern Peninsula of Sulawesi

encountered, either as fossils or members of living populations, my identification is a hypothesis, and one that is reasonable considering the morphology of the fragmentary remains and the known altitudinal distribution of B. chrysocomus elsewhere in Sulawesi. The species does occur in high mountain forests but has been more commonly encountered at intermediate and moderately low elevations. The montane forests on Gunung Lompobatang are inhabited by B. coelestis , which has not been collected below 1830 m (see gazetteer for B. coelestis ). Bunomys andrewsi is the only other member of the genus recorded from lower altitudes in the southwestern peninsula, where it is represent- ed by modern specimens at 1100 m on the flank of Gunung Lompobatang, and subfossils excavated from cave deposits in the lowlands (see account of that species).

The next account describes a strictly montane member of the Bunomys chrysocomus

TABLE 28 Measurements (mm) of Mandibular Molars from Subfossil and Modern Samples of Bunomys chrysocomus and B. andrewsi , and Modern Samples of B. coelestis Mean ± 1 SD and observed range (in parentheses) is listed for the modern specimens, which are identified in footnotes. The subfossil fragments are described in tables 27 and 56. Subfossils are from the southwestern peninsula as are the modern samples of B. coelestis and B. andrewsi . The west-central region is the source for the sample of modern B. chrysocomus .

group, one found only on the high volcano Gunung Lompobatang at the southern end of the southwestern peninsula of Sulawesi.