Scotophilus marovaza, Goodman & Ratrimomanarivo & Randrianandrianina, 2006

Goodman, Steven M., Ratrimomanarivo, Fanja H. & Randrianandrianina, Félicien H., 2006, A new species of Scotophilus (Chiroptera: Vespertilionidae) from western Madagascar, Acta Chiropterologica 8 (1), pp. 21-37 : 23-35

Scotophilus marovaza sp. nov.

Holotype

FMNH 184050, an adult male ( Figs. 1–4 ; Tables 1–2 ), collected on 11 December 2004 by S. M. Goodman and F. H. Ratrimo- manarivo, field No. SMG 14474. The spec- imen was conserved in formalin and the skull extracted and cleaned. Both the speci- men and skull are in good condition. Tissue samples are preserved in EDTA.

Etymology

The name of the type locality (Maro- vaza) is placed in apposition to the generic name. Type locality

Madagascar, Province de Mahajanga, Marovaza, 14°56’S, 47°16’E, 5 m above sea level (see Fig. 1 ).

Habitat

The type specimen was collected roost- ing during the day in dry palm leaves (Bi- smarckia nobilis ) forming the roof soffit of a building in a remote coastal area of central western Madagascar. The principal habitats surrounding the village and to the north and east is degraded dry deciduous forest with anthropogenic savanna domi- nated by the same palm species, and to the west the Mozambique Canal. Within 100 m south of the collection site are extensive limestone outcrops, many eroded into pin- nacle forms, which are known as tsingy in Malagasy.

Diagnosis

A member of the genus Scotophilus based on a number of characters ( Hayman and Hill 1971; Robbins et al., 1985; Koop- man, 1994), including the long tapering tragus, no notable inflation of rostrum near the lacrymal, anterior palatal emargination, sin- gle pair of upper incisors, I 3 not reduced in size, M 1 and M 2 with reduced mesostyle and indistinct W-shaped pattern, and M 3 notably small. Adult dental formula 1/3-1/1- 1/2-3/3.

Scotophilus marovaza is distinguished from other described members of this genus by its diminutive body size with, for exam- ple, an average forearm length of 43.8 mm (range 41–45 mm, n = 6), which is notably smaller than any other described species of this genus (see Table 1 ). Muzzle is notably broad and short, giving a pug-like appearance. There is a distinct rostral swelling an- terior to each eye. The nostril openings are crescent in shape and are pointed in an out- ward direction. Tragus notably long, sickleshaped, and tapering to a fine point at the apex ( Fig. 2 ). The outer margin of the tragus is convex and with a circular lobe at its base. Dorsal pelage is relatively short, red- dish-brown in color with the exception of a distinctly lighter brownish-red band extend- ed across central back ( Fig. 3 ). Ventrum and throat a uniform shiny light brownish-yel- low. Wing membranes dark brown. Sagittal crest is well developed, particularly in males, and bifurcates at the level of the interorbital region and extends as a weak crest to the front of the orbits. Lambdoid crests are not well developed.

Paratypes

MNHN 1984.433 collected at Mahabo (20°23’S, 44°38’E) on 29 April 1869; UADBA 46965 (R. B. Jenkins [RBJ] 215) obtained at Antafinimihakatra , Parc Na- tional d’Ankarafantsika (16°16’S, 46°48’E) on 24 November 2004 by Félicien H.

Randrianandrianina and Hanta Julie Razafi- manahaka; and FMNH 184051, 184052, 184085, 184086 obtained at the holotype lo- cality between 21 and 22 April 2005 by Steven M. Goodman and Mamy Ravokatra. The specimen label of the Mahabo speci- men is without the collector’s name. This date conforms to the period Alphonse Gran- didier visited the village of Mahabo ( Vérin and Mantaux, 1971: 22) and there can be lit- tle doubt that the specimen was obtained by him.

Description

In the fresh material of S. marovaza available to us the reddish-brown dorsal pelage is similar in all individuals. Some dorsal hairs are lighter in color towards their tips and give a slightly shiny appearance to the pelage. In a few of the individuals there is a distinctly lighter brownish-red band ex- tended across the central portion of the back. The brownish-yellow throat and un- derside are generally similar in coloration and with no clear demarcation between these two regions, although some speci- mens show a slightly progressive darkening ventrally. One specimen (UADBA 46965), an adult female, shows a distinctly light- er yellowish-brown ventrum. The wing

membrane and uropatagium are dark brownish-black and show no notable change in coloration. Dorsally, particularly close to the humerus head, and ventrally there is a slight extension of the corporal body fur on to the wing membranes.

The ear length in S. marovaza is relatively consistent and does not differ markedly from the other diminutive members of this genus, with the exception of the larger bodied S. kuhlii in which ear length is notably smaller ( Table 1 ). The antitragus in S. marovaza is a well-formed slightly asymmetric semi-round structure measuring 3 mm in width × 2 mm in height and is separated from the ear by a distinct notch. The tragus is more elongated and sickle-shaped in S. marovaza than in any other species of Scotophilus occurring on Madagascar ( Fig. 2 ). At the base of the tragus there is a distinct elongated ridge that extends posteriorly along slightly less than one half the tragus length.

The skull of S. marovaza is notably small for a species of Scotophilus (Tables 1 and 2). The braincase is relatively narrow and when seen in profile the sagittal crest extends posteriorly as a sort of helmet- shaped structure ( Fig. 4 ). The bifurcation of the sagittal crest over the edge of the orbital

region forms a distinct brow. The rostrum is relatively short and broad, without any no- table expansion or swelling in the lacrymal region. Slight ovoid flaring to the zygomat- ic arches. The interorbital constriction is not pronounced. Anterior emargination of pal- ate is relatively deep and broad. Posterior palatal extension terminates as a small acute spine.

The tooth formula and structure is char- acteristic of other species of Scotophilus ( Koopman, 1994: 128) . The single upper pair of incisors is trifid and the upper and lower canines well developed and seeming- ly powerful for a bat of this size. M 1 and M 2 have reduced mesostyles and in the former the cusps form a distorted ‘W-shape’ and in the latter a distinct ‘W-shape’ M 3 is notably reduced in size. The second lower premolar (PM 1) and fourth lower premolar (PM 2) have the trigonid distinctly more developed than the talanid. There is a conspicuous swollen gland in the interior of the mouth at the base of the toothrows.

Distribution

This species is known from three sites in the western portion of Madagascar (north to south): Marovaza, Ankarafantsika, and Ma- habo (see Fig. 1 ). Given the different habi- tat types, including synanthropic settings, this species has been recorded, we suspect that it has a broad range across much of western lowland Madagascar.

COMPARISONS

When describing S. tandrefana , Good- man et al. (2005 a) had access to three spec- imens that they referred to this taxon. One of these, MNHN 1984.433 collected at Ma- habo in 1869, was smaller in most external, cranial, dental, and wing measurements than the other two specimens. Although pelage coloration was one of the diagnostic characteristics to differentiate S. tandrefana

from other diminutive members of the genus, particularly the holotype that was recently collected, the Mahabo specimen was notably faded in coloration after being stored in alcohol for nearly 140 years. Areevaluation of the identification of this specimen (MNHN 1984.433), based on a variety of characters and measurements, indicates that is falls within the range of S. marovaza, rather than S. tandrefana .

The reddish-brown dorsal and uniform shiny light brownish-yellow ventral pelage distinguishes S. marovaza from other diminutive members of this genus including S. kuhlii — chestnut-brown dorsally and pale brown ventrally; S. leucogaster — light to medium brown dorsally and white to dirty-brown ventrally; S. tandrefana — dark brown dorsally and medium brown ventrally; and S. viridis — yellowish-brown dorsally and white, grayish-brown to yellowish dorsally ( Goodman et al., 2005 a).

Scotophilus marovaza is a notably diminutive Scotophilus , with the shortest average forearm length of any known mem- ber of this genus from Madagascar (Table 1). The ear is similar in length to the other four diminutive species of Scotophilus , with the exception of the generally larger-bodied S. kuhlii , in which it is shorter. The tragus is more elongated, sickle-shaped, and finely pointed towards the apex in S. marovaza than in any other species of Scotophilus occurring on Madagascar (see Fig. 2 ). Further, the outer margin of the tragus is convex and with a circular lobe at its median base. The most notable difference in tragus shape is that in S. marovaza there is a distinct posterior ridge that extends inferiorly as a noncurved structure and in S. tandrefana the ridge is not as extensive and curved ( Fig. 2 ). In Figure 2 of Goodman et al. (2005 a) the ears and tragi of three different individuals of Scotophilus are illustrated, including the holotype of S. tandrefana (UADBA 46923), an individual identified as S. cf. borbonicus

(MNHN 1976.420), and an individual orig- inally allocated to S. tandrefana (MNHN 1984.433) but herein referred to S. marova- za. Amongst the six specimens of S. maro- vaza with measurable tragi, the average is 9.8 mm (range 9–11 mm), as compared to two individuals of S. tandrefana with lengths of 7 mm. The tibia length in S. marovaza is shorter (x = 17.1, range 16.7–17.3, n = 4) than in S. tandrefana (17.8 and 18.9, n = 2), and there is no overlap in these measures based on the limited avail- able material.

The skull is notably smaller in S. maro- vaza than any of the other diminutive mem- bers of this genus, including S. tandrefana ( Table 1 ), and there is no overlap between these two species in greatest skull length and condyloincisive length. Principal com- ponents analyses of cranial measurements indicate heavy loadings for these two vari- ables in separating out the five species of small Scotophilus compared in this study (Table 3). The cumulative percentage of cranial variation explained in the first two components is 90.2%, of which the first component accounts for 80.0% of the varia- tion, and S. marovaza forms a separate group from the other small congeneric spe- cies ( Fig. 5A). On the basis of this analysis and the grouping within the diagram, it is the smallest and morphologically discrete member of this genus.

Of the various dental measurements made there are few variables that allow clear separation of the examined species, particularly in this case between S. maro- vaza and S. tandrefana ( Table 2 ). These two species are notably similar in most dental measurements, but smaller than the other three species ( S. kuhlii , S. leucogaster , and S. viridis ) they were compared to. In the three larger species there is considerable intraspecific variation in dental measure- ments. Although C–M 3 and I –M had high 1 3 principal components loadings (Table 3), these variables did not allow for the clear separation of S. marovaza from S. tandre- fana ( Fig. 5B). Further, within the scatter of points of S. marovaza , there are also indi- viduals of S. leucogaster and S. viridis .

NATURAL HISTORY

Scotophilus marovaza is currently known from three sites spanning a consider- able area of the western portion of Madagascar ( Fig. 1 ). The direct line distance from the northern-most locality, Marovaza, to the southern-most site, Mahabo, is about 660 km. The holotype and other specimens from Marovaza were collected in a village setting 5 m a.s.l. and within 50 m of the sea; the specimen from Ankarafantsika at the ecotone between savanna and disturbed dry deciduous forest at approximately 65 m altitude and 90 km inland; and the third specimen from Mahabo, assumed to have been collected by A. Grandidier in 1869, in a pre- sumed synanthropic setting at about 60 m a.s.l. and about 40 km inland. Based on direct and in direct evidence five of the six specimens were collected in and around villages and one individual in an open area close to natural forest.

The holotype of S. marovaza was ob- tained in December 2004 within several dense layers of palm leaves ( B. nobilis ) that were attached to the roof soffit of a build- ing, where it was roosting within the thatching ( Fig. 6 ). In late April 2005, when the site was revisited, three individuals were found roosting together in the same exact place as the December specimen. These included two females and a third unsexed individual that escaped before it could be captured, but was pursued to three different sites associ- ated with palm thatching. At all of these three day-roost sites, within 30 m of one another, there was a well-defined opening amongst the palm leaves, as well as the distinct musky odor of this Scotophilus , and

the group probably had several day-roost sites in the same immediate vicinity. Al- though African and Asian members of the genus Scotophilus are known to commonly occur in synanthropic roost sites (e.g., Kingdon, 1974; Bates and Harrison, 1997), this is the first evidence of such a situation for Malagasy species. Subsequently, S. ro- bustus has been captured at localities in eastern and southeastern Madagascar in synanthropic settings ( Ratrimonanarivo and Goodman, 2005).

The Ankarafantsika specimen of S. ma- rovaza was captured in a mist net placed in a slight depression of a dry riverbed and parallel to the banks. This site was at the edge of a slightly disturbed dry deciduous forest. Standing B. nobilis trees were not common in the immediate vicinity of the capture site, although about 300 m away several houses had roof thatching made of palm leaves. No specific details are available on the site A. Grandidier obtained the Mahabo specimen of S. marovaza in 1869. However, it is assumed to have been close to or in this village. During the middle of the 19th cen- tury the predominant building materials for houses in this portion of Madagascar are presumed to be of wood for the main structure and palm leaves for the roof. We suspect that this specimen was collected in a synanthropic context.

The palm B. nobilis , known as satrana in Malagasy, has a broad distribution across much of the dry portions of Madagascar and occurs in heavily degraded anthropo- genic grassland ( Dransfield and Beentje, 1995). The attached lower leaf stems of a standing tree often hang vertically, with respect to the ground, and the dried and col- lapsed leaves form relatively dense layers. The position and form of these leaves is very similar to the synanthropic setting S. marovaza was found roosting in at the holotype locality. We strongly suspect that palm fronds are amongst the natural day roosting sites of this bat species. This style of roost site in collapsed palm fronds has been reported in S. heathi in the Philippines ( Rickart et al., 1989). On the basis of the recently collected specimens the following inferences can be made about reproduction in S. marovaza . The female captured at Ankarafantsika in late November 2004 had greatly enlarged mammae and appeared to be lactating. Thus, parturition would appear to coincide with the start of the rainy season, as is known in the South African population of S. viridis living in a seasonally arid zone ( Van der Merwe et al., 1988). The male from Marovaza collected in the first half of December 2004 had enlarged descended testes (8 × 3 mm) and convoluted epidi- dymes. Of the four individuals obtained at Marovaza in late April 2005, three were adult females with large or slightly enlarged mammae, no embryos, and single placental scars in one horn of the uterus and one was an adult male with enlarged descended testes (9 × 4 mm) and convoluted epididymes. On the basis of this limited information there would appear to be a defined breeding season in females, coinciding with the start of the rainy season (November to February). Males, on the other hand, appear to maintain their reproductive capacity for a distinctly broader portion of the year, as is known in S. viridis ( Van der Merwe et al., 1988; Van der Merwe and Rautenbach, 1989).

Scotophilus marovaza is not known to occur in sympatry with S. tandrefana , the other notably small Malagasy member of this genus. We suspect with further explo- ration of lowland western Madagascar, particularly in zones with B. nobilis palms, these two diminutive species of Malagasy Scotophilus may be found to occur at the same sites. Only two localities are known

on Madagascar where species of Scoto- philus occur in sympatry — Sarodrano with S. cf. borbonicus and S. tandrefana and Bemaraha with S. robustus and S. tan- drefana ( Goodman et al., 2005 a, 2005 b). Scotophilus robustus is also known to occur in eastern humid forest settings.

In their revision of African Scoto- philus, Robbins et al. (1985: 76) noted that amongst the few specimens from

Madagascar available to them in the Mu- séum National d’Histoire Naturelle, Paris, there appeared to be three different species: S. robustus , S. cf. borbonicus , and S. cf. viridis . Thus, there was already an indica- tion that species richness of this genus on the island was higher than the single species concept of Peterson et al. (1995). The de- scription of S. marovaza brings the number of endemic Madagascar representatives of the genus Scotophilus to three, the other two being S. robustus and S. tandrefana . Given that African Scotophilus show con- siderable variation in pelage and mensural characters, resulting in problems of diag- nosing species, the lingering question re- mains if S. tandrefana and S. marovaza are conspecific. Additional specimens and data sets, such as vocalizations, should help to resolve this question. Amolecular study is being currently conducted on African and Malagasy Scotophilus by R. Trujillo, which will address the question of their phylo- genetic relationships and species limits. Asimilar case of a cryptic species of Sco- tophilus has been recently found in south- ern Africa and combined morphological, vocalization, and molecular datasets have resolved their differentiation ( Jacobs et al., 2006)

.

The discovery of S. marovaza , which lives synanthropically, further highlights how little is known about the mammal fau- na of the island, specifically in this case the bats of western Madagascar. Within a short period after the completion of a generic re- vision of Malagasy members of the genus Scotophilus ( Goodman et al., 2005 a) , based on all of the world’s known museum hold- ings of specimens collected on the island of this genus, six other individuals were ob- tained at two different localities, which rep- resent the new species described herein. Given the considerable range of vegetation types in the western portion of the island, overlaid on significant meteorological clines and a remarkable range of geological formations ( de Wit, 2003; Gautier and Goodman, 2003), and that significant por- tions of the region are zoologically un- known, other species of mammals new to science are certain to be discovered in this region.

Figures

FIG. 1. Map showing sites at which Scotophilus marovaza and S. tandrefana have been collected, as well as other localities

FIG. 2. Right ear and tragus of Scotophilus spp. from Madagascar: A — holotype of S. marovaza (FMNH 184050), B — S. tandrefana (UADBA 51344), C — S. cf. borbonicus (MNHN 1976.420), D — S. robustus (FMNH 166186)

FIG. 3. Photograph views of holotype of S. marovaza (FMNH 184050; SMG 14474). Upper — dorsal view, and lower — ventral view. (Photographs taken by S. M. Goodman)

FIG. 4. Different views of the skull of S. marovaza (holotype FMNH 184050, SMG 14474). Upper left — dorsal view of cranium, upper right — ventral view of cranium, and lower — lateral view of cranium and madible. The greatest skull length of this specimen is 16.9 mm. (Photograph taken by John Weinstein, FMNH image No. Z94430–05d)

FIG. 6. The specific synanthropic setting where the holotype and a portion of the type series of S. marovaza were collected. The arrow indicates the site and the direction bats would have entered into the day roost site within the palm leaves. (Photograph taken by Mamy Ravokatra)