Podogymnura intermedia, Balete & Heaney & Rickart & Quidlat & Rowsey & Olson, 2023

Balete, Danilo S., Heaney, Lawrence R., Rickart, Eric A., Quidlat, Roselyn S., Rowsey, Dakota M. & Olson, Link E., 2023, A re-assessment of diversity among Philippine gymnures (Mammalia: Erinaceidae Podogymnura), with a new species from eastern Mindanao, Zootaxa 5228 (3), pp. 244-266 : 258-262

Podogymnura intermedia new species

Figs. 5 , 7 , 8 , and 9; Tables 1 and 2

Holotype. FMNH 186805, adult male, collected on 28 July 2005 (original number 3769 of D. S. Balete); initially fixed in formalin, now preserved in 70% ethyl alcohol with the skull removed; skull in good condition. A sample of fresh muscle tissue was removed from the left thigh and preserved in 90% ethanol; otherwise the body is in good condition. The holotype has been cataloged and is currently housed at FMNH but will be transferred to the National Museum of the Philippines, Manila.

Type Locality. 3.7 km S, 1.4 km E of Mt. Hamiguitan peak, Mati Municipality , Davao Oriental Province, Mindanao Island, Philippines, 950 m elev., 6 º 42’ 26.2” N, 126 º 11’ 42.8” E ( Fig. 1 ) .

Specimens examined. Mt. Hamiguitan : (N = 4) Three additional specimens from the type locality (FMNH 190152, 190153, 190167) and one (FMNH 190151) from 17.5 km S, 4 km E of Mt. Hamiguitan peak, San Isidro Municipality, ca. 1,128 m elevation, 6 º 43’3” N, 126 º 11’1.9” E. These include two males and one female, and a specimen of undetermined sex prepared as a skull only (FMNH 190167). The juvenile male (FMNH 190151), adult male (FMNH 190152), and young adult female (FMNH 190153) have had their skulls removed and cleaned. The bodies of the adult male and young-adult female had partially decomposed prior to preservation, but that of the juvenile male is in good condition. The prepared skulls have broken crania, including one with broken coronoid and condyloid processes (FMNH 190152) .

Mt. Kampalili : (N = 12) Three males (FMNH 194750, 194751, 194752) from 2 km S, 2 km W of Mt. Kampalili peak, Maragusan Municipality, Compostela Valley Province, Mindanao Island, Philippines, ca. 1,900 m elevation, 7° 17’ 11.7” N, 126° 15’ 30.9” E; two females (FMNH 194748, 194749) from 2.75 km S, 0.5 km W of Mt. Kampalili peak, ca. 1,500 m elevation, 6 º 17’39” N, 126 º 15’38.4” E; two females (FMNH 208700, 208701) and three males (FMNH 208699, 208702, 208705) at 2.25 km S, 3.5 km E of Mt. Kampalili peak, 1,470 m elevation, 7.29112 º N, 126.31520 º E; and two females (FMNH 208703, 208704) at 1.75 km S, 4.25 km E of Mt. Kampalili peak, 1,640 m elevation, 7.29522 º N, 126.31602 º E. Three females (FMNH 194748, 208700, 208703) and three males (FMNH 194750, 194752, 208705) have had their skulls removed and cleaned; others preserved intact. Two females (FMNH 194748, 208700) have crushed crania, and one male (FMNH 194752) has a broken left zygomatic arch; and one male (FMNH 208705) has a short crack on the occipital .

Distribution. Currently known from montane forest over ultramafic soil between ca. 950 and 1,128 m on Mount Hamiguitan, and in montane and mossy forest from ca. 1,470 m to 1,900 m on Mount Kampalili ( Fig. 1 ).

Etymology. From the combined Latin inter (between) + medius (middle), to highlight its intermediate morphology between the two smaller species of Podogymnura and the large P. aureospinula . We propose eastern Mindanao gymnure as its English common name.

Diagnosis. A member of the genus Podogymnura as diagnosed above, of intermediate to small size (Mt. Hamiguitan average HB = 171 mm, weight 96 g; Mt. Kampalili average HB = 145, weight 77 g; Table 1 ), defined by the following combination of characters. Dorsal pelage generally coarse in Hamiguitan, softer in Kamapalili specimens, with long guard hairs of two types: scattered long, black hairs, and many slightly shorter guard hairs having conspicuous golden-yellow tips that produce an appearance of shiny, golden streaks ( Fig. 7 ). Both types of guard hairs become progressively shorter laterally and anteriorly over the head and snout. Underfur soft, gray, and dense, becoming sparser over head but more conspicuous laterally as guard hairs become sparser laterally and absent ventrally, where silver highlights become apparent. Ventral pelage shorter and paler, lacking golden streaks. Ears short (average = 20 mm), pigmented grayish-brown. Relative to congeners, hindfoot longer in Hamiguitan (average HF = 36 mm), shorter in Kampalili (34 mm) but short relative to HB (21–23 % of HB; Table 1 ); plantar surface, including plantar pads, darkly pigmented or with mottled grayish-brown areas. Tail pigmented medium to dark grayish brown dorsally, and variable ventrally, usually dark but occasionally mottled with white. Tail relatively short compared to length of head and body (average TV = 53–54 mm; 32–37 % of HB; Table 1 ). Skull of Hamiguitan specimens ( Figs. 5 , 8 ) large (holotype CIL = 43.4 mm, BBC = 16.8 mm), that of Kampalili specimens smaller, (CIL = 40.6 mm, BBC = 16.1 mm). Sagittal and nuchal crests low but readily visible, rostrum long and deep. Incisive foramina relatively long and wide in Hamiguitan specimens, narrower and shorter in Kampalili specimens. Upper toothrow long (average I1– M3 = 21.1 – 22.2 mm). Post-palatal region proportionately long in specimens from Mt. Hamiguitan, average in Kampalili, both samples with paired concavities between the bullae, bisected by a low medial ridge. Mandible long and robust in Hamiguitan (average LMI = 33.5 mm), shorter and more slender in Kampalili (average LMI = 31.6 mm). Lingual lobe of P3 present in Hamiguitan specimens, absent in Kampalili. P4 proportionately large and square-shaped. A small, inconspicuous cusp present at base of talonid on first and second lower molars ( Fig. 8E ).

Description and Comparisons. Because specimens from Mt. Hamiguitan (the type locality) differ from those from Mt. Kampalili, we include comparisons of specimens from these two places along with comparison to other species of Podogymnura .

A medium-sized Philippine gymnure, Hamiguitan specimens larger and more robust than specimens from Mt. Kampalili, P. minima , and P. truei , but smaller and less robust than P. aureospinula ( Tables 1 and 2 , Figs. 4 , 5 ). Dorsal pelage of P. intermedia from Hamiguitan is distinctly darker on head and rostrum, venter slightly paler brownishgray ( Fig. 4 ); coarse overfur consists of long, stiff guard hairs, ca. 20 mm on mid-dorsum, longer on the rump, ca. 25 mm. The long, coarse, grayish-brown dorsal pelage contains both long black guard hairs and long golden-yellow guard hairs that produce a golden-streaked appearance. Mt. Kampalili specimens have soft, dark brown dorsal pelage with shorter black guard hairs and many short golden-yellow-tipped hairs that produce a golden-speckled appearance. Dorsal pelage of P. aureospinula is uniformly paler and golden-brown overall and overfur is shorter and bristly; venter brownish-gray. P. truei has soft dorsal pelage that is dark brown with small, inconspicuous speckles of golden-brown at the tips, without conspicuous long and stiff guard hairs. P. minima has short, soft, reddish-brown dorsal pelage with golden-brown speckles at the tips that are more conspicuous than those of P. truei but are darker and smaller than those of P. intermedia from Mt. Hamiguitan or specimens from Mt. Kampalili. Females of all species have two pairs of small, inconspicuous mammae, one pair inguinal and one pair axial; these are well hidden by the fur.Adult males have a swollen area from the base of the tail to the area around the penile sheath; the sheath is small, ca. 1.5 mm wide and long; no scrotum is evident. In specimens from Hamiguitan, the swollen area is covered by typical abdominal fur, but in specimens from Kampalili, the swollen area is bare.

Ears of all Podogymnura are short relative to body size, and sparsely covered with short, nearly invisible hairs; ears of specimens from Hamiguitan are pigmented dark gray but from Kampalili are paler. P. aureospinula ears are palest of the known species. Ears of P. truei and P. minima average slightly longer and paler than in P. intermedia ( Table 1 ). Length of tail relative to head and body (32%) in P. intermedia from Hamiguitan is shortest among all Podogymnura ( Table 1 ). Skin of tail of Hamiguitan specimens is uniformly dark gray throughout; on Kampalili specimens it is ventrally pale brown or mottled with white. Tail of P. aureospinula is longer but overlaps in relative length (33% of HB). Tail of P. truei is substantially longer both absolutely and proportionately ( Table 1 ). Although P. minima is smaller overall, tail is equal in length and proportionately longer. Hind foot of P. intermedia is average among Podogymnura excepting the larger P. aureospinula , but proportionately shorter than all except P. aureospinula ( Table 1 ). Hindfoot skin is pigmented medium gray dorsally and ventrally, including digits and plantar pads, paler and often mottled with white in those from Kampalili. Hind feet of P. aureospinula , P. truei and P. minima are unpigmented, both dorsally and ventrally.

Skull of P. intermedia ( Fig. 8 , Table 2 ) is smaller than the much larger P. aureospinula ( Fig. 4 ), but larger than its congeners in most respects, with Mt. Hamiguitan specimens larger than those from Kampalili ( Fig. 5 ). It is similar to P. truei and P. mimima in its limited development of the prominent nuchal and sagittal crests that are hallmarks of P. aureospinula . Maximum height of sagittal crest is 0.8 mm in P. intermedia . The nuchal crest of P. intermedia slants slightly posteriad relative to the cranium but does not project beyond occipital margins ( Fig. 8 ), which it does in P. aureospinula ( Fig. 4 ).

In lateral view, skull of P. intermedia from Hamiguitan ( Fig. 8 ) cuts a nearly straight slanting profile from top of braincase to tip of narrow and tapered rostrum, whereas in specimens from Kampalili the profile is slightly concave. Frontals of P. aureospinula are dorsolaterally inflated, making them only about 9% narrower than braincase, and in dorsal view producing a narrow-waisted hour-glass shape in interorbital region ( Fig. 4 ). In lateral view, prominent frontal swellings in P. aureospinula produce a convex dorsal profile. All three small-bodied Podogymnura share an interorbital region in which there is a relatively broadly-waisted hourglass shape, although lacrimal and interorbital breadths of P. intermedia from Hamiguitan are greater than in Kampalili and the other two species ( Table 2 ), and all lack the temporal ridges that in P. aureospinula form a low crest converging at the interorbital region. In P. intermedia and the two other small-bodied species, the parietals are dorsolaterally inflated from the anterior edge of interparietals, forming a cranium that tapers anteriad to the frontal region and flattens posteriad to the occipital region ( Fig. 8 ). Incisive foramina cordate, similar to those of P. minima and P. truei in size, in contrast to the wider and longer foramina in P. aureospinula and P. intermedia . Palatal length, width of the posterior palatal ridge, and lingual palatal breadth at M 3 of P. intermedia are large (except in comparison to P. aureospinula ; Table 2 ). Postpalatal length of P. intermedia from Hamiguitan is the greatest among the small Podogymnura , with specimens from Kampalili averaging shortest ( Table 2 ).

The basicranium of P. intermedia is similar to its congeners, differing mainly in the large size of the basicranial area, auditory bulla, and paraoccipital process ( Fig. 8 ). Aside from overall size, the basicranium of P. intermedia is similar to that of P. aureospinula (and unlike other Podogymnura species) in having paired, shallow concavities traversed medially by a fine, short ridge that runs parallel to the bullae from its base to the tip of the tympanic wing, although in P. aureospinula the depressions are more expansive and the mid-ventral ridge longer and larger. The medial ridge is low and poorly defined in P. truei and nearly absent in P. minima , and the concavities are absent in both.

Mandible of P. intermedia ( Fig. 8 , Table 2 ) relatively long and thick, except in comparison to P. aureospinula ( Fig. 5 ). P. aureospinula has larger, wider, and longer angular, coronoid, and condyloid processes than all of its congeners. In P. intermedia from Hamiguitan, the angular process is narrower but longer, coronoid wider, and condyloid process longer and more robust than in specimens from Kampalili, P. minima , and P. truei . Position of mandibular foramina is similar in all species.

Dental features of P. intermedia ( Figs. 8 , 9A, 9B , Table 2 ) are similar to those of congeners in most respects (see Podogymnura Diagnosis), usually differing only in relative sizes. The presence of a discernible lingual lobe in P 3 in specimens from Hamiguitan is shared with P. aureospinula ; this lobe is absent among all other Podogymnura . P4 is proportionately larger and more square-shaped in P. aureospinula and P. intermedia than in P. truei or P. minima . A small, inconspicuous cusp at base of talonid on m1 and m2 is present in all specimens of P. intermedia from Hamiguitan ( Fig. 8E ) and P. aureospinula ( Heaney & Morgan 1982) ; a poorly-developed version is present in a small percentage of P. truei , and is absent in other populations, including P. intermedia from Kampalili.

Ecology. We recorded P.intermedia on Mt. Hamiguitan and Mt. Kampalili in different types of forest formations, and so we present the ecological information separately .

On Mt. Hamiguitan, we captured P. intermedia in primary montane forest over ultramafic soil at 950 m to 1,128 m ( Balete et al. 2006). We did not record it in lowland forest at 525 m in 924 trap-nights. At 950 m, three individuals were caught in 228 trap-nights with earthworm bait (1.3% success) compared to one individual caught in 672 trap-nights with roasted coconut coated with peanut butter (0.15%); none were captured in traps set above ground on vines and trees. On Mt. Kampalili, we recorded this species in upper montane and mossy forest at ca. 1,470 m – 1,900 m elevation; forested habitats below and above these elevations were not surveyed. Seven P. intermedia recorded during 2010 were captured in 247 trap-nights with live earthworm bait (2.83 % trap success); none were captured in 506 trap-nights using coconut bait. All were captured on the ground, and none in traps set in trees or on vines, and nearly all were captured at night. On the adjacent peak of Mt. Kangayag (ca. 1,630 m) of the same mountain range, we captured no gymnures in 2,140 trap-nights, of which 250 were baited with live earthworms.

The apparent absence of P. intermedia in the lowlands and restriction to montane and mossy forest is similar to P. minima , which occurs in secondary and old-growth montane and mossy forest from ca. 1,300 m to 2,800 m ( Heaney et al. 1998, 2006), and to P. truei , which has been recorded from montane and mossy forest at ca. 1,640 m to at least 2,250 m ( Hoogstraal 1951, Sanborn 1952). In contrast, P. aureospinula occurs in secondary and oldgrowth lowland forest at low elevations ( Heaney & Morgan 1982; Heaney & Rabor 1982; Heaney et al. 2010).

Stomach contents of two individuals from Mt. Hamiguitan contained mainly chewed remains of arthropod exoskeletons, including coleopterans and their larvae, as well as an operculum and shell fragments of small land snails. A few pieces that appeared to be partially digested bits of small earthworms were present. Stomach contents of three specimens from Mt. Kampalili contained chewed remains of arthropod exoskeletons, including coleopterans and centipedes, and two contained pieces of earthworms. The presence of land snails in the diet of this species is the first record of this food item among Podogymnura . These diet and trapping data indicate that, as with other Podogymnura , P. intermedia forages on the ground for leaf-litter invertebrates. These feeding habits may differ from those of P. minima , which feeds more commonly on earthworms than arthropods ( Heaney et al. 2006), although this difference may simply reflect differences in prey availability.

An adult male from Mt. Hamiguitan taken in May had testes measuring 11 x 5 mm; an adult female was nulliparous. The presence of a juvenile in May suggests that some breeding occurred earlier in the year. None of the specimens from Mt. Kampalili captured in February and May (five adult males, three adult females, three young adult females and one young adult female) showed signs of reproductive activity.

Three species of murid rodents ( Batomys hamiguitan , Bullimus bagobus , and Rattus everetti ) were documented as being sympatric with P. intermedia on Mt. Hamiguitan along with the Mindanao shrew ( Crocidura beatus ; Balete et al. 2006, 2008). In addition to these native species, we recorded the non-native spiny ricefield rat ( Rattus exulans ) at two disturbed sites near the type locality: a narrow patch of non-native cogon grass, Imperata cylindrica , surrounding the shoreline and dry lakebed of Tinagong Dagat, a seasonal lake; and in disturbed vegetation along a foot-trail, but not in the nearby forest interior. On Mt. Kampalili this species was associated with Apomys sp. , Bullimus bagobus , Rattus everetti, Baletemys kampalili ( Rowsey et al. 2022), an undescribed species of Tarsomys , and one squirrel, Sundasciurus philippinensis (specimens in FMNH). The commensal house shrew, Suncus murinus , was also present. All of the native co-occurring species are endemic to the Philippines, and all but R. everetti are restricted to the Mindanao Faunal Region ( Heaney 1986; Heaney et al. 2006, 2010).

Figures

FIGURE 1. Map of Mindanao and adjacent islands showing some major topographic features; mountains where Podogymnura truei (Mt.Apo), P. minima (Mt. Kitanglad Range), P. aureospinula (Bucas Grande and Dinagat Islands), and P. intermedia n. sp. (Mt. Hamiguitan and Mt. Kampalili) occur, and other important peaks, are shown.

FIGURE 4. Photographs of skull of Podogymnura aureospinula, holotype, DMNH 4386, approximately life size. Adapted from Heaney & Morgan 1982.

FIGURE 5. Photographs of skulls of Podogymnura intermedia (holotype, FMNH 186805, A-D), P. truei (FMNH 56169, E-H), and P. minima (FMNH 146594; I-L). All skulls approximately life size.

FIGURE 7. Podogymnura intermedia (FMNH 186805, holotype), adult male. Photographed 28 July 2005 by D. S. Balete.

FIGURE 8. Dorsal (A), ventral (B) and lateral (C) views of the skull and lateral view of the mandible (D) of Podogymnura intermedia (FMNH 186805, holotype); scale bar refers to these images. E, occlusal view of the second mandibular molar of Podogymnura intermedia holotype; arrow points to a small cusp at the base of talonid, between the entoconid and metaconid.

FIGURE 9. Maxillary and mandibular dentition of Podogymnura intermedia from Mt. Hamiguitan (A, B; FMNH 186805, holotype); and (C, D; FMNH 194751), from Mt. Kampalili. Scale bar = 5mm.