Gerrhopilus papuanorum, Kraus, 2023

Kraus, Fred, 2023, A revision of Gerrhopilus inornatus (Squamata: Gerrhopilidae) reveals a multi-species complex, Zootaxa 5231 (1), pp. 1-23 : 8-9

Gerrhopilus papuanorum sp. nov.

Figs. 4A, B

Holotype. BPBM 17236 (field tag FK 7488), obtained 22 February 2003 by Fred Kraus from a local collector at Bunisi Village, NE slope Mt Simpson, 10.0171° S, 149.6002° E, 1420 m a.s.l., Milne Bay Province, Papua New Guinea.

Paratypes. BPBM 17237 , Siyomu Village , NE slope Mt Simpson, 10.0145° S, 149.5970° E, 1300 m a.s.l., Milne Bay Province, Papua New Guinea, 23 February 2003 ; BPBM 17238 , Ikara Village , NE of Mt Simpson, 9.9801° S, 149.6311° E, 800 m a.s.l., Milne Bay Province, Papua New Guinea, 2 March 2003

Diagnosis. A Gerrhopilus species characterized by the unique combination of having a rounded snout in lateral view; LSR = 22 at midbody; TSR = 407–414; loreal absent; supralabial imbrication pattern T-V; subocular scale one; presubocular scale absent; a sharp, protruding, tail spine that is black basally and corneous distally; 1–5 glands in the prefrontal, 0–4 in the supraocular, 0–3 in the ocular, 18–28 in the preocular, 0 in the frontal, 0–2 in the subocular; L/W = 51.2–53.5; TL/SVL = 0.021 –0.026; and a uniformly dark-brown venter. Its size is large for this species group ( Table 1 ).

Comparisons with other species. Gerrhopilus papuanorum is distinguished from G. fredparkeri , G. hades , G. inornatus , G. slapcinskyi , and G. suturalis in having 22 longitudinal scale rows at midbody (vs 16 in G. fredparkeri , 18 in G. hades and G. suturalis , and 20 in G. inornatus and G. slapcinskyi ). It is further distinguished from G. fredparkeri in its lower number of transverse scale rows (407–414 vs 539 in G. fredparkeri ); from G. hades in having 22–24 longitudinal scale rows behind the head (vs 18 in G. hades ) and more and smaller glands in the center of the preocular (18–28 vs 10–11 in G. hades ); from G. inornatus in having more transverse scale rows (407–414 vs 374–375 in G. inornatus ) and in being more slender (L/W = 51.2–53.5 vs 36.4–47.8 in G. inornatus ); from G. slapcinskyi in having more transverse scale rows (407–414 vs 298–318 in G. slapcinskyi ), fewer glands in the ocular (0–3 vs 4–9 in G. slapcinskyi ) and preocular (18–28 vs 35–39 in G. slapcinskyi ), and in being more slender (L/W = 51.2–53.5 vs 35.5–38.6 in G. slapcinskyi ) and having a shorter tail (TL/SVL = 0.021 –0.026 vs 0.034 –0.043 in G. slapcinskyi ); and from G. suturalis in having a single postocular on each side of the head (vs two in G. suturalis ) and lacking a presubocular (vs present in G. suturalis ).

Description of the holotype. Female. L = 235.5 mm, SVL = 230 mm, TL = 5.6 mm, HW = 4.0 mm, SN = 2.3 mm, SW = 3.5 mm, PSN = 1.0 mm, RW = 1.9 mm, EW = 0.4 mm, W = 4.4 mm, VW = 3.9 mm, TW = 3.4 mm, L/W = 53.5, TL/SVL = 0.024. Head slightly wider than neck. Snout rounded in dorsal and lateral views. Snout anterior to lower jaw horizontal. Rostral moderately large (RW/HW = 0.48), oval dorsally, lateral margins convex, posterior border extending slightly more than halfway between naris and eye, posterior margin straight; ventrally surface papillose, with straight sides and posterior margin concave. Nasals separated dorsally by prefrontal ( Fig. 4A ); superior nasal large, with sinuous posterior margin, concave dorsally, convex ventrally ( Fig. 4B ). External naris semicircular, oriented obliquely, close to rostral, anterior half covered by inferior nasal; superior nasal suture extending anterodorsally from naris to rostral; inferior nasal suture complete, contacting second supralabial well posterior to latter’s contact with first supralabial. Prefrontal and supraoculars subequal in size, slightly larger than frontal, parietals, and interparietal, which are also subequal in size. Preocular large, triangular; larger than ocular but smaller than superior nasal. Ocular large, smaller than preocular, extending dorsally well above preocular, extending ventrally to ~2/3 depth of preocular, bordered posteroventrally by subocular of approximately half its size. Eye small and rather ill defined, with indistinct iris margin and large pupil, situated at widest point of ocular and approximately midway along its height, anterior third covered by preocular plate in lateral view. Five postoculars bordering ocular and subocular between parietal and fourth supralabial. Four supralabials, third the largest, all with long axis oblique to long axis of body, first approximately rectangular. Supralabial imbrication pattern T-V, posterior border of second supralabial overlaps anteroventral margin of preocular, that of third supralabial overlaps anteroventral margin of subocular and ends at rear margin of preocular. Mental crescentic, wider than long, projecting slightly beyond curve of lower jaw and fitting into notch on upper lip when mouth is closed. Infralabials two on each side, second much longer.

Longitudinal scale rows 24 behind head, 22 at midbody, and 22 anterior to vent; transverse scale rows 408, no intercalary scales along vertebral row; subcaudals 15; dorsocaudals 14; apical region with sharp apical spine that extends only short distance (0.2 mm) past last scales.

Rostral, nasals, and preoculars densely covered in pale glands; oculars and frontal without glands, preoculars with 28 (R) and 26 (L), supraoculars with 2 (R) and 4 (L), prefrontal with 5; and suboculars with 2 glands.

In preservative, 19 years after preservation, body dark brown above and below, venter slightly lighter; no sharp distinction between dorsal and ventral shading; each scale uniformly dark. Anterior half of rostral, area around nares, first supralabials, mental, first infralabials, and center of throat to 1.5 scales behind mental pale straw yellow; second and third supralabials pale straw yellow ventrally, brown dorsally. Head glands pale straw yellow; tail spine black basally, corneus brown distally. Iris pale gray distally, dark gray adjacent to pupil, distal margins indistinct; pupil paler gray.

Variation. Both paratypes too are female, but they have 22 longitudinal scale rows behind the head and throughout the body ( Table 1 ). BPBM 17237 is smaller (L = 215 mm) than the holotype; BPBM 17238 is larger (L = 262 mm). Their L/W ratios are virtually the same (51.2, 52.4, respectively) to the holotype, as are their relative tail lengths (TL/SVL = 0.026 and 0.021, respectively) and number of transverse scale rows (407, 414, respectively). The eye is half covered by the preocular scale in BPBM 17237 and half to two-thirds covered in BPBM 17238. Glands are uniformly absent from the frontal in the type series and from the ocular in BPBM 17237, but BPBM 17238 has two glands in the right ocular and three in the left. Glands in the preocular vary from 18–24 in the two paratypes, those in the subocular from 0–1, in the supraocular from 0–2, and in the prefrontal from 1–4. The rostral is slightly narrower in BPBM 17237 (RW/HW = 0.43) than in BPBM 17238, which is identical to the holotype. Color pattern is identical in all specimens.

Etymology. The species name is a genitive plural honorific for the people of Papua New Guinea, the generosity and friendliness of many of whom made my expeditions to that country most pleasant and rewarding.

Distribution. Known only from the northern slope of Mt Simpson, Milne Bay Province, PNG, at elevations from 800–1420 m a.s.l. ( Fig. 2 ).

Ecology. Each of the three specimens was brought to the author by local villagers. It seems most likely that each was uncovered while the villagers were working their gardens during the day. The areas around each village are now widely cleared for gardens or converted to grasslands for hunting ( Fig. 3B ) but would have comprised lowermontane rainforest originally.

Figures

FIGURE 2. Map of southern Papua New Guinea showing collecting localities for Gerrhopilus inornatus (star), G. flavinotatus (diamond), G. lorealis (hexagon), G. papuanorum (square), G. polyadenus (open circles), G. slapcinskyi (filled circle), and G. wallachi (triangle).

FIGURE 3. Habitats for members of the Gerrhopilus inornatus Group. A Forest at Varirata National Park, very near the type locality of G. inornatus (photo M. O’Shea); B the hills around Bunisi and Siyomu from which G. papuanorum was collected (photo F. Kraus).

FIGURE 4. Dorsal and lateral views of heads for members of the Gerrhopilus inornatus Group having 22 midbody scale rows and uniformly dark venters. A, B holotype of Gerrhopilus papuanorum (BPBM 17236); C, D holotype of Gerrhopilus polyadenus (BMNH 1901.11.27.10).