Prasinohaema scurrula, Slavenko & Shea & Oliver, 2025

Prasinohaema scurrula sp. nov.

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Figs. 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6

Holotype SAMA R65176 (Field number SJR12137), Apalu Reke (-5.4862, 142.3019), 2,875 m a.s.l., Muller Range , Hela Province, Papua New Guinea, collected by Stephen Richards on 21 September 2009. GoogleMaps

Paratype. PNGNM 24992 Tari Gap (nearest town Tari), 2,700 m a.s.l., Hela Province, Papua New Guinea, collected by Clifford Frith between 24 December 1988 to 30 January 1989. Approximate coordinates are -5.9515, 143.1463, georeferenced based on aerial photo in Frith & Frith (1990), detailing the location of a Pteridophora alberti Meyer, 1894 nest next to which the paratype was collected (C. Frith pers. comm.) GoogleMaps .

Diagnosis. Prasinohaema scurrula sp. nov. can be differentiated from all other Lobulia group skinks by the combination of adult SVL up to at least 70 mm, snout short and relatively blunt; prefrontals not in contact, primary temporal not divided, parietals fully separated by interparietal, lower eyelid with two enlarged opaque scales centrally, more than two chin shields in medial contact, posterior chin shields separated from infralabials by a short row of 2–3 genials, subdigital lamellae only moderately expanded (distal lamellae typically around double width of proximal lamellae), lining of mouth blue in life, dorsal pattern of dark-brown crossbands, and venter with dark brown chequerboard pattern.

Description. Snout short, dorsal margin convex in lateral profile; rostral wider than tall, in contact posteriorly with first supralabial, nasals and frontonasal, median lobe slightly rounded; frontonasal wider than long, in contact posteriorly with prefrontals and frontal, suture with frontal narrower than that with rostral and narrower than width of frontal at level of suture between second supraocular and frontoparietal; prefrontals moderately separated, in contact posteriorly with frontal, first supraocular and first supraciliary; frontal kite-shaped, longer than wide (paratype with anterior angle hived off as a small azygous scale, and posterior angle partially cleft longitudinally); one pair of frontoparietals, left overlapping right; supraoculars four, second extending most medially, third narrowest, first two contacting frontal, last three contacting frontoparietals; interparietal kite-shaped, shorter and narrower than frontal (paratype with anterior lobe of interparietal hived off as an azygous scale between frontoparietals), posteriorly completely separating parietals ( Fig. 2 View FIGURE 2 ); parietal eye spot absent ( Fig. 3A&F View FIGURE 3 ).

Nasal oblique, anteroventral to posterodorsal length shorter than anterodorsal to posteroventral length, contacting frontonasal dorsally and anterior loreal posteriorly; nostril central in nasal; a weak postnarial groove beginning ventral to nostril, arcing around posterior margin to posterodorsal side; no supranasal or postnasal; anterior loreal taller than long, partially (holotype) or completely (paratype) divided into smaller upper scale and larger lower scale, and dorsally contacting frontonasal and prefrontal, posteriorly contacting posterior loreal; posterior loreal squarish, but narrower ventrally, contacting prefrontal and first supraciliary dorsally, and first preocular and first presubocular posteriorly; on right side of paratype, posterior loreal divided into smaller upper and larger lower scale, together slightly taller than wide; supraciliaries nine (eight on R side of paratype), first four (three on R side of paratype) contacting first supraocular (fourth only narrowly so), first longer than the rest, narrowly separated from frontal, last two progressively arcing medially behind fourth supraocular, last overlapping parietal; a large anterior preocular wedged between first supraciliary and first presubocular, reaching posterior loreal anteriorly, followed by small second preocular that subtends both upper and lower palpebral rows; presuboculars three; postsuboculars four, first (lowermost) interdigitating between fifth and sixth supralabials, uppermost overlapped by last supraciliary, overlapping corner of parietal; upper palpebrals in contact with supraciliary row along most of its length, anterior part of row separated from supraciliaries by one (holotype) or 2L/3R (paratype) oblique scales; lower palpebrals shallow; the two central subpalpebrals enlarged, equivalent to a “window” but opaque; primary temporal single, overlapped by upper three postsuboculars and penultimate supralabial; secondary temporals two, upper longer than tall, overlapped by parietal, uppermost postsubocular and primary temporal; lower secondary temporal overlapped by upper secondary, primary and last supralabial; supralabials seven, first four squarish, last two pentagonal, first dorsally contacting nasal and narrowly anterior loreal (holotype) or just nasal (paratype), second contacting anterior loreal broadly and posterior loreal more narrowly, without (holotype) or narrowly with (paratype) contact with nasal as well, third narrowly contacting posterior loreal, broadly contacting first presubocular, and very narrowly contacting second presubocular, fourth contacting second and third presuboculars, fifth below centre of eye, separating pre- and postsubocular series, contacting 6L/5R (holotype) or 3L/2R (paratype) granules of lower eyelid; postsupralabials two; nuchals irregularly and asymmetrically differentiated, holotype with first pair of enlarged nuchals extending laterally to reach upper secondary temporals followed by 2L/1R narrower nuchals, paratype with two scales between paravertebral scales and upper secondary temporals bilaterally, and first few paravertebrals of irregular width; ear ovoid, taller than long, height about equal to height of lower eyelid, with two (holotype) or three (paratype) low lobules along anterior margin.

Mental similar width to rostral, but shallower on midline; postmental slightly narrower than mental; infralabials seven (holotype) or 8L/7 R (paratype), first two contacting postmental, second to third (L on holotype, R on paratype) or second to fourth contacting chin shields, remainder separated by one or more rows of intervening scales; paratype with first two pairs of chin shields in median contact, third pair of chin shields medially separated by two scales; fourth pair of chin shields separated medially by three scales; holotype with asymmetrical chin shields, first two on left contacting first on right, second on right narrowly separated from its partner on the left by a single scale, third pair separated by two scales, but right scale laterally shortened to allow contact between second and fourth chin shield of that side, fourth pair separated by three/four irregular scales.

Body scales glossy, in 32 (holotype) or 34 (paratype) longitudinal rows at midbody; dorsals irregularly longitudinally grooved (holotype) or smooth (paratype), slightly wider than long, paravertebral series not enlarged, 62 to level of anterior margin of hindlimb (both specimens), 65 (holotype) or 66 (paratype) to posterior margin of hindlimb; medial precloacals enlarged and laterally overlapping the adjacent precloacals; median subcaudals slightly wider than laterally adjoining subcaudals; tip of tail rounded with slight development of a ventral “pad”.

Limbs pentadactyle, third and fourth fingers of similar length; fourth toe longest. On toes, basal subdigital lamellae only slightly wider than distal subdigital lamellae, and width gradually diminishes distally.Fourth toe slightly dorsally arched at second interphalangeal joint; fifth toes slightly arched at first interphalangeal joint. Lamellae under fourth toe 16L/19R (holotype) or 20/20 (paratype); terminal three scales above fourth toe undivided.

Measurements and proportions

Holotype: SVL 70 mm, AGL 37 mm (52.9% of SVL); tail autotomised at base; FLL 18 mm (25.7% of SVL); HLL 27 mm (38.6% of SVL); (FLL + HLL)/AGL 121.6%; HL 13.4 mm (19.1% of SVL); HW 10.0 mm (74.6% of HL); HD 7.4 mm (55.2% of HL).

Paratype: SVL 64 mm; AGL 31.5 mm (49.2% of SVL); TL 93 mm (145% of SVL); FLL 18 mm (28.1% of SVL); HLL 27 mm (42.2% of SVL); (FLL + HLL)/AGL 142.9%; HL 13.6 mm (21.3% of SVL); HW 10.1 mm (74.3% of HL); HD 8.0 mm (58.8% of HL).

Colouration (in preservative). Description based on holotype and paratype. Dorsal ground colour light olive brown ( Figs. 3 View FIGURE 3 & 4 View FIGURE 4 ). Dorsal head shields with small irregular dark brown spots along some scale margins, particularly medially. Neck and body dorsum with irregular darker brown transversely oriented macules, only weakly aligned to become broken bands, giving appearance of a “chequerboard” pattern of light and dark patches. Dark macules and pale interspaces both about 2–3 scales long from anterior to posterior. Tail dorsum with similar rectangular markings, but less contrasting (mid brown) and more transversely aligned to create bands.

Laterally, ground colour transitioning from light brown dorsally to light yellow-grey ventrally. An irregularly edged dark brown stripe beginning over loreal region (where narrowest), along upper and lower edges of orbit, over upper temporal region (containing a few paler spots), then along upper flanks, where it broadens and breaks up into a coarse dark brown reticulum (containing some spots of pale ground colour) blending with the lateral parts of the dorsal pattern, and extending more ventrally as mid-brown barring. Lateral surface of tail with extensions of the mid-brown dorsal bands.

Venter yellow-grey, throat immaculate, body and tail with mid-brown extensions of the lateral pattern of blotches towards the midline (but not reaching it in the paratype).

Forelimbs light brown above with weakly defined and coarse brown reticulum above, yellow-grey below; palms yellowish-grey. Hindlimbs light brown above, anteriorly and posteriorly with a coarse dark brown reticulum, yellow-grey below with weak extensions of the dark reticulum encroaching; soles pale yellow.

Parietal peritoneum black, visceral peritoneum unpigmented.

Colouration (in life). Description based on holotype and unvouchered photographed specimen. Dorsal ground colour light olive brown to golden brown ( Fig. 5A–C View FIGURE 5 ). Irregular spotting on dorsal head shields and macules along the dorsum dark brown to black.

Dorsal surface of head sometimes with light greenish tint. Laterally, ground colour transitioning from light brown dorsally to pale ventrally. Venter pale grey. Lining of mouth blue.

Reproduction. Both specimens are female. The holotype has 1L/2 R thin-shelled eggs in the oviduct indicating viviparity, while the paratype is non-reproductive but mature (oviduct well-developed with obliquely pleated walls).

Etymology. From the Latin masculine noun scurrula, a small clown, in reference to the bright chequerboard pattern, resembling that often used in the dress of clowns and jesters.

Distribution. Prasinohaema scurrula sp. nov. is known from three locations spanning approximately 1,000 km 2 of Hela Province between the Muller Range in the northwest and the Tari area and Gigira Ridge in the southeast ( Fig. 6 View FIGURE 6 ). The Gigira Ridge (-5.972, 142.753, 2,175 m a.s.l.) record is based on an unvouchered photograph taken by S. Richards on 24 June 2015 ( Fig. 5A–B View FIGURE 5 ).

Ecology. Prasinohaema scurrula sp. nov. is a montane species. All specimens were found in mid-montane habitats at elevations between 2,175 –2,900 m a.s.l. The holotype was found on a log in a patch of sun in a fern meadow ( Fig. 5D–E View FIGURE 5 ) at Apalu Reke in the Muller Range (see Takeuchi 2011 for a detailed habitat description). The specimen from Gigira Ridge was found on the ground in sunny conditions on an artificially created limestone scree slope at the edge of a road in dense mid-montane forest. Later surveys at the Gigira Ridge location in 2017, 2019, and 2024 did not detect this species. The paratype was found 40’ (roughly 12 m) high in a pandanus tree (see detailed habitat information in Frith & Frith (1990)). This suggests arboreal habits for the species, which may explain why observations are rare despite intensive surveys at Apalu Reke and Gigira Ridge, where Pandanus trees were common.

Prasinohaema scurrula . sp. nov. was not observed during a survey at 500 m a.s.l. in the Muller Range, nor at surveys between 1,340 –2,220 m a.s.l. elsewhere in that range (F. Kraus pers. comm.); altitudes below 2,175 m a.s.l. on Gigira Ridge were not sampled.

Relatively few other skink species have been observed in sympatry with the new species. An undescribed species of Papuascincus (most likely lineage III from Slavenko et al. 2020) was abundant at both Apalu Reke and Gigira Ridge. A single unidentified Emoia Gray, 1845 was observed but not captured at Gigira Ridge and a few specimens of an unidentified species of Lobulia were also recorded there. This Lobulia possibly belongs to an asyet-undescribed species that occurs in the Muller Range, and that is genetically divergent from other species of Lobulia present in the Central Cordillera ( Lobulia lobulus ( Loveridge, 1945) and Lobulia marmorata Slavenko, Tamar, Tallowin, Kraus, Allison, Carranza & Meiri, 2021 ) ( Slavenko et al. 2022).

Suggested IUCN conservation status. Prasinohaema scurrula sp. nov. is known from three locations spanning approximately 1,233 km 2 of Papua New Guinea’s Central Cordillera. The Tari Gap and Gigira Ridge locations are respectively about 107 and 73 km east from the Muller Range locality, and separated from each other by ~ 44 km. However, these two most proximate localities are separated by the much lower (down to ~ 1,200 m a.s.l.) valley of the Tagari River which may represent a significant barrier to dispersal. In contrast, bands of unbroken terrain above 1,600 m a.s.l. connect the Muller Range locality with both Tari Gap and Gigira Ridge. Whether these intervening areas of montane forest and meadow support additional populations of this species is unknown. There are relatively large areas of apparently suitable habitat in the region, and the species has a moderately broad elevational range— suggesting that it is not at imminent risk from climate change. Nonetheless, its distribution, habitat requirements and potential threats remain poorly understood. One striking feature of this species is that at two of the known locations (Apalu Reke and Gigira Ridge), only single individuals were encountered despite intensive surveys lasting at least several days and (at Gigira Ridge) up to a month over several years. In contrast, other montane skinks ( Papuascincus spp. ) were abundant at these sites. However, if P. scurrula sp. nov. is arboreal, as suggested by the collection details of the paratype, it would be difficult to detect using terrestrial surveys. Given the moderately broad known range and apparent extensive availability of suitable habitat without major known threats, we recommend that this species should be considered Least Concern.

Comparisons with other species. Prasinohaema scurrula sp. nov. differs from all other species of Prasinohaema sensu stricto in the short blunt snout (vs long, slender and pointed). This is most obvious in lateral profile.Additional features distinguishing it from individual species are covered below.

Prasinohaema flavipes is the type species of the genus and is widely distributed along the Central Cordillera and in the Huon Peninsula. Prasinohaema scurrula sp. nov. additionally differs from it in the combination of smaller size (mature individuals 64–70 mm vs 74.5–104 mm), fewer supralabials (seven vs eight or more); lower eyelid with two enlarged opaque scales centrally (vs modally with an opaque to translucent window covering the same area, although some individuals have the window divided into two scales as in P. scurrula sp. nov.); basal subdigital lamellae not abruptly broader than distal lamellae (vs basal 7–11 lamellae change abruptly to 7–10 narrow distal lamellae) and with rounded distal edges (vs flat distal edges); temporal scalation without any fragmentation (primary temporal single, upper and lower secondary temporal undivided, last two supralabials undivided) rather than with irregular fragmentation (with at least the primary temporals and last supralabial divided, often with the homologies of the fragmented scales not apparent); parietal scales fully separated by interparietal (vs usually in contact); dorsal colour pattern of alternating dark brown and light brown rectangular regions of roughly equal width in a chequerboard pattern (vs completely banded with dark and light brown regions, or with a broad dorsal stripe or unpatterned; Greer & Raizes, 1969; Kraus, 2010); and ventral surface with extensive dark-brown chequerboard pattern (vs plain, or with at most scattered light brown blotching).

Prasinohaema flavipes paniaiensis is a subspecies from the Wissel Lakes region of Indonesian New Guinea that has been largely ignored in the literature since it was described. Geographically isolated from nominate P. flavipes in Papua New Guinea, no evidence was provided at the time of description that it is more closely related to P. flavipes than to any of the other Prasinohaema , and it has yet to be included in any genetic analyses. It probably warrants recognition at the species level. We provide a comparison based on its original description in Brongersma (1949). Prasinohaema scurrula sp. nov. shares with P. flavipes paniaiensis the separation of the parietal scales by the interparietal, but it differs from it in having the dorsal scales smooth or bluntly grooved (vs with a texture of numerous fine grooves), fewer supralabials (seven vs modally eight), fewer supraciliaries (modally nine vs 9–12, usually 10 or 11), no fragmentation of scales in the temporal region (vs irregular fragmentation), lower eyelid with two large central opaque scales (vs usually a transparent disk, sometimes divided into two or three transparent scales), ear with 2–3 low lobules along anterior margin (vs lacking lobules), basal subdigital lamellae only slightly and gradually diminishing in width distally (vs basally broad, more abruptly transitioning to narrow distal scales), fewer paravertebral scales (65–66 to posterior edge of hindlimbs vs 79–88) and dorsal colour pattern of alternating dark brown and light brown rectangular regions of roughly equal width (vs unbanded, or, if banded, with dark brown and light brown regions of greatly differing width); and ventral surface with extensive dark-brown chequerboard pattern (vs plain, or with at most scattered light brown blotching).

Prasinohaema prehensicauda is widely distributed along the Central Cordillera. P. scurrula sp. nov. is similar to it in body size (mature-sized individuals 64–70 mm vs 59–72 mm) and in the separation of the parietals by the interparietal. Prasinohaema scurrula sp. nov. differs from P. prehensicauda in having prefrontals not in contact (vs in contact), fewer supraoculars (4 vs modally 5), fewer supraciliaries (modally nine vs 9–12, usually 10 or more), fewer postsuboculars (4 vs 5–7), fewer supralabials (7 vs 8–10), lower eyelid with two enlarged opaque subpalpebral scales centrally (vs a transparent window formed by a single scale covering the same region), no fragmentation of the temporal region (vs fragmentation), dorsal scales smooth and polished (vs finely shagreened, giving a dull appearance), fewer paravertebrals (65–66 to posterior edge of hindlimbs vs 70–85), longer limbs (FLL/SVL 25.7– 28.1% vs 20.4–25.6%; HLL/SVL 38.6–42.2% vs 25.2–32.3%), more subdigital lamellae (16–20 vs 11–16) and the basal subdigital lamellae only slightly diminishing distally (vs basally broad, more abruptly transitioning to narrow distal scales) and with rounded distal edges (vs flat distal edges). Prasinohaema prehensicauda is sexually dichromatic ( Greer & Raizes 1969; Woodruff 1972; Kraus 2010). In the absence of male P. scurrula sp. nov., comparison of colouration can only be made with females, but female P. scurrula sp. nov. differ from P. prehensicauda in having a dorsal pattern of alternating dark brown and light brown rectangular regions of roughly equal anteroposterior width (vs narrow dark bands separated by wider pale intervals containing paler spots).

Prasinohaema parkeri is only known from the holotype, from the Utakwa River in Indonesian New Guinea, approximately 500 km to the west of the known distribution of P. scurrula sp. nov. and has not yet been included in any phylogenetic analysis. Like P. semoni and P. virens , it may not be part of a monophyletic Prasinohaema . However, because it has not yet been excluded from Prasinohaema sensu stricto, we include a comparison with the new species, based on the description in Smith (1937) and our examination of the holotype. The holotype exhibits a number of unusual scalation features, and it is not known whether these are individual anomalies (part of an apparent pattern in many Prasinohaema species that exhibit fragmentation or asymmetrical scalation anomalies, e.g., Brongersma 1949) or are character states of the species. We treat these peculiarities as if they characterise the species. Prasinohaema scurrula sp. nov. differs from P. parkeri in having the anterior loreals distinct, and with partial or complete separation of an upper anterior loreal (vs anterior loreals fused to frontonasals), fewer supralabials (7 vs 8), frontal posteriorly entire, and contacting first two supraoculars, with the frontal overlapping the second supraocular over the entire sutural contact (vs posterior part of frontal partially separated, and this posterior hemiscale contacting (right) or only just separated from (left) the third supraocular, and overlapped by second supraocular); supraoculars unfragmented (vs with fragmentation of the lateral extremities of the second and third supraoculars), supraciliaries 8–9 (vs 13L/12 R), interparietal separating parietals (vs parietals in broad contact posteriorly), temporal region not fragmented (vs fragmented, including division of at least primary temporal and last supralabial), and ventral surface with extensive dark-brown chequerboard pattern (vs plain).