Bavayia loyaltiensis sp. nov., 2022

Bauer, Aaron M., Telma, Alex & Sadlier, Ross A., 2022, A New Species of Bavayia (Squamata: Diplodactylidae) from the Loyalty Islands, Proceedings of the California Academy of Sciences 67 (13), pp. 315-328 : 319-325

Bavayia loyaltiensis sp. nov.

Figures 2–4 .

Holotype ( Fig. 2A ).— MNHN-RA 2022-0037 (ex. AMS R.125775) Cengeite , Maré Island, Loyalty Islands, Province des Îles Loyauté, New Caledonia, 21°36 ʹ S, 167°54 ʹ E, coll. H.G. Cogger and R.A. Sadlier, 19 August 1987.

Paratypes ( Fig. 2B ).— AMS R.125763 , R.125767–68 , R.125776–77 , same data as holotype ; AMS R.125802 , R.125811 , same locality and collectors as previous, 20 August 1987 ; AMS R.125823 , same locality and collectors as previous, 21 August 1987 ; CAS 38826 , Maré Island , Loyalty Islands, Province des Îles Loyauté, New Caledonia, coll. F. Sarasin and J. Roux, December 1911 .

Referred Material (all localities in Province des Îles Loyauté).— AMS R 125764–66, R.125769–74, R.125786 , R.125803 , R.125812–14 , Cengeite, Maré Island , Loyalty Islands, 21°36 ʹ S, 167°54 ʹ E ; NHMB 7007–22 , Netché, Maré Island , Loyalty Islands, 21°29 ʹ S, 167°51 ʹ E ; NHMB 7020–21 Medou [= Medu], Maré Island , Loyalty Islands, 21°37 ʹ S, 167°57 ʹ E ; NHMB 7022 , Penelo, Maré Island , Loyalty Islands, 21°34 ʹ S, 168°06 ʹ E .

Diagnosis. — Bavayia loyaltiensis sp. nov. is a small member of the Bavayia sauvagii group (maximum 45 mm SVL), characterized by its gracile body, relatively short tail, digits II– V relatively narrow, claw of digit I of manus and pes borne lateral to a single medial apical scansor, usually single row of precloacal pores occupying a distinctive scale row, large number of cloacal spur scales, dorsal pattern of four largely symmetrical, well demarcated, dark transverse markings between the limb insertions, and pale head dorsum with a pair of pale nape stripes. It is distinguished from members of the B. cyclura group ( B. cyclura , B. montana , B. crassicollis , B. robusta , B. goroensis , B. nubila and a number of undescribed species in this group) by having the claw of digit I of the manus and pes borne lateral to a single medial apical scansorial pad (vs. in a notch within an asymmetrically divided apical scansor), having beige to brownish ventral coloration (vs. yellow ventral coloration), having a gracile habitus (vs. robust) and small size (maximum 45 mm SVL vs.> 50 mm except in B. goroensis [max. SVL 48.6 mm]), and in usually having a single row of precloacal pores (vs. usually two or more). Within the B. sauvagii group it may be distinguished from B. geitaina by its much smaller size (45 mm vs. 72 mm maximum SVL), lower number of dorsal dark markings (4 vs. 5 between limb insertions), dorsal scale rows per tail whorl 7 (vs. 9), and absence of a dark “H” or “X”-shaped marking on parietal region; from B. ornata by its much smaller size (45 mm vs. 69 mm maximum SVL), shorter snout (<40% HeadL vs.>40% HeadL), shorter tail (<110% SVL vs.>110% SVL), and absence of distinct whitish spots or small blotches on limbs; and from B. septuiclavis by its greater number of precloacal pores (16–25, usually>20 vs. 8–14), and predominantly transverse body markings (vs. predominantly longitudinal body markings or patternless). It differs from the similarly sized B. exsuccida and B. pulchella and several related undescribed taxa in having digit I of the manus and pes borne lateral to a single medial apical scansor ( Figs. 3D–E ; versus lying between a larger medial and a smaller lateral scansor) and in having transverse body markings (vs. predominantly longitudinal markings, patternless, or with a bright white “ V ” shaped marking on the nape), and pale markings on tail much longer than darker interspaces (vs. dark interspaces longer). Bavayia loyaltiensis is most similar to B. sauvagii and a suite of related undescribed taxa, with which it shares a similar color pattern and morphology of digit I. It differs in body size from its mainland relatives (maximum 45 mm vs. 60 mm SVL in B. sauvagii sensu stricto and at least 50 mm in undescribed taxa) and exhibits a distinctive differentiation of the precloacal pore-bearing scale row from the adjacent scale rows both anterior and posterior to it ( Fig. 3F ; vs. no such differentiation). Male B. loyaltiensis also may have cloacal spurs comprising clusters of up to at least 8 enlarged scales (see Fig. 3G ), whereas in B. sauvagii and related taxa this number may be up to 6 but is usually 3 or 4.

Description. — (based on holotype — MNHN-RA 2022-0037 (ex. AMS R.125775), an adult male; Figs. 2A , 3–4 ). Snout-vent length ( SVL) 44.9 mm; trunk relatively long (TrunkL 45% SVL) gracile, depressed. Head oblong, large (HeadL 29% SVL), relatively slender (HeadW 67% HL), not depressed (HeadH 41% HeadL), distinct from neck; interorbital/frontal region with slight midline depression, canthus well developed; snout short (SnEye 39% HeadL), less than twice eye diameter (OrbD 21% HL). Granular scales on anterior snout approximately 2–3 times diameter of those on occipital region. Pupil vertically oriented with crenelated margins; several superciliary scales in posterodorsal quadrant of orbit conical, moderately elongate, pointed. Ear opening approximately 1.5 times higher than wide, canted slightly posterodorsally to anteroventrally; eye to ear distance greater than the diameter with of eye (EyeEar 126% OrbD). Rostral rectangular, much broader than high, no median crease, contacted posteriorly by five, roughly rectangular internasals and two slightly enlarged supranasals, contacted posteroventrally by first supralabial. Nostrils oval and anterolaterally oriented, surrounded by two postnasals, one supranasal, the rostral, and in broad contact with first supralabial. Mental subtriangular, approximately as wide as deep; a single elongate, median, septagonal postmental in narrow contact with apex of mental, separating first infralabials form one another; first infralabials each in contact posteriorly with median postmental and one (L) or two ( R) smaller lateral postmental chin shields. First 4–5 rows of chin shields larger than remaining throat scales. 11 L, 12 R enlarged supralabial scales, of which 7th–11th (L) and 8th–12th ( R) beneath the eye; 11 L, 9 R infralabial scales; 48 interorbital scale rows between superciliaries at midpoint of orbit, 18 interorbitals between the orbital margins of the frontal bone.

Dorsal scales small, homogeneous, very slightly conical, granular; ventral scales slightly larger than dorsals, juxtaposed anteriorly becoming subimbricate and somewhat enlarged posteriorly on the body. Posterior abdominal scales rounded, mid-abdominal scales elongate, diamond-shaped. Approximately 139 scale rows around midbody. Scales of the limbs not differing from dorsals. Scales on palms and soles smooth, flattened. Precloacal pores variable in size, in a single scale row of 23 pored scales, clearly set off from the anterior scale rows and the single following scale row. Forearm and crus relatively short (ForeaL 13% SVL, CrusL 14% SVL); axillary pockets shallow. Digits long and moderately narrow, all bearing claws, those on digit I of both manus and pes reduced and partially sheathed; relative length of digits of manus: IV~III>II~ V >I, and of pes: IV~ V >III>II>I; digits weakly webbed; digits III and IV of pes tightly bound along length of elongate metatarsals. Subdigital lamellae typically paired, except variably single or fragmented at the base of digits. Distalmost lamella of digits II– V, manus and pes, undivided. Claw of digit I positioned lateral to a single apical scansor. Lamellar counts from right side of holotype 6-10-9-10-10 manus and 5-10-10-10-10 pes.

Tail 45.0 mm (distal ~ 26 mm regenerated), approximately 100% of snout-vent length, tapered, stout, roughly cylindrical in cross-section; tail base at cloacal spurs swollen. Caudal scales small, flat, rectangular, arranged in regular rows. Surface of tail weakly segmented, caudal scale rows forming whorls, each whorl 7–8 dorsal scale rows and 6 ventral scale rows long; midventral caudal scales not enlarged. Scales on pygal portion of tail one third to one half size of those on postpygal tail. Cloacal spurs consisting of five large, compressed, flattened, conical, posterodorsally directed scales, just posterolateral of the colaca.

Color in preservative: Dorsum and flanks mottled light brown with small, irregularly distributed darker brown markings, with a bold pattern of four medium brown, wavy transverse markings between the limb insertions, each with scattered small, ill-defined buff spots along its anterior margin, especially evident at the lateral extremes of the dark markings. These markings each preceded by a pale blotch with vague lateral and anterior margins. Additional dark markings present on the sacrum and extending on to the postaxial margins of the thighs as a thin line, and on the nape, appearing as a medial marking and a pair of lateral ones, separated from one another by a pair of bifurcating buff-colored longitudinal stripes. Buff neck stripes converge posteriorly to form the pale blotch anterior to the first dark transverse markings of the trunk (i.e., at the shoulder). Anteriorly the buff stripes curve inward to meet the posterolateral corners of a large buff area on the parietal table. The area enclosed by the stripes laterally and the parietal anteriorly is darkest and narrowest posteriorly, becoming much lighter and quadrupling in width anteriorly yielding a bulbshaped outline. The sides of the neck, lateral to the buff stripes, are a very diffuse brown and this coloration extends forward across the lower temporal region, through and beneath the eye and on to the snout, although anterior to the orbit it is incomplete in places. The dorsum of the head bears some faint, irregular markings formed by individual darker granules or small clusters of granules; a faint irregular blotch is present over the nasal bones and continues to the tip of the snout as a thin wavy dark line. The margins of the orbit are pale with some diffuse whitish markings; the labial scales are brown with scattered pigment-poor areas yielding a whitish spotting on the margins of the jaw. The sides of the head posterior to the orbit and ventral to the temporal streak are densely spotted with ill-defined whitish to cream spots, which continue posteriorly on to the flanks. The largest and most conspicuous longitudinal row of such spots extends from the ventral margins of the temporal streak, over the forelimb insertions, down the flanks, over the hindlimb insertions and on to the ventrolateral margins of the original tail. Limbs similar to ground color of trunk, with irregular, faint, scattered medium brown markings. The pygal portion of the tail bears a cream to buff-colored dorsal marking that traverses the tail base constriction and extends on to the first segment of the postpygal tail. This is bordered posteriorly by a thin, broken, border of medium brown and then by a pale brown interspace that is shorter than the cream marking. Two similar markings and a portion of a third continue on the original portion of the tail, with each cream marking with irregular, but mostly symmetrical shape and with a faint brown central marking. The regenerated tail is predominantly buff with irregular, ill-defined medium brown dashes. Body venter beige with darker pigmentation under the limbs, around the cloaca, at the body margins and on the chin and throat. Subcaudal surfaces light to medium brown with scattered beige to cream markings.

Color in life. — Based on images ( Fig. 4 ) of the holotype and a paratype ( AMS R.125776) in life. Ground color grayish- to pinkish-brown with very small dark brown and white granules and clusters of granules interspersed. Dorsal dark transverse bars dark brown, each with a thin (one granule wide) anterior margin. Dorsal pale blotches and streaks on neck and temporal region grayish brown. Lateral spots bright white; larger, more prominent dorsal series extending from behind eye to sacrum. Ventral series of smaller spots running from posteroventral aspect of orbit, below ear and above forelimb insertion to flanks; anteriorly this row of spots is in series with white spots on the supralabials. Snout dark brown; orbital rims pale yellowish; iris coppery. Limbs and lower sides of neck light brown, with neither grayish- or pinkish-undertones, similar to flanks at ventrolateral margins. Tail grayish-brown to gray. Original portion of post-pygal tail bearing gray dorsal blotches with dark brown margins, alternating with mottled gray-brown interspaces. Regenerated portion of tail gray with scattered, irregular, dark brown longitudinal lines and dashes.

Variation. — Mensural and some meristic features of paratypes are presented in Table 1. All paratypes with 5 internasals contacting the rostral. First infralabials separated behind the mental in all paratype except AMS R.125776 (in contact) by an enlarged median postmental chin shield. Collectively, the first infralabials border 2–5 (usually 3) enlarged chin shields. Midbody scale rows 131–145 (mean 137). Male paratypes with a single row of ~16–24 precloacal pores (except AMS R. 125823 in which there is a single median pored scale in a second row); no pores or dimpled scales in females. Cloacal spurs up to eight enlarged scales on each side (e.g. AMS R.125811). Subdigital lamellae vary contralaterally within individuals as well as between individuals; usually 5–6 under digit I of both manus and pes and a maximum of 12 under the longest digits. All specimens have partly regenerated tails, a common condition among Bavayia spp. Longest regenerated tail 100% SVL (holotype). Color pattern very conservative, differing among the paratypes primarily in the boldness, extent and continuity of the dark markings of the trunk, and the nape and head markings. In paratypes with more complete original tails as many as 10 pale tail markings are present (e.g., AMS R.125802).

Etymology. —Named for the Loyalty Islands (Îles Loyauté), to which the species is restricted.

Distribution. — Restricted to Maré, the southernmost island of the Loyalties (Province deÎles Loyauté). It is possible that it may occur on the nearby islands of Tiga (Tokanod) and Dudune ( Fig. 1 ).

Natural History. — The species occupies daytime retreats under exfoliating tree bark ( Fig. 5 ) and has been found active on building walls on Maré (Sadlier and Bauer 1997).

Conservation Status. — Bavayia loyaltiensis meets the criteria (B1ab(ii, iii, v) + 2ab(ii, iii, v)) to be categorized as Vulnerable on the IUCN Red List. The species is endemic to Maré Island in the Loyalty Islands and has a very small distribution with

an estimated extent of occurrence of 650 km ². It is presumed to have suffered past declines in population size and extent of occurrence as a result of loss of forest habitat from clearance for occupation and agriculture. It is considered to be at a high level of threat from further loss and degradation of forest habitat from clearance for agriculture and settlement, from predation by cats, and from the introduced Fire Ant Wasmania auropunctata, which has the potential to displace geckos from ground sheltering sites and arboreal foraging sites, and to affect the abundance and composition of invertebrate prey ( Jourdan et al. 2001).

Remarks. — This species has previously been consistently included within Bavayia sauvagii sensu stricto ( Roux 1913; Bauer and Vindum 1990; Bauer and Henle 1994; Sadlier and Bauer 1997; Bauer and Sadlier 2000). Roux (1913) noted the small size of specimens from Maré ( SVL 45 mm) relative to B. sauvagii from the Grande Terre which is, in fact, diagnostic for this species. Subfossil material from Tiga may be referrable to this species ( Daza et al. 2015). Recent collections are lacking from Tiga, but its proximity to Maré makes the occurrence of B. loyaltiensis plausible, at least historically.

Figures

FIGURE 2. Bavayia loyaltiensis sp. nov. A) Holotype, MNHN-RA 2022-0037 (ex. AMS R.125775). B) Paratype series. Scale bars = 10 mm.

FIGURE 3. Holotype of Bavayia loyaltiensis sp. nov. (MNHN-RA 2022-0037). A) Dorsal view of head. B) Ventral view of head. C) Lateral view of head. D) Right manus. E) Right pes. F) Cloacal region showing distinctive pore-bearing scale row and closacal spurs. G) Close up of left cloacal spure of paratype AMS R.125811 showing the diagnostic large cluster of enlarged scales. Scale bars A–C = 5 mm, D–F = 1 mm, G = 0.5 mm.

FIGURE 4. Bavaya loyaltiensis sp. nov. in life. A) Holotype (MNHN-RA 2022-0037). B) Paratype AMS R.125776. Photos courtesy of H.G. Cogger.

FIGURE 1. Map of New Caledonia and the Loyalty Islands (left)with enlargement of Maré and adjacent islets showing distribution of Bavayia loyaltiensis. Star indicates type locality, dots indicate other vouchered locations. Cartography by Jonathan DeBoer.

FIGURE 5. Habitat of Bavayia loyaltiensis in forest near the Trou de Bone, southern Maré.