Pachydactylus mclachlani 2006
Male of Pachydactylus mclachlani.
© M. Barts.
Clutch of Pachydactylus mclachlani. Note the split eggs.
© M. Barts
Captive born hatchling of Pachydactylus mclachlani.
© M. Barts
Captive born hatchling of Pachydactylus mclachlani.
© M. Barts
Originalbeschreibung / Original description
BAUER, A., T. LAMB & B. BRANCH (2006): A Revision of the Pachydactylus serval and P. weberi Groups (Reptilia: Gekkota: Gekkonidae) of Southern Africa, with the Description of Eight New Species. – Proc. California Acad. Sci., Fourth Series, 57 (23): 595–709. — Terra typica: Namibia, Karas Region, Karasburg District, Noordoewer (28°39′48″S, 17°49′23″E).
ETYMOLOGY.— The specific epithet is a patronym honoring the late Geoff McLachlan (1923–2005), ornithologist and herpetologist, former director of the Port Elizabeth Museum and later Curator of Herpetology at the South African Museum. Geoff devoted much of his later life to the study of Pachydactylus and his pioneering studies on P. serval and its relatives highlighted the taxonomic difficulties of this group. The name is constructed in the masculine genitive.
DIAGNOSIS.— Amoderately large species, to 48.7 mm SVL (NMNW R 10496). Pachydactylus mclachlani may be distinguished from all other members of the P. serval/ weberi group by the combination of the following characters: nasal region moderately inflated; rostral narrowly excluded from nostril; supranasals in broad or narrow contact anteriorly; scales on snout and canthus granular, rounded to oval, flattened to weakly domed, much larger than granular scales of interorbital and parietal regions; small, rounded, conical tubercles, smaller than snout scales, interspersed among granules of interorbital and parietal regions; dorsal scalation heterogeneous, with moderately large, oval, strongly keeled tubercles arranged in 14–18 regular rows; thighs bearing enlarged conical tubercles; toes relatively long, toe pads moderately broad; typically six undivided lamellae beneath digit IV of pes; tail to at least 112% of SVL, annulate, bearing whorls of slightly enlarged, oval, flattened to weakly keeled tubercles, each well-separated from one another; adult pattern midbrown to purplish-brown with two thin light (cream to grayish- or purplish-brown) transverse bands, one on nape and one on trunk anterior to midbody. A broader pale band, just anterior to the hindlimb insertion, is less well developed or inconspicuous in some adults (Figs. 93–97). In some larger specimens the basic pattern is augmented by additional dark spots and incomplete bars; tail uniform brown to grayish-brown or with weakly contrasting alternating light and dark segments, caudal tubercles whitish; juvenile pattern very dark brown trunk with lighter head, a pale nape band and very thin anterior trunk band, area from just anterior to sacrum to tail base, including hindlimbs, ashy to pale purplish-brown, with or without a dark band across pygal portion of tail; tail orange.
DESCRIPTION (based on holotype).— Adult male. Snout-vent length (SVL) 43.0 mm. Body relatively depressed, moderately long (TrunkL/SVL ratio 0.39). Head relatively short (HeadL/SVL ratio 0.30), moderately wide (HeadW/HeadL ratio 0.67), somewhat depressed (HeadH/HeadL ratio 0.36), distinct from neck. Lores and interorbital region inflated. Snout moderately long (Sn-Eye/HeadL ratio 0.36), longer than eye diameter (OrbD/Sn-Eye ratio 0.72); scales on snout and canthus large, smooth, flattened to domed; scales of interorbital and parietal regions strongly heterogeneous, with tiny granules interspersed with larger, domed to conical, rounded tubercles, each 50–70% size of large snout scales. Enlarged conical tubercles regularly scattered across occipital and temporal regions as far posterior as nape. Eye moderate (OrbD/HeadL ratio 0.26); orbits without extra-brillar fringes; 4–5 supracilliary scales at posterodorsal corner of orbit bearing very small spines; pupil vertical, with crenelated margins. Ear opening oval, angled at 45% to horizonatal, large (EarL/HeadL ratio 0.11); eye to ear distance equal to diameter of eyes (EyeEar/OrbD ratio 1.01). Rostral approximately 55% as deep (0.8 mm) as wide (1.4), no rostral groove, contacted by two enlarged supranasals and first supralabials; nostrils oval, oriented laterally, each surrounded by two postnasals, supranasal, and first supralabial; supranasals in contact anteriorly, separated by a single granule posteriorly; dorsal postnasals much larger than ventral postnasals, separated by a single granule; nostril rims weakly inflated, bordered posteriorly by a distinct notch; 1–2 rows of scales separate orbit from supralabials; mental with nearly parallel sides, approximately 2.4 times deeper (1.9 mm) than wide (0.8 mm); no enlarged postmentals or chin shields. Enlarged supralabials to angle of jaws 13/13 (9/9 to mid-orbit); infralabials 8/8; interorbital scale rows at midpoint of orbit 22 (9 across narrowest point of frontal bone).
Dorsal tubercles large (8–10 times size of adjacent scales), largest on midflanks and smallest along dorsal midline and on anterior one third of trunk, rounded, with a pronounced median keel, forming 14 regular longitudinal rows on trunk, grading into conical granular scales on lower flanks; each tubercle surrounded by a regular to irregular rosette of small granular scales; ventral scales flattened, oval, subimbricate to imbricate, becoming larger posteriorly, largest on posterior abdomen and in precloacal region, approximately 35 between lowest conical granular rows on flank at midbody; tubercular scales on dorsum at midbody much larger than ventral scales at same level; chin granules approximately one fourth size of ventral scales, increasing in size rather abruptly on throat. No preanal or femoral pores. Scales on palm, sole, and ventral surface of forelimb smooth, granular; scales on ventral aspect of thighs enlarged, continuous with enlarged scales of precloacal region; scales on dorsal aspect of forelimb smooth, heterogeneous, subimbricate; scales on dorsum of thigh and crus greatly enlarged, conical.
Forelimbs short, stout (ForeaL/SVL ratio 0.16); hindlimbs short (CrusL/SVL ratio 0.17); digits relatively long, claws absent except for minute stylets on digits II and V of pes; subdigital scansors, except for distalmost, entire, present only on distal portion of toes, approximately 1.3 times wider than more basal (non-scansorial) subdigital scales; interdigital webbing absent. Relative length of digits (manus): III > IV > II > V > I; (pes): IV > III ~ V > II > I (distal portion of digit IV of left pes missing in holotype). Subdigital scansors (excluding small distal divided scansor) I (4), II (4), III (4), IV (4), V (4) – manus; I (5), II (5), III (5), IV (6), V (6) – pes.
Tail sub-cylindrical, weakly depressed; original tail longer than snout-vent length (TailL/SVL ratio 1.09; based on CAS 125850); tail smoothly tapering, with distinct whorls of scales; each transverse row of enlarged, pointed, oval, pointed, keeled tubercles separated by 3 rows of smaller scales; adjacent keeled dorsal caudal tubercles separated by 1–4 rectangular to oval, smooth to very weakly keeled, smaller scales (a few tubercles in direct contact); subcaudal scales subimbricate; midventral caudal scales enlarged relative to adjacent scales (6–8 times size of dorsal caudal scales); 2 enlarged, pointed, dorsally-projecting postcloacal spurs on each side of tailbase, anterior considerably larger than posterior.
Coloration (in preservative): Dorsum mid-brown with three faded grayish-brown transverse bands bordered by thinner dark brown edges. Anterior band extending from posteroventral border of orbit, through ear and across nape. Trunk band thinner, anterior to midbody, just posterior to position of elbow of adpressed forelimb. A third, broader pale band just anterior to hindlimb insertion is less conspicuous than the anterior bands. Dark anterior border of nape band passes through ventral portion of orbit to nostril; a cream band extending from anterodorsal margin of orbit to nostril. Top of head light brown with a slightly darker “V” shaped marking from supranasals to above anterior part of orbit; relatively symmetrical mid-brown markings at frontoparietal border and across mid-parietal table. Labials brown with areas of reduced pigment, especially around sutures and on posterior scales. Limbs slightly more yellowish than body dorsum. Tail relatively uniform grayishbrown with tubercles with white keels. Venter grayish-beige with very light, scattered brown pigment, densest along margins of flanks, limbs, and chin.