Ancylodactylus laikipiensis, Malonza & Bauer, 2022

Malonza, Patrick K. & Bauer, Aaron M., 2022, Resurrection of the African gecko genus Ancylodactylus Müller, 1907 (Squamata: Gekkonidae) and description of six new species from Kenya, Zootaxa 5141 (2), pp. 101-139 : 121-124

Ancylodactylus laikipiensis sp. nov.

Laikipia Pygmy Forest Gecko

( Figures 9–10 )

Cnemaspis dickersonae (part) Spawls et al. 2018:80.

Holotype. NMK-L3214/1, adult female, Ol Ari Nyiro Ranch-Laikipia Nature Conservancy at Mukutani Gorge Lodge, Laikipia County, Kenya (00.61500° N, 36.36889° E; 1775 m), collected 31 July 2009 by Victor D. Wasonga, Mike Roberts & J. Benjamin. Note that the largest female was chosen as the holotype because in both male paratypes not enough of the post-pygal tail was present to adequate evaluate the condition of caudal tuberculation.

Paratypes. NMK-L1462/1, L1462/2, adult males Mukutani Gorge in the vicinity of the holotype locality (00.62215° N, 36.372276° E; 1682m), collected 18 April 2012 by Victor D. Wasonga & Justus Ochong; NMK- L3152, adult female, Mukutani Gorge in the vicinity of holotype locality (00.61472° N, 36.36917° E), collected 9 July 2008 by Victor D. Wasonga & Joash O. Nyamache.

Diagnosis. A small-sized Ancylodactylus with a maximum SVL of approximately 35 mm. Dorsal scalation mostly homogeneous with no trunk tubercles, but some variation in granular scale size on the trunk. Limbs and digits long, with enlarged basal lamellae under and proximal to penultimate interphalangeal joint (3 under digit IV). Length of intact original tail unknown. Tail dorsum distal to the pygal portion of the tail atuberculate; median subcaudal scales in a single row of large, but not transversely widened scales. Male precloacal pores in a single continuous row of 7. Dorsal pattern of pale fleurs-de-lis and spots on a dull, yellowish-brown background. Ventral coloration of trunk, limbs and underside of head bright yellow, tail venter yellow to orange; no dark markings on chin, throat or trunk, chin and anterior throat whitish with diffuse dark longitudinal stripes. Whitish with faint darker markings on throat and trunk.

Comparisons with Congeners. Ancylodactylus laikipiensis sp. nov. may be distinguished from A. spinicollis and A. petrodroma in lacking an enlarged preaxial metatarsal scale and from these two species plus A. alantika in having a series of flattened, rectangular lamellae subtending the second and third phalanges of the pedal digits, rather than single enlarged, rounded scale (plaque of Perret 1986) at the penultimate joint of each digit. It is distinguished from A. uzungwae , A. quattuorseriatus , A. dickersonae (but see Spawls et al. 2018), A. petrodroma , A. occidentalis , A. spinicollis , A. alantika , A. kituiensis sp. nov., and A. spawlsi sp. nov. by lacking tubercles on the post-pygal (autotomic) portion of the tail dorsum. It lacks dorsal tubercle rows on the trunk, a feature that differentiates it from all congeners except A. dickersonae (0–6 fide Perret 1986; 0–4 fide Spawls et al. 2018), and A. mathewsensis sp. nov. (0–2). It possesses a lower number of precloacal pores (7) than A. africanus (9–12), A. barbouri (14), A. dilepis (8), A. petrodroma (8–12), A. occidentalis (8–12), A. alantika (11), A. gigas (15–16), A. kenyaensis sp. nov. (8), A. kituiensis sp. nov. (8–13), and A. chyuluensis sp. nov. (8). It may also be distinguished in having an single median series of enlarged, but not transversely widened subcaudals in contrast to A. spinicollis , A. petrodroma , and A. occidentalis (irregular subcaudals), A. elgonensis , A. barbouri , A. uzungwae , A. kenyaensis sp. nov., and A. kituiensis sp. nov. (alternating single and paired scales), and A. dilepis , A. gigas , A. africanus , A. quattuorseriatus , A. dickersonae , and A. koehleri , (single row of median subcaudals, but transversely widened or not uniform throughout). In having yellow on most of the venter it differs from A. barbouri , A. uzungwae , A. quattuorseriatus , A. gigas , A. kenyaensis sp. nov., A. kituiensis sp. nov. and A. chyuluensis sp. nov., and it is the only Kenyan Ancylodactylus in which the entire venter is yellow, including the underside of the head. Among Kenyan congeners A. laikipiensis sp. nov. (35 mm maximum SVL) is significantly smaller than A. kenyaensis sp. nov. (maximum SVL 65 mm) and A. kituiensis sp. nov. (maximum SVL 50 mm), marginally smaller than A. mathewsensis sp. nov. (maximum SVL 40 mm), and larger than A. spawlsi , sp. nov. (maximum SVL 30 mm) and A. chyuluensis sp. nov. (maximum SVL 28 mm).

Description of holotype. Specimen generally in good condition. Body somewhat dorsoventrally flattened, tail cut through third post-pygal segment. Holotype measurements: SVL = 33.2; TAL = N/A (cut); HL = 9.6; HW = 5.9; OD = 1.5; SE = 3.6.

Head elongate (HL/SVL = 0.29), relatively narrow (HW/HL = 0.61), depressed, and distinct from the neck, loreal region flattened, canthus rostralis prominent ( Fig 9A ). Scales on snout and loreal region domed, about twice as large as scales of interorbital region and crown. Eyes small (OD/HL = 0.15), ear opening slit-like; four internasals, 5 infralabials and 5 supralabials. Mental scale triangular, 4 postmentals, left postmental fragmented into two scales, which together match the rightmost postmental in size and shape; central postmental much smaller, hexagonal with anterior indent from apex of mental; 6 post-post mentals, Dorsal pholidosis mostly homogenous, covered by minute granular scales ( Fig 9A, 9B ), scales on anterior trunk and mid-dorsally only about as half the size of the largest granules on the dorsolateral surface of the abdomen. Ventral scales larger than dorsal, smooth, imbricate, larger in precloacal and femoral regions than on chest and belly, smallest in gular region; approximately 15 at midbody. Scales on lateral aspect of neck granular. A weakly developed ventrolateral fold evident. Fore-and hind limbs relatively long, slender, covered by granular to slightly enlarged sub-imbricating scales, the latter chiefly on the preaxial surfaces. All digits moderately long and slender, strongly clawed; penultimate phalanx of all digits curved, arising angularly from distal portion of wider basal toe pad; three wide basal lamellae, the distalmost larger than the more proximal, and 9 narrower distal lamellae under digit IV of pes ( Fig. 9C ). Enlarged basal lamellae on digits of pes: I:1, II:2, III:2, IV:3, V:2.

Tail dorsum smooth with granular scales, depressed and oval in transverse section. Tail of paratype L3152 almost half the body length (TAL/SVL = 0.86); ventral scales larger than dorsal, with a single median scale row slightly enlarged transversely. Tail (cut through third post-pygal segment) slightly depressed, original tail length unknown. Original portion of tail dorsum covered in small, mostly uniform juxtaposed squarish to oval scales ( Fig. 9E ); segmentation of tail obscure. Sacral region with scattered, rounded tubercles about three times the size of adjacent granules. The post-pygal portion of the tail bears no dorsal tubercles ( Fig. 9E ). Subcaudal scales larger than dorsals; enlarged midventral subcaudal scales in a single row, but not especially broadened transversely ( Fig. 9F ).

Coloration (in preservative). Dorsum dark grayish-brown with a series of grayish-beige chevrons or diamondshaped marks along the back, largely confluent forming a pale vertebral stripe of varying width from the occiput to the tail base ( Fig. 9A ). Margins of individual chevrons partly demarcated by scattered dark brown flecks. A series of pale spots along the flanks. Crown of the head grayish-brown with beige around the margins of the parietal table. Small scattered dark brown markings on the crown and irregular transverse markings between the anterior margins of the orbit; more discrete brown lines from orbit to snout and from posteroventral margin of orbit towards the jaw. Limbs light brown with darker transverse mottling or banding; dark bands on all digits. Tail base dorsum slightly lighter than trunk with large beige diamond-shaped markings and a pair of dark brown spots located just posterior to the sacrum. More distal parts of original tail dull yellowish-brown with a series of pale diamond-shaped markings, each flanked anteriorly by a pair of dark brown markings. Pattern of regenerate mottled light and dark brown. Body venter and subcaudal surfaces whitish.

Coloration (in life). Based on photographed holotype (see Fig. 10 ). Base color a dull yellowish-brown with dorsal series of eight overlapping chevrons or fleurs-de-lis ranging from whitish on nape to light brown on sacrum. A more irregularly-shaped whitish marking from occiput on to anterior nape. Lateral surfaces with a series of approximately 15 round spots extending from the posterior part of the head, across the shoulder and down the flanks to the sacrum; largest spots between the limb insertions. A parallel series of smaller, less conspicuous pale spots runs between the fleurs-de-lis and flank spots. Like the fleurs-de-lis, both rows of spots are more whitish anteriorly, becoming a yellowish-brown after the midbody ( Fig. 10A ). Small, dark brown flecks scattered across body, forming 1–2 irregular rows along the lower flanks and also roughly paralleling the pale markings on the dorsum. Markings on head as described above, with pale markings around parietal table whitish and scattered cream-to-beige markings on the snout and interorbital area, and medium brown lines emanating from the orbit. Labial scales alternating cream and brown. Limbs paler and more yellowish than body, with medium to dark brown markings and banding on the digits. Tail dorsum similar to trunk, with large, beige-to-cream diamonds mid-dorsally (all tails broken or regenerated, so number of markings unknown). Pair of very dark brown spots over posterior sacrum. Ventral color of throat, trunk and limbs bright yellow ( Fig. 10B ). Subcaudal coloration yellow at base, becoming more orange distally, a duller yellowish-brown on regenerated portion of tail; scattered yellow-orange single scales extending on to ventrolateral margins of tail. Palms and soles yellow mottled with gray.

Variation. Mensural data for the type series is given in Table 5 . All the paratypes generally resemble the holotype. The paratypes are all in general good condition with some showing the clear dorsal chevron marks. The most extensive tail (regenerated) is 86% of SVL (NMK-L3152). In neither male paratype was enough of the post-pygal tail present to unambiguously confirm the atuberculate condition No clear sexual dimorphism in size and color. Two males have a continuous series of 7 precloacal pores ( Fig 9 , Table 5 ); hemipenial bulge not pronounced, postcloacal spurs tiny .

Etymology. Named for the Laikipia Plateau area, the type locality.

Natural History. This is a diurnal, arboreal gecko found mainly on rock outcrops and rock faces with crevices, as well as on trees. In the mixed forest of Mukutani Gorge it co-occurs with other arboreal tree species including the Mt. Kilimanjaro Forest Lizard Adolfus kibonotensis , which may use the same rock crevices as retreats.

Habitat and Distribution. This a mid-altitude forest species. It is endemic to Laikipia Plateau and is currently known only from the Mukutani Gorge area and Lolldaiga Hills where it is sympatric with Ancylodactylus spawlsi sp. nov.

Figures

FIGURE 9. Preserved specimens of Ancylodactylus laikipiensis sp. nov. A) Dorsal view of holotype, NMK-L3214/1. Scale bar = 10 mm. B) Trunk dorsum of holotype at midbody showing granular scalation. C) Ventral view of right hind foot of holotype. D) Precloacal region of adult male paratype, NMK-L1462/1, showing single series of 7 precloacal pores (arrows mark the lateralmost pores). E) Dorsal view of holotype tail showing atubercular scalation. F) Ventral surface of holotype tail showing single median row of enlarged, athough not particularly wide, subcaudal plates.

FIGURE 10. Freshly dead Ancylodactylus laikipiensis sp. nov. showing A) dorsal and B) ventral coloration of holotype (NMK- L3214/1). Note uniformly yellow ventral surfaces. Mukutan Gorge area. Photos © Domnick Victor Wasonga.