Ancylodactylus spawlsi, 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 : 124-129

Ancylodactylus spawlsi sp. nov.

Spawls’ Pygmy Forest Gecko

( Figures 11–12 )

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

Holotype. NMK-L3470, adult male, Lolldaiga Farm , Lolldaiga Hills Conservancy, Laikipia County, Kenya (00.21300° N, 37.12985° E; 2120 m), collected 30 October 2013 by Stephen Spawls, Patrick K. Malonza & Vincent Muchai.

Paratypes. NMK-L4007/1, adult male, Kirimiri Forest , Embu County, Kenya (00.42740° S, 37.54967° E; 1573 m), collected 23 June 2017 by Arthur M. Gitari; NMK-L3997/1, adult female, and NMK-L3997/2, male, Kirimiri Forest, Embu County, Kenya (00.42715° S, 37.54862° E; 1612 m and 00.42760° S, 37.54748° E; 1563 m, respectively), collected 17 May 2017 by Arthur M. Gitari .

Diagnosis. A an extremely small-sized Ancylodactylus with a maximum SVL of approximately 30 mm. Dorsal scalation mostly homogeneous with a single pair of rows of very small tubercles along the flanks; other scales minute and granular. Limbs and digits long, with enlarged basal lamellae under and proximal to penultimate interphalangeal joint (3 under digit IV). Length of intact original tail slightly longer than SVL. Tail dorsum distal to the pygal portion of the tail bearing tubercles throughout its length; six tubercles per row proximally, decreasing to four and becoming flatter and less conspicuous distally; median subcaudal scales in a single row of large, but not transversely widened scales. Male precloacal pores in a single continuous row of 6. Dorsal pattern of pale fleurs-de-lis and spots on a grayish- to mustard-brown background. Ventral coloration of trunk and limbs, pale to bright yellow, fainter on the undersides of limbs than elsewhere; chin and anterior throat grayish to bright white with faint or bold dark markings, and a yellow wash onto the posterior throat.

Comparisons with Congeners. Ancylodactylus spawlsi 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. africanus , A. elgonensis , A. barbouri , A. koehleri , A. dilepis , A. gigas , A. kenyaensis sp. nov., A. mathewsensis sp. nov., A. laikipiensis sp. nov., and A. chyuluensis sp. nov by bearing rows of tubercles on the post-pygal (autotomic) portion of the tail dorsum. It has only two tubercle rows on the trunk, one on each flank, a feature that differentiates it from all congeners except some A. dickersonae (0–6 rows fide Perret 1986; 0–4 fide Spawls et al. 2018) and A. mathewsensis sp. nov. (0–2 rows), and A. chyuluensis sp. nov. (2 rows). It possesses the lowest number of precloacal pores (6) of any of its congeners, distinguishing it from A. africanus (9–12), A. barbouri (14), A. dilepis (8), A. spinicollis (7–11), 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), A. laikipiensis sp. nov. (7), and A. chyuluensis sp. nov. (8). It may also be distinguished in having 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 differs from A. laikipiensis sp. nov. in having a white throat (versus yellow). Among Kenyan congeners A. spawlsi sp. nov. (30 mm maximum SVL) is rivaled in small size only by A. chyuluensis sp. nov. (maximum SVL 28 mm).

Description of holotype. Specimen in moderate condition. Body dorsoventrally flattened, tail tip clipped ( Fig 11A ). Measurements: SVL = 29.0; TAL = 24.0; HL = 9.2; HW = 5.0; OD = 1.9; SE = 3.7. Head elongate (HL/SVL = 0.32), narrow (HW/HL = 0.54), depressed, and distinct from the neck, loreal region flattened, canthus rostralis rounded. Scales on snout and loreal region domed, only somewhat larger than scales of interorbital region and crown. Eyes moderately small (OD/HL = 0.21), ear opening slit-like; two large internasals, 5 infralabials, 6 supralabials. Mental scale subtriangular; 3 postmentals, the outer pair in contact with the first infralabials and mental, central postmental hexagonal and only marginally smaller than its neighbors; 5 post-post mentals.

Dorsal pholidosis mostly homogenous, body covered by minute granular scales. Very small (~ twice size of granular scales), somewhat elongate tubercles present in a sparse row from the neck to the lower flanks ( Fig. 12A ). Additional scattered tubercles (2–3 times granule size) scattered on lumbar and sacral regions ( Fig. 12C ). Ventral scales much larger than dorsals, smooth, imbricate, slightly larger in precloacal and femoral regions than on chest and belly, smallest in gular region; approximately 14 at midbody. Scales on lateral aspect of neck granular. No distinct ventrolateral folds. 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 much larger than the more proximal, and 9 narrower distal lamellae under digit IV of pes ( Fig. 11C ). Enlarged basal lamellae on digits of pes: I:1, II:2, III:4, IV:3, V:1.

Male precloacal pores in a single continuous row of 6 ( Fig. 11B ). Hemipenial bulge not pronounced, a single pair of small postcloacal spurs ( Fig. 12A ). Tail slightly depressed in cross section and distinctly segmented. Length of tail (with tip removed) 83% of SVL. Scales of tail dorsum granular, bead-like, rounded, larger than trunk granules; bearing enlarged rounded to elongate, somewhat flattened, tubercles. Caudal tubercles in rows at the posterior margins of each segment; six tubercles per row in basal segments, decreasing to four distally and becoming less prominent ( Figs. 11A, 11C, 11E ). Subcaudal scales larger than dorsals; enlarged midventral subcaudal scales in a single row, but not greatly broadened transversely ( Fig. 11D, 11F ).

Coloration (in preservative). Dorsum grayish-brown with a series of light gray blotches or chevrons along the back, partly confluent and elsewhere separated from one another by narrow brown transverse bands ( Fig. 11A ). Dark brown flecks scattered along the flanks. Crown of the head dark grayish-brown, mostly uniform except for a light grayish marking on the occiput. Limbs grayish-brown with darker transverse mottling or banding; dark bands on all digits. Tail dorsum slightly lighter and less grayish than trunk with thin transverse bands largely aligned with the segmental margins ( Figs. 11A, 11D ). Pattern of regenerate mottled light and dark brown. Body venter and subcaudal surfaces whitish.

Coloration (in life). Based on specimens photographed in life (see Fig. 12 ). Base color a dull grayish-brown or mustard-brown, with dorsal series of seven adjacent cream to beige chevrons or fleurs-de-lis from the nape to the sacrum. An additional smaller pale marking (cream to orangish) on the occiput may be connected or not to the more posterior vertebral markings. Anterior margins of pale markings with dark brown anterior borders, expanding laterally to form pairs of blotches lateral to the anterior apices of the fleurs-de-lis ( Figs. 12A–C, 12E ). Lateral surfaces with a series of approximately 10 roundish, cream to pale yellowish spots extending from the neck, across the shoulder and down the flanks to the sacrum; largest spots between the limb insertions. Parallel series of smaller, less conspicuous pale spots run dorsal and ventral to this line of spots and numerous small dark brown flecks are distributed in the interstices between all of the pale flank markings. The head is complexly and variably patterned. A dark brown line passes from the snout, through the eye and there is an irregular dark brown border around the parietal table, enclosing the pale occipital blotch; the two maybe nearly confluent ( Fig. 12A ) or may be disjunct ( Fig. 12E ). A diffuse brown patch or band is present over the anterior edge of the orbit and another is on the snout. Irregular whiteish to cream or beige markings cover other parts of the head. Labial scale markings alternate cream and dark brown and in some specimens there is a dark brown line extending posteroventrally from the corner of the mouth ( Fig. 12A ). Limbs similar in color to body or pale pinkish ( Fig. 12E ), with medium to dark brown markings or discrete bands, and alternating pale yellowish-white and narrower dark brown bands on the digits. Tail dorsum similar to trunk, with large, beige-to-cream fleurs-de-lis or diamonds mid-dorsally; approximately 12 such markings on intact tails ( Fig. 12B ), each with a pair of dark brown markings flanking the central apex. Ventral color of trunk pale ( Fig. 12D ) to bright yellow ( Fig. 12F ). Subcaudal coloration yellow to orange; distally duller under regenerated portion of tail; scattered yellow-orange single scales extending on to ventrolateral margins of tail. Ventral surfaces of limbs less brightly pigmented than trunk or lacking yellow/orange pigment entirely; palms and soles grayish brown. Chin, gular region and anterior region of throat off-white to bright white, with some suffusion of yellow posteriorly ( Fig. 12D ) or continuing anteriorly in the form a scattered pale yellow scales ( Fig. 12F ). Throat with only vague, pale diffuse darker mottling or with discrete and extensive contrasting blackish mottling.

Variation. Mensural data for comparative material is given in Table 6 . Paratypes generally resemble the holotype with tails tapering to a fine tip (TAL 111% SVL in paratype NMK-L3997/1 with intact original tail). The paratypes are all in general good condition with some showing the clear dorsal chevron marks or stripe. No clear sexual dimorphism in size and color. Males have a continuous series of 6 precloacal pores ( Fig 11 , Table 6 ).

Etymology. Named in honor of Stephen Spawls (born 1953), who specifically collected the holotype specimen inside the wooden house (Lolldaiga Farm House) where our collecting party were staying.

Natural History. This is a diurnal, arboreal gecko. In Lolldaiga the holotype specimen was collected resting inside a wooden house. In Kirimiri Forest the majority were collected in degraded forest replanted with exotics, mainly Eucalyptus , Casuarina and Nandi flame ( Spathodea campanulata ). Here they were present on the base of trunks or on loose bark of peeling or dead trees. The single specimen in the Croton megalocarpus- dominated indigenous Kirimiri Forest was on a fallen log. In the Lolldaiga Hills, on other wooden houses and on walls of other farm structures we commonly found Lygodactylus keniensis Parker. We expect the species to be present where retreats are provided by rock crevices or by the loose bark of scattered mature cedar trees ( Juniperus procera ). The lacertid Adolfus kibonotensis also occurs on trees in the area. In Kirimiri Forest and Ngaya Forest—Nyambene Hills the species coexists with the much larger Ancylodactylus kenyaensis sp. nov. In Ngaya Forest—Nyambene Hills the species was common on small tree trunk crevices and cracks. In Kijege Hill—Chiakariga individuals where collected hidden in or basing outside small rock cracks and crevices/slabs. In the Borana Wildlife Conservancy montane forest individuals were also found in the crevices of tree trunks. On either substrate (trees or rocks), individuals are very alert and agile and dash swiftly into their retreats where they wedge tightly, making extraction difficult. A female specimen from Kirimiri Forest was gravid with two eggs clearly visible through the abdomen ( Fig. 12F ) and small trombiculid mites were present, though sparse in front of the shoulder ( Fig. 12A ), on the flank ( Fig. 12E ) and near the axillae and throat ( Fig. 12F ) in three different individuals.

Habitat and Distribution. This appears to be a sporadically distributed highland montane forest species endemic to the highland areas around Mt Kenya. The presence of five isolated populations to the northwest ( Lolldaiga Hills , Laikipia), north ( Borana Wildlife Conservancy , Laikipia Plateau , Laikipia County, 00.27338° N, 37.32976° E; 1952 m), northeast ( Ngaya Forest , Nyambene Hill, Meru County, 00.31622° N, 38.02033°E; 1223 m), east ( Kirimiri Forest , Embu County, Kenya), and southeast (Kijege Hill, Chiakariga, Tharaka-Nithi County, 00.27217° S, 37.93591°E; 1033 m) of Mt. Kenya suggests that it should occur in other similar suitable forest areas in the region. Kijege Hill is a quite isolated dryland rocky hill with only a small patch of montane forest at the Chiakariga community, otherwise the rest of the hill is covered by dry rocky bushland. In montane areas this species appears to adapt to human modified habitats like forest plantations and wooden structures.

Figures

FIGURE 11. Ancylodactylus spawlsi sp. nov. A) Dorsal view of holotype, NMK-L3470. Scale bar = 10 mm. B) Precloacal region of holotype showing series of 6 precloacal pores. C) Ventral view of right hind foot of paratype, NMK-L4007/1. D) Dorsum of tail of holotype illustrating rows of tubercles near the posterior margins of each tail segment.

FIGURE 12. Ancylodactylus spawlsi sp. nov. A) Holotype NMK-L3470 in life. B) Male (NMK-L1237, non-type) on tree in Ngaya Forest. C–D) Dorsum and venter, respectively of male specimen (NMK-L221L/1, non-type) from Kijege Hill. E–F) Dorsum and venter, respectively of female paratype (NMK-L4007/1) from Kirimiri Forest. Photo A © Stephen Spawls, photos B–F © Patrick K. Malonza.