Hemidactylus mrimaensis, Malonza, Patrick K. & Bauer, Aaron M., 2014

Malonza, Patrick K. & Bauer, Aaron M., 2014, A new species of arboreal forest-dwelling gecko (Hemidactylus: Squamata: Gekkonidae) from coastal Kenya, East Africa, Zootaxa 3786 (2), pp. 192-200 : 193-198

Hemidactylus mrimaensis sp. nov.

( Figures 2–4)

Holotype. National Museums of Kenya, Nairobi ( NMK) L3397 (Field Number JN0115) adult female collected on 29 August 2010 in Kaya Mrima Forest (04o29.286’S, 0 39o 15.821’E; 257 m elevation) by Patrick K. Malonza & Joash Nyamache.

Paratypes. NMK-L3233/4 (PK139), L3233/5 (PK140), L3233/2 (PK105), L3233/3 (PK103) females; NMK- L3233/1 (PK101) adult male collected on 24 October 2009, in Kaya Jibana Forest (03o50.624’S, 0 39o 40.155’E; 309 m elevation). NMK-L3240/3 (PK034), L3240/7 (PK064) adult males; NMK-L3240/5 (PK027), L3240/4 (PK031), L3240/2 (PK030), L3240/1 (PK001), L3240/6 (PK066) females collected 17–19 October 2009 at same locality as holotype. All specimens collected by Patrick K. Malonza & Joash Nyamache.

Other material examined. NMK-L3398 (JN0130) female collected by the same collectors on 31 August 2010 in Kaya Kinondo Forest (04o23.576’S, 0 39o 32.810’E; 1 m elevation).

Diagnosis. A small-sized Hemidactylus , with males reaching 42 mm SVL and females 50 mm. Dorsal scalation heterogeneous with enlarged, regularly-arranged, keeled tubercles in 11–14 longitudinal rows ( Fig. 2). Two well developed postmentals, the inner pair larger and in extensive contact behind the triangular mental, which is entire. Infralabials 8–9, supralabials 9–10. Four scansors beneath first toe, eight beneath fourth toe, all but distalmost divided ( Fig. 3 A). Original tail depressed, oval in transverse section, slightly constricted at base, tapering to a fine point; enlarged tubercles on the tail pointed and larger than those on the dorsum ( Fig. 3 B), subcaudal scales with median row of enlarged scutes ( Fig. 3 C).

Hemidactylus mrimaensis sp. nov. may be distinguished from all other Kenyan congeners by a number of species or group specific characters. It may be differentiated from most of the terrestrial species by its long and tapering tail and gracile body, as opposed to a thick, short tail and relatively stout body. Unlike Hemidactylus mrimaensis sp. nov., H. modestus , H. isolepis and H. funaiolli have homogenous dorsal scales. H. squamulatus , H. barbouri and H. tropidolepis do not have enlarged tubercles and their small heterogeneous dorsal scales are not arranged in regular rows. Among the arboreal species, H. angulatus , H. macropholis and H. ruspolii have enlarged tubercles that are strongly keeled on the back and tail. In addition, H. macropholis is fairly large (80 mm maximum SVL versus 50 mm), whereas H. angulatus in addition has a thick tail, and in H. ruspolii the original tail exhibits a striking basal constriction. Hemidactylus mrimaensis sp. nov. may be distinguished from its sympatric and phenetically similar congener H. platycephalus , by its smaller size (max SVL 50 mm versus 94 mm), slender body and distinctive brown-golden coloration, as well as the lower number of male precloacal-femoral pores (34 versus 45–57). The new species is most similar to another large (SVL up to 70 mm) sympatric species, H. mabouia . The dorsal part of the thighs and arms of Hemidactylus mrimaensis sp. nov. have enlarged scattered tubercles in contrast to the those of H. mabouia which are smooth. In addition, the digits (of both manus and pes) of H. mabouia are stout, whereas those of H. mrimaensis sp. nov. are relatively slender. It is also noteworthy that the body and tail tubercles of the latter species are more prominent, with the caudal tubercles particularly large and spiny in comparison to H. mabouia . In general habitus, Hemidactylus mrimaensis sp. nov. is similar to forest geckos in the genus Cnemaspis Strauch , although, of course, it differs in all aspects of pholidosis and digital structure from these geckos.

Description of Holotype. Specimen condition generally good, but with skin torn on occipital region and part of left thigh. Body dorsoventrally flattened. Tail slightly bent, tail tip is missing (stored for future phylogenetic analysis in the personal collection of PKM).

Holotype measurements: SVL = 45.0; TAL = 49.0 (excluding the clipped tip); TRL = 21.7; BW = 10.8; CL = 7.6; HL = 14.4; HW = 8.6; OD = 3.7; NE = 4.8; SE = 6.2; EE = 4.2.

Head elongate (HL/SVL = 0.32), moderately wide (HW/HL = 0.60), depressed, and distinct from the neck, loreal region flattened, canthus rostralis prominent. Scales on snout and loreal region much larger than scales of interorbital region and crown. Eyes small (OD/HL = 0.25), ear opening slit-like. Rostral incompletely divided dorsally; two larger internasals separated in the midline by a longitudinal series of two smaller granular scales, one postnasal, one enlarged supranasal each smaller than an internasal. Nostril surrounded by internasal, supranasal, one post nasal, rostral first suplabial. Nine infralabials and 10 supralabials to corner of mouth, 9 supralabials to mid-point of eye. Mental scale triangular; two pairs of postmentals, inner pair longer and in extensive contact behind the mental, outer pair approximately half the size of and immediately posterior to the inner pair, widely separated from one another. Inner postmental bordered by mental, outer postmental, first and second infralabials, and a series of four smooth, imbricate gular scales; outer postmental bordered by the inner postmental and completely separated from the second and third infralabials by small subimbricate gular scales and by the first in a row of enlarged lateral scales medial to the infralabials. Posteriorly, each outer postmental bordered by five smooth gular scales.

Body moderately elongate (TRL/SVL = 0.48). Dorsal pholidosis heterogeneous; enlarged tubercles, approximately 10 times size of adjacent granular scales, in 14 rows ( Fig. 2). Tubercles broad, triangular, with a central keel and a series of radiating secondary keels; tubercles near tail base more strongly keeled and larger than those on middorsum, tubercles on nape and shoulder smaller, those on occipital and temporal regions smallest. Tubercles becoming irregular towards sacral region. Ventral scales larger than dorsal, smooth, imbricate, slightly larger on precloacal and femoral regions than on chest and belly. Midbody scale rows across belly 20–24 counted from the transition of dorsal granular scales to smooth ventral scales; no distinct ventrolateral folds. Gular region with sub-imbricate scales smaller than those on chest, those on lateral aspect of neck granular. Scales on the palm and sole smooth, imbricate, rounded; irregular enlarged tubercles on dorsal aspect of both hind and fore limbs smaller than those on the dorsum. Fore-and hind limbs relatively long, slender; fore arm short; tibia short (CL/SVL = 0.17); all digits moderately short, strongly clawed; terminal phalanx of all digits curved, arising angularly from distal portion of expanded toe pad; scansors divided across widest part of digits, with a single small undivided scansor distally and 1–3 enlarged undivided scales proximal to basalmost divided scansor. Four lamellae under digit I and eight beneath digit IV of both manus and pes, including terminal undivided scansor ( Fig. 3 A). Precloacal-femoral pores extending well onto thigh, in a series of 17 pores on each side separated by a single poreless scale in the ventral midline. Tail with enlarged tubercles ( Fig. 3 B), depressed and oval in transverse section and slightly longer than body length, excluding the clipped tip (TL/SVL = 1.09); dorsum of each tail whorl with a series of four enlarged, strongly keeled and posteriorly-pointed tubercles, much more acuminate than those of body dorsum. Ventral scales larger than dorsal, with a single median scale row enlarged transversely ( Fig. 3 C).

Coloration (in preservative). Dorsum grayish-brown. Dorsolateral tubercles mostly light brown. Crown of the head brown with some light marks; infralabials and supralabials pale with dark stippling; limbs brown with slightly darker transverse mottling or bands. Tail gray-brown with obscure dark bands. The body venter is creamwhite with dark stippling including the thighs; palms and soles light brown to cream. Tail venter light brown with dark stippling, forming longitudinal stripes under the proximal portion of the tail.

Coloration (in life). In life dorsal color quite variable but mainly shades of light grayish-brown, with dull brownish-golden patches and 6–7 more-or-less transversely-oriented darker marks ( Fig. 4 ). Upper parts of the limbs with similar dark bands. Iris golden with a dark vertical pupil. Tail with 9–10 transverse dark marks (bands) with some whitish borders up to the tip. Head light brown with some darker and paler scattered markings; a dark band from the nostril through the eye onto the lateral side of the head. This is sometimes affected by the substrate on which the gecko is resting; individuals found in sheltered places were dull colored whereas those exposed to some light were paler. Venter whitish, with some adult specimens having the underside of the tail orange.

Variation. Mensural data for the type series and additional material is given in Table 1 . All the paratypes generally resemble the holotype. The paratypes are all in general good condition with some showing clear dorsal dark marks. Venter in some with dark spots. Some specimens have twisted bodies and a few (NMK-L3240/7, L3240/4, L3233/2) have part of the tail missing. All have their mouths closed. Range of supralabials (9–10) and infralabials (8–9). The scales across the belly range from 21 to 25. The enlarged dorsal tubercle rows vary from 11– 14 in both males and females. There is sexual dimorphism in size. Females are larger in body length and girth than males (maximum SVL 50 versus 42 mm), but there is no well-marked sexual dichromatism. Males have a continuous series of 32–34 precloacal pores (L3240/3 — 17/17; L3240/7 and L3233/1 — 16/16).

Etymology. The specific epithet mrimaensis is derived from the Kaya Mrima forest where the first specimen of the new gecko was collected. The common English name, Kaya Gecko is given to reflect the current restricted distribution in coastal kaya forests.

Natural history. This appears to be a cathemeral species. It seems to be active diurnally, but is likely also active at night. This is in strong contrast to most of its congeners, which are predominantly nocturnal. During the day this species can be found on tree trunks or stumps and mainly preferring to perch on stems of small diameter, a short distance from the ground. The species is quite agile and hard to capture. In Kaya Mrima individuals where found occupying the same trunk side by side with other geckos such as the tropical house gecko, H. mabouia , yellow-headed dwarf gecko Lygodactylus picturatus (Peters) and white-headed dwarf gecko, L. mombasicus Loveridge. No interspecific confrontations were observed and individuals of each species maintained some distance from each other.

Habitat, distribution and conservation status. The new species is currently known only from the three kaya forests along the Kenya coast which are remnants of the once continuous moist East African costal forest. We expect the species to be present in other remnant kaya forests or coastal forests including the larger Shimba Hills National Reserve, Gongoni, Buda, Dzombo and Marenji on the south coast and Arabuko-Sokoke forest, Witu forest and Boni-Dondori forest on the north coast of Mombasa. However, this is yet to be established. They appear to be restricted to indigenous forest fragments and absent from human habitation or highly disturbed areas away from indigenous forest patches. Wherever they are found they occur in very low abundance; at the type locality only eight individuals versus 29 specimens of H. mabouia were located in 16 person hours of searching and at Kaya Jibana 13 H. mrimaensis were found compared to 27 H. mabouia in 13 person hours of search effort. Unlike other sympatric gecko species, no individuals were found in isolated trees within human homesteads, except on the forest edge. Using the IUCN criteria the species can be categorized as Endangered (B1a, b (ii, iii)) given that its extent of occurrence, area of occupancy, and habitat quality are declining. Most of the kaya forests are degrading continuously due to the erosion of customary laws ( FitzGibbon 1994). However, at the same time efforts are being made to educate the people to conserve them for ecotourism and other sustainable use initiatives.

Figures

FIGURE 3. Holotype (NMK-L 3397) of Hemidactylus mrimaensis sp. nov.: (A) ventral view of right pes, (B) tail dorsum and (C) tail venter.

FIGURE 4. Female paratype NMK-L 3240 / 1 of Hemidactylus mrimaensis sp. nov. in life in Kaya Mrima Forest.

Tables

TABLE 1. Measurements and morphological characters analysis of Hemidactylus mrimaensis sp. nov. separately for males and females. Measurements (in mm) given as mean (in bold) ± standard deviation, minimum-maximum. Ranges only presented for meristic characters. Values based on entire type series as well as one additional specimen examined (n = 3 males, 11 females) unless otherwise indicated.

Character	Males	Females
SVL TAL TRL	41.1 ± 0.88, 40.1–41.8 46.8 ± 4.84, 43.4–50.2 (n = 2) 16.8 ± 3.17, 13.3–19.6	42.9 ± 4.55, 35.6–49.6 49.3 ± 6.79, 39.7–59.8 (n = 7) 20.9 ± 3.58, 15.9–29.3
BW	8.5 ± 0.46, 8.0–9.0	10.3 ± 0.92, 8.3–11.2
HL	13.7 ± 0.57, 13.1–14.3	14.0 ± 0.98, 12.3–15.8
HW	7.9 ± 0.20, 7.8–8.2	8.2 ± 0.47, 7.1–8.8
OD	3.5 ± 0.51, 3.0–4.0	3.4 ± 0.42, 2.5–3.8
NE	3.9 ± 0.22, 3.8–4.2	4.3 ± 0.46, 3.5–5.0
SE	6.1 ± 0.44, 5.6–6.5	6.2 ± 0.54, 5.4–7.1
EE	3.8 ± 0.07, 3.8–3.9	3.9 ± 0.33, 3.4–4.4
Dorsal tubercle rows	12–14	11–14
Infralabials	8	8–9
Supralabials	9–10	9–10
Internasals	2	2
Precloacal-femoral pores	32–34	—