Hemidactylus tamhiniensis, Thackeray & Agarwal, 2021

Thackeray, Akshay Khandekar Tejas & Agarwal, Ishan, 2021, A cryptic new species of rupicolous Hemidactylus Goldfuss, 1820 (Squamata: Gekkonidae) allied to H. aaronbaueri Giri, 2008 from the northern Western Ghats of Maharashtra, India, Zootaxa 5020 (3), pp. 434-456 : 437-445

Hemidactylus tamhiniensis sp. nov.

( Figures 2–4 , 5A–F , 6A , 7A , 8A ; Table 3)

Hemidactylus aaronbaueri Lajmi et al. (2020)

Holotype. NRC-AA-1131(AK 1285; Figures2 , 3 , 4A , 5A , 6A , 7A , 8A ),adult male,from Tamhini Ghat(18.398402°N, 73.385258°E; ca. 390 m asl.), Raigad district , Maharashtra state, India, collected by Akshay Khandekar, Satpal Gangalmale and Swapnil Pawar on 16 June 2019.

Paratypes. NRC-AA-1132 (AK 1286; Figures 4B , 5B ), NRC-AA-1133 (AK 1287; Figure 5C ), BNHS 2805 (AK 1288; Figure 5D ), adult females, same data as holotype ; BNHS 2806 (AK 1289; Figure 5E ), adult female ,

BNHS 2807 (AK 1290; Figure 4C , 5F ), sub-adult female, same collection data as holotype except collected from Tamhini Ghat (18.472910°N, 73.420590°E; ca. 680 m asl.), Pune district , Maharashtra state, India .

Etymology. The specific epithet is a toponym for Tamhini Ghat in Pune and Raigad Districts of Maharashtra, the type and currently only known locality for this species.

Suggested Common Name. Tamhini giant rock gecko or Basalt giant rock gecko.

Diagnosis. A large-sized Hemidactylus , maximum SVL 126 mm (n =6). A single enlarged internasal scale between two supranasal scales; dorsal pholidosis at mid-body heterogenous, composed of small, subcircular, smooth and flattened granular scales intermixed with fairly regularly arranged rows of enlarged, subcircular, weakly to strongly keeled and pointed tubercles; 17–21 dorsal tubercle rows at mid-body; 29–32 tubercles in paravertebral rows; ventrolateral folds distinct; 54–59 transverse ventral scale rows at mid-body; digits with transversely enlarged scansors, lamellae in straight transverse series; 8–10 undivided basal lamellae beneath first finger and 6–8 beneath first toe; 2–4 undivided basal lamellae beneath fourth finger and 4–6 beneath fourth toe; 12–14 lamellae (including undivided and divided) beneath first finger and 10–12 beneath first toe; 12 or 13 lamellae (including undivided and divided) beneath fourth finger and 13–15 beneath fourth toe; male with series of 18 (on right side) and 17 (on left side) femoral pores separated medially by seven poreless scales (n =1); tail with 4–12 enlarged, keeled, conical tubercles forming whorls; median row of subcaudal plates large, covering almost entire underside of tail. Dorsal colouration brown with five transversely arranged dark wavy markings outlined by black and light grey running from the occiput to the sacrum, numerous off-white blotches on side of throat, flanks, back of femur and lateral edge of tail.

Comparison with members of the prashadi group. Hemidactylus tamhiniensis sp. nov. can be easily distinguished from members of the prashadi group based on the following differing or non-overlapping characters: male with 17 or 18 FP and seven SBFP (versus 19–21 FP and 13 or 14 SBFP in H. acanthopholis Mirza & Sanap ; 15–19 FP and 2–4 SBFP in H. depressus ; 23–28 FP and 1–3 SBFP in H. graniticolus Agarwal, Giri & Bauer ; 22–24 FP and 3–6 SBFP in H. hunae Deraniyagala ; 18–21 FP and four SBFP in H. kangerensis Mirza, Bhosale & Patil ; 21–25 FP and two or three SBFP in H. kolliensis Agarwal, Bauer, Giri & Khandekar ; 10–12 FP and 16–18 SBFP in

H. paaragowli Srikanthan, Swamy, Mohan & Pal ; 17–20 FP and 1–3 SBFP in H. pieresii ; 17–20 FP and three SBFP in H. prashadi ; 11–15 FP and three SBFP in H. sahgali ; 16–18 FP and 13–15 SBFP in H. sirumalaiensis Khandekar, Thackeray, Pawar & Agarwal ; 17 or 18 FP and five SBFP in H. siva Srinivasulu, Srinivasulu & Kumar ; 20–23 FP and 3–6 SBFP in H. sushilduttai Giri, Bauer, Mohapatra, Srinivasulu & Agarwal ; 7–9 FP and 1–3 SBFP in H. triedrus ; 17–22 FP and 10 or 11 SBFP in H. vanam Chaitanya, Lajmi & Giri ; seven or eight FP and three SBFP in H. whitakeri Mirza, Gowande, Patil, Ambekar & Patel ; FP absent, only precloacal pores present in H. scabriceps ); 54–59 MVSR (versus 35–40 in H. acanthopholis ; 28–36 MVSR H. depressus ; 40–46 MVSR in H. graniticolus ; 28–30 MVSR in H. kangerensis ; 32–34 MVSR in H. kolliensis ; 28–34 MVSR in H. maculatus ; 33–39 MVSR in H. paaragowli ; 36–38 MVSR in H. prashadi ;>30 MVSR in H. sahgali ; 36–38 MVSR in sirumalaiensis ; 27–30 MVSR in H. siva ; 30–33 MVSR in H. sushilduttai ; 30–32 MVSR in H. triedrus ; 34–40 MVSR in H. vanam ; 28–30 MVSR in H. whitakeri ); maximum SVL up to 126 mm (n =6) (versus SVL up to 108 mm in H. acanthopholis ; SVL up to 76 mm in H. depressus ; SVL up to 111 mm in H. graniticolus ; SVL up to 95 mm in H. kangerensis ; SVL up to 80 mm in H. kolliensis and H. pieresii ; SVL up to 78 mm in H. sahgali ; SVL up to 48 mm in H. scabriceps ; SVL up to 95 mm in H. sirumalaiensis ; SVL up to 105 mm in H. siva and H. sushilduttai ; SVL up to 76 mm in H. triedrus ; SVL up to 112 mm in H. vanam ; SVL up to 60 mm in H. whitakeri ).

Hemidactylus tamhiniensis sp. nov. closely resembles H. aaronbaueri and H. cf. aaronbaueri however, it can be easily distinguished from both on the basis of the following differing or non-overlapping characters: a single enlarged internasal scale separating supranasal scales behind rostral (n =6) (versus two small internasal scales separating supranasal scales behind rostral (n =4) or internasals in contact (n =2) in H. aaronbaueri and 2–4 small internasal scales between supranasal scales behind rostral in H. cf. aaronbaueri (n =11); Figure 5 ); dorsal pholidosis at mid-body heterogenous, composed of small, subcircular, smooth and flattened granular scales intermixed with fairly regularly arranged rows of enlarged, subcircular, weakly to strongly keeled, pointed tubercles (versus dorsal pholidosis at mid-body heterogenous,composed of small, subcircular, smooth and flattened granular scales intermixed with fairly regularly arranged rows of enlarged, subcircular, smooth to very weakly keeled, flattened tubercles in H. aaronbaueri ; Figure 6 ); 8–10 undivided lamellae under first finger (versus six or seven undivided lamellae under first finger in H. aaronbaueri and five or six undivided lamellae under first finger in H. cf. aaronbaueri ; Figure 6 ); dark dorsal bands with light centre, numerous white blotches on side of neck and flanks (versus dark dorsal bands with similar coloured centre, few white spots on lateral aspects of body in H. aaronbaueri ; Figure 4,7).

Description of holotype. The holotype is in good condition except fourth terminal phalanx of finger on right side missing, a 4.7 mm long incision in abdomen region for tissue collection and right hemipenis partially everted ( Figure 2 ). Adult male, SVL 122.9 mm. Head short (HL/SVL 0.25), moderately elongate (HW/HL 0.75), not strongly depressed (HH/HL 0.45), distinct from neck. Loreal region inflated, canthus rostralis indistinct ( Figure 3A, C ). Snout short (SE/HL 0.43); slightly longer than twice eye diameter (ED/SE 0.46); scales on snout, canthus rostralis, forehead, and inter-orbital region heterogeneous, mostly granular and conical; scales on the snout and loreal region much larger than those on occiput, forehead and inter-orbital regions; granular scales on occiput and forehead region intermixed with enlarged, smooth and conical tubercles ( Figure 3A ). Eye small (ED/HL 0.20); pupil vertical with crenulated margins; supraciliaries small, mucronate, gradually increasing in size towards front of the orbit ( Figure 3C ). Ear opening oval (greatest diameter 2.6 mm); eye to ear distance slightly greater than diameter of eye (EE/ED 1.44). Rostral slightly wider than high (RH/RW 0.58), divided dorsally by a weakly developed rostral groove for about half of its length; two enlarged supranasals, separated from each other by a single, slightly smaller internasal; postnasal absent on either side; rostral in contact with nostril, first supralabial, supranasals and internasal; nostrils small (1.3 mm), oval; surrounded by supranasals, rostral, first supralabial and four much smaller scales posteriorly on either side; two or three rows of scales separate orbit from supralabials on each side. Mental subtriangular; two pairs of well-developed postmentals, both roughly rectangular; the inner pair shorter (3.2 mm) than the mental (5 mm), and in strong contact with each other (0.9 mm) below mental, outer about half the size (1.7 mm) of inner pair and separated from each other largely by inner pair and six chin scales behind inner pair ( Figure 3B ). Inner postmentals bordered by mental, first infralabial, outer postmental and three smaller chin scales on either side; outer postmentals bordered by inner postmental, first and second infralabial, and four enlarged chin scales; two rows of enlarged, slightly elongate scales below second to fourth infralabials, inner row bordering infralabial with scales slightly larger and elongate than lower row; rest of the gular region with small, subcircular, smooth, weakly conical, granular scales, becoming slightly larger and imbricate on lateral aspect on either side ( Figure 3B ). 13 (left) and 12 (right) supralabials up to angle of jaw and 10 at mid-orbital position on either side; 10 infralabials up to angle of jaw and seven at mid-orbital position on both sides ( Figure 3C ).

Body relatively stout (BW/SVL 0.23), trunk relatively short (TRL/SVL 0.41), with weak ventrolateral fold on either side ( Figure 2A, B ). Dorsal pholidosis at mid-body heterogenous, composed of small, subcircular, smooth and flattened granular scales intermixed with fairly regularly arranged rows of enlarged, subcircular, weakly to strongly keeled and pointed tubercles in 19 longitudinal rows that are heterogeneous in shape and size, extending from occiput to tail; enlarged tubercles on the two most medial parasagittal rows smaller than rest on mid-body dorsum and the rows most broadly spaced from one another, gradually increasing in size, becoming conical and weakly keeled towards flanks, largest on mid-lateral position; last two rows on ventrolateral flanks marginally larger or equal to medial parasagittal rows, weakly keeled and blunt ( Figure 6A ); each enlarged tubercle surrounded by a rosette of 9–12 small granules with 3–6 granules between two longitudinally adjacent enlarged tubercles (5–8 between parasagittal rows at mid-body); enlarged tubercles on nape and shoulder smaller and conical, those on occiput and temporal region still smaller and conical ( Figure 2A ). Ventral scales much larger than dorsal body granular scales, smooth, imbricate, subequal from pectoral region to cloaca; 55 transverse ventral scales across belly at mid-body ( Figure 2B ). Three subequal, smooth postcloacal spurs on each side, smaller than dorsal tubercles at mid-body; slightly increasing in size from anterior to posterior. A series of 18 (on left side) and 17 (on right side) femoral pores on the lower most enlarged row of femoral scales, separated medially by a diastema of seven poreless scales ( Figure 3D ).

Scales on palm and sole larger than the dorsal body granules, subcircular, smooth and flattened; those on dorsal aspect of upper and lower arm heterogenous, composed of granular scales (larger than dorsal body granules) intermixed with enlarged tubercles that are similar to outermost rows of enlarged tubercles on dorsum in shape and size, smooth and weakly pointed; those near forearm insertion much smaller than dorsal body granules, smooth and elongate; scales on dorsal aspect of palm and wrist smooth, flattened and subimbricate; scales on ventral aspect of upper arm granular, much smaller than dorsal body granules, smooth and weakly conical; scales on ventral aspect of lower arm much smaller than ventral body scales, smooth, flattened and subimbricate ( Figure 2A, B ). Scales on dorsal aspect of thigh and shank heterogenous, consisting of granular scales intermixed with enlarged, weakly keeled and weakly pointed tubercles except those on knee flat, imbricate; scales near limb insertions granular, slightly smaller than dorsal body granules; scales on dorsal aspect of sole small, smooth, flattened and subimbricate; scales on ventral aspect of thigh subequal, smooth and imbricate ( Figure 2A, B ). Fore and hind limbs relatively short, stout; forearm short (FL/SVL 0.13); tibia short (CL/SVL 0.16); digits moderately short, strongly clawed; all digits of manus and digits I–IV of pes indistinctly webbed; terminal phalanx of all digits curved, arising angularly from distal portion of expanded lamellar pad, half or more than half as long as associated lamellar pad; scansors beneath each digit in a straight transverse series (the number of undivided basal lamellae in parentheses): 13(8)- 12(2)-12(2)-13(2)-13(3) (left manus), 13(8)-12(2)-12(2)-12(2)-13(3) (right manus; Figure 3E ); 11(6)-13(3)-13(2)- 14(5)-13(2) (left pes), 12(8)-13(3)-13(2)-15(5)-14(3) (right pes; Figure 3F ). Relative length of digits (measurements in mm in parentheses): IV (7.2*) <I (9.0) <II (10.2) = III (10.2) <V (10.9) (right manus); I (8.9) <II (12.2) ~ III (12.3) = V (12.3) <IV (12.7) (right pes).

Tail original except 41.3 mm which is regenerated, depressed, flat beneath, verticillate, with well-defined median furrow; tail slightly shorter than snout-vent length (TL/SVL 0.89) ( Figure 2A, B ). Dorsal scales at tail base granular, similar in size and shape to those on mid-body dorsum, gradually becoming larger, pointed and subimbricate posteriorly, intermixed with series of 4–12 much enlarged, keeled, conical tubercles forming whorls; tubercles in ventrolateral aspect weakly keeled to smooth; 12 enlarged tubercles in first two segment and 10 in third and fourth segments, eight in fifth and sixth segments; rest with four or five enlarged tubercles, lacking tubercles in ventrolateral furrow on either side. Ventral scales at tail base subequal, smooth, imbricate, slightly larger than midbody ventral scales; rest of tail with large plate-like subcaudal scales (median row) covering almost entire portion of the tail, first two subcaudal scales divided, rest entire, roughly rectangular; median row bordered laterally by one or two rows of large, smooth, imbricate scales ( Figure 2B ).

Colouration in life. ( Figure 4A , 7A , 8A ) Dorsal ground colour of head, body, limbs and tail grey-brown; numerous white blotches along side of neck, flanks, back of femur and lateral edge of tail. A fine, light preorbital streak runs from anterior of eye to nostril and continues as a thicker postorbital streak till above tympanum. Labials off-white with some indistinct darker bands/ spots. Head with irregular black markings and white blotches. Dorsal pattern of five dark transverse markings each roughly formed by the fusion of three diamonds, single band on nape, three on back and one on tail base; bands dark black on the edges, outlined by light grey and with numerous fine yellow/ brown spots toward the centre. Original portion of tail with four light and four dark bands, regenerated portion purplish-grey. Dorsum of limbs and digits with irregular black and light grey bands and numerous light grey spots. Ventral surfaces dirty white with faint pale saffron-yellow speckles, most prominent and mixed with dark markings on underside of tail; gular region with dark markings; palm and sole grey. Iris bronze.

Variation and additional information from type series. Mensural and meristic data for the type series is given in Table 3. There is a single sub-adult and four adult female specimens, SVL ranging from 78.5–126.0 mm. All specimens resemble the holotype male (NRC-AA-1131) except for the following variations: chin scales bordering inner postmental (seven in NRC-AA-1133 and BNHS 2805 ; five in BNHS 2806 and BNHS 2807 ); chin scales bordering outer postmental on each side (five on left and three on right in NRC-AA-1132; five on left and four on right in NRC-AA-1133; five on each side in BNHS 2805 and BNHS 2807 ; four on left and five on right in BNHS 2806 ); and there is no variation in the contact of postmentals with infralabials between holotype and paratypes. NRC-AA-1133 has an original and complete tail, marginally longer than body (TL/ SVL 1.08 ) and with 10 alternating light and dark bands; three paratypes —NRC-AA-1132, BNHS 2805 and BNHS 2807 with original and complete but partially regenerated tail, marginally longer or equal to body (TL/ SVL 1.14 , 1.00 and 1.01 respectively); BNHS 2806 with an entirely regenerated but complete tail, marginally shorter than body (TL/ SVL 0.95). Postcloacal spur number and relative size. All paratypes closely agree with the holotype in colouration except for sub-adult female specimen BNHS 2807 which has fewer or less prominent white spots on lateral sides of the head and ventrolateral sides of the body ( Figure 4C ); and the colouration of the regenerated tail in life is light to dark grey-brown, sometimes with irregular yellowish dorsal blotches ( Figure 4 ) .

Distribution and Natural history. Hemidactylus tamhiniensis sp. nov. is so far known only from the type locality and close by (Tamhini Ghat in Pune and Raigad districts of Maharashtra) at elevations of ~ 390–680 m asl. ( Figure 1 ). The type series were collected a few hours after sunset (1830–2030hrs) from a large basaltic rock cliff and a concrete culvert near the road-side in Tamhini Ghat ( Figure 9A, B ). The species was observed in a stretch of ~ 10 km aerial distance along the ghat section (only on rocks or culverts) between Plus Valley viewpoint (Pune district) to Seri viewpoint (Raigad district). At the collection site, we spotted 10–12 individuals in total on the rock cliff between 3–10 m height, and four individuals on either side of the concrete culvert below 3 m height. Individuals were observed to be sluggish and made no effort to escape when approached or even during catching. Sympatric lizards encountered at the locality include Hemidactylus frenatus Duméril & Bibron , Hemidactylus parvimaculatus Deraniyagala , Hemidactylus murrayi Gleadow , Hemidactylus maculatus , Cnemaspis mahabali Sayyed, Pyron & Dileepkumar , Eutropis macularia (Blyth) , and Calotes versicolor (Daudin) .

Figures

FIGURE 1. Left panel: elevation map showing sampling locations of Hemidactylus tamhiniensis sp. nov. (1, solid star = type locality, Tamhini Ghat); 2, star with grey fill = Plus Valley), H. aaronbaueri (4, solid circle = type locality, Ghatgar; circles with grey fill: 3 = Peth Fort, 5 = Naneghat), and H. cf. aaronbaueri (6, circle with white fill = Malshej Ghat); right panel: ND2 maximum likelihood phylogeny of the prashadi group with sampled localities indicated by symbols and numbers. Numbers at nodes indicate bootstrap support in %; value <80 and outgroups not shown.

FIGURE 2. Hemidactylus tamhiniensis sp. nov. (holotype, NRC-AA-1131): (A) dorsal view of body, and (B) ventral view of body. Scale bars 10 mm; photos by Akshay Khandekar & Satpal Gangalmale.

FIGURE 3. Hemidactylus tamhiniensis sp. nov. (holotype, NRC-AA-1131): (A) dorsal view of head, (B) ventral view of head, (C) lateral view of head, (D) view of femoral region showing femoral pores, (E) ventral view of right manus, and (F) ventral view of right pes. Scale bars 10 mm; photos by Akshay Khandekar & Satpal Gangalmale.

FIGURE 4. Hemidactylus tamhiniensis sp. nov. in life: (A) male, holotype, NRC-AA-1131; (B) female, paratype, NRC-AA- 1132; and (C) female (sub-adult) paratype, BNHS 2807. Photos by Akshay Khandekar.

FIGURE 5. Photos of head dorsal showing number of internasal scales between supranasals. Hemidactylus tamhiniensis sp. nov. (A–F): (A) holotype NRC-AA-1131, (B) NRC-AA-1132, (C) NRC-AA-1133, (D) BNHS 2805, (E) BNHS 2806, (F) BNHS 2807; H. aaronbaueri (G–L): (G) BNHS 1739, (H) NRC-AA-1134, (I) NRC-AA-1135, (J) NRC-AA-1136, (K) NRC- AA-1137, (L) NRC-AA-1138; H. cf. aaronbaueri (M–O): (M) NRC-AA-1153, (N) NRC-AA-1158, (O) NRC-AA-1148. Scale bar 10 mm; photos by Akshay Khandekar and Satpal Gangalmale.

FIGURE 6. Detailed dorsal pholidosis at mid-body: (A) Hemidactylus tamhiniensis sp. nov. (holotype, NRC-AA-1131; photo by Akshay Khandekar & Satpal Gangalmale), and (B) Hemidactylus aaronbaueri (holotype, BNHS 1739; photo by Varad Giri). Scale bars 10 mm.

FIGURE 7. Dorsal colouration in life of (A) Hemidactylus tamhiniensis sp. nov. (holotype, NRC-AA-1131; Photo by Akshay Khandekar), and (B) topotypic Hemidactylus aaronbaueri (uncollected individual; Photo by A. Captain & Sanjay Thakur).

FIGURE 8. Colouration in life on dorsolateral side of head: (A) Hemidactylus tamhiniensis sp. nov. (holotype, NRC-AA- 1131), and (B) topotypic Hemidactylus aaronbaueri (uncollected individual). Photos by Akshay Khandekar.

FIGURE 9. Habitat photos of Hemidactylus tamhiniensis sp. nov. at the type locality (Tamhini Ghat, Raigad, Maharashtra): (A) basaltic rocky cliff, and (B) concrete culvert under the road from where the type series were obtained. Photos by Akshay Khandekar.