Cyrtodactylus siahaensis, Purkayastha & Lalremsanga & Litho & Rathee & Bohra & Mathipi & Biakzuala & Muansanga, 2022

Purkayastha, Jayaditya, Lalremsanga, Hmar Tlawmte, Litho, Beirathie, Rathee, Yashpal Singh, Bohra, Sanath Chandra, Mathipi, Vabeiryureilai, Biakzuala, Lal & Muansanga, Lal, 2022, Two new Cyrtodactylus (Squamata, Gekkonidae) from Northeast India, European Journal of Taxonomy 794, pp. 111-139 : 127-132

Cyrtodactylus siahaensis sp. nov.

urn:lsid:zoobank.org:act:CC5D593B-6611-4C72-BEAB-144F8595D61C

Figs 3D–I , 5B , 8 , 9 ; Tables 1–3

Diagnosis

Cyrtodactylus siahaensis sp. nov. is a moderate-sized gecko (adult SVL 42.6–63.9 mm); 9–11 supralabials; 9–11 infralabials; dorsal tubercles are rounded, bluntly conical and feebly keeled in 22–24 longitudinal

rows; 36–39 paravertebral tubercles between the level of the axilla and the level of the groin; 34–37 mid-ventral scale rows; 7 precloacal pores in males; 15–18 subdigital lamellae under IV toe; no single row of transversely enlarged subcaudal scales; dorsal markings are dark brown, irregular blotches; tail with alternating dark and light bands.

Differential diagnosis

Genetically, Cyrtodactylus siahaensis sp. nov. is a sister to C. bengkhuaiai differing from each other by an uncorrected p-distance of 8.33% as in Fig. 2 and Table 2 . Morphological and meristic measurements are as shown in Table 3 . Cyrtodactylus siahaensis sp. nov. has been compared morphologically with all known members of the genus Cyrtodactylus within the khasiensis group. Morphologically, Cyrtodactylus siahaensis sp. nov. can be differentiated from C. exercitus sp. nov. by having a larger maximum adult size, 72.0 mm max. (vs 68.0 mm max. in Cyrtodactylus exercitus sp. nov.), seven precloacal pores in a continuous series vs 11–15 precloacal pores in C. exercitus and 36–39 paravertebral tubercles between the level of axilla and groin vs 32–34 tubercles in C. exercitus .

Cyrtodactylus siahaensis sp. nov. differs from other members of the C. khasiensis group by the following characters: a moderate body size with a maximum SVL of 72.0 mm max. vs 81.7 mm in C. arunachalensis , 78 mm. in C. ayeyarwadyensis , 81.6 mm in C. aunglini , 77.0 mm in C. bapme , 88.0 mm in C. brevidactylus, 83.8 mm in C. chrysopylos , 62.3 mm in C. gansi , 64.5 mm in C. himalayicus , 96.2 mm in C. jaintiaensis , 80 mm. in C. kazirangaensis , 81.1 mm in C. khasiensis , 61.7 mm in C. mandalayensis , 82 mm in C. martinstolli , 78.2 mm in C. montanus , 59.0 mm in C. myaleiktaung and 90 mm in C. tamaiensis ; 7 PcP in a continuous series in males vs 10–28 PcP in C. ayeyarwadyensis , 11–18 PcP in C. agarwali , 12–13 PcP in C. aunglini , 5–7 PcP in C. bengkhuaiai , 8 or 9 PcP in C. brevidactylus , 8–13 PcP in C. chrysopylos , 10 in C. himalayicus , 11–12 PcP in C. jaintiaensis , 10–11 PcP in C. kazirangaensis , 10–12 PcP in C. khasiensis , 0–8 PcP in C.martinstolli , 9–11 PcP in C. mombergi , 8–10 PcP in C. montanus , 14 PcP in C. septentrionalis , 9–12 PcP in C. urbanus , 16–29 PcFP in C. gansi , 26–39 PcFP in C. guwahatiensis , 34–38 PcFP in C. karsticola , 40 PcFP in C. tamaiensis , 29–37 PcFP in C. tripuraensis ,; 22–24 rows of tubercles throughout the dorsum vs 24–26 in C. arunachalensis , 27–30 rows in C. brevidactylus , 16–20 rows in C.chrysopylos , 19–21 rows in C. himalayicus , 19–20 rows in C. jaintiaensis , 18 rows in C. cayuensis and C. mandalayensis , 14–15 rows in C. markuscombaii , 16–18 rows in C. nagalandensis , 21 rows in C. tamaiensis , 19–21 rows in C. tripuraensis , 34–37 rows of scales across the venter vs 38 rows in C. arunachalensis , 47–49 rows in C. aunglini , 37–42 rows in C. bengkhuaiai , 28–34 rows in C. cayuensis , 39–55 rows in C. chrysopylos , 40–42 rows in C. jaintiaensis , 37–43 rows in C. kazirangaensis , 32 rows in C. mandalayensis , 38–39 rows in C. markuscombaii , 57 rows in C. myaleiktaung and 30–34 in C. urbanus ; 36–39 paravertebral tubercles between the level of axilla and groin vs 30–35 in C. chrysopylos and 30–34 in C. jaintiaensis ; 15–18 subdigital lamellae beneath toe IV vs 19–22 subdigital lamellae in C. khasiensis and C. mombergi ; 13 in C. martinstolii and 10 in C. gansi ; 8–10 dark blotches in the dorsum vs 11–12 blotches in C. aaronbaueri , six in C. myaleiktaung ; indistinct light and dark blotches in C. karsticola and C. nagalandensis and an indistinct pattern of thick dark reticulations enclosing lighter blotches in C.montanus ; a higher TRL/SVL ratio (min. 0.47 max. 0.52 avg.0.5 vs min. 0.42 max. 0.48 avg. 0.45 in C.agarwali , min.0.35 max. 0.46 avg. 0.43 in C.guwahatiensis , min. 0.44 max. 0.47 avg. 0.46 in C.septentrionalis , min 0.43, max 0.49, avg 0.46 in C.bengkhuaiai , min. 0.43 max. 0.47 avg. 0.45 in C.bapme ). Cyrtodactylus siahaensis sp. nov. can again be differentiated from C. aaronbaueri by having a lower TRL/SVL ratio, min. 0.47 max. 0.52 avg.0.5 vs min 0.5, max 0.56, avg 0.52 in C. aaronbaueri . Cyrtodactylus siahaensis sp. nov. also differs from C.bapme by having 0–3 pitted scales in females (vs 0–13 precloacal pits in the latter). Furthermore, Cyrtodactylus siahaensis sp. nov. can again be differentiated from C. ayeyarwadyensis by the absence of white punctuations bordering the dark dorsal spots in the dorsum (vs presence of dark blotches usually bordered posteriorly by white punctuations in C. ayeyarwadyensis ). In Cyrtodactylus siahaensis sp. nov. the underneath of the tail with small uniform scale vs enlarged median scale line in C. cayuensis , C. khasiensis , C. martinstolli .

Etymology

The origin of specific epithet ‘ siahaensis ’ is derived from the name of the town, Siaha (a district capital of Siaha District) from where the type series was collected.

Suggested common name

Siaha bent-toed gecko.

Suggested local name

Khotlia (Mara ethnic language, which means bent-toed geckos).

Holotype INDIA • adult ♂; Mizoram state, Siaha district, Siaha town, New Colony-I , opposite to residential buildings nearby Meisavaih road; 22.490565°N, 92.9789525°E; 1025 m a.s.l.; 13 Jul. 2021; B. Litho, B. Nohro, V. Mathipi, L. Biakzuala and H.T. Lalremsanga leg.; retaining wall ( Fig. 7B ); GenBank accession number OK247677 ; MZMU2445 ( Figs 3F , 8 ).

Paratypes (n = 5) INDIA • 1 adult ♂; same collection data as for holotype; MZMU2444 ( Figs 3E , 9 ) • 1 adult ♀; Mizoram state, Siaha district, Siaha town, New Colony-I , roadside rocky wall near Evangelical Church of Maraland; 22.490098°N, 92.980885°E; elevation 1055 m a.s.l.; 13 Jul. 2021; B. Litho, B. Nohro and L. Muansanga leg.; crevices and horizontal cleft ( Fig. 7C ); MZMU2443 ( Figs 3D , 9 ) • 1 adult ♂; same collection data as for preceding; MZMU2446 ( Figs 3G , 9 ) • 1 juvenile ♀; same collection data as for preceding; MZMU2448 ( Fig. 9 ) • 1 juvenile ♀; Mizoram state, Siaha district, Siaha town, New Colony-I ; 22.489605°N, 92.978440°E; elevation 1038 m a.s.l.; 13 Jul. 2021; B. Litho, B. Nohro and H.T. Lalremsanga leg.; rock bedding wall ( Fig. 7D ); GenBank accession number OK247678 ; MZMU2449 ( Figs 3H , 9 ) .

Description of holotype

Holotype is in generally good preservation condition with a crease on the nape region ( Fig. 8A–F ). Adult male, SVL 57.4 mm.

HEAD. Longer than broad (HW/HL 0.55), about one-third of SVL (HL/SVL 0.32), distinct from neck and somewhat depressed (HD/HW 0.61) interorbital area flat, canthus rostralis broadly rounded; loreal region inflated with granular scales; snout less than half of the head length (SO/HL 0.28); scales on the canthus rostralis, snout and forehead are homogeneous; scales from the posterior margin of the eyes to the nape are slightly smaller than those of the forehead, somewhat blunt and juxtaposed; scales on the interorbital and occipital regions somewhat heterogeneous in size, having indistinct tubercles; eye approximately one-quarter of the head length (OD/HL 0.22) ( Fig. 8D ); vertical pupil with crenulate margins; supraciliaries moderate in size, blunt and somewhat oval and circular, those present in the midportion of the supraciliaries (above the orbit) are large and more prominent; ear opening oval, obliquely orientated, small (EL/HL 0.09); orbit to ear distance is less than the eye diameter (OE/OD 0.83); rostrum wider than long (RL/RW 0.90), partially and dorsally divided by a poorly developed rostral groove; single enlarged supranasal on either side, separated by two small granular internasals which are about the same size as enlarged scales on the snout; rostral in contact with the first supralabials, nasals, two supranasals and two internasals; nostrils semicircular, openings laterally orientated, posterior half covered by the nasal pad, each nasal is in broad contact with the rostral and surrounded by the supranasal, first supralabial, and three postnasals ( Fig. 8E ); a single row of small granular scales separate the orbit from the supralabials; mental wider than long (ML/MW 0.65), triangular; two well developed postmentals on either side; the inner pair of postmentals more than one and a half of the size of the outer pair (PMIIL/PMIL 0.6), bordered by the mental, infralabial I, the outer postmental and four gular scales; outer postmentals bordered by inner postmental, infralabials I and II, and four to five gular scales on either side; ten supralabials on the left and nine on the right side, bordered by a row of medium to large sized scales, somewhat flat and elongated; nine infralabials on each side, a row of enlarged gular scales (largest anteriorly) ventrally bordering infralabials I to III; gular region with small granular scales throughout except for a few scale rows bordering the mental, postmentals and infralabials which are larger, flat and juxtaposed ( Fig. 8F ).

BODY. Moderately slender, trunk length approximately half of the snout to vent length (TRL/SVL 0.51); dorsal scales are mostly heterogeneous, small rounded granule like scales intermixed with irregularly arranged, bluntly conical and feebly keeled enlarged tubercles (3–4 times the size of granular scales) which becomes more conical and slightly smaller towards the flanks, the largest on the sacral region; tubercles extending posteriorly from the occipital region to the second segment of the tail and are smaller on the nape than those of the dorsum; 23 mid-dorsal tubercle rows; 36 paravertebral tubercles between the level of the axilla and the level of the groin ( Fig. 8C ); ventrolateral folds are poorly developed, not denticulate but with a single row of continuous, projected smooth tubercles; ventral scales smooth, cycloid ( Fig. 8B ), imbricate to subimbricate, much larger than dorsals and are slightly smaller in size under thighs; 34 midventral scale rows; seven distinct precloacal pores in a continuous series ( Fig. 5B ); a single row of three scales (median scale being the largest) between the precloacal pores and the vent; a weakly developed postcloacal tubercle on each side of the tail base.

LIMBS. Forearm (FL/SVL 0.17) and tibia (CL/SVL 0.19) short; digits narrow, without a scansorial pad, strongly inflected at each joint, all bearing robust, recurved claws; sub-digital lamellae transversely widened beneath the basal phalanx; basal lamellae 4–5–5–5–3 on the right manus, 3–4 –5–7–5 on the right pes; distal lamellae (intervening rows of nonlamellar granular scales between the basal and distal lamellae series in parentheses): 6(1)–7(1)–8(1)–8(1)–7(1) on the right manus, 7(1)–8(1)–11(0)–11(0) –9(2) on the right pes; interdigital webbing absent from both manus and pes; relative length of digits: I <II <III<V<IV on the right manus, I <II <III<V<IV on the right pes; scales on the palms and soles are smooth, weakly raised, subimbricate; scales on the forelimbs are heterogeneous in size, comprising flat,imbricate to subimbricate scales on the upper arms, and those on forearms are heterogeneous in size, ventral portion covered with heterogenous sized imbricate scales; scales on the hindlimbs are heterogeneous in size, dorsal surfaces of the thighs and shanks have slightly larger scales, intermixed with scattered, enlarged, conical, feebly keeled tubercles; anterior portion of thighs and ventral aspect of hindlimbs have enlarged, smooth, imbricate scales.

TAIL. Regenerated from the seventh tail segment, oval in cross-section, dorsoventrally depressed; dorsal tubercles on the tail base (tail portion containing the hemipenes) are enlarged, flat, and pointed; few enlarged, flat and distinctly keeled, tubercles randomly scattered near the first segment of the tail, remaining dorsal caudal scales smooth, flat, heterogenous in size and shape; subcaudal scales smooth, imbricate and heterogeneous in size, forming a mid-ventral series of granular scales; no enlarged transverse or paired row of subcaudals.

COLOURATION IN LIFE. Dorsum brown in colour with a greenish tinge; head is primarily greenish brown; nape has a indistinct ‘W-shaped’ marking intermixed with whitish spots; an indistinct dark brown coloured postocular stripe present which runs till the anterior margin of ear opening. Eight pairs of dark brown blotches present on the dorsum, somewhat forming a reticulated pattern; hind limbs and forelimbs have indistinct whitish or cream coloured blotches intermixed with light brown blotches. Tail (regenerated from the seventh segment) has alternating dark and light bands ( Fig. 3F ). The ventral region is off-white in colour.

COLOURATION IN PRESERVATIVE. The colour is pale in comparison to the live specimen. The dark spots on the dorsum have darkened to brownish-black ( Fig. 8 ).

Taxonomic remarks

Refer to Table 3 for meristic, morphometric and basic pholidosis variation within the type series of Cyrtodactylus siahaensis sp. nov. The type series of C. siahaensis sp. nov. comprises two adult males (MZMU 2445 and MZMU 2446) and four females (two adults (MZMU2443 and MZMU2444) and two sub-adults (MZMU2448 and MZMU2449)). Paratype MZMU2444 has three visible pitted scales on its precloacal region.

Ecology and distribution

This species is only known from the type locality near human settlements in the centre of Siaha town ( Fig. 7B–D ). The type series was collected from an area within 1 km 2 on 13 July 2021 from inside and outside of crevices and clefts of rock bedding. Being a strictly nocturnal species, they are most active two to five hours after dark and are mostly seen in and around crevices, clefts, rock beddings and rock walls. All the individuals were encountered and collected from a height of approximately 90 cm to 170 cm above the ground. All handled specimens were very active, offensive and inclined to bite. The habitat is comprised largely of anthropogenic area with small patches of homestead garden under moderately disturbed secondary growth tropical evergreen forest. All the collection sites are located in the vicinity of water sources, like small hill stream, spring and well with rocky moist, damp and shady places. Vegetation around microhabitats include, Ageratum conyzoides (L.) L., Calocasia sp., Chromolaena odorata (L.) R.M.King & H.Rob., Cynodon dactylon (L.) Pers., Hibiscus sp. , Mikania micrantha Kunth , Mimosa pudica L., Molineria crassifolia Baker , Semecarpus anacardium L.f., Thysanolaena latifolia (Roxb. ex Hornem.) Honda , Viburnum sp. etc. Most surface areas of the rocky microhabitat were covered by patches of lichens and bryophytes, while more shady areas were flourished with ferns and grasses.

Figures

Fig. 3. Cyrtodactylus exercitus sp. nov. in life (A. MZMU2542. B. MZMU2543. C. MZMU2545); Cyrtodactylus siahaensissp. nov.in life (D. MZMU2443.E. MZMU2444.F. MZMU2445.G. MZMU2446. H. MZMU2449. I. uncollected).

Fig. 5. The arrangement of precloacal pores in A. Cyrtodactylus exercitus sp. nov., holotype (MZMU2542) B. Cyrtodactylus siahaensis sp. nov (MZMU2445).

Fig. 8. Cyrtodactylus siahaensis sp. nov., holotype (MZMU2445). A. Dorsal view. B. Ventral view. C. Details of dorsal pholidosis. D. Dorsal view of head. E. Lateral view of head. F. Ventral view of head.

Fig. 9. Type series of Cyrtodactylus siahaensis sp. nov.

Fig. 2. Maximum Likelihood phylogeny of the Cyrtodactylus khasiensis group; numbers at nodes represent bootstrap support (preceding the species name is the NCBI accession number).

Fig. 7. Microhabitats showing the collection sites of our newly described species of Cyrtodactylus from Northeast India. A. Collection site of Cyrtodactylus exercitus sp. nov. in Umroi military cantonment area, Ri-Bhoi district, Meghalaya state. B–D. Collection sites of C. siahaensis sp. nov. in Siaha town, Siaha district, Mizoram state.