Gekko mizoramensis, Lalremsanga & Muansanga & Vabeiryureilai & Mirza, 2023

Lalremsanga, Hmar Tlawmte, Muansanga, Lal, Vabeiryureilai, Mathipi & Mirza, Zeeshan A., 2023, A new species of Parachute Gecko of the subgenus Ptychozoon (Sauria: Gekkonidae: Gekko) from the Indo-Burma region, Salamandra 59 (2), pp. 1-11 : 4-8

Gekko mizoramensis sp. n.

Figs 3–5 , Tables 1–3

urn:lsid:zoobank.org:act:51325DE1-F3C0-47AB-9105-A96D-023D5B35

Ptychozoon lionotum PAWAR & BISWAS (2001) : 101; BHUIYAN et al. (2020): 17161

Holotype. Adult female, NCBS NRC-AA-4514 (ex-MZMU-2879), collected from the partition wall inside the Circuit House (22.53502° N, 92.89177° E; 830 m a.s.l.), Electric veng , Lawngtlai town, Lawngtlai District, southern Mizoram, India, at around 09:30 h on 2 May 2022 by LAITHANG LIANI.

Paratypes. Adult female, BNHS 1445 , collected by SAMRAAT PAWAR on 21 April 1999, same collection locality as the holotype; another adult female ( MZMU 2883 ) from the outside wall of a building at Chawnhu (22.50456° N, 92.89520° E; 1057 m a.s.l.), outskirts of Lawngtlai town, southern Mizoram, India, collected by RO TEA on 17 May 2022 at around 20:00 h; MZMU 3031 , female, from N. Hlimen , Kolasib District, northern Mizoram (24.230092° N, 92.806047° E; 684 m a.s.l.) by ALFRED J. C. RALTE on 4 November 2022.

Referred material. MZMU 2880 , juvenile, collected by LAITHANG LIANI on 2 May 2022 at around 12:00 h with the same collection data as the holotype ; adult female, NCBS NRC-AA-4515 (ex-MZMU-1609) collected from a partition wall of a residential house (22.53698° N, 92.89821° E; 894 m a.s.l.) near the Baptist Church of Mizoram (BCM), Vengpui, Lawngtlai town by LAL RUATTHARA at 21:30 h on 19 October 2019.

Diagnosis. Gekko mizoramensis sp. n. differs from all other members of the genus Gekko (other than the subgenus Ptychozoon ) in bearing patagia along the forelimbs, trunk and hind limbs. The new species differs from all members of the subgenus Ptychozoon by exhibiting the following unique combination of characters: maximum SVL 100 mm; supranasals not in contact; 11–13 supralabials of which the 9 th or 10 th is situated at mid-orbit; 9–10 infralabials; caudal tubercles present; 32 ventral scales; no enlarged femoral scales; 12 enlarged non-pored (at least in females) precloacal scales in a transverse row; 5 rows of enlarged post-precloacal scales; 14–17 subdigital lamellae under the fourth toe; enlarged dorsal caudal scales form whorls.

Comparison. The new species differs from members of the subgenus Ptychozoon by exhibiting the following nonoverlapping set of characters: supranasals not in contact (vs. supranasals in contact in G. nicobarensis [DAS & VIJAYAKUMAR, 2009], G. trinotaterra [BROWN, 1999], G. kaengkrachanensis [SUMONTHA, PAUWELS, KUNYA, LIMLIKHITAKSORN, RUKSUE, TAOKRATOK, ANSERMET & CHANHOME, 2012]); infra-auricular cutaneous flap present (vs. absent in G. rhacophorus [BOULENGER, 1899]); prominent infra-auricular cutaneous lobe absent (vs. present in G. cicakterbang [GRISMER, WOOD, GRISMER, QUAH, THY, PHIMMACHAK, SIVONGXAY, SEATEUN, STUART, SILER, MULCAHY, ANAMZA & BROWN, 2019]); tubercles on dorsum absent (vs. present in G. intermedius [TAYLOR, 1915]), G. kuhli [STEJNEGER, 1902], G. rhacophorus , G. trinotaterra ); fourth toe lamellae 14–17 (vs. 13 or 14 in G. popaensis [ GRISMER, WOOD, THURA, M GRISMER, BROWN & STUART, 2018], 11–13 in G. horsfieldii [GRAY, 1827], 9–14 in G. intermedius , 12–16 in G. kuhli , 12–14 in G. linotus , 11–13 in G. rhacophorus , 12–14 in G. trinotaterra ). The new species is most similar to G. popaensis from which it differs as follows: mid-dorsal caudal tubercles present (vs. absent in G. popaensis ); 15–16 caudal lobes (vs. 25); distal caudal lobes fused into a long caudal flap (vs. caudal lobes fairly distinct and not forming a long caudal flap); fourth toe lamellae 14–17 (vs. 13 or 14); 12–13 supralabials (vs. 9–11); a thick dark postorbital stripe absent (vs. present); see Table 3 for a summary of the comparison with members of the G. lionotum clade.

Etymology. The specific epithet refers to the state of Mizoram in which the new species was discovered. The suggested common English name is Mizoram Parachute Gecko.

Description of the holotype ( Figs 3–4 , 5a ). The specimen is in a good state of preservation except for a longitudinal incision on the venter and is more depressed than in the paratypes, likely an artefact of preservation. Morphometric and meristic details are presented in Tables 2 and 3 .

Adult female, SVL 100 mm; head long (HL/SVL 0.17), wide (HW/SVL 0.20), depressed (HD/HL 0.52), distinct from neck; snout rounded at the tip in dorsal view; interorbital region flat; lores rounded; rostral scale large, rectangular, with a dorsomedial groove visible in dorsal view, in contact posteriorly with two supranasals, the internasal, and laterally with nostrils and the first supralabials; supralabials (12R,13L), 10th supralabial in mid-orbital position; infralabials (9R,10L); nostrils round, each bordered anteriorly by the rostral, dorsally by the supranasal, posteriorly by two postnasals, and ventrally by the first supralabial; scales on rostrum granular, slightly larger than the granular scales on the top of the head and occiput; no ridges of tubercles along the mandibles; eyes large (ED/HL 0.27), but smaller than the snout length and EAO distance; pupil vertically elliptical, crenulated; supraciliaries elongate, posteriormost ones spinose; auricular opening rounded, lacking enlarged lobes; tympanum deeply sunk; infra-auricular flap broad, rounded, extending from the lower corner of the mouth to the base of the neck, measuring 3 mm at its widest point; dorsal scales of infra-auricular flap large, subimbricate proximally, small and juxtaposed distally, minute and granular ventrally; infra-auricular flap on the right side deeply notched; mental triangular, wider than deep, bordered laterally by the first infralabials and posteriorly by paired, rectangular postmentals, contacting medially for 100% of their lengths; posterior postmentals small, half the length of the anterior one; one row of enlarged sublabials bordering the infralabials, anteriormost ones largest; gular scales small, rounded, grading abruptly into larger imbricate scales on the throat and venter.

Body dorsoventrally depressed, relatively stout (AG/ SVL 0.44); axilla-groin cutaneous expansion (flap) 6.6 mm at midpoint of body and bearing enlarged, juxtaposed, rectangular scales dorsally, and minute, juxtaposed, subrectangular scales ventrally; dorsal body scales minute, flat, rounded, juxtaposed, largest mid-dorsally; 32 transverse rows of large, smooth, flat, subimbricate ventrals, much larger than dorsals, decreasing in size laterally; 12 enlarged non-pored precloacal scales; five rows of enlarged, post-precloacal scales; scales immediately anterior to vent granular. Limbs short, robust (FL/SVL 0.11; TBL/SVL 0.15); dorsal scales of forelimbs flat, juxtaposed, slightly larger than dorsal body scales, and juxtaposed ventral forelimb scales; anterior and posterior margins of forelimbs, posterior margins of hind limbs, and anterior margins of forelegs bearing wide, cutaneous flaps extending to the bases of digits Iand V, bearing subimbricate, moderately larger scales dorsally and smaller, wide, imbricate scales ventrally; a wide predigital notch in the pre-antebrachial flap; palmar scales smooth, rounded; digits fully webbed, relatively short, dorsoventrally compressed; undivided transverse subdigital lamellae of left manus 11 (I), 15 (II), 15 (III), 16 (IV), 13 (V), distalmost lamellae V-shaped; claws II–V arise from within the dorsal surface of the digital pads; first digit lacks a claw; dorsal scales of hind limbs flat, juxtaposed, smaller than dorsal body scales, and flat, subimbricate scales on the thighs; posterior margins of thighs and forelegs, and anterior margins of forelegs have wide, cutaneous flaps bearing subimbricate, moderately large scales dorsally and much smaller, subimbricate scales ventrally; pretibial flap not contacting the base of digit V; post-tibial flap contacts base of digit I; plantar scales smooth, subimbricate; digits fully webbed; transverse subdigital lamellae of left pes 15 (I), 14 (II), 16 (III), 17 (IV), 15 (V), distalmost lamellae V-shaped; claws II–V arise from within the dorsal surface of digital pads; and first digit lacks a claw.

Tail original, flattened, moderate in length (TaL/SVL 1.04); 5–7 medianrows of heterogeneous, transversely widened, smooth subcaudals; a single large postcloacal spur, domed, imbricate; dorsal caudals flat, juxtaposed, larger than dorsal body scales, arranged in whorls; 6–8 smaller scales between larger scales delimiting whorls; tail width and caudal lobes decrease slightly posteriorly; 17R/15L caudal lobes on each side, slightly angled posteriorly; lobes fused at their bases, prior to grading posteriorly into short, straight-edged appendages.

Coloration in life ( Fig. 5 ). Grey with darker grey blotches edged with black and black reticulations on the head, and paired black bands on the trunk and the tail. The nape exhibits a sub-ovate mark, and the temporal region an undefined reticulate pattern, which becomes obsolete posteriorly as both join the first band on the trunk. The first black band is at the level of the forelimbs, followed by two on the trunk and a fourth at the level of the hindlimbs. The bark bands are 2–3 scales wide, and the paler interspaces span more than 70 scales. The tail is alternately banded with five dark- and light-coloured bands and has a dark tip. The legs are patterned with diffuse reticulations. The ventral side is cream coloured, but the underside of the tail exhibits the same banded pattern as the dorsal side.

Coloration in preservative ( Figs 3 and 4 ): The coloration in preservation is more faded, with only the black markings evident. The overall background colour is grey to greyish brown.

Natural history and distribution. The type specimens were collected only from the Lawngtlai town area, particularly during the monsoon season (April to October) in the state. However, this species is not only known from the type locality, but was also encountered in various other areas in Mizoram during the survey period ( Fig. 6 ). All individuals were discovered and collected at heights of approximately 150 to 360 cm above the ground or floor. Being nocturnal, they were observed active from the onset of dusk and hunted or ambushed their prey of beetles, roaches, moths and other insects attracted by light sources. All collected individuals remained motionless if not disturbed; however, they then responded aggressively, attempting to bite when handled. The habitat lies within a largely anthropogenic settlement with small scattered patches of homestead gardens, surrounded by moderately disturbed secondary tropical evergreen forest. The vegetation around the microhabitats where the new species has been collected includes tree species like Crataegus monogyna, Ficus geniculata, Mangifera indica and Schima wallichi . Other common sympatric lizard species found during the survey were Calotes irawadi , Gekko gecko and Hemidactylus frenatus .

Figures

Figure 3. Gekko mizoramensis sp. n. holotye female NCBS NRC-AA-4514 showing habitus (a) dorsal view, (b) ventral view. Scale bar = 20 mm. Photos by ZEESHAN A. MIRZA.

Figure 4. Gekko mizoramensis sp. n. holotype, female, NCBS NRC-AA-4514, head in (a) left lateral view, (b) dorsal view, (c) ventral view. Photos by ZEESHAN A. MIRZA.

Fig. 5. Gekko mizoramensis sp. n., coloration in life, (a) holotype NCBS NRC-AA-4514, (b) juvenile MZMU-2880. Photos by LAL MUANSANGA.

Figure 6. Map of the Indo-Burma region with the known distribution of Gekko mizoramensis sp. n. (1) Lawngtlai (type locality ‘black star’), (2) Thingkah, (3) Hnahthial, (4) Thenhlum, (5) Dampa Tiger Reserve, (6) Mizoram University Campus, (7) Kolasib, (8) Pualreng Wildlife Sanctuary and (9) Sangu Wildlife Sanctuary (BHUIYAN et al 2020). Map generated with QGIS.