Thursday, May 11, 2023

[Herpetology • 2023] Hemidactylus quartziticolus • A Remarkable New Species of Gecko (Squamata: Gekkonidae: Hemidactylus) from scrublands at the southern Tip of India


Hemidactylus quartziticolus  
Khandekar, Thackeray, Mariappan, Gangalmale, Waghe, Pawar & Agarwal, 2023


Abstract
We describe a new species of Hemidactylus based on an integrative taxonomic framework from scrub habitats at the southern tip of India, in Thoothukudi District, Tamil Nadu. The new species has the most densely packed tubercles among Indian Hemidactylus, almost resembling the most tuberculate Indian Cyrtopodion. Hemidactylus quartziticolus sp. nov. is phylogenetically placed within the brookii group of Indian Hemidactylus, where it is sister to the H. gleadowi complex from western-central India. The new species is 14.5–23.7% divergent in ND2 mitochondrial sequence data from other brookii group members, and can be easily diagnosed from regional congeners by its unique dorsal scalation, the number and arrangement of precloacal-femoral pores, the number of dorsal tubercle rows at midbody, number of lamellae under digit I and IV of manus and pes. The new species is currently known only from two isolated, low quartzite hillocks 45 km apart with scrubby, thorn forests and loose, stony soil.

Keywords: Hemidactylus brookii, morphology, peninsular India, taxonomy, Tamil Nadu

Hemidactylus quartziticolus sp. nov.in life:
 A male, holotype NRC-AA-1256, B female, paratype NRC-AA-1264, and C uncollected juvenile.
Photos by Akshay Khandekar.


Hemidactylus quartziticolus sp. nov.

Diagnosis: A small-sized Hemidactylus, snout to vent length less than 57 mm (n = 10); a single internasal scale behind rostral and between supranasals. Dorsal pholidosis heterogenous, composed of much smaller, subcircular, smooth and flattened granular scales intermixed with 18 regularly arranged rows of distinctly enlarged, subcircular, strongly keeled and pointed tubercles at midbody; tubercles largest on flanks; 18–20 paravertebral tubercles between forelimb and hindlimb insertions; ventral scales much larger than dorsal body granular scales, smooth, subimbricate, sub-equal from chest to vent, 24–29 scales across belly at mid-body, 48–54 longitudinal scales from fore arm insertions to anterior margin of cloaca; subdigital scansors smooth, mostly divided in oblique series; four lamellae under digit I of manus and pes, six or seven lamellae under digit IV of manus and pes; males with continuous series of 35–38 precloacal-femoral pores (n = 8/10); dorsal scales at tail base heterogeneous, granular scales similar in size and shape to those on mid-body dorsum, gradually becoming larger, pointed and subimbricate posteriorly, intermixed with series of 4–10 much enlarged, keeled, conical tubercles forming whorls; median row of sub-caudals smooth, enlarged, undivided, roughly rectangular, plate-like scales covering almost entire portion of the tail. Dorsal colouration beige to tan, scattered dark blotches on dorsum occasionally forming horizontal X-shaped markings on dorsum.

Etymology: The specific epithet is a combination of the German noun “quartz” + the Latin suffix -ite (used to denote rocks and minerals) and the Latin suffix -cola that means inhabitant or dweller of, referring to the quartzite rock formations the new species inhabits.

Suggested Common Names: Quartzite brookiish gecko 
or Thoothukudi brookiish gecko.
 
Habitat of Hemidactylus quartziticolus sp. nov.:
A general habitat at the type locality, B quartzite rock formation on which individuals of the new species were seen at the type locality, and C general habitat at Kurumalai, from where a few paratypes of the new species were collected.
Photos by Akshay Khandekar (A and B), and Ishan Agarwal (C).


Akshay Khandekar, Tejas Thackeray, Rameshwaran Mariappan, Satpal Gangalmale, Vivek Waghe, Swapnil Pawar and Ishan Agarwal. 2023. A Remarkable New Species of Gecko (Squamata: Gekkonidae: Hemidactylus) from scrublands at the southern Tip of India. Vertebrate Zoology 73: 433-450. DOI: 10.3897/vz.73.e101871