Thursday, August 2, 2018

[Herpetology • 2018] First Appearance Deceives Many: Disentangling the Hemidactylus triedrus species complex Using An Integrated Approach; Hemidactylus whitakeri & H. sahgali


Hemidactylus triedrus Daudin, 1802

Hemidactylus whitakeri 
 Hemidactylus sahgali
Mirza​, Gowande, Patil, Ambekar & Patel, 2018
  DOI: 10.7717/peerj.5341 

 Abstract
The gekkonid lizard genus Hemidactylus Oken is the second most species-rich genus of geckos with greatest diversity in the tropical regions of the world. Some species of the genus are commensal and widespread; however, there are several endemic lineages with restricted distribution. India is home to at least 35 species, with 20 endemic species and the number is steadily increasing with exploration of new habitats and integrated taxonomic approach including molecular data. We made investigations into the molecular and morphological variation throughout the distribution of Hemidactylus triedrus Daudin, 1802 based on fresh specimens, literature review, museum material and molecular data. Results from morphological, molecular and micro-CT based anatomical data are unequivocal and show that H. triedrus is a species complex represented by three species, H. triedrus sensu stricto and two undescribed taxa. H. subtriedrus Jerdon, 1854 syn. nov. was found to be morphologically similar to the type specimen of H. triedrus, and genetically embedded in a clade containing H. triedrus sensu stricto and is here treated as a junior synonym of H. triedrus, whereas H. lankae Deraniyagala is referred to as nomen dubium given that the types are presently not traceable and the original description is inadequate in diagnosing the taxon. The populations from western-central India and parts of Pakistan, and from southern Karnataka are distinct and diagnosable, and are herein described as two new species, respectively. Morphological and molecular data support the distinctiveness of the new species. The present work resolves a taxonomic turmoil that lasted over two centuries highlighting the need for studies that integrate morphological and molecular data.

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Hemidactylus triedrus species group
Species included: H. triedrus, H. sahgali sp. nov., H. whitakeri sp. nov.

Definition: Members of the group grow to a medium size ranging from 45–74 mm in SVL with a rather robust habitus. Dorsum with distinct dark bands may be edged with white or lighter shade of brown. Scales on the dorsal aspect of trunk granular intermixed with large keeled sub-trihedral or trihedral tubercles arranged in 15–20 fairly regular rows. Supralabial eight to nine and infralabials seven to eight to angle of jaw. Lamellae on digit one of manus and pes range from seven to eight and on digit four of manus and pes range from 8–10. Males possess a series of 7–15 precloacal femoral pores interrupted medially by a diastema of one to three non-pored scales. A single or a pair of sub-conical to rounded post cloacal spur. Tail with usually eight keeled tubercles in a whorl on segment I, the number subsequently reduces with progression of tail segments.

Distribution: Widespread across dry zones of India and Sri Lanka and parts of Pakistan.

Figure 4: Coloration in life of Hemidactylus triedrus.
 (A) male NCBS AU703 from Nellore, (B) an uncollected female from Pondicherry, (C) uncollected juvenile from Pondicherry.

Hemidactylus triedrus Daudin, 1802
Gecko triedrus Daudin, 1802:155
Hemidactylus triedrus Lesson, 1834:311; Boulenger, 1885:133 (in part); Smith, 1935:88 (in part)
Hemidactylus subtriedrus Jerdon, 1854:467; Smith, 1935:89 syn. nov.
Hemidactylus triedrus lankae Somaweera & Somaweera, 2009:180
Hemidactylus lankae Bauer et al., 2010:350

Diagnosis: A medium sized fairly stout gecko, adults ranging 58–76 mm in SVL. Dorsum in a shade of light brown with paired, thin black edged white bands at regular intervals. Dorsal scalation on trunk, granular, intermixed with enlarged, keeled 19–20 trihedral tubercle rows arranged in fairly regular longitudinal series. Seven lamellae under digit I of pes and manus, eight to nine under digit four of manus and pes. An angular series of seven to nine precloacal femoral pores separated at mid-pelvic by a diastema of one to three non-pored scales.

Suggested common name: Southern termite hill gecko.

Natural history: A species generally associated with termite mounds. Several individuals of different age classes can be seen occupying a single mound. Individuals can be seen at the entrance of the openings of termite mounds just after dusk and will retreat in the mound with the slightest disturbance. Juveniles when disturbed will attain a posture with their bodies high and the tail is moved slowly in a curling and uncurling manner, likely to draw attention toward the tail. Several individuals were found in a single mound when the termite mound was dug, along with scorpions of the genus Heterometrus sp., and frogs of the genus Uperodon sp. Individuals also seek shelter under boulders, abandoned houses during the day emerging just after dusk. Mostly terrestrial in its habits but will climb trees too. Breeding likely takes places from February to May as hatchlings and eggs have been seen in the months of April–May in Pondicherry and Kanyakumari. Occupies areas that are dry like scrub, dominated with boulders and even in cities closer to the coast. Widely distributed from Visakhapatnam in north to Kanyakumari in south and recorded from elevation ranging from 17 to 1,913 m AMSL. Recorded from the following states/Union territories in India: Kerala, Tamil Nadu, Andhra Pradesh and Pondicherry (Fig. 6).


Figure 7: Coloration in life of Hemidactylus whitakeri sp. nov. (A) Holotype female NCBS AU712, (B) uncollected juvenile from Bangalore.

Hemidactylus whitakeri sp. nov.
Hemidactylus subtriedrus Bauer et al., 2010
Hemidactylus triedrus Bansal & Karanth, 2010

Diagnosis: A medium sized fairly stout gecko, adults ranging 45–60 mm in SVL. Dorsum in a shade of light brown with paired, thin black edged white bands at regular intervals. Dorsal scalation on trunk granular, intermixed with enlarged, keeled 16–17 sub-trihedral tubercle rows arranged in fairly regular longitudinal series on dorsum. Seven lamellae (rarely six) under digit I of pes and manus, eight to nine under digit four of manus and pes. An angular series of seven to eight precloacal femoral pores separated at a mid-pelvic by a diastema of three non-pored scales.

Etymology: The specific epithet is a patronym honoring Romulus Earl Whitaker for his valuable contribution toward the study and conservation of reptiles of India.

Suggested common name: Whitaker’s termite hill gecko.

Natural history: The types were found moving actively at a quarry site around 20:30 h. The holotype female contains two eggs in her body cavity suggesting that this species breeds during the months of November. Several hatchlings of the new species were encountered at Kengiri near Bangalore in the month of April. Similar in its habits to H. triedrus and can be seen on termite mounds. Its distribution is not well known and known from Bangalore in the state of Karnataka and the Nilgiri district in Tamil Nadu (Fig. 6).


Figure 9: Coloration in life of Hemidactylus sahgali sp. nov.
(A) Paratype female NCBS AU709, (B) an uncollected male from Gautala Wildlife Sanctuary, Maharashtra, (C) uncollected juvenile from Pune.

Hemidactylus sahgali sp. nov.
Hemidactylus triedrus Boulenger, 1885:133 (in part); Smith, 1935:88 (in part); 
Minton, 1966:85; Bauer et al., 2010

Diagnosis: A medium sized fairly stout gecko, adults ranging 56–78 mm in SVL. Dorsum in a shade of light brown with paired, broad black edged white bands at regular intervals. Dorsal scalation on trunk, granular, intermixed with enlarged, keeled 15–16 trihedral tubercle rows arranged in fairly regular longitudinal series. Seven to eight lamellae under digit I of pes and manus, 8–10 under digit four of manus and pes. An angular series of 11–15 precloacal femoral pores separated at a mid-pelvic by a diastema of one to three non-pored scales.

Etymology: The specific epithet is a patronym honoring Bittu Sahgal, Editor and founder of Sanctuary Asia magazine for his contribution toward conservation of wildlife.

Suggested common name: Sahgal’s termite hill gecko.

Natural history: A species associated with termite mounds as its related species H. triedrus. Found in dry open scrub areas with boulders. Seen actively moving about on the ground just after dusk. Hatchlings have been seen in the month of May. Distributed throughout the Deccan Traps, its distribution extends beyond the traps north-west into Pakistan. In India, it is recorded from the following states: Maharashtra, Gujarat, Madhya Pradesh, Rajasthan and Chhattisgarh records ranging in elevation from 11 to 1,191 m AMSL. All records of the species from Pakistan are from elevation ranging from 15 to 25 m AMSL.


Zeeshan A. Mirza​, Gaurang G. Gowande, Rishikesh Patil, Mayuresh Ambekar and Harshil Patel. 2018. First Appearance Deceives Many: Disentangling the Hemidactylus triedrus species complex Using An Integrated Approach.  PeerJ. 6:e5341  DOI: 10.7717/peerj.5341

    

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