Journal of Threatened Taxa | www.threatenedtaxa.org | 26 August 2018 | 10(9): 12147–12162

 

 

Appearances are deceptive: molecular phylogeny recovers the Scaly Gecko Hemidactylus scabriceps (Reptilia: Squamata: Gekkonidae) as a member of a scansorial and rupicolous clade

 

Achyuthan N. Srikanthan 1 , Gandla Chethan Kumar 2, Aishwarya J. Urs 3 & Sumaithangi Rajagopalan Ganesh 4

 

1 Center for Ecological Sciences, Indian Institute of Science, Bengaluru, Karnataka 560012, India

2 Wildlife Biology and Taxonomy Lab, Department of Zoology, University College of Science, Osmania University, Hyderabad, Telangana 500007, India

2 Wildlife Institute of India, Post Box #18, Chandrabani, Dehradun, Uttarakhand 248001, India

3 No. 94, 5th Cross, Raghavendra Colony, Vidyaranyapura, Bengaluru, Karnataka 560097, India

4 Chennai Snake Park, Rajbhavan Post, Chennai, Tamil Nadu 600022, India

1 peltopelor@gmail.com (corresponding author), 2 g.chethankumar@gmail.com, 3 aishwaryaj.urs@gmail.com, 4 snakeranglerr@gmail.com

 

 

 

 

doi: https://doi.org/10.11609/jott.3964.10.9.12147-12162   |  ZooBank: urn:lsid:zoobank.org:pub:03BEA8A8-A142-4E6A-AE94-CBEFF5C8D656

 

Editor: Salvador Carranza, Institute of Evolutionary Biology (CSIC-UPF), Barcelona, Spain.          Date of publication: 26 August 2018 (online & print)

 

Manuscript details: Ms # 3964 | Received 18 December 2017 | Final received 01 June 2018 | Finally accepted 02 August 2018

 

Citation: Srikanthan, A.N., G.C. Kumar, A.J. Urs & S.R. Ganesh (2018). Appearances are deceptive: molecular phylogeny recovers the Scaly Gecko Hemidactylus scabriceps (Reptilia: Squamata: Gekkonidae) as a member of a scansorial and rupicolous clade. Journal of Threatened Taxa 10(9): 12147–12162; https://doi.org/10.11609/jott.3964.10.9.12147-12162

 

Copyright: © Srikanthan et al. 2018. Creative Commons Attribution 4.0 International License. JoTT allows unrestricted use of this article in any medium, reproduction and distribution by providing adequate credit to the authors and the source of publication.

 

Funding: None.

 

Competing interests: The authors declare no competing interests.

 

Author Details: Achyuthan N. Srikanthan is currently working with the Indian Institute of Science, studying the ecomorphology and evolutionary osteology and specialized integument microstructure characterisation of the amphibian and reptile groups. G. Chethan Kumar is currently working in Wildlife Forensic and Conservation Genetics laboratory, Wildlife Institute of India, Dehradun, solving cases related to morphology and DNA evidences. His research includes, studying reptiles, amphibians and mammalian fauna of India. His primary research interest includes documenting herpetofaunal diversity of under-explored eco-regions, ecology and characterization of species by both classical and molecular approaches.  Aishwarya J. Urs works on Geographic Information Systems (GIS) developing models and maps for wildlife biology and related fields.  Dr. S.R. Ganesh is working as Deputy Director & Scientist at the Chennai Snake Park, conducting research on reptiles and amphibians of Southern India. His research themes include documenting diversity of under-explored eco-regions, updating and refining species characterizations and elucidating modern day distribution patterns with respect to southern India’s herpetofauna.

 

Author Contributions: NSA, GCK conducted fieldwork and did the morphological as well as genetic analyses. AJU conducted mapping analysis. SRG led the writing with inputs from NSA, GCK and AJU. All the authors equally contributed in refining the manuscript drafts and approved the final version.

 

Acknowledgements: We thank our respective organizations for supporting our research activities. SRG thanks the Executive Secretary, Chairman and Trustees of Chennai Snake Park for supporting his research activities.  The authors would like to thank V. Abinaya Bharathi, A. Harishvara Venkat, Yunus Wagh, N.V. Srikanthan, Raja Vetri, M. Nandini, G. B Pravalikha, the members of the “Mid-Week” Group, Coimbatore for all the help and support with the fieldwork for this study. We thank researchers at CES – IISc, Dr. Ishan Agarwal, Dr. S.P. Vijaykumar, Dr. Kartik Shanker, Aparna Lajmi and Dr. Praveen Karanth, Indian Institute of science for all the inputs and access to the specimens of CES.  We are also thankful to the researchers at VUB - Dr. Franky Bossuyt and at NCBS-TIFR - Dr. Varad Giri for their invaluable inputs.  We would also like to thank Saunak Pal, V. Rahul Khot and V. Hegde for the inputs and help with depositing the specimen at BNHS.  Special thanks go to Vivek Philip Cyriac, IISER Tiruvananthapuram and Yinxin Tok for helping with the measurements and specimen information used in this study.  GCK acknowledges UGC (University Grant Commission, Delhi) for the research funding, Dr. C. Srinivasulu, Osmania University for permitting the use of lab facilities for this study, Dr. S.K. Gupta, Wildlife Institute of India for guidance.  And our sincere thanks to Mr. Marcel Widmann for sharing pictures of Hemidactylus imbricatus.  We thank M. Rameshwaran for providing his photograph that is used here.  ANS sincerely thanks Dr. Deepak Veerappan for his valuble  Inputs.

 

 

 

 

 

Abstract: We reassess the systematics of Hemidactylus scabriceps, a recently rediscovered and poorly known gecko, and elucidate its phylogenetic position using molecular data for the first time.  Contrary to previous speculations prompted by its morphological resemblance to other terrestrial Hemidactylus, our phylogenetic analyses recovered H. scabriceps to be a part of a clade consisting of the large-bodied, rock-dwelling Hemidactylus – the H. prashadi group.  Hemidactylus scabriceps also shows high levels of intraspecific genetic divergence, indicative of cryptic diversity.  We also confirm the synonymy of the monotypic genus Lophopholis (erected for H. scabriceps) with Hemidactylus.  We elaborate on the morphology of the type specimen and other recent voucher specimens, and compare it with sister species and other ground-dwelling Hemidactylus in peninsular India.  Species distribution of this ‘outlier’ clade member has been modeled using MaxEnt.  These exercises confirm that it is primarily a smooth-scaled, plain-dwelling, terrestrial species unlike other members in its clade.  This unexpected pattern of genetic alliance and contrasting body form plus habitat associations further underscores the unstudied complexity of peninsular India’s geological history.  Historical denudation of rock formations could have driven evolution of some of these otherwise rupicolous, scansorial gekkonids into smaller terrestrial lizards.

 

Keywords: Clade member, distribution modeling, habitat associations, Indian dry zone, morphology, phylogenetic position, rock dwelling.

 

 

 

INTRODUCTION

 

Hemidactylus Oken, 1817 is one of the most speciose gekkonid genera in the world, with about 150 congeners currently recognized, of which around 34 are found in India (Carranza & Arnold 2006; Giri & Bauer 2008; Bauer et al. 2010; Uetz & Hošek 2018; Chaitanya et al. 2018).  The Indian Hemidactylus are part of a tropical Asian radiation, and consist of five major clades - H. prashadi, H. flaviviridis, H. brookii, H. frenatus and H. platyurus groups (Bansal & Karanth 2010).  Of these, the H. brookii group encompasses all the thus-far sampled ground-dwelling Hemidactylus that are found in central and peninsular India (Bansal & Karanth 2010;  2013).  Previous studies show that the ground dwelling clade of geckos are sister to H. brookii, the clade that consists of five currently recognized terrestrial species namely H. reticulatus Beddome, 1870, H. albofasciatus Grandison & Soman, 1963, H. satarensis Giri & Bauer, 2008, H. imbricatus Bauer, Giri, Greenbaum, Jackman, Dharne & Shouche, 2008, H. gracilis Blanford, 1870 (Bansal & Karanth 2010).  Hemidactylus scabriceps was considered to be closely related to the ground-dwelling Hemidactylus due to its superficial morphological similarities such as a reduced subdigital scansorial apparatus, imbricate tail scales, reduced subcaudal scales and a terrestrial lifestyle (Bauer et al. 2010).  Similar assumptions were made for Dravidogecko anamallensis (Günther, 1875) which was later resolved and found to be sister to the Indian Hemidactylus radiation (Bansal & Karanth 2013).  In the past, H. scabriceps has been misidentified on many occasions with other marginally co-occurring terrestrial congeners such as H. reticulatus, despite its distinctive scalation (Ganesh et al. 2017).

Annandale (1906) originally described this species as Teratolepis scabriceps based on its imbricate scalation, as the second congener next to T. fasciatus (currently H. imbricatus, after Bauer et al. 2008).  Later, a new monotypic genus Lophopholis was erected by Smith & Deraniyagala, 1934 to accommodate this species as it was considered quite unique (Smith 1935).  Parker & Taylor (1942) reassigned the species back to Teratolepis along with various other African geckos such as H. isolepis and H. ophiolepis, attributing this generic transfer to the imbricate scalation.  Due to the similarity of H. scabriceps with other oriental Teratolepis and Hemidactylus geckos, it was called the ‘Oriental imbricate-scaled Hemidactylus.  Subsequently, the generic allocation of this species was debated and later the genus Lophopholis was synonymized with Hemidactylus by Loveridge (1947).  Furthermore, Bauer et al. (2008) synonymized the genus Teratolepis with Hemidactylus based on a multilocus molecular phylogeny and mentioned the possible close relationship of H. scabriceps with H. imbricatus (Image 5), along with other small-bodied, ground-dwelling endemic geckos such as H. albofasciatus, H. gracillis and H. reticulatus, which themselves are genetically-tested clade members (Bansal & Karanth 2010).

Since its description, H. scabriceps was not re-sighted for 104 years till an uncollected specimen was reported from Mayiladuthurai in the Coromandel Coastal Plains (Ganesh & Chandramouli 2010).  More recently, Ganesh et al. (2017) dug up some obscure publications reporting this species under a wrong name, described a series of preserved specimens including its hemipenal morphology, provided natural history notes and mapped its locality based on newer fieldwork.  Hemidactylus scabriceps, however, still remains an intriguing gecko for both Indian and Sri Lankan herpetologists due to its assumed rarity and unknown phylogenetic relationships, since it is underrepresented and poorly sampled (Bauer et al. 2010).  In this paper, we provide for the first time data on its phylogenetic position, elaborate on its morphology, habitat associations and distribution.

 


MATERIALS AND METHODS

 

Specimens of H. scabriceps were opportunistically collected from three ecoregions: Coimbatore plateau, Thanjavur delta and Kalakad foothills, abutting Western Ghats in peninsular India. The specimens were deposited in the collections of BNHS (Bombay Natural History Society, Mumbai), IISc - CES (Indian Institute of Science, Bengaluru - Center for Ecological studies), and IISER (Indian Institute of Science, Education and Research, Thiruvananthapuram).  Tissue samples were collected from the tail tips and liver of the specimens and sent for molecular analysis and sequencing at the Indian Institute of Science (IISc), Bengaluru and Osmania University, Hyderabad.  The geographic coordinates of the localities were obtained from Garmin 62 GPS.  Other comparative materials, including the type specimens, were examined at the Natural History Museum, London (BMNH).

 

Morphological analysis

Morphological and meristic data were collected following methods described by Giri & Bauer (2008) and Mahony (2009) with Mitutoyo™ digital calipers (to the nearest 0.1mm).  The following measurements were taken from collected specimens and the museum types: snout vent length (SVL; from tip of snout to vent), trunk length (TRL; distance from axilla to groin measured from posterior edge of forelimb insertion to anterior edge of hind limb insertion), body width (BW; maximum width of body), crus length (CL; from base of heel to knee); tail length (TL; from below vent to tip of tail), tail width (TW; measured at widest point of tail near the tail base); head length (HL; distance between retroarticular process of jaw and snout-tip), head width (HW; maximum width of head), head height (HH; maximum height of head, from occiput to underside of jaws), forearm length (FL; from base of palm to elbow); ear length (EL; longest dimension of ear); orbital diameter (OD; greatest diameter of orbit), nares to eye distance (NE; shortest distance between anterior most point of eye and nostril), snout to eye distance (SE; distance between anterior most point of eye and tip of snout), eye to ear distance (EE; distance from anterior edge of ear opening to posterior corner of eye), internarial distance (IN; distance between nares), interorbital distance (IO; shortest distance between left and right supraciliary scale rows).  Scale counts and external observations of morphology, meristic characters were made using a Wild M5 dissecting microscope.

 

Species distribution modeling

 Species distribution modeling was carried out using MaxEnt v.3.3 (Phillips et al. 2006), which is based on maximum entropy modeling.  MaxEnt, a machine learning program that estimates the probable species distribution based on constraints of the environment.  It uses presence-only data for prediction and studies show that it has good success rate for small sample sizes compared to other SDMs (Elith et al. 2006; Wisz et al. 2008).  We have considered 21 environmental variables - the 19 bioclimatic layers, one topographic layer representing elevation (Hijmans et al. 2005) and one vegetation layer-NDVI (NRSC, ISRO). The 13 location points used in the model were obtained from the recent collections, literature which includes historical points Adayar (13.00120N & 80.25650E), and Maricukatte (8.5880N & 79.9330E).  The environmental layers were derived from globally interpolated datasets observed from climate stations around the world.  All the layers are of approximately 1,000m resolution, clipped for the Indian subcontinent including Sri Lanka and projected on WGS84 Lat-Long map datum.  The layers were subjected to a multicollinearity test and 10 bioclimatic variables that were least correlated (Pearson’s correlation coefficient r<0.85) were selected for the distribution modeling.

MaxEnt program with following changes was used in the model: auto feature for environmental variables was selected.  The random test percentage was set to 20%, making the training percentage 75%.  The regularization multiplier and maximum number of background points for sampling was kept at 1 and 10,000 respectively.  With subsampling as replicating model, 15 replicates were used.  Maximum iterations were set to 5,000, with 10-5 as convergence threshold with threshold rule of 10 percentile training presence as it relatively better at predicting suitable habitat for endemic species (Escalante et al. 2013).  The logistic output of the model shows the suitability of the habitat, graded over a range of 0 to 1.

 

Molecular analysis

Genomic DNA was isolated from 95–100 % ethanol preserved liver tissue sample using phenol: chloroform: isoamyl alcohol reagent (25:24:1 v/v) as described by Sambrook & Russell (2001).  Two partial mitochondrial markers, cytochrome b (cyt b) and NADH dehydrogenase 2 (ND2) along with two nuclear markers, Recombination Activation Gene 1 (RAG-1), Phosducin (PDC) were used to infer the phylogeny of H. scabriceps (see Agarwal et al. 2011).  These molecular markers were useful for resolving the phylogenetic relationships at deeper nodes.  Primers and PCR conditions used were as described in Bauer et al. (2008).  PCR products were purified and sequences were obtained commercially from Bioserve Biotechnologies, Hyderabad, India.  All PCR amplifications were carried out in 25µL reaction volumes, with 12.5µL of the 2X PCR master mix (Thermo Scientific), 0.5µL forward primer, 0.5µL reverse primer (10 pm/ µL concentration each) and 2µL template DNA added and the final volume was adjusted with nuclease-free water.  Reactions were carried out with Thermo Scientific Mastercycler gradient thermocycler.  The sequence integrity was analyzed by BLAST tool (Altschul et al. 1997), processed and submitted to NCBI GenBank under the accession numbers given in Table 3 (Appendix 1).

 

Phylogenetic analysis

The mitochondrial genes cyt b (379 bp), ND2 (981 bp) and the nuclear genes PDC (400 bp) and RAG-1 (1000 bp) sequences of representative members of major, well supported Hemidactylus groups - H. flaviviridis, H. brookii, H. prashadi and H. frenatus (Bansal & Karanth 2010, 2013; Murthy et al. 2015; Giri et al. 2017; Chaitanya et al. 2018) were downloaded from GenBank (accession numbers listed in Table 3 in the appendix). Sequences were aligned with default gap penalties using ClustalW (Thompson et al. 1994) in MEGA 7.0. (Tamura et al. 2011).  Protein-coding genes were translated to amino acids to check for the reading frame and premature stop codons.  Uncorrected pairwise distances were calculated using the inbuilt program in MEGA.

Sequences of the members of the H. brookii sensu lato group that were published prior to the revisions of the group (Mahony 2011; Lajmi et al. 2016) were labeled as H. brookii due to the inability to trace and identify the specimens from which the sequences were derived.  The same revision, however, shows that the group including the ground-dwelling Hemidactylus is monophyletic and is sister to the H. frenatus group.  Hence, the H. brookii epithet is used here indicating individuals that may represent H. murrayi, H. gleadowi, H. treutleri, H. kushmorensis or H. parvimaculatus (Lanfear et al. 2012).

We used Partition Finder 2.1.1 to pick the partitions and best substitution model for the analysis.  The concatenated gene dataset (cyt b, ND2, PDC and RAG1) comprise a total of 2760 bp.  We built a maximum likelihood (ML) tree in RAxML HPC 7.4.2 through RAxMLGUI v1.3.1 (Silvestro & Michalak 2012) by running ML + thorough bootstrap for 10 runs and 1000 repetitions.

 

 

RESULTS

 

Molecular phylogeny and relationships

Our tree (Image 1) recovered H. scabriceps as member of a clade containing H. triedrus of peninsular Indian plains, H. lankae of Sri Lankan plains, H. maculatus of the northern Western Ghats, H. prashadi of central Western Ghats, H. acanthopholis and H. vanam of southern Western Ghats, H. hunae of Sri Lankan hill tracts, H. graniticolus of southern Eastern Ghats, H. sushilduttai and H. kangenerensis of northern Eastern Ghats and Chota Nagpur plateau, and more closely with H. depressus of Sri Lanka.

From a broader perspective, the ML analyses on the concatenated dataset with sequence lengths of 2760 bp yielded a tree (Image 1) of similar topology to previous studies (Chaitanya et al. 2018).  Comparing tree topologies from prior works corroborated the integrity of our trees.  Dravidogecko anamallensis is sister to all Indian Hemidactylus that consists of four well-supported groups, H. flaviviridis, H. brookii, H. prashadi and H. frenatus (Bansal & Karanth 2010; 2013).  As previously known, H. brookii sensu lato is sister to the H. frenatus group; while H. scabriceps falls within the H. prashadi group (support seen in tree).  The relationship of H. scabriceps with other rock-dwelling Indian and Sri Lankan Hemidactylus is strongly supported in our tree.

From a species-specific viewpoint, the pairwise distance matrix revealed 6% divergence in the cyt b gene between the two individuals of H. scabriceps sampled from different localities (Thanjavur and Coimbatore). The genetic distance between H. scabriceps and other species of the H. prashadi and H. brooki clades are given in Table 1.  The high genetic divergence between the populations sampled may indicate that H. scabriceps could be a potential species complex that requires further study.

 

Morphology and body configurations (n=7, in mm) (Images 2 & 3)

A small-sized Hemidactylus (30.1–41.3); head short (9.6–13.8); distinct from neck; head broader (4.3–7.4) than high (3.9-6.9); forehead flat; snout (3.5–4.6) longer than orbital diameter (1.0–2.7); snout concave; covered with heterogeneous granular scales; scales on head keeled; small warty scales on parietal region intermixed with granular scales; scales largest on canthal region, size similar to tubercles on parietal region; pupil vertically elliptical with sharp crenellated edges, supraciliaries large when compared to scales on canthal region; pointed posteriorly; becoming smaller and less pointed towards posterior; spinose posteriorly; nostrils close to snout-tip (2.8–3.0), moderately wide (1.3–2.7), fairly close to eye (2.3–3.5); ear opening small (0.2–1.5); orbital diameter slightly smaller than orbit to ear distance; eyes distant from each other (1.4–3.8); rostral large; subrectangular to pentagonal in shape; in contact with nostril and the 1st supralabial, medial groove dorsally, extending more than half the length of the rostral depth; supralabials 7/7 (left/right); infralabials 6/6 (left/right); mental triangular; two pairs of post mentals, inner pair in contact with mental and each other, outer pair not in contact with each other; a pair of smaller chin shields in contact with the outer postmentals followed by elongated shields in two rows in contact with the infralabials; no chin shields posterior to the postmentals; a row of smaller, slightly elongated scales with slightly pentagonal scales wedged in the intersection of the postmental scales; gular covered with small granular scales; trunk of moderate size (13.1–20.7); body slightly depressed, oval in cross-section, dorsolateral fold weak to indistinct; dorsum covered with mildly keeled, imbricate scales with no tubercles; granular scales from head gradually changing into sub-imbricate scales on nape and imbricate scales towards torso; mild keels on dorsal scales distinct, gradually disappearing towards ventral scales, scales at paravertebral line comparatively smaller than other dorsal scales; ventral scales imbricate till femoral region; slightly smaller, rounded sub-imbricate scales posterior to femoral region; preanofemoral pores 2–4 on each side separated by 1–2 pore-less scales; forelimbs slender, covered with small, imbricate scales reducing in size and sub-imbricate to granular scales ventrally, forelimbs moderate, crus (5.4–6.7) longer than forearm (4.0–5.1); hindlimbs slender, covered with imbricate scales both ventrally and dorsally; dorsal part of manus and pes covered with small granular scales; digits short, free, with interdigital webbing absent, a distinct short curved claw present in all the digit tips; all digits with initial few lamellae divided, other lamellae fused; lamellar formula of manus 4-6-5-5-5 and pes 5-7-8-8-5; basal lamellae narrow; tail fairly long, (21.2–43.2) subequal to body length, robust and thickset in width (3.2–4.9); blunt at tip, round in cross section, covered with imbricate scales subequal to size of scales on dorsum, tubercles absent; dorsum light brown with dark brown bands extending from above the dorsolateral fold region sometimes forming ‘x’s along the body from nape to vent region with large white spots or scales sometimes forming stripes across the body found; smaller white and black spots intermixed with the light brown parts of the body; head covered with dark and light-colored spots, labials characterized with a black patch forming a stripe pattern throughout the labials, sometimes extending into stripes in the gular region; venter dirty white, rarely with small black dots; mental shields with small black blotches; manus and pes darker beneath.

 

Distribution and niche modeling

Hemidactylus scabriceps has so far been recorded from the dry, low-elevation plains of Tamil Nadu ranging from 10 to 380 m (Image 4).  In the Coromandel Coastal Plains this species is known from Adayar (in Madras) near Palar Bay, southwards to Mannampandal near Cauvery Delta, further down in Ramanathapuram and Thoothukudi north and south of the Palk Strait, respectively.  Apart from the earlier records we sighted this species from Thitai (11.0830N & 77.0310E; 44m) in Thanjavur Delta region, Kalapatti (11.0830N & 77.03170E, 385m) further westwards in the Coimbatore Plateau, south in Pottal (8.6440N & 77.4840E, 77m) just east of Tirunelveli foothills and Mariccukatte (Marichchukkaddi) in Sri Lanka (8.5800N & 79.9460E).

The input for species distribution modeling are nine least correlated bioclim variables, altitude and NDVI layers with 13 sample locations of the species.  The logistic output of the model shows the suitability of the habitat, graded over a range of 0–1.  A binary map is created indicating suitable and unsuitable habitat for occurrence of H. scabriceps.  A threshold of 0.3491 was selected to classify the suitability which is the average value of the threshold rule used for the MaxEnt model. The AUC for the run/model is above 0.9 showing high goodness of fit.  The AUC value of the model is 0.987 indicating that the resultant model is reliable.

The relative contribution (approx.) of the environmental variables to the MaxEnt model is as shown in Table 4.  It is observed that the following variables are the major contributors to the model - bio2 (mean diurnal temperature range), bio12 (Annual Precipitation) and alt12 (altitude) signifying that the habitat most suitable for H. scabriceps is low altitudes, less rainfall and relatively less change in maximum and minimum temperature with annual mean temperature of approximately around 28.50C.

As per the output of MaxEnt modeling (Image 4), H. scabriceps is predicted to be distributed from the far south of Tamil Nadu (including Tirunelveli and Tuticorin) northwest till about Coimbatore, northeastwards till about Madras (currently Chennai), with high possibilities of being present in dry parts of northern Sri Lanka.  This species is possibly confined to this range within the dry parts of Tamil Nadu, Kerala and Sri Lanka, bound by the Western and Eastern Ghats; and the highlands in central Sri Lanka.

 

 

DISCUSSION

 

Hemidactylus scabriceps is a member of a clade comprising large-bodied, rock-dwelling, scansorial geckos, although it has a small terrestrial body-build and is found in low-elevation plains that are not dominated by rock formations.  Our new molecular phylogenetic analyses provide a radically different and contrasting relationship for Hemidactylus scabriceps, as shown in Image 1.  To untangle this complex interplay between morphology, habitat associations / distribution and genetic relationships, we herein elaborate on these three seemingly disparate features and discuss their dynamics in light of potential evolutionary trajectories that might have acted upon this species shaping it into what it is now.

The morphological characterization and ecological data of our new individuals are for the most part in conformity with literature reports (Annandale 1906; Smith 1935; Ganesh & Chandramouli 2010; Ganesh et al. 2017).  Another important facet of morphology of H. scabriceps is the persistence of transverse series of white spots / dotted lines across the trunk, typical of all the known members of H. prashadi group and absent in H. albofasciatus, H. imbricatus, H. reticulatus and H. sataraensis (Smith 1935; Bauer et al. 2008; Giri & Bauer 2008).  We postulate that the white spots and barred pattern on the back are a synapomorphy of the H. prashadi clade, present either bold or diffuse in all of its members.  Based on our phylogeny we postulate that the under-developed or rudimentary claws and digits in general, along with the partial fusion of digital lamellae of H. scabriceps, are ecologically derived traits consequent upon a strictly terrestrial lifestyle.  Similar to the phenotypically biased taxonomic allocations that taxa from the H. brookii clade have had, the current study confirms that the genus Lophopholis, originally erected for H. scabriceps, is actually a synonym of Hemidactylus (also see Bauer et al. 2008).

We observed this species in grassland/ dry thorn scrub jungle dominated by palmyra trees, in coconut grove and paddy fields. The species is strictly nocturnal, found resting under rocks during the day, preferably on mounds of gravel under moderately large rocks.  It was repeatedly observed to be in a ‘s’ shaped position under rocks and trying to stay still and not trying to get away while the rock was disturbed.  This behavior was also observed in H. reticulatus (Ganesh et al. 2017; this work) and H. sataraensis (see Bauer & Giri 2008).  It is also common for H. scabriceps to be found in sympatry with H. triedrus (Image 8).  Some specimens were also found inside termite-eaten and weathered palm and coconut logs, leaves and fruits.  This species was observed to be highly territorial.  Two individual male specimens in the same vicinity showed territorial behavior, circling each other making chirping calls to each other (the only time the species was heard vocalizing) with a raised waving tail, stretched legs and arched body, and trying to bite at the neck of opponent male.  Individuals were found to occur at quite a distance from one another (15–20 m).  Thus our observations on the microhabitat associations of H. scabriceps along with previously published notes (Ganesh & Chandramouli 2010; Ganesh et al. 2017) do attest its strictly terrestrial lifestyle.

We found some of our adult male individuals to have either 2 or 4 pores on a single side, whereas it usually numbers 3 (Ganesh et al. 2017).  Such variations in characters of diagnostic importance in gecko taxonomy, coupled with high levels (6% in cyt b) of inter-individual genetic divergence point out to the possibility of cryptic speciation within this complex. It is also noteworthy to highlight that though the original description (Annandale 1906) and subsequent expanded characterizations, both historical (Smith 1935) and recent (Ganesh & Chandramouli 2010; Ganesh et al. 2017) of this species still stems from Coromandel Coastal Plains population, except for the sole record of a specimen from near Madurai (see Ganesh et al. 2017).

Thus the current study describes previously unsampled populations from Coimbatore near the foothills of the Western Ghats, a different ecoregion altogether.  Even here, we observed fine-scale landscape partitioning between H. scabriceps and the ecologically similar H. reticulatus (see Ganesh et al. 2017).  This makes H. scabriceps the only member of H. prashadi clade to be distributed exclusively in a primarily sandy alluvial plains terrain not dominated by rock outcrops.  The loose occurrence of individuals of H. scabriceps at some distance between each other was observed to be similar to other Hemidactylus species such as H. mabouia (see Regalado 2003).  Our niche distribution model shows an indication that rivers Cauvery and Amaravathi (a tributary of Cauvery) could be geographic barriers between the Coimbatore plateau population and the Cauvery delta and Palk Strait populations, which might explain the high genetic divergence between the individuals sampled from these distinct populations.

Other ground-dwelling Hemidactylus occur both in the H. prashadi and the H. brookii clades.  In the H. prashadi clade, in as far as is known, only H. triedrus is terrestrial and is currently known to be distributed in most of the dry zones of peninsular India including the transitional zones of the Western Ghats.  From the H. brookii clade, H. reticulatus is a similarly distributed terrestrial species, closely associated with rocky habitats.  Hemidactylus gracillis has its close affinities with black soil throughout its distribution in central India and northern peninsular India, while H. albofasciatus and H. satarensis are distributed in parts of the northern Western Ghats occupying rocky plateaus.  Hemidactylus scabriceps occupies the dry zone of Tamil Nadu and northern Sri Lanka (rainfall <1,000mm/year), restricting itself to the grasslands of the alluvial plains and sandy regions in Northern Sri Lanka and towards the east of Tamil Nadu and red soils towards its west in the Tamil Nadu uplands till the foothills of the Western Ghats.  The rocky outcrops in Tamil Nadu (both Eastern and Western Ghats), though interrupted by H. scabriceps habitat, are occupied by H. reticulatus.  Both the Western and Eastern Ghats in the west and north respectively restrict H. scabriceps within Tamil Nadu.  Informed by our MaxEnt analysis, we hypothesize that the farthest inland locality of H. scabriceps disclosed herein (Coimbatore) is inhabited by this species largely because of the deep erosion of the plateau created by the Cauvery River system, engraving a low, alluvial, plains ecosystem into the table-land, much far west than in other nearby parts of the peninsula.  This scenario is comparable to the Moyar Gorge being an important biogeographic barrier for terrestrial lizards such as Sitana sp. that are predominantly plateau dwelling (Deepak & Karanth 2018).  Hemidactylus scabriceps also shows the contrast of shared fauna between the dry zones of Tamil Nadu and Sri Lanka (Guptha et al. 2015; Deepak et al. 2016; Deepak & Karanth 2018).

Our findings have a direct bearing on the evolutionary history of this species.  The inferred trees from the current work showed strong support for the previously known groups—H. prashadi, H. flaviviridis, H. brookii, H. frenatus and H. platyurus.  From our study, it is also revealed that H. scabriceps belongs to the H. prashadi group (recognized by Bansal & Karanth 2010).  The reduced subdigital scansoral apparatus, imbricate tail scales, imbricate dorsal scales, reduced subcaudal scales and a terrestrial lifestyle are traits that seem to be visually convergent within sub-groups of Hemidactylus geckos both from Africa (H. isolepis, H. ophiolepis) and India (H. imbricatus) (Bauer et al. 2008).  The ground dwelling clade of geckos that share similar traits was previously known to be sister to the H. brookii group of geckos and H. scabriceps was assumed to be related to this group (Bauer et al. 2008).  Our phylogenetic analysis reveals that H. scabriceps is related to the large rock dwelling clade of geckos contrary to what was previously assumed prompted by morphological similarity.

The unexpected and contrasting genetic relationship of the morphologically and ecologically discordant H. scabriceps and H. prashadi group underscores the complexity of peninsular India’s geological history.  Previous studies on peninsular India’s terrestrial lizard species have all revealed such discordant patterns of genetic alliance and eco-morphology.  Agarwal & Karanth’s (2015) molecular phylogenetic analyses revealed that the fat-bodied, forest-floor dwelling taxa ‘Geckoella’ is actually a part of primarily scansorial and rupicolous Cyrtodactylus radiation.  Deepak et al.’s (2015) study on ‘Brachysaura minor also points out a similar structure, i.e. the short body form and completely terrestrial habits of that taxon, contrary to its arboreal congeners in the genus Calotes, is nothing but a result of reduction in tree cover and other associated landscape changes (Stromberg 2011; Ponton et al. 2012).  Similarly, the Miocene landscape changes such as aridification of the Indian sub-continent has shown large influence on lizard groups such as Cyrtodactylus, Ophisops, Sitana and Sarada in the Indian subcontinent (Agarwal & Karanth 2015; Agarwal & Ramakrishnan 2017; Deepak & Karanth 2018).  Similar to the phenotypically biased taxonomic allocations the above taxa have had, the current study confirms that the genus Lophopholis, originally erected for H. scabriceps, is actually a synonym of Hemidactylus (also see Bauer et al. 2008).

Although previous studies on other peninsular Indian lizard taxa have revealed such unexpected yet consistent patterns of genetic and eco-morphological discordance, such an instance within the better-studied Indian Hemidactylus radiation (Bansal & Karanth 2010; 2013; Bauer et al. 2008, 2010) exhibiting this sharp a contrast is without precedent.  This is particularly intriguing, especially when another member of the H. prashadi clade, H. triedrus, occurring in areas inhabited by H. scabriceps (see Smith 1935) can afford to survive in sandy low-elevation alluvial tracts without changing its body form too much.  But it must be borne in mind that though H. triedrus occurs in plains habitat it could still scale vertical rock surfaces when such formations are present within its range, whereas H. scabriceps cannot (Ganesh et al. 2017; this work).  Additionally, in most of the range of H. scabriceps, there are no other strictly-terrestrial geckoes, neither Hemidactylus nor other genera (Smith 1935; Somaweera & Somaweera 2009; Ganesh et al. 2017; this work), thereby throwing open prospects of an empty niche for a potential species to exploit.  Thus the current work brings to light a case of so far hidden historical competition between a eurytopic (H. triedrus, H. lankae) versus a stenotopic (H. scabriceps) clade member.  These species are geographically sympatric (Image 6), in India and Sri Lanka respectively, genetically related but morphologically very different (see Image 1).  This sharp discordance amply illustrates the complex interplay of historical landscape changes, eco-morphological reactions and resource-use competition.

 

 

 

 

 

 

Table 1. Percentage values of uncorrected pairwise divergence (p-distance) for the cyt b, RAG-1, PDC and ND2 genes between the closely related congeners of H. scabriceps and morphologically similar members of H. prashadi and H. brookii clades.  The percentage divergence of cyt b gene between the two specimens of H. scabriceps used in this study is 6.3 %.

 

 

Pairwise genetic distance with H. scabriceps from Coimbatore

ND2 distances

RAG-1 distances

PDC distances

cyt b distances

H. scabriceps (Tanj)*

-

0.4

2.1

6.3

H. prashadi

13.8

1.4

2.5

15.3

H. maculatus

17.5

2.5

2.5

15.3

H. kangerensis

-

-

-

18.8

H. depressus

8.8

1.8

3.8

18.2

H. vanam

-

1.4

2.5

19.3

H. sushilduttai

-

-

-

17.0

H. graniticolus

-

1.8

3.0

19.3

H. hunae

15.0

1.8

3.0

21.6

H. triedrus ^

11.2

2.2

2.1

18.8

H. lankae #

11.2

2.2

2.5

18.2

H. acanthopholis

12.5

1.8

3.0

19.9

H. reticulatus

 

 

 

24.4

H. albofasciatus

 

 

 

19.9

H. gracilis

 

4.7

5.5

22.2

H. imbricatus

21.3

3.9

6.4

22.7

H. parvimaculatus

16.2

3.6

5.1

21.1

 

 

Foot notes: * - intraspecific distance; ^ - syntopic clade-member in peninsular India; # - syntopic clade-member in Sri Lanka.

 

 

 

 

Table 2. A comparison of synapomorphic morphological characters that is convergent to H. scabriceps with the ground-dwelling Hemidactylus clade and the H. prashadi clade. Note the commonly shared characters of H. scabriceps with both the ground dwelling Hemidactylus and the H. prashadi clade.

 

Species

Series of white spots/ dotted line

Series of black stripes in the infralabials and gular

H. scabriceps

Present

Present

H. prashadi

Present

Absent

H. parvimaculatus

Present

Absent

H. maculatus

Present

Absent

H. kangerensis

Present

Absent

H. sushilduttai

Present

Absent

H. graniticolus

Present

Absent

H. hunae

Present

Absent

H. triedrus

Present

Absent

H. lankae

Present

Absent

H. acanthopholis

Present

Absent

H. reticulatus

Absent

Present

H. albofasciatus

Absent

Present

H. gracilis

Absent

Present

H. imbricatus

Absent

Present

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3. List of specimens used for the molecular analysis and genetic comparison with the museum numbers, localities and GenBank accession numbers. Highlighted species are the samples used in this study.

 

 

 

Species

Museum No.

Locality

cyt b

ND2

RAG-1

PDC

Cyrtodactylus ayeyarwadyensis

CAS 216446

Myanmar, Rakhine State, Than Dawe District

EU268380

JX440526

JX440685

JX440634

Cyrtodactylus consobrinus

LLG 4062

-

EU268381

EU268349

EU268288

EU268318

Cyrtodactylus loriae

FK 7709

Papua New Guinea: Milne Bay, Bunisi

EU268382

EU268350

EU268289

EU268319

Hemidactylus scabriceps

BNHS 2421

Kalapatti, Coimbatore, Tamil Nadu

KX902971

*

KX902973

KX902972

Hemidactylus scabriceps

VPC-GK-029

Tanjore, Tamil Nadu

KX902975

BankIt2106186

KX902977

KX902976

Hemidactylus brasilianus

MZUSP 92493

Brazil, Piauí, Parque Nacional Serra das Confusões

EU268383

EU268351

EU268290

EU268320

Hemidactylus imbricatus 1

JS11

Pakistan (captive specimen)

EU268385

EU268353

EU268292

EU268322

Hemidactylus imbricatus 2

JFBM2

Pakistan (captive specimen)

EU268386

EU268354

EU268293

EU268323

Hemidactylus flaviviridis 1

FMNH 245515

Pakistan, Punjab Province

EU268387

EU268355

EU268294

EU268324

Hemidactylus flaviviridis 2

ID 7626

India, Rajasthan, Kuldhara

EU268388

EU268356

EU268295

EU268325

Hemidactylus flaviviridis 3

ID 7640

India, Rajasthan, Jaisalmer

HM559596

HM559628

HM559694

HM559661

Hemidactylus frenatus 1

AMB 7411

Sri Lanka, Pidipitiya 1

EU268389

EU268357

EU268296

EU268326

Hemidactylus frenatus 2

LLG 6745

Malaysia, Pulau Pinang, Empangon Air Hitam 2

EU268390

EU268358

EU268297

EU268327

Hemidactylus frenatus 3

AMB 7420

Sri Lanka, Rathegala 3

EU268391

EU268359

EU268298

EU268328

Hemidactylus frenatus 4

LLG 4871

Malaysia, Pahang, Bukit Bakong 4

GQ375289

GQ458049

GQ375308

GQ375301

Hemidactylus frenatus 5

CES07035

India, Tamil Nadu, Valparai 5

HM595655

 

HM622356

HM622371

Hemidactylus turcicus

LSUMZ H-1981

USA, Louisiana, Baton Rouge

EU268392

EU268392

EU268299

EU268329

Hemidactylus karenorum

CAS 210670

Myanmar, Mandalay Division, Kyaukpadaung Township, Popa

EU268394

EU268362

EU268301

EU268331

Hemidactylus garnotii 3

CAS 215549

Myanmar, Sagaing Division, Mon Ywa District 3

HM559597

HM559631

HM559697

HM559664

Hemidactylus garnotii 2

CAS 222276

Myanmar, Mon State, Kyaihto Township, Kyait Hti Yo 2

EU268396

EU268364

EU268303

EU268333

Hemidactylus garnotii 1

CAS 223286

Myanmar, Rakhine State, Taung Gok Township, Ma Ei Ywa 1

EU268395

EU268363

EU268302

EU268332

Hemidactylus brookii 1

LLG6754

 

EU268397.1

EU268365.1

EU268304.1

 

Hemidactylus brookii 2

LLG6755

 

EU268398.1

EU268366.1

EU268305.1

 

Hemidactylus angulatus 1

MVZ 245438

Nigeria, Togo Hills, Nkwanta

EU268399

EU268367

EU268306

EU268336

Hemidactylus angulatus 2

EBG 746

Guinea, Daniah River at Koulete River

HM559588

HM559620

HM559686

HM559653

Hemidactylus palaichthus

LSUMZ 12421

Brazil, Roraima State

EU268400

EU268368

EU268307

EU268337

Hemidactylus greefii

CAS 219044

São Tome and Principe, São Tome Island, Praia da Mutamba

EU268401

EU268369

EU268308

EU268338

Hemidactylus fasciatus 1

WRB no number

Gabon, Rabi 1

EU268402

EU268370

EU268309

EU268339

Hemidactylus fasciatus 2

CAS 207777

Equatorial Guinea, Bioko Island, 3.6 km N of Luba 2

EU268403

EU268371

EU268310

EU268340

Hemidactylus bowringii 1

 

 

EU268405.1

EU268373.1

EU268312.1

 

Hemidactylus bowringii 2

 

 

EU268406.1

EU268374.1

EU268313.1

 

Hemidactylus robustus 1

MVZ 248437

Pakistan, Thatta District, 40km S of Mipur Sakro 1

EU268408

EU268376

EU268315

EU268345

Hemidactylus robustus 2

FMNH 245519

Pakistan, Baluchistan Province, Gwadar Division, Makran 2

HM559610

EU054287

EU054271

EU054255

Hemidactylus robustus 3

MVZ 234374

Iran, Lorestan Province, 99km SW (by road) of KhorramAbah 3

HM559611

HM559644

HM559710

HM559677

Hemidactylus reticulatus 1

AMB 5730

India, Tamil Nadu, Vellore 1

EU268410

Hemidactylus reticulatus 2

CES07016

India, Karnataka, Pavgada 2

HM595669

Hemidactylus reticulatus 3

CES06024

India, Karnataka, Bangalore 3

HM595670

Hemidactylus parvimaculatus 1

AMB 7475

Sri Lanka, Kandy 1

GQ375290

GQ458055

GQ375309

GQ375302

Hemidactylus parvimaculatus 2

ADS36

Sri Lanka, Kartivu 2

GQ375291

GQ458053

GQ375310

GQ375303

Hemidactylus parvimaculatus 3

AMB 7466

Sri Lanka, Mampuri 3

GQ375292

GQ458056

GQ375311

GQ375304

Hemidactylus craspedotus

LLG 5613

Malaysia, Perak, Temengor

HM559586

HM559618

HM559684

HM559651

Hemidactylus platyurus 1

KU 304111

Philippines, Lubang Id., Occidental Mindoro Prov., Lubang 1

HM559587

HM559619

HM559685

HM559652

Hemidactylus depressus 1

ADS 29A

Sri Lanka, Galkotte 1

HM559589

HM559621

HM559687

HM559654

Hemidactylus depressus 2

ADS 69A

Sri Lanka, Kuruwekotha 2

HM559590

HM559622

HM559688

HM559655

Hemidactylus depressus 3

AMB 7440

Sri Lanka, Dumbulayala 3

HM559591

HM559623

HM559689

HM559656

Hemidactylus depressus 4

AMB 7445

Sri Lanka, Ritigala 4

HM559592

HM559624

HM559690

HM559657

Hemidactylus depressus 5

AMB 7481

Sri Lanka, Matale 5

HM559593

HM559625

HM559691

HM559658

Hemidactylus depressus 6

AMB 7524

Sri Lanka, Galle 6

HM559594

HM559626

HM559692

HM559659

Hemidactylus giganteus 1

JB03

India (captive specimen) 1

HM559598

HM559632

HM559698

HM559665

Hemidactylus giganteus 2

CES08013

India, Karnataka, Hampi 2

HM595657

 

HM622357

HM622372

Hemidactylus haitianus 1

AMB 4188

Dominican Republic, Santo Domingo 1

HM559599

HM559633

HM559699

HM559666

Hemidactylus haitianus 2

AMB 4189

Dominican Republic, Santo Domingo 2

HM559600

HM559634

HM559700

HM559667

Hemidactylus leschenaultii 1

AMB 7443

Sri Lanka, Polonnaruwa 1

HM559601

HM559635

HM559701

HM559668

Hemidactylus leschenaultii 2

JB05

India (captive specimen) 2

HM559602

HM559636

HM559702

HM559669

Hemidactylus leschenaultii 3

CES07041

India, Tamil Nadu, Chidambaram 3

HM595662

 

HM622360

 

Hemidactylus longicephalus

CAS 218939

São Tomé et Principe, São Tomé

HM559603

HM559637

HM559703

HM559670

Hemidactylus mabouia 1

AMB 8301

South Africa, Limpopo Prov., nr. Huntleigh 1

HM559604

HM559638

HM559704

HM559671

Hemidactylus mabouia 2

YPM 14798

USA, Florida, Monroe Co., Little Torch Key 2

HM559605

HM559639

HM559705

HM559672

Hemidactylus hunae

AMB 7416

Sri Lanka, Pitakumbura

HM559606

HM559640

HM559706

HM559673

Hemidactylus maculatus

BNHS1516

India, Maharashtra, Raigad District, Zirad

HM559607

HM559641

HM559707

HM559674

Hemidactylus prashadi 1

CES07037

India, Maharashtra, Ratnagiri 1

HM595666

Hemidactylus prashadi 2

CES06170

India, Karnataka, Udupi 2

HM595667

Hemidactylus prashadi 3

CES07040

India, Karnataka, Castle Rock 3

HM595668

 

HM622364

HM622378

Hemidactylus prashadi 4

JB02

India (captive specimen) 4

HM559608

HM559643

HM559708

HM559675

Hemidactylus prashadi 5

JB30

India (captive specimen) 5

HM559609

HM559644

HM559709

HM559676

Hemidactylus lankae

AMB 7453

Sri Lanka, nr. Medavachchiya

HM559615

HM559648

HM559714

HM559681

Hemidactylus triedrus 1

JB09

India (captive specimen) 1

HM559616

HM559649

HM559715

HM559682

Hemidactylus triedrus 2

JB08

Pakistan (captive specimen) 2

HM559617

HM559650

HM559716

HM559683

Hemidactylus triedrus 3

CES07007

India, Karnataka, Ramnagar 3

HM595673

HM622365

HM622379

Hemidactylus aaronbaueri 1

CES08022

India, Maharashtra, Pune 1

HM595640

Hemidactylus aaronbaueri 2

CES08016

India, Maharashtra, Raigad District 2

HM595641

 

HM622352

HM622367

Hemidactylus albofasciatus 1

CES07038

India, Maharashtra, Sindhudurg District, Malvan 1

HM595642

Hemidactylus albofasciatus 2

CES08018

India, Maharashtra, Sindhudurg District, Malvan 2

HM595643

Dravidogecko anamallensis

CES08029

India, Kerala, Eravikulam,

HM595644

 

HM622353

HM622368

Hemidactylus gracilis

CES07039

India, Maharashtra, Pune

HM595660

HM622359

HM622374

Hemidactylus persicus

CES08027

India, Rajasthan, Jaisalmer

HM595665

HM622362

HM622376

Hemidactylus yajurvedi 1

CES12006

Kanker, Chhattisgarh, India 1

KT601564

KT601569

KT601566

Hemidactylus yajurvedi 2

CES12007

Kanker, Chhattisgarh, India  2

KT601565

KT601568

KT601567

Hemidactylus treutleri

CES06108

India, Telangana, Hyderabad

KU720681

KU720742

 

Hemidactylus graniticolus

CES08028

India, Tamil Nadu, Nilgiri Hills

HM595664

HM622361

HM622375

Hemidactylus vanam

BNHS2329

India, Tamil Nadu, Meghamalai

MG711527.1

MG711532.1

MG711540.1

MG711535.1

Hemidactylus sushilduttai

ESV 112

Simhachalam, Visakhapatnam District, Andhra Pradesh, India

MF668228.1

 

 

 

Hemidactylus kangerensis

BNHS 2486

Kanger Valley National Park, Bastar District, Chhattisgarh

KY938009.1

 

 

 

Hemidactylus acanthopholis

CES17066

Tamil Nadu, India

MG711526.1

MG711531.1

MG711539.1

MG711534.1

 

*accession number pending

 

 

 

 

Table 4. Analysis of variable contributions of H. scabriceps Maxent model. The names of the variables are as follows: _bio3_28 = Isothermality, _bio2_28 = Mean diurnal range, _bio1_28 = Annual mean temperature, _bio15_28 = Precipitation seasonality, _bio14_28 = Precipitation seasonality, _bio19_28 = Precipitation of coldest quarter, _bio18_28 = Precipitation of the warmest quarter, _bio8_28 = Mean temperature of the wettest quarter and _bio12_28 = Annual temperature

 

 

Variable

Percent contribution

Permutation importance

bio2

43.5

49.3

bio12

23

26.5

alt

11.9

20.5

bio1

9.7

2.9

bio18

6.5

0

bio3

4.8

0.2

veg

0.5

0.3

bio19

0.1

0

bio14

0.1

0.1

bio8

0

0.1

 

 

 

 

 

REFERENCES

 

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Agarwal, I. & U. Ramakrishnan (2017). A phylogeny of open-habitat lizards (Squamata: Lacertidae: Ophisops) supports the antiquity of Indian grassy biomes. Journal of Biogeography 44(9): 2021–2032.

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Bansal, R. & K.P. Karanth (2010). Molecular phylogeny of Hemidactylus geckos (Squamata: Gekkonidae) of the Indian subcontinent reveals a unique Indian radiation and an Indian origin of Asian house geckos. Molecular Phylogenetics and Evolution 57(1): 459–465; http://doi.org/10.1016/j.ympev.2010.06.008  

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Appendix 1. Hemidactylus scabriceps material examined

 

Syntype: BMNH 1946.8.22.40, adult female, Ramnad, Madras District (=Ramnad, Tamil Nadu, India), collected by Col. Annandale, 1906.

BMNH 1920.12.14.2, adult female, Adiyar, Madras (= Chennai, Tamil Nadu, India), collected by D.W. Devanesan, 1920.

BMNH 1933.11.24.1, adult male, Mariccukatti, Northern Province, Ceylon (= Sri Lanka), collected by P.E.P. Deraniyagala, 1934.

CESL 503 & CESL 504, Adult male and female, Kalakad, Tamil Nadu, India, Collected by Saunak Pal, 2012.

BNHS 2421, Adult Male, Kalapatti, Coimbatore, Tamil Nadu, India, Collected by Achyuthan, N. Srikanthan and Chethan Kumar Gandla, 2014.

VPC-GK-029 (IISER, Thiruvananthapuram), Adult male, Thanjavur, Tamil Nadu, India, collected by Gopal Murali, 2014.