This book is a preliminary summary of some aspects of our research and fieldwork in the southern Western Ghats over the past few decades. National Geographic Explorer project provided support for field surveys to document the diversity and compile this field guide.

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The publication of this booklet (freePDF) and some of the underlying research (field surveys between 2020–2022) was funded by
the National Geographic Society grant NGS-63816R-19.

Table of Contents

The Western Ghats is one of the oldest mountain ranges in India. The Indian plate is estimated to have separated from Madagascar approximately 80 million years ago, which was part of the Gondwana supercontinent. The southern Western Ghats is the range’s most geographically complex and species-rich part. The highest “sky island” forest-grassland mosaic habitats differ substantially from those at lower elevations. These sky islands are separated from each other physically and environmentally but have similar communities of species distinct from those elsewhere in the Western Ghats. This book covers 58 species of reptiles (30 snakes and 28 lizards) from four mountain ranges in the Southern Western Ghats. Most of the species covered in this book are found at elevations >1,500 m (except in Agasthyamalai species >1,000 m were included). Some species are also found in the mid-elevations, but many widespread species are not covered in this book. The book had a checklist of species found in high elevations (<1,000 m). Eighteen of the 58 species covered in this book were described in the past five years, highlighting the probable incompleteness of taxonomically accurate reptile inventories for this biodiversity hotspot. This book is a preliminary summary of some aspects of our research and fieldwork in the southern Western Ghats over the past few decades. National Geographic Explorer project provided support for field surveys to document the diversity and compile this field guide.

This book is mainly a photographic field guide with brief species accounts and a history of systematic studies on lizards and snakes from this region. Species coverage in this book is not exhaustive – we lacked photograph and/or precise elevation data for some species. We tried to include photographs of both sexes where the species are sexually dimorphic, in some cases we also illustrate some of the observed colour variation. We have broadly divided this book into two sections, one for snakes and another for lizards and these main sections are further subdivided into families within these two broad groups. Maximum known total length (TL) and snout-vent length (SVL) is provided for each species in the top right corner. For snakes, dorsal scaled round the body were recorded one head-length behind the neck, at midbody and one head-length ahead of the vent. Locality information on the map is shown only for the four hill ranges covered in this book and some species distributions may extend beyond those depicted in this book. Current IUCN Red List status is given as abbreviated symbols for each species. The colour-coded checklist at the end of this book might be helpful to monitor future range shifts for species occurring in these hill ranges. A glossary of the terms used in the identification section is provided.

Ahaetulla dispar
Ahaetulla travancorica
Ahaetulla perroteti
Proahaetulla antiqua
Boiga thackerayi
Oligodon venustus
Oligodon travancoricus
Oligodon brevicauda
Hebius beddomei
Calliophis nigrescens
Xylophis mosaicus
Xylophis perroteti
Xylophis stenorhynchus
Craspedocephalus anamallensis
Craspedocephalus travancoricus
Craspedocephalus malabaricus
Craspedocephalus strigatus
Craspedocephalus peltopelor
Craspedocephalus macrolepis
Plectrurus perroteti
Platyplectrurus madurensis
Platyplectrurus trilineatus
Teretrurus sanguineus
Teretrurus rhodogaster
Melanophidium punctatum
Uropeltis liura
Uropeltis madurensis
Uropeltis pulneyensis
Uropeltis rubromaculata
Uropeltis rubrolineata

Calotes grandisquamis
Microauris aurantolabium
Monilesaurus acanthocephalus
Monilesaurus ellioti
Monilesaurus montanus
Psammophilus dorsalis
Salea anamallayana
Salea horsfieldii
Cnemaspis anandani
Cnemaspis australis
Cnemaspis beddomei
Cnemaspis indica
Cnemaspis nilagirica
Cnemaspis nimbus
Cnemaspis palanica
Cnemaspis rubraoculus
Cnemaspis wallaceii
Dravidogecko anamallensis
Dravidogecko douglasadamsi
Dravidogecko janakiae
Dravidogecko meghamalaiensis
Dravidogecko tholpalli
Dasia subcaerulea
Kaestlea bilineata
Kaestlea palnica
Kaestlea travancorica
Ristella rurkii
Ristella travancorica

Anal plate: in snakes the terminal ventral scale or scute, overlying the anus or vent.

Arboreal: Active in trees and bushes.

Biogeography: the study of the distribution of species and ecosystems in geographic space and through geological time.

Caudal: Pertaining to the tail or region of the tail; any pattern, plate, scale or structure on the tail.

Carinate: Having carinae (ridges or keels), as seen on the scales of particular lizards and snakes. (Bicarinate: having two keels. Tricarinate: having three keels).

Compressed: In reference to body or tail shape, somewhat flattened
from side to side providing a greater depth than width.

Crepuscular: Active during twilight.

Crest: Any elevated, flexible, cutaneous ridge or fold on the tails
and/or backs of many lizards.

Cycloid: Descriptive of a reptile scale possessing an evenly curved, free border.

Diurnal: Active during the day.

Dimorphism: Bimodal difference in morphology between members
of same species, often between the sexes (sexual dimorphism).

Diversification: an increase in lineages, phenotypes or genotypes during evolution from a common ancestor.

Endemic: occurring only in a particular area.

Femoral pores: Small openings in some enlarged scales on the

undersides of the thighs in some lizards. The pores contain a wax- like material consisting of cellular debris which may, in breeding males, project from the scales’ surface, forming a comb.

Flank: the side of an animal’s body, generally between the fore- and

Frontal: Pertaining to the scale, scales, or the space occupied by them (frontal area), on the top of the head situated between the supraocular scales, in lizards and snakes.

Dewlap: A pendulous fold or flap of skin under the throat (gular region) of some lizards. Typically used as a term for the often extensible structure that can, in some taxa, be raised or lowered by the action of the hyoid bone (well-developed in fan-throated lizards) during behavioural displays.

Genials: A term used to refer to chinshield. Any one of the large, paired, elongated scales situated immediately behind the first pair of infralabials on either side of the mid-
line on the lower jaw.

Heterogenous: Having a colour, pattern or size that is not uniform.

Homogenous: Having a colour, pattern or size that is uniform.

Juvenile: A young, typically sexually immature individual.

Imbricate: Having adjacent edges overlapping, used to describe scales.

Iridescence: In reptiles, rainbow-like sheen on surface of smooth scales.

Iris: The often distinctly coloured muscular tissue between the pupil and the edge of the front of the eye.

Keel: Ridge on back, tail or scale.

Labial: Of, or pertaining to, the upper or lower lip; any one of the

row of scales bordering the mouths of snakes and lizards on the upper and lower lips and termed upper/supra labial and lower/infra labial respectively.

Lamella (plural lamellae): In herpetology, used most frequently for the series of thin, either single or divided, transverse plates extending across the underside of the digits in many lizard species.

Lineage: An evolutionary lineage is composed of species or individuals that comprise all of the descendents of a particular common ancestor.

Loreal: A scale situated between those of the nostril (nasal scales) and those of the eye (preocular scales), but not touching either nostril or eye, in snakes which usually have only one per side, and in lizards which may have several.

Nasal: A scale, situated on the side of the head, that borders or contains a nostril (or naris).

Nocturnal: Active during the night.

Nostril (naris): Either one of the pairs of external openings to the air passages, situated at the end of the snout.

Nuchal: Pertaining to the (typically the back or upper part of the) neck region.

Orbit: The bony socket of the eye; the border of skin around the eye of a reptile or amphibian.

Ossicle: Any small, often irregularly-shaped bone in the body of an animal, especially one of those in the middle ear.

Parietal: Either one of a pair of large scales on the top of the head in snakes, directly behind the frontal and lying at least partly over the parietal bones that form the main part of the roof of the back of the skull.

Phylogenetics: The study of evolutionary relationships among organisms.

Postocular: Behind the eye, as in ‘postocular scale’ which refers to
any scale situated on the rear edge of the eye socket (orbit).

Preocular: Situated in front of the eye, as in ‘preocular scale’ which
refers to any scale situated on the front edge of the eye socket (orbit).

Precloacal pores: A structure, seemingly similar in function to the femoral pore, situated anterior to the anus or cloacal region, in some lizards. The pore opens to the exterior on the upper surface of the preanal scale.

Precloacal/preanal Scale: Any one of the rows of scales situated in the pelvic region, directly in front of the cloaca. In some lizards several of these scales may have precloacal pores.

Pupil: The opening (aperture) in the centre of the front of the eye surrounded by the iris. In reptiles and amphibians, the constricted pupil can be any one of a number of shapes: usually circular, vertically elliptical, horizontally elliptical, heart-shaped or triangular, all useful features in the identification of these animals.

Rostrum: A beak-like projection, especially a stiff snout or anterior
prolongation of the head.

Rupicolous: Living on, or among, rocks.

Scalation: Pattern of scales on body or on a specific part of body.

Scale: Is a small rigid, thin and horny plate growing out of the skin.

Scute(s): Any one of the larger scales on a reptile and alternatively termed a shield or plate.

Shola(s): colloquial regional term for subtropical evergreen montane forests in the southern Western Ghats typically in mosaics of grassland.

Spine: Any firm, pointed structure or process on the body or a scale.

Subcaudals: The scales on the underside, or ventral surface, of the tail from the vent to the tail tip (or terminal scute forming the tail tip). In most snake species the subcaudals are divided or paired, lying in a double row. In others they may be single, or a mixture of single and divided.

Supraocular: Any scale or scales situated above the eye and referring in particular to, in lizards, any one of the scales situated on the back of the eye socket (orbit) or, in snakes, the often enlarged scale directly above the eye which may, in certain species, project slightly to form a supraocular ridge.

Supraocular/Supraorbital ridge: The prominent elongated margin of the supraocular scale that overshadows the eye in a number of snake species, especially vipers.

Systematics: The branch of biology that deals with classification and nomenclature; often considered as an umbrella term for taxonomy and phylogenetics.

Temporal(s): Of, on, or relating to, the region of the temple on the side of the head, for example, any one of the more or less enlarged scales situated behind the postocular scales, beneath the parietal and above the upper labial scales at the angle of the jaw in snakes and lizards.

Terrestrial: Living on ground.

Tubercles: Small rounded projections or protuberances, especially on a bone or on the surface (often scales) of an animal.

Tympanum: The external eardrum, a membrane separating the middle ear from the outer ear. In many reptiles the tympanum is exposed at the skin surface, while in others it may be hidden from external view or completely lacking.

Ventrals: The typically broad scales on the under surface, or venter, of a snake, from back of the head to the anal plate.


About the authors

Deepak is currently a Humboldt postdoctoral fellow at the Senckenberg Natural History Museum, Dresden,Germany . Deepak has been involved in scientific research in South Asia since 2004,
focusing on herpetofauna. He started his research on lizards in the Western Ghats in 2004 and continued to work in the Ghats on the ecology and behaviour of tortoises for his Ph.D. His own surveys across India as part of his research along with collaborative work led to the discovery of 31 new species of reptiles and recognition of a new subfamily of snakes (Xylophiinae).


Surya is currently working at ATREE, Bengaluru with a special focus on the taxonomy of Indian reptiles and loves to make taxonomic illustrations of snakes. He has also published several natural history notes on the Indian snakes. Apart from
reptiles, he is interested in the molluscan taxonomy and phylogeny. He is also a naturalist who likes to spend a substantial amount of time in the field.

Sandeep Das is an EDGE Fellow of the Zoological Society of London, working towards the research and conservation of Nasikabatrachus sahyadrensis in the Western Ghats. He is interested in the taxonomy and biology
of amphibians and reptiles of the Western Ghats. Sandeep has been working on herpetofauna in the Kerala part of the Western Ghats since 2010.


Rajkumar is a herpetologist who is currently pursuing a Ph.D. on herpetofaunal diversity in the marshy grassland ecosystems in Periyar Tiger Reserve and on the status, distribution, activity pattern and vocalization of the
Endangered Travancore Bush Frog (Raorchestes travancoricus). He is also an EDGE Fellow working on the ecology of the Galaxy Frog (Melanobatrachus indicus) in the Western Ghats as part of the EDGE (Evolutionarily Distinct and Globally Endangered) of existence programme.

Saunak is scientist at the Bombay Natural History Society, Mum- bai. He is primarily in- terested in the systemat- ics and biogeography of endemic reptiles, especially agamid and gekkonid lizards of the
Western Ghats. Saunak has been involved in various studies across the Western Ghats, trying to understand the factors that influence the diversification of amphibians and reptiles, patterns of distribution, and causes of endemism. Currently, he is involved in curating the herpetofauna specimens as well as digitization of the collections at BNHS. He is also involved in various biodiversity mapping and con- servation projects across the country. Saunak’s collaborative studies in the Western Ghats have led to the discovery of over 30 new spe- cies of reptiles along with recognition of two new genera of agamid lizards and a new genus of snake.

Jason is an independent researcher with a Masters in Wildlife biology. Jason has a keen interest in herpetology and has been part of various conservation activities focused on reptiles since 2013. He has surveyed many parts of Tamil Nadu
(Kodaikanal and Meghamalai) regions for reptiles.

Dave conducts collections based research on the systematic and evolutionary biology of amphibians and reptiles, working at the Natural History Museum, London. His main taxa of interest and expertise are caecilians,  snakes  (especiallyf ossorial and aquatic species), and Triassic archosauromorphs. He has been interested in and contributing to the understanding of South Asian herpetology since his first visit to the region in 1998.


Deepak, Surya, Sandeep, Rajkumar, Saunak, Jason and David have collectively spent several decades studying these unique high-altitude ecosystems and are impeccably qualified to do justice to the incredible snakes and lizards that inhabit them.

Several species that have been previously depicted only in

scientific papers are featured in this book.

Included in each species description are diagnostic characters, morphometric information, and distribution maps to aid identification in the field (which I must caution, is not always possible)!

I congratulate the authors on collaborating to produce a book that documents one aspect of the incredibly rich biodiversity that exists in these isolated ‘islands’ that (mostly) tower above 1,500m in the southern Western Ghats of India.

Ashok Captain

Pune, India April 2022


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