Hemidactylus triedrus

Kumbhargaon Village Outskirts, Bhigwan Bird Sanctuary

Geckos, lizards belonging to the clade Gekkota, are wide-spread, and species rich. They feature in the popular culture in anything from toy companies to children television series (Djeco, PJ Masks), usually depicted as the wall-clinging, broad-toed nocturnal animals that many of them really are. The Gekkota is a sister group to all other squamates, except for the enigmatic Dibamidae (e.g., Reeder et al., 2015; Harrington et al., 2016; Zheng and Wiens, 2016; Pyron, 2017). Gecko fossils are known from deposits 100–112 million years old (Arnold and Poinar, 2008; Daza et al., 2014) and fossilised gecko eggs are reported from Valanginian-Hauterivian (~130 million years) deposits (Moreno-Azanza et al., 2016). Additionally, the Late Jurassic lizards, Eichstaettisaurus schroederi and Ardeosaurus digitatellus are probably stem-group geckos (Simões et al., 2017), pushing gekkotan ancestry even further into the past (Kimmeridgian to the Tithonian, Simões et al., 2017; i.e., before 145–157 million years). Geckos have therefore diverged from other groups at least some 150 million years ago, and can thus be expected to differ markedly from even their closest living kin. 

To the south of Bhigwan, bereft of any hills, lie the wide Ujni backwater wetlands. A shallow waste water reserve formed by the discharge of water from the Pune region dams like Panshet, Pawna, Khadakwasla, Varasgaon, Temghar, etc. This semi waste water has created an excellent wetland based ecosystem supporting a large variety of water birds, both endemic and migratory, and also helped with the local agriculture. Nearly 300 species of endemic and migratory birds have been recorded here. The rainfall in the Pune region decides the water level in Ujni dam. Lesser the water, the shallower it is and therefore more birds make it their home in the winter. 

Surrounding this lush ecosystem are the rich grasslands and fertile farms home to an impressive list of birds, mammals and reptiles. The area around these backwaters are also unique with rich farmlands and dry deciduous scrub forest with interspersed grasslands. Home to an impressive list of birds, mammals and reptiles they protect many mammals like the Chinkara, Indian Mongoose, Near Threatened Striped Hyena, the Endangered Indian Grey Wolf & Indian Fox and are also popular for grassland birds and the birds of prey, including some magnificent eagles & harriers. My trip this time was focused only a few species like the Striped Hyena, Indian Grey Wolf and Jungle Cat. On our way back from the grasslands we decided to spend some time exploring the outskirts of the village hoping to find the Indian Chameleon and various geckos. We saw this Termite Hill Gecko for a brief moment before it disappeared into the darkness.

Some of the stunning birds of prey that populate the grasslands are magnificent eagles and harriers like the Endangered Steppe Eagle, the Vulnerable Greater Spotted Eagle, the rare and Vulnerable Eastern Imperial Eagle & the Pallid Harrier, Montagu’s Harrier & Eurasian Marsh Harrier. Apart from these there are other spectacular species like the Short-eared Owl, Spotted Owlets & the Indian Courser inhabiting the grasslands.

During my time here I was hosted by & had the expert help of Sandip Nagare and his team of knowledgeable guides from the Agnipankha Bird Watcher group, especially Ganesh Bhoi, who went out of their way to ensure I had fantastic opportunities to explore, discover, observe & photograph my target species on this trip. Like earlier, I stayed at Sandip’s homestay and once again had the added pleasure of indulging in delectable home cooked food. 

Read about my birds from Kumbhargaon & the Bhigwan Bird Sanctuary here and watch the videos on my Youtube channel - WildArtWorks.

Kumbhargaon Village, Bhigwan Bird Sanctuary

The Ujni or Ujjani Dam, also known as Bhima Dam or Bhima Irrigation Project, on the Bhima River, a tributary of the Krishna River, is an earth-fill cum Masonry gravity dam located near the Ujjani village of Madha Taluk in the Solapur district of the state of Maharashtra in India. The Bhima River, which originates in Bhimashankar of the Western Ghats, and forms the Bhima Valley with its tributary rivers and streams, has twenty-two dams built on it of which the Ujjani Dam is the terminal dam on the river and is the largest in the valley that intercepts a catchment area of 14,858 km² (which includes a free catchment of 9,766 km²). The construction of the dam project including the canal system on both banks was started in 1969 at an initial estimated cost of ₹400 million and when completed in June 1980 the cost incurred was of the order of ₹3295.85 million.

The reservoir created by the 185 feet high earth cum concrete gravity dam on the Bhima River has a gross storage capacity of 3.320 km³. The annual utilisation is 2.410 km³. The project provides multipurpose benefits of irrigation, hydroelectric power, drinking, and industrial water supply and fisheries development. The irrigation supplies benefit 500 km² of agricultural land, particularly in the Solapur district. Water supplied from the reservoir to irrigate agricultural areas primarily aims to reduce the incidence of famines and scarcity during drought conditions. The reservoir operation also lessens the threat due to floods to cities such as Pandharpur (an important religious pilgrimage centre for the Hindus). As a result of irrigation facilities, some of the important crops grown under irrigated conditions are sugarcane, wheat, millet and cotton.

This huge reservoir, almost seeming like a sea, is home to hundreds of birds - flamingos with their slender necks, egrets, painted storks, ruddy shelducks and many more. A man-made wetland, these backwaters are a winter sojourn of many migratory birds like the Brown-headed Gulls & Bar-headed Geese making it a mesmerising spectacle. This reservoir is one of the largest backwaters in India created by the Ujni dam. This life giving and sustaining reservoir fulfils multiple purposes - irrigation for agriculture, particularly in the Solapur district, being the primary one - but it also has rural, urban and industrial activities that are equally consuming.

Presently India has 26 sites designated as wetlands of International Importance according to Ramsar Convention. As far as Maharashtra goes, of its multiple natural and man-made reservoirs, none are designated as a Ramsar site. But according to Ramsar’s important identification criteria of population of migratory birds, the Ujni backwaters are amongst the six important wetlands of Maharashtra hosting around 250 species of migratory and resident birds ranging from the pied kingfisher, northern shoveler, bar-headed geese, great egret, painted stork, Indian cormorant, Eurasian coot, common moorhen, black-headed ibis, Asian open-bill, the list is pretty long.

With such a blessed habitat harbouring many species of flora and fauna, this wetland has tremendous benefits to the villages around it. Sufficient water for agriculture, livelihoods to many through fishing and tourism, flood control and shoreline stability are some of the aspects this wetland caters to. Though created strategically for economic development, today, the value of these wetlands function far beyond the scope of any instrument of economic growth.

But the modern day demands on this resource are tremendous. Cash crops requiring huge irrigation, unmonitored use of pesticides, untreated and excessive sewage and industrial waste disposals, uncontrolled urban growth and the changing mindsets of people for newer lifestyles are slowly and steadily affecting this huge wetland.  Decline in the fish density in the major tributaries of River Krishna, increase in exotic weed species in water are some of the indicators of quality degradation of the wetland recorded by researchers. This isn’t the only threat to this spectacular habitat and its wildlife but it also has long term adverse effects on the present and future human population who are consumers of this wetland in the various ways they utilise it.

The conservation of such a large reservoir isn’t a simple task. It requires judicious water usage for local, agricultural and industrial purposes, advocating advanced irrigation technologies to avoid and minimise wastage and banning diversions of water for non-priority purposes can be some of the large-scale measures possible with equal participation of the Government and people alike. Conservation awareness among the local communities for wetlands and its flora-fauna can help in a long run.

On a smaller scale the villagers are doing their bit by consciously avoiding plastic litter, controlled fishing and adopting rowing instead of engines for tourist boats wherever possible. These are some of their simple but effective ways to stop draining these life giving wetlands.

Termite Hill Gecko

Geckos are reptiles and are found on all the continents except Antarctica. They are a hyper-diverse, ancient, and globally distributed group which have diverged early from other squamates and thus can be expected to differ from them along multiple ecological, life history, and biogeographic axes. These colourful lizards have adapted to habitats from rain forests to deserts, to cold mountain slopes. Over a long period of time, geckos have developed special physical features to help them survive and avoid predators. Gecko tails serve many purposes. They help balance their weight as they climb branches, they act as fuel tanks to store fat, and as camouflage to help them disappear into their environment. Geckos are also able to shed their tails if a predator grabs them. Geckos are spread across six families: Carphodactylidae, Diplodactylidae, Eublepharidae, Gekkonidae, Phyllodactylidae, and Sphaerodactylidae. Of these, the eublepharids—a group that includes the banded geckos (Coleonyx) of the southwestern United States, the cat geckos (Aleuroscalabotes) of Indonesia and the Malay Peninsula, and others—have movable eyelids.

Most geckos are nocturnal, which means they are active at night, but day geckos are active during the day and nibble on insects, fruits, and flower nectar. Most geckos make noises such as chirping, barking, and clicking when they are defending their territory or attracting a mate. Female geckos lay their eggs in leaves and bark. Most geckos don’t have movable eyelids and instead have one transparent eyelid which they keep clean by licking it with their tongues.

Few traits completely separate geckos from other lizard taxa, yet they differ to a large degree along many axes: they are more restricted to low latitudes and altitudes, are especially diverse on islands, but relatively scarce in America. They are small lizards, that lay small, fixed clutch sizes, for which they compensate only partially by laying frequently. Because they mature at relatively similar ages and have similar lifespans to other lizards, geckos produce fewer offspring over a year, and over their lifetimes, perhaps implying that they enjoy higher survival rates. While being the only large lizard clade of predominantly nocturnal lizards a large proportion of species is active by day. Gecko body temperatures and preferred temperatures are lower than those of other lizards –even when they are compared to lizards with similar activity times. Worryingly, most geckos have small ranges that often reside completely outside of protected areas – much more frequently than in other reptile and vertebrate taxa.

There are many species of geckos. Depending on the species, their endangered status can range from least concern to critically endangered.

Termite Hill Geckos (Hemidactylus triedrus) comprises of a group of closely related species spread over a wide geographical area including parts of Pakistan, India and Sri Lanka. Several species were thought to represent H. triedrus leading to taxonomic confusion, which has now been successfully resolved. “My colleagues and I have been working on documentation of reptiles across peninsular India. The fascination that my colleagues and I have for reptiles and documenting its diversity was the main motivation behind this study”, shares Mr Zeeshan Mirza, a researcher from NCBS and an author of the study.

The taxonomy of H. triedrus has an exciting history. The first description of this species was of a male by an unknown collector. Another researcher described a species from Nellore, Andhra Pradesh as H. subtriedrus and marked it as a distinct species without much molecular or morphological evidence. Thus, the validity of H. subtrierdus as a species was questioned. Following this, in 1871-72, another researcher reported H. subtriedrus from Erode, Tamil Nadu. In 1905, Nelson Annandale, a Scottish herpetologist, regarded the specimen from Erode as one that is an intermediate between H. triedrus and H. subtriedrus. However, in due course, the type specimen, based on which the description of subsequent discoveries of Hemidactylus genus is made, was lost from Annandale’s list of Indian gekkonid collection.

William Theobald, a naturalist and staff of the then Geological Survey of India and Burma, presented two accounts of the species concerning Hemidactylus; H. subtriedrus Jerdon (1853) and H. subtriedrus Theobald (1876). Hemidactylus triedrus lankae, the Sri Lankan population, was attributed as a subspecies of H. triedrus. Another group of  researchers proposed the validity of H. subtriedrus without any morphological data and declared that H. triedrus lankae was a species. Nonetheless, the specimens of H. triedrus lankae, based on which the nomenclature is carried out, are now missing or lost, making identification impractical.

In this study, the researchers set out to verify whether H. subtriedrus is a species by itself. They started by collecting a male specimen from Nellore, Andhra Pradesh, where the first specimen of this species was described and compared it with existing museum specimens. Given the widespread distribution and heterogeneity of landscapes in which the species is found, they also collected H. triedrus specimens from Pondicherry, Chennai, Maharashtra, Karnataka, Andhra Pradesh and Gujarat. Upon observation, they found that the specimen from Nellore was identical to those collected from Pondicherry and Chennai, confirming that H. subtriedrus is a synonym of H. triedrus, implying that both are the same species.

The results revealed two new species in addition to H. triedrus—the highlight of the study. H. triedrus sensu stricto comprises of individuals from Nellore, Pondicherry and Sri Lankan, while the new species, called H. whitakeri sp. nov. and H. sahgali sp. nov. comprised of populations from from Karnataka, and Maharashtra, Gujarat and parts of Pakistan respectively.

What are the distinct characteristics of these new species? “Males of most gecko species possess a series of scales with a single pore around the cloacal region, and these may extend to the thigh of the animal. These pores are important diagnostic characters, and each species has a fixed number of these pores”, says Mr Mirza.  So, H. sahgali bears 11-15 of these pores and the other two species, H. triedrus and H. whitakeri bear 6-9. On the other hand, H. triedrus has trihedral tubercles, large modified scales which look like pimples, on their back whereas H. whitakeri has sub-trihedral tubercles.

The researchers believe that more work needs to be done regarding the discovery. “We are interested in defining the distribution of each of these species as there is limited data on the distribution, especially for H. whitakeri and H. triedrus. It will be interesting to find out if the ranges of these two species overlap or if they share the same habitat. Results from these will help formulate more interesting projects to study competition, hybridisation etc.”, says Mr Mirza before signing off.

The adult Termite Hill Gecko is a large lizard and grows to a maximum of about 7 inches from tip of snout to tail tip. This is also a gecko with black and white dots forming bands making it look very handsome; this and the larger size make it easy to identify. The large head is also quite characteristic.

Like all other geckos these too have the ability to drop their tails only to re-grow the same eventually.The head is large, oviform; snout longer than the distance between the eye and the ear-opening, 1.4 times the diameter of the orbit; forehead concave; ear-opening large, suboval, oblique, measuring about half the diameter of the eye. Body and limbs moderate. Digits free, moderately dilated, inner well developed; infra-digital lamellae slightly oblique, 6 or 7 under the inner digits, 8 to 10 under the median digits. Snout covered with convex granules, which may be keeled; hinder part of head with minute granules intermixed with roundish tubercles. Rostral subquadrangular, not twice as broad as deep, with median cleft above; nostril pierced between the rostral, the first labial, and three or four nasals; 8 to 10 upper and 7 or 8 lower labials; mental large, triangular or pentagonal, at least twice as long as the adjacent labials; four chin-shields, median pair largest and in contact behind the mental. Upper surface of body covered with small flat granular scales, and large trihedral tubercles arranged in 16 to 20 more or less irregular longitudinal series; these tubercles vary somewhat in size according to specimens, but the largest never exceed two fifths the diameter of the eye. Abdominal scales large, smooth, rounded, imbricate. Males with a series of preanal pores, interrupted mesially; 6 to 8 pores on each side Tail rounded, feebly depressed, tapering, covered above with irregular, small, smooth imbricated scales and rings of large, pointed, keeled tubercles, beneath with a median series of transversely dilated plates. Light pinkish brown above, generally with more or less defined transverse darker bands bordered by pure white tubercles surrounded by deep-brown rings; young very regularly barred with dark brown, there being four dark bars between head and hind limbs; a more or less defined dark-brown streak, white-edged above, on the side of the head, passing through the eye; lower surfaces white.

Geckos occur in warm regions throughout the world. They are especially species-rich in SW Africa, Madagascar, the southern coasts of the Arabian Peninsula, South and SE Asia, and Australia. However, geckos are much less species in the New World: they comprise just 12% of American lizards (12% in the Neotropics, 4% in the Nearctic), but 35% of lizard species elsewhere (from 28% in Oceania and Australia to 47% in the Indo-Malay Realm). Gecko “cold spots” are generally found in cold places. Geckos are mostly absent from cold places, and do not reach the highest latitudes that lizards inhabit, such as most of the USA, parts of the Andes, the Tibetan Plateau, parts of the Caucasus and Eastern Turkey, and much of central and northern Eurasia. Geckos are more likely to be insular than other lizards: 661 of 1896 gecko species (35%) are island endemics, compared with 1419 of 4980 (28%) in other lizards (χ2 = 265.3, p < 0.0001). From a similar perspective, 32% of insular endemic lizards are geckos, but they comprise only 26% of non-insular endemic species. Geckos generally do not reach high altitudes. The Atlas Mountains day gecko, Quedenfeldtia trachyblepharus, is the gecko reaching the highest elevation of the 1160 species (4000 m; Comas et al., 2014), but at least 81 other lizard species (of 3285 species with data) reach higher altitudes. On average, the maximum altitudinal limit of geckos is 870 m, vs. 1480 in other lizards (t = 18.7, p < 0.0001).

Despite being small-bodied, geckos age and survive in a similar fashion to other lizards: the mean age at maturity, across 160 gecko species is 18.0±11.9SD months vs. 22.6±19.1 months in other lizards (n = 568 species; the difference is statistically significant, but not when mass is corrected for: t = 1.22, p = 0.22). Similarly, the maximum gekkotan longevity is 10.1±8.6SD years vs. 10.5±9.9 years in other lizards (across 191 and 581 species, respectively; see also Stark et al., 2020, this volume). Thus maximum reproductive lifespan (defined here as maximum longevity minus average age at maturity) is 8.6 years in geckos and 8.7 years in other lizards.

Found over parts of Pakistan, India and Sri Lanka, the Termite Hill Gecko is shy and nocturnal in habit. Perhaps, these geckos feed primarily on cockroaches when they take up residence in human dwellings. Away from an urban setting, they are probably at home under large stones or in crevices and burrows. They feed on a variety of insects which could include grasshoppers, crickets, beetles and of course, termites. Though they are known to be frequently found in termite mounds, I have seen one peep from a termite mound only once in all these years…no points for guessing why the lizard gets its name!

Most geckos have feet modified for climbing. The pads of their long toes are covered with small plates that are in turn covered with numerous tiny hairlike processes that are forked at the end. These microscopic hooks cling to small surface irregularities, enabling geckos to climb smooth and vertical surfaces and even to run across smooth ceilings. Some geckos also have retractable claws.

In their efforts to avoid predators, geckos appear to be fast enough to sprint across the surface of a water body without sinking. Although this ability has been shown in only one species, the flat-tailed house gecko (Hemidactylus platyurus), herpetologists argue that many other geckos may also possess it.

Like snakes, most geckos have a clear protective covering over the eyes. The pupils of common nocturnal species are vertical and are often lobed in such a manner that they close to form four pinpoints. A gecko’s tail may be long and tapering, short and blunt, or even globular. The tail serves in many species as a storehouse of fat upon which the animalcan draw during unfavourable conditions. The tail may also be extremely fragile and if detached is quickly regenerated in its original shape. Unlike other reptiles, most geckos have a voice, the call differing with the species and ranging from a feeble click or chirp to a shrill cackle or bark.

Most species are oviparous, the eggs being white and hard-shelled and usually laid beneath the bark of trees or attached to the underside of leaves. A few species in New Zealand give birth to live young.

On the face of it, geckos are as threatened as the next lizards. Thirteen percent of gecko species are listed by the IUCN as threatened (251 species in categories VU, EN, CR and EW), similar to the 12% proportion of other lizards. Similarly, in both groups, 8% of species are listed as data deficient, and while 44% of geckos are non-threatened (classified as LC or NT) and 34% are left to be evaluated by the ICUN, the corresponding figures for other lizard taxa are very close at 45% and 35%, respectively. Thus, for both groups, species with helpful, classifiable categories form 57% of the total number of species whereas non-classifiable taxa (data deficient or non-evaluated) form 43%. The population trends are also broadly similar across geckos and other lizards: 12.2% of gecko species are listed as decreasing, 0.7% as increasing, and 38.2% of the species are classified as ‘stable’. For other lizards these numbers are 14.8, 0.3 and 39.9%. I note, however, that for nearly half the species (49% of geckos, 45% of other taxa) the population status is unknown. Five gecko species (Phelsuma edwardnewtoni, P. gigas, Hoplodactylus delcourti, Tarentola albertschwartzi and Nactus soniae) have gone extinct in the last few centuries. Lepidodactylus listeri is extinct in the wild.

The following are the few pictures I got of the gecko before it disappeared into the undergrowth.

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