The Haly's tree skink (''Dasia haliana'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

lizard Lizards are a widespread group of squamate reptiles, with over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic since it excludes the snakes and Amphisbaenia alt ...

in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Scincidae. The species is native to

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

. Earlier thought to be found also in the Western Ghats, taxonomic studies have shown ''D. haliana'' to be a Sri Lankan

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

, differentiated from the Indian '' D. subcaeruleum''. ''D. haliana'' is the only arboreal skink in Sri Lanka.

Description

An arboreal skink, with a snout-to-vent length (SVL) of about , ''D. haliana'' is distinct from all other sister species in having a smaller number of scale rows at the mid-body (22-24) and an enlarged set of

vertebra The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...

l row scales. Like other reptiles its

taxonomic Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

identification is based on

scalation In most biological nomenclature, a scale ( grc, λεπίς, lepís; la, squāma) is a small rigid plate that grows out of an animal's skin to provide protection. In lepidopteran (butterfly and moth) species, scales are plates on the surface o ...

. It has a pointed snout, and the distance from the nostril to the tip of the snout is longer than the diameter of the eye. The scales above the nostril are not in contact with each other and the fronto-nasal scale is equal in width and length. The prefrontals are large and are separated from another narrow frontal. The interparietal scale is variable in size and when large separates the parietals. There are a pair of nuchal (nape) scales. There are four scales above the eye with the second being largest and the first and second in contact with the

frontal Front may refer to: Arts, entertainment, and media Films * ''The Front'' (1943 film), a 1943 Soviet drama film * ''The Front'', 1976 film Music *The Front (band), an American rock band signed to Columbia Records and active in the 1980s and ea ...

. There are 7 or 8 supraciliaries, with the first being longer than the others. There are two loreals which are longer than their height. The

temporal scale Temporal may refer to: Entertainment * Temporal (band), an Australian metal band * ''Temporal'' (Radio Tarifa album), 1997 * ''Temporal'' (Love Spirals Downwards album), 2000 * ''Temporal'' (Isis album), 2012 * ''Temporal'' (video game), a 200 ...

s are larger than the scales on the sides of the neck. The tympanum of the ear is sunken and is less than a fourth of the diameter of the eye. The

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

have 3 or 5 blunt keels, and the two vertebral rows of dorsal scales are wider than the rest. The tail tapers to a point and is as long as the head and body. The limbs are short, and the toes are long, with 17 or 18 lamellae (or plate like scales) beneath the fourth toe. The palms and soles have flat tubercles with larger ones on the heel, especially in the male. The colouration is yellowish-olive above, with broad black bands which are as wide as the spaces between them. There are 5 or 6 of these bands on the neck and body, with a black mark on the occiput extending forward as streaks on top of the head. There are two lateral stripes passing through the eye and nostril. The underside is yellow. Smith, M.A. (1935). ''The Fauna of British India, Including Ceylon and Burma. Reptilia and Amphibia. Vol. II.—Sauria.'' London: Secretary of State for India in Council. (Taylor and Francis, printers). xiii + 440pp. + Plate I + 2 maps. (''Dasia haliana'', new combination, pp. 278–279).

Behaviour and geographic range

''D. haliana'' is the only arboreal skink in Sri Lanka. It is known much from the dry zone of the country, including

Pallegama Pallegama is a village in Sri Lanka. It is located within Central Province. The Kotmale Oya drains into the Mahaweli River The Mahaweli River ( si, මහවැලි ගඟ, literally "Great Sandy River"; ta, மகாவலி ஆறு 'm ...

, Dambulla,

Polonnaruwa Poḷonnaruwa, ( si, පොළොන්නරුව, translit=Poḷonnaruva; ta, பொலன்னறுவை, translit=Polaṉṉaṟuvai) also referred as Pulathisipura and Vijayarajapura in ancient times, is the main town of Polonnaruwa Dis ...

Bakamuna Bakamuna ( si, බකමුණ) is a village town in Sri Lanka. It is located within North Central Province. History It has many ancient ruins in Sri Lanka such as ''Buduruwayaya temple'', ''Oru bedi Siyambalawa'', and the city is located near ...

Horana Horana ( si, හොරණ, , ta, ஹொரணை) is a town in Kalutara District, in the Western Province of Sri Lanka. It is on the A8 highway between Panadura and Ratnapura, away from Ratnapura and away from Panadura. Horana is connected wi ...

Anuradhapura Anuradhapura ( si, අනුරාධපුරය, translit=Anurādhapuraya; ta, அனுராதபுரம், translit=Aṉurātapuram) is a major city located in north central plain of Sri Lanka. It is the capital city of North Central ...

Palatupana Palatupana is a coastal village located in the Hambantota District of Southern Province, Sri Lanka. Geography Palatupana lies along B499 road, where that road crosses Yala National Park Yala (යාල) National Park is the most visited and se ...

, Gampaha and

Jaffna Jaffna (, ) is the capital city of the Northern Province of Sri Lanka. It is the administrative headquarters of the Jaffna District located on a peninsula of the same name. With a population of 88,138 in 2012, Jaffna is Sri Lanka's 12th most ...

. It was also reported from southern India but the species that occurs there was found to be different and given the name of ''Dasia johnsinghi''.

Habitat

The preferred natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

of ''D. halianus'' is

forest A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

, at altitudes of .

Ecology

''D. haliana'' is confined to the dry and intermediate zones of the island of Sri Lanka, where it is found on large vine-covered trees, occupying tree holes as refuge.

Reproduction

''D. haliana'' is

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

. www.reptile-database.org. Clutch size is two eggs. Copulation is known in late January, and eggs are laid in early March.

References

Other sources

* Annandale N (1906). "New and interesting lizards in the Colombo Museum". ''Spolia Zeylandica'' 3: 189–192. * Deraniyagala PEP (1931). "Some Ceylon Lizards". ''Ceylon Journal of Sciience B'' 16: 139–180. * Greer AE (1970). "The Relationships of the Skinks Referred to the Genus ''Dasia''". ''Breviora'' (348): 1–30. *Joshua, Justus; Sekar, A.G. (1985). "Range extension of the skink ''Dasia haliana'' (H. Nevill, 1887)". ''Journal of the Bombay Natural History Society'' 82 (2): 422–423. * Karthikeyan S (1991). "Sighting of the arboreal skink ''Dasia haliana'' at Mundanthurai Wildlife Sanctuary, Tamil Nadu". ''J. Bombay Nat. Hist. Soc.'' 88 (1): 122–123. {{Taxonbar, from=Q3016752 haliana Reptiles of Sri Lanka Endemic fauna of Sri Lanka Reptiles described in 1887 Taxa named by Hugh Nevill