''Boiga trigonata'', commonly known as the Indian gamma snake or common cat snake, 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 ...
of
rear-fanged colubrid
Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a family of snakes. With 249 genera, it is the largest snake family. The earliest species of the family date back to the Oligocene epoch. Colubrid snakes are found on ever ...
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 ...
to
South Asia
South Asia is the southern subregion of Asia, which is defined in both geographical and ethno-cultural terms. The region consists of the countries of Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.;;;;;;;; ...
.
Description
:''See
snake scales
Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joints ...
for terms used''
''B. trigonata'' has anterior palatine and mandibular teeth scarcely larger than the posterior. Its eyes are as long as the distance from its nostril; the
rostral
Rostral may refer to:
Anatomy
* Rostral (anatomical term), situated toward the oral or nasal region
* Rostral bone, in ceratopsian dinosaurs
* Rostral organ, of certain fish
* Rostral scale, in snakes and scaled reptiles
Other uses
* Rostral colu ...
is broader than deep with the
internasal scales
In snakes, the internasal scales are those on top of the head between the scales that surround the nostrils. Wright AH, Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates. (7t ...
shorter than the
prefrontal scales
The prefrontal scales on snakes and other reptiles are the scales connected to the frontals, towards the tip of the snout, which are in contact with the internasals.
See also
* Snake scales
* Scale (zoology)
In most biological nomenclature, a ...
. The frontal scales are longer than their distance from the end of the snout and shorter than the
parietal scales
Parietal scale refers to the scales of a snake which are on the head of the snake and are connected to the frontals towards the posterior. These scales are analogous to and take their name from the parietal bone which forms the roof and sides of ...
. The loreals are as long as they are deep, or, they can be deeper than they are long. ''B. trigonata''
's one
preocular
In scaled reptiles, the ocular scales are those forming the margin of the eye.Wright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . The name originates from the term ''oculus'' which ...
does not extend to the upper surface of the head. The species has two
postocular
In scaled reptiles, the ocular scales are those forming the margin of the eye.Wright AH, Wright AA. 1957. ''Handbook of Snakes''. Comstock Publishing Associates (7th printing, 1985). 1105 pp. . The name originates from the term ''oculus'' which ...
s, temporals 2+3, and 8 upper labials, with the third, fourth, and fifth entering the eye. They can have 4 or 5 lower labials in contact with the anterior chin-shields, which are about as long as the posterior. ''B. trigonatas body is moderately laterally compressed with smooth
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 ...
in 21 (or rarely 19) rows, with apical pits, disposed obliquely, with the vertebrals very feebly enlarged. There are 229-269 ventral scales, 79-92 divided subcaudal scales, and a single anal scale.
''B. trigonata'' has a yellowish-olive or pale grey colour along the back and a white black-edged zigzag band along the length of the head with two brown bands edged with black, diverging posteriorly. The belly is white and can have a series of small brown spots along each side.
The total length is around 3 feet (91 cm) with a 7-inch (18 cm) tail.
[Boulenger, G.A. 1890. ''The Fauna of British India, Including Ceylon and Burma. Reptilia and Batrachia.'' Secretary of State for India in Council. (Taylor and Francis, Printers.) London. xviii + 541 pp. (''Dipsas trigonata'', p. 358.)]
Geographic range
''B. trigonata'' is found in the Perso-Baluchistan frontier.
It is distributed throughout
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 ...
,
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
,
Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
,
Nepal
Nepal (; ne, नेपाल ), formerly the Federal Democratic Republic of Nepal ( ne,
सङ्घीय लोकतान्त्रिक गणतन्त्र नेपाल ), is a landlocked country in South Asia. It is mai ...
,
Bangladesh
Bangladesh (}, ), officially the People's Republic of Bangladesh, is a country in South Asia. It is the eighth-most populous country in the world, with a population exceeding 165 million people in an area of . Bangladesh is among the mos ...
,
Afghanistan
Afghanistan, officially the Islamic Emirate of Afghanistan,; prs, امارت اسلامی افغانستان is a landlocked country located at the crossroads of Central Asia and South Asia. Referred to as the Heart of Asia, it is bordere ...
(Leviton 1959: 461), southern
Turkmenistan
Turkmenistan ( or ; tk, Türkmenistan / Түркменистан, ) is a country located in Central Asia, bordered by Kazakhstan to the northwest, Uzbekistan to the north, east and northeast, Afghanistan to the southeast, Iran to the sout ...
, southern
Uzbekistan
Uzbekistan (, ; uz, Ozbekiston, italic=yes / , ; russian: Узбекистан), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi, italic=yes / ; russian: Республика Узбекистан), is a doubly landlocked cou ...
, southeastern
Tajikistan
Tajikistan (, ; tg, Тоҷикистон, Tojikiston; russian: Таджикистан, Tadzhikistan), officially the Republic of Tajikistan ( tg, Ҷумҳурии Тоҷикистон, Jumhurii Tojikiston), is a landlocked country in Centr ...
, and
Iran
Iran, officially the Islamic Republic of Iran, and also called Persia, is a country located in Western Asia. It is bordered by Iraq and Turkey to the west, by Azerbaijan and Armenia to the northwest, by the Caspian Sea and Turkmeni ...
.
The race ''melanocephala'' is found in Pakistan; this form is variously considered as a
subspecies
In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
, color variant, or full species.
Mimicry
''Boiga trigonata'' strongly resembles
venom
Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...
ous ''
Echis carinatus
''Echis carinatus'', known as the saw-scaled viper,Mallow D, Ludwig D, Nilson G (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. 359 pp. . Indian saw-scaled viper, little I ...
'' in coloration and shape. Also, in India, these two species have almost identical geographic ranges.
References
Further reading
*
Annandale, N. 1904. Additions to the Collection of Oriental Snakes in the Indian Museum. J. Asiat. Soc. Bengal 73: 207–211.
*Gans, C., and M. Latifi. 1973. Another Case of Presumptive Mimicry in Snakes. Copeia 1973 (4): 801–802.
*Leviton, A.E. 1959. ''Systematics and Zoogeography of Philippine Snakes''. Unpublished Ph.D. thesis.
*
Schneider, J.G. ''in''
Bechstein, J. M. 1802. ''Herrn de Lacépède's Naturgeschichte der Amphibien oder der eyerlegenden vierfüssigen Thiere und der Schlangen. Eine Fortsetzung von Buffon's Naturgeschichte aus dem Französischen übersetzt und mit Anmerkungen und Zusätzen versehen. Vierter Band''
olume 4 Industrie Comptoir. Weimar. xx + 298 pp. + 48 plates. (''Coluber trigonatus'', pp. 256–257 + Plate 40, Figure 1.)
External links
*
ImageImage
{{Taxonbar, from=Q2707516
trigonata
Reptiles of Afghanistan
Reptiles of Central Asia
Reptiles of Iran
Reptiles of Pakistan
Reptiles of India
Reptiles described in 1802
Taxa named by Johann Gottlob Theaenus Schneider