Hardella Thurjii
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The brahminy river turtle or crowned river turtle (''Hardella thurjii'') is a
species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...
in the
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Geoemydidae The Geoemydidae (formerly known as Bataguridae) are one of the largest and most diverse families in the order Testudines (turtles), with about 70 species A species () is often defined as the largest group of organisms in which any two in ...
. The species is
endemic Endemism is the state of a species being found only 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 foun ...
to
South Asia South Asia is the southern Subregion#Asia, subregion of Asia that is defined in both geographical and Ethnicity, ethnic-Culture, cultural terms. South Asia, with a population of 2.04 billion, contains a quarter (25%) of the world's populatio ...
.


Taxonomy

The genus ''Hardella'', to which the species ''Hardella thurjii'' belongs, is a
monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...
genus.


Geographic range

''Hardella thurjii'' is found in northern
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
,
Pakistan Pakistan, officially the Islamic Republic of Pakistan, is a country in South Asia. It is the List of countries and dependencies by population, fifth-most populous country, with a population of over 241.5 million, having the Islam by country# ...
, and
Bangladesh Bangladesh, officially the People's Republic of Bangladesh, is a country in South Asia. It is the List of countries and dependencies by population, eighth-most populous country in the world and among the List of countries and dependencies by ...
in the
watershed Watershed may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, an area of land where surface water converges (North American usage) Music * Watershed Music Festival, an annual country ...
s of the
Ganges The Ganges ( ; in India: Ganga, ; in Bangladesh: Padma, ). "The Ganges Basin, known in India as the Ganga and in Bangladesh as the Padma, is an international which goes through India, Bangladesh, Nepal and China." is a trans-boundary rive ...
,
Brahmaputra The Brahmaputra is a trans-boundary river which flows through Southwestern China, Northeastern India, and Bangladesh. It is known as Brahmaputra or Luit in Assamese, Yarlung Tsangpo in Tibetan, the Siang/Dihang River in Arunachali, and ...
, and
Indus The Indus ( ) is a transboundary river of Asia and a trans- Himalayan river of South and Central Asia. The river rises in mountain springs northeast of Mount Kailash in the Western Tibet region of China, flows northwest through the dis ...
rivers.


Description

''Hardella thurjii'' has a shell with a large, moderately flat, dark brown or black
carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...
(
dorsal surface Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...
) and a yellow or black
plastron The turtle shell is a shield for the ventral and dorsal parts of turtles (the Order (biology), order Testudines), completely enclosing all the turtle's vital organs and in some cases even the head. It is constructed of modified bony elements such ...
(ventral surface). The shell is up to in length in females, and is shorter in males. The lower jaw is heavily dented.


Sexual dimorphism

''Hardella thurjii'' exhibits
sexual dimorphism Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...
. Mature females are three times the size of mature males. According to Das, maximum straight carapace length in females is , but in males maximum straight carapace length is only .


Reproduction

The reproductive habits of ''H. thurjii'' are unique among reptiles in that the females lay their eggs under water rather than on dry land. Their reproductive cycle follows seasonal changes in the water levels of the rivers in which they live. In autumn, females lay their eggs under water, where higher water levels submerge the eggs for 40 to 45 days. In the winter, lower water levels expose the eggs for five months. The rising water levels of spring submerge the almost mature eggs once again, and the turtles hatch in the river. Indian zoologist Dhruvajyoti Basu first documented the unique reproductive habits of the brahminy river turtle in 2011. The
Prague Zoo Prague Zoological Garden (Czech: ''Zoologická zahrada hl. m. Prahy'') is a zoo in Prague, Czech Republic. It was opened in 1931 with the goal to "advance the study of zoology, protect wildlife, and educate the public" in the district of Troja (Pra ...
incubated the first brahminy river turtle which was born in captivity in 2012.


References


External links

*


Further reading

* Das I (1984). "Record length of the Brahminy River Turtle ''Hardella thurjii ''". ''Hamadryad'' 9 (3): 18. *Das I (2002). ''A Photographic Guide to Snakes and other Reptiles of India''. Sanibel Island, Florida: Ralph Curtis Books. 144 pp. . (''Hardella thurjii'', p. 126). * Gray JE (1831). ''Synopsis Reptilium; or Short Descriptions of the Species of Reptiles. Part I.—Cataphracta. Tortoises, Crocodiles, and Enaliosaurians.'' London: Treuttel, Wurtz, and Co. viii + 85 pp. (Diggens and Jones, printers). (''Emys thurjii'', new species, p. 22). (in English and Latin). * Smith MA (1931). ''The Fauna of British India, Including Ceylon and Burma. Reptilia and Amphibia. Vol. I.—Loricata, Testudines.'' London: Secretary of State for India in Council. (Taylor and Francis, printers). xxviii + 128 pp. + Plates I-II. (''Hardella thurgi'', pp. 122–124 + Figure 4 facing p. 50). {{Taxonbar, from1=Q596348, from2=Q14566135 Hardella Reptiles of Pakistan Reptiles of India Turtles of Asia Reptiles described in 1831 Taxa named by John Edward Gray