''Chelodina'', collectively known as snake-necked turtles, is a large and diverse genus of long-necked chelid turtles with a complicated nomenclatural history. Although in the past, ''Macrochelodina'' and ''Macrodiremys'' have been considered separate genera and prior to that all the same, they are now considered subgenera of the ''Chelodina'', further ''Macrochelodina'' and ''Macrodiremys'' are now known to apply to the same species, hence ''Chelydera'' is used for the northern snake-necked turtles. ''Chelodina'' is an ancient group of chelid

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 ...

s native to

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

New Guinea New Guinea (; Hiri Motu: ''Niu Gini''; , fossilized , also known as Papua or historically ) is the List of islands by area, world's second-largest island, with an area of . Located in Melanesia in the southwestern Pacific Ocean, the island is ...

, the Indonesian

Rote Island Rote Island (, also spelled ''Roti'') is an island of Indonesia, part of the East Nusa Tenggara Provinces of Indonesia, province of the Lesser Sunda Islands. According to legend, this island got its name accidentally when a lost Portuguese people ...

, and

East Timor Timor-Leste, also known as East Timor, officially the Democratic Republic of Timor-Leste, is a country in Southeast Asia. It comprises the eastern half of the island of Timor, the coastal exclave of Oecusse in the island's northwest, and ...

. The turtles within this subgenus are small to medium-sized with oval shaped

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 ...

. They are side-necked turtles, meaning they tuck their head partially around the side of their body when threatened instead of directly backwards. ''Chelydera'' represents those species that have often been termed the ''Chelodina'' B group or thick necked snake neck turtles. The subgenus was described in 2020 by Thomson & Georges (in Shea et al. 2020). They are a side-neck turtle of the family Chelidae with extremely long necks and long flattened heads. They are specialist fish eaters using a strike and gape mode of feeding. They are medium to large species with the largest '' Chelodina (Chelydera) expansa'' reaching shell lengths of some .Macrochelodina expansa (Grey, 1856) - Broad-Shelled Turtle
The first fossils (''C. (Chelydera) alanrixi'') are known from

Queensland Queensland ( , commonly abbreviated as Qld) is a States and territories of Australia, state in northeastern Australia, and is the second-largest and third-most populous state in Australia. It is bordered by the Northern Territory, South Austr ...

from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

period (Lapparent de Broin, F. de, & Molnar, R. E., 2001). ''Macrochelodina'' (Wells & Wellington, 1985) is a monotypic subgenus of the ''Chelodina''. Its sole member is the enigmatic ''Chelodina'' (''Macrochelodina'') ''oblonga'' from

Western Australia Western Australia (WA) is the westernmost state of Australia. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to the south, the Northern Territory to the north-east, and South Australia to the south-east. Western Aust ...

Taxonomy

Current taxonomy follows that of Georges & Thomson, 2010 with updates from van Dijk et al. 2014 and Shea et al. 2020. Synonymous names for the ''Chelodina'' Fitzinger 1826 genus include: ''Hydraspis'' Bell 1828, ''Chelyodina'' Agassiz 1846:79 (

nomen novum In biological nomenclature, a ''nomen novum'' (Latin for "new name"), replacement name (or new replacement name, new substitute name, substitute name) is a replacement scientific name that is created when technical, nomenclatural reasons have mad ...

), ''Hesperochelodina'' Wells and Wellington 1985 (

nomen nudum In Taxonomy (biology), taxonomy, a ''nomen nudum'' ('naked name'; plural ''nomina nuda'') is a designation which looks exactly like a scientific name of an organism, and may have originally been intended to be one, but it has not been published ...

). The type species for the ''Chelodina'' subgenus is '' Chelodina longicollis'' (Shaw, 1794). The type species for the ''Chelydera'' subgenus is '' Chelodina parkeri'' Rhodin and Mittermeier 1976. The type species for ''Macrochelodina'' is '' Chelodina oblonga'' Gray 1841.

List of species

Extinct species

There are three identified extinct species of ''Chelodina'': *†'' Chelodina alanrixi'' de Broin and Molnar, 2001 is a species of snake-necked fossil turtle which was described in 2001 using material gathered in Redbank Plains,

. It is a member of the

Chelidae Chelidae is one of three living families of the turtle suborder Pleurodira, and are commonly called Austro-South American side-neck turtles. The family is distributed in Australia, New Guinea, parts of Indonesia, and throughout most of South Amer ...

Pleurodira The Pleurodira are one of the two living suborders of turtles, the other being the Cryptodira. The division between these two suborders represents a very deep evolutionary divide between two very different types of turtles. The physical differ ...

. The fossil has been dated to the Eocene Epoch. *†'' Chelodina insculpta'' de Vis, 1897de Vis, C.W. (1897). The extinct freshwater turtles of Queensland. ''Annals of the Queensland Museum'' 3: 3-7. is an extinct

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 snake-necked turtle that was described in 1897 from material gathered in Darling Downs, Queensland, Australia, restricted.Thomson, S. A. 2000. A Revision of the Fossil Chelid Turtles (Pleurodira) Described by C.W. De Vis, 1897. ''Memoirs of the Queensland Museum'' 45(2):593-598. It is a member of the Chelidae; Pleurodira. The fossil has been dated as

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

. *†'' Chelodina murrayi'' Yates, 2013 is an extinct species of snake-necked turtle from the Waite Formation on the Alcoota Scientific Reserve, north-east of

Alice Springs Alice Springs () is a town in the Northern Territory, Australia; it is the third-largest settlement after Darwin, Northern Territory, Darwin and Palmerston, Northern Territory, Palmerston. The name Alice Springs was given by surveyor William ...

in the Northern Territory of Australia. The species would appear to belong to the '' Chelodina novaeguineae'' group of species within the subgenus ''Chelodina''.

Notes

References

External links

Overview of the genus ''Chelodina'' with original literature
{{Taxonbar , from=Q532358 Turtles of Australia Turtle genera Taxa named by Leopold Fitzinger