Cyclemys

Cyclemys is a genus of freshwater turtles, commonly referred to as Asian leaf turtles, from the family Geoemydidae. The genus occurs throughout Southeast and South Asia, and currently contains seven species.

This article is about the genus collectively known as 'Asian leaf turtles'. For the particular species known as the 'Asian leaf turtle', see Cyclemys dentata.

Asian leaf turtles
A young Cyclemys dentata from Java, Indonesia.
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Geoemydidae
Subfamily: Geoemydinae
Genus: Cyclemys
Bell, 1834
Type species
Cyclemys orbiculata
Bell, 1834
Species

7 sp., see text

Distribution of Cyclemys: The exact range of individual species is uncertain.[1]

Asian leaf turtles average 25 cm (9.8 in) in length. They are mostly brown to greenish in color, with round to rectangular shells. Their carapaces bear a superficial resemblance to plant leaves, hence their common name. They can be found around shallow, slow-moving bodies of water in hilly forests. Adults are primarily terrestrial, though juveniles are more aquatic.

Taxonomy and nomenclature

Cyclemys turtles belong to the family Geoemydidae under the subfamily Geoemydinae. They were first described in 1834 by English zoologist Thomas Bell in his work A Monograph of the Testudinata.[2][3] Cyclemys and closely related genera (Cuora, Pyxidea, and Notochelys) are believed to have diverged from a common Heosemys-like ancestor.[4][5][6]

The characteristic round carapace of the genus, shown here by an adult Cyclemys dentata

Cyclemys taxonomy and phylogeny have been historically difficult to ascertain due to the morphological similarity between species, as well as changes in the color patterns during growth.[7] Until recently, the genus was thought to comprise only one or two morphologically variable species, C. dentata and C. oldhamii.[1][8] Subsequent investigation has now put the number of species under the genus to seven, though this remains controversial. The status of C. enigmatica as a valid species is contested, as is the recognition of C. atripons and C. pulchristiata, both of which are nearly impossible to tell apart morphologically.[1][9]

Previously recognized species, C. tcheponensis ( = C. tiannanensis) and C. shanensis, have been merged into C. oldhamii following mtDNA sequencing. The conclusions of which showed that the morphological differences between them (the presence or absence of neck/head stripes, and hatchling color patterns) were not enough to classify them as separate species.[1] C. ovata has been similarly subsumed into C. dentata.[10]

The two distinct morphological differences between Cyclemys species are based on the main color of their plastrons - species with yellow bellies (C. atripons, C. dentata, and C. pulchristiata), and species with dark bellies (C. enigmatica, C. fusca, C. gemeli, and C. oldhamii).[1]

Synonyms of Cyclemys (ex errore) include: Cyclemus Li, Cyclemis Good, and Cyclemy Mao.[11]

The generic name Cyclemys comes from the Greek κύκλος (kyklos, meaning 'round' or 'circle', referring to the shape of the carapace) and εμύς (emys; 'freshwater turtle').[12] They are known under the common name Asian leaf turtles or simply leaf turtles, again because of the appearance of their carapaces. They share the collective name 'leaf turtles' with turtles of the genus Geoemyda, as well as turtles with 'leaf' in their names, such as the Annam leaf turtle (Mauremys annamensis), among others.[12][13] 'Asian leaf turtle' is also the specific common name of C. dentata.

Description
The pattern of scutes on the carapace (upper left) and plastron (upper right) of the shell of Cyclemys: Shown in broken lines are the secondary divisions of the abdominal scutes, a distinguishing characteristic of the genus which only occurs in adults.

Cyclemys turtles are characterized by more or less round carapaces, which are typically dark green, brownish, tan, or olive in color. The shell may have a prominent vertebral keel running from head to tail. Serrated marginal scutes are common in juveniles. In adults, only the posterior marginal scutes are serrated.[14]

Adults of Cyclemys also develop a joint in the middle of their plastrons (known as a plastral hinge), enabling them to articulate the front and rear halves to some extent. Unlike the closely related Cuora, which can completely close its shell because of the hinge,[15] Cyclemys plastral hinges only close the shell partially.[6][16] The plastral hinge may also play a significant role in facilitating egg-laying in adult females.[13]

A distinguishing characteristic of the genus is the secondary division of the abdominal scutes (the middle pair of scutes in the plastron) due to the development of the plastral hinge as the turtle matures. It eventually leads to the formation of small triangular additional scutes between the abdominal and pectoral scutes.[17]

Cyclemys turtles are cryptodires, having the ability to pull their heads straight back and vertically into their shells instead of folding them sideways like pleurodires. The head varies between species from dull to striped with bright red or orange bands of color. The plastron can have a dark or light (tan to yellow) background which can be uniform or patterned with fine lines radiating from the center of each plastral scute.[14]

Their feet are partially webbed and well developed for either aquatic or terrestrial mobility. They can grow to about 25 cm (9.8 in) in length.[12]

Cyclemys species achieve sexual maturity after seven to 12 years, earlier for males and later for females.[14][18] Sexual dimorphism is apparently mostly absent, though females are likely to outgrow males.[1][19] Females usually deposit 10 to 15 eggs per clutch.[13]

Lifespan

A C. dentata individual has been recorded living up to 14.7 years in captivity.[20] However, an adult specimen caught in the wild has also been recorded living another 14 years, making it likely that the maximum lifespan of Cyclemys species has been underestimated.[21]

Distribution and habitat
A Cyclemys turtle along a perennial stream (Upper Dikorai) in Pakke Tiger Reserve

The distribution ranges of individual species of Cyclemys remain unclear, but the genus occurs in South Asia and Indochina (Vietnam, Myanmar, Laos, Cambodia, Myanmar, Thailand, central to southern China, Bangladesh, Nepal, and northeastern India), as well as the Southeast Asian countries of Malaysia, Indonesia, Brunei, and the Philippines.[1]

Adults spend most of their time on land. They can be found near ponds, streams, and other shallow, slow-moving bodies of water in hilly forests.[12][13] Although more common in lower elevations, they have been found in higher elevations exceeding 1,000 m (3,300 ft) above sea level.[22]

They are omnivorous,[23] but juveniles tend to be more carnivorous. Because their prey are typically aquatic, the younger turtles are found in water more often than adults.[12]

Species

The species are listed alphabetically along with common names, identifying adult characteristics, and known geographical distribution.[11] They are divided into two morphologically distinct groups.[1]

The yellow plastron of a juvenile Cyclemys dentata.

Yellow-bellied species

Dark-bellied species

Several species previously classified under Cyclemys – C. amboinensis, C. flavomarginata, C. mouhotti, and C. trifasciata – are now classified under the genus Cuora. C. annandalii is now classified under Heosemys, C. annamensis under Mauremys, and C. giebelii as Notochelys platynota.[10]

Conservation

Cyclemys species are often caught and sold for the pet trade, food, or traditional medicine.[24] On August 25, 1998, Forest Protection authorities of Vietnam confiscated a shipment of about 700 turtles with an estimated 30 individuals of C. oldhamii.[25] In May 2007, more than 3000 individuals of Cyclemys, along with Asian box turtles, were confiscated in hundreds of crates in Yangjiang, China.[26]

The most commonly encountered species of Cyclemys in the pet trade, C. dentata, is now being captive bred. They are usually preferred, as they are healthier, more acclimated to handling, and captive breeding minimizes the impact on wild populations.[12][27]

The confusion over their exact taxonomy and distribution led to an incomplete assessment of their conservation status by the IUCN.[8] In 1991, with only two species recognized, Cyclemys was given the Action Plan Rating of 3 - in need of some conservation action.[28] In the last assessment in 2000 by the Asian Turtle Trade Working Group of IUCN, the different species currently recognized under the genus Cyclemys were treated as all belonging to the species C. dentata. This resulted in the current incorrect classification of all of the species as lower risk/near threatened.[8] Until now, the true conservation status, the actual effects of wildlife trade, deforestation, and habitat loss on individual Cyclemys species, have yet to be studied.[14][22]

See also

References
  1. Fritz, U.; Guicking, D.; Auer, M.; Sommer, R. S.; Wink, M.; Hundsdörfer, A. K. (2008). "Diversity of the Southeast Asian leaf turtle genus Cyclemys: how many leaves on its tree of life?" (PDF). Zoologica Scripta. 37 (4): 367–390. doi:10.1111/j.1463-6409.2008.00332.x. S2CID 85899075.
  2. Gray, John Edward (1855). Catalogue of Shield Reptiles in the Collection of the British Museum. Order of the Trustees, British Museum (Natural History).
  3. Fritz, Uwe; Nowak-Kemp, Malgosia (2010). "Chelonian type specimens at the Oxford University Museum" (PDF). Zootaxa. 1 (19). Archived from the original (PDF) on March 16, 2012. Retrieved March 27, 2011.
  4. Honda, Masanao; Yasukawa, Yuichirou; Hirayama, Ren; Ota, Hidetoshi (2002). "Phylogenetic Relationships of the Asian Box Turtles of the Genus Cuora sensu lato (Reptilia: Bataguridae) inferred from Mitochondrial DNA Sequences" (PDF). Zoological Science. 19 (11): 1305–1312. doi:10.2108/zsj.19.1305. PMID 12499674. S2CID 45461277. Archived from the original (PDF) on July 19, 2011. Retrieved March 28, 2011.
  5. Zhang, Yanyun; Nie, Liuwang; Huang, Yuqing; Pu, Youquang; Zhang, Li (2009). "The Mitochondrial DNA Control Region Comparison Studies of Four Hinged Turtles and its Phylogentic Significance of the Genus Cuora Sensu Lato (Testudinata: Geoemydidae)". Genes and Genomics. 31 (5): 349–359. doi:10.1007/BF03191253. S2CID 8082431.
  6. Bramble, Dennis M. (1974). "Emydid Shell Kinesis: Biomechanics and Evolution". Copeia. 1974 (3): 707–727. doi:10.2307/1442685. JSTOR 1442685.
  7. Fritz, Uwe; Fritz, UWE (2008). "Historical DNA from museum type specimens clarifies diversity of Asian leaf turtles (Cyclemys)". Biological Journal of the Linnean Society. 94 (1): 131–141. doi:10.1111/j.1095-8312.2008.00966.x.
  8. Asian Turtle Trade Working Group 2000. Cyclemys dentata. In: IUCN 2010. IUCN Red List of Threatened Species Archived June 27, 2014, at the Wayback Machine. Version 2010.4. Retrieved March 25, 2011.
  9. Artner, H. (2008). "The World's Extant Turtle Species" (PDF). Emys. 15 (3). Archived from the original (PDF) on September 12, 2011. Retrieved March 27, 2011.
  10. Fritz, Uwe; Havaš, Peter (2007). "Checklist of Chelonians of the World" (PDF). Vertebrate Zoology. 57 (2): 149–368. ISSN 1864-5755. Archived from the original (PDF) on December 29, 2010. Retrieved March 27, 2011.
  11. Turtle Taxonomy Working Group (Rhodin, A.G.J., van Dijk, P.P, Iverson, J.B., and Shaffer, H.B.).2010. Turtles of the World, 2010 update: annotated checklist of taxonomy, synonymy, distribution, and conservation status. In: Rhodin, A.G.J., Pritchard, P.C.H., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Iverson, J.B., and Mittermeier, R.A. (Eds.). Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Chelonian Research Monographs No. 5. pp. 000.85-000.164, doi:10.3854/crm.5.000.checklist.v3.2010
  12. Tabaka, Chris; Senneke, Darrell (January 28, 2003). "Genus: Cyclemys (Asian Leaf Turtles)". World Chelonian Trust. Retrieved March 27, 2011.
  13. Franklin, Carl J. (2007). Turtles: An Extraordinary Natural History 245 Million Years in the Making. Voyageur Press. ISBN 978-0-7603-2981-8.
  14. Melstrom, Keegan (November 17, 2009). Dr. Kenneth Angielczyk (ed.). Cyclemys dentata (Gray, 1831). Encyclopedia of Life. Retrieved March 27, 2011.
  15. Dodd, C. Kenneth (2002). North American Box Turtles: A Natural History. Animal Natural History. University of Oklahoma Press. p. 14. ISBN 978-0-8061-3501-4.
  16. "Asian Leaf, Yellow-headed Temple, Striped-necked Leaf, & Borneo Black Leaf Turtle". Free Pet Care Tips Newsletter. Retrieved March 29, 2011.
  17. Praschag, Peter; Hundsdörfer, Anna K.; Fritz, Uwe (2009). "Further specimens and phylogenetic position of the recently described leaf turtle species Cyclemys gemeli (Testudines: Geoemydidae)" (PDF). Zootaxa. 29 (37). ISSN 1175-5326. Retrieved March 29, 2011.
  18. Paul Coleman (1995). "The Asian Leaf Turtle (Cyclemys dentata)". UKchelonia.info. Retrieved March 29, 2011.
  19. Karen A., Jensen; Indraneil, Das (2006). "Biological Observations on the Asian Soft-Shell Turtle in Sarawak, Malaysian Borneo, with notes on the Biology and Conservation of other Non-marine Turtles". Testudo. 6 (3). Archived from the original on March 21, 2012. Retrieved March 30, 2011.
  20. "AnAge entry for Cyclemys dentata". AnAge database at the Human Ageing Genomic Resources. Retrieved March 28, 2011.
  21. Joao Pedro de Magalhaes (2010). "Cyclemys dentata Gray 1831, Lifespan, longevity, and ageing". Encyclopedia of Life. Retrieved March 28, 2011.
  22. Rui, Kalu Ram (2004). "Ecological Distribution Of Cyclemys Oldhamii(Gray 1863) From Nepal". Our Nature. 2 (7).
  23. David T. Kirkpatrick (1996). "An Overview of Common Semi-Aquatic Turtles". University of North Carolina. Retrieved March 28, 2011. External link in |publisher= (help)
  24. "Leaf Turtle". Nam Kading Research & Training Centre. Archived from the original on August 22, 2011. Retrieved March 27, 2011.
  25. Hendrie, Douglas (November 1, 1998). "Protecting Vietnam's Turtles" (PDF). Cuc Phuong Conservation Project. Retrieved March 29, 2011. Cite journal requires |journal= (help)
  26. United Nations Environment Programme (2007). Beijing 2008 Olympic games: an environmental review. UNEP Division of Communications and Public Information. ISBN 978-92-807-2888-0.
  27. Hopson, Mary. "Asian Leaf Turtles". The Turtle Puddle. Retrieved March 27, 2011. Cite journal requires |journal= (help); External link in |publisher= (help)
  28. IUCN/SSC Tortoise and Freshwater Turtle Specialist Group (1989). Tortoises and freshwater turtles: an action plan for their conservation. IUCN/WWF. ISBN 978-2-88032-974-7.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.