View source for Biology:Big-headed turtle

{{Short description|Species of turtle}}
{{for |the similarly named species from Madagascar |Madagascan big-headed turtle}}
{{Speciesbox
| name = Big-headed turtle
| image = Zolw wielkoglowy.jpg
| image_caption = A big-headed turtle (Platysternon megacephalum) 
| status = CR
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 15 November 2021">{{cite iucn |author=Fong, J. |author2=Hoang, H. |author3=Li, P. |author4=McCormack, T. |author5=Rao, D.-Q. |author6=Timmins, R.J. |author7=Wang, L. |author8=van Dijk, P.P. |date=2021 |title=''Platysternon megacephalum'' |volume=2021 |page=e.T17585A1423706 |doi=10.2305/IUCN.UK.2021-2.RLTS.T17585A1423706.en |access-date=15 November 2021}}</ref>
| status2 = CITES_A1 
 | status2_system = CITES 
 | status2_ref = <ref>{{Cite web|title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=2022-01-14|website=cites.org}}</ref>
| display_parents = 3
| grandparent_authority = Gray, 1869<ref name="Rhodin107">{{Harnvb|Rhodin|2010|pp=000.107}}</ref>
| genus = Platysternon
| parent_authority = Gray, 1831<ref name="Rhodin107"/>
| species = megacephalum
| authority = Gray, 1831<ref name="Rhodin107"/>
| synonyms =
; ''Platysternon megacephalum megacephalum''
* ''Platysternon megacephalum'' <small>Gray, 1831</small>
* ''Platisternon megacephalus'' <small>Gray, 1834</small>
* ''Platysternon megacephalus'' <small>Gray, 1835</small>
* ''Emys megacephala'' <small>Schlegel, 1838</small>
* ''Platysternon magacephalum'' <small>Fitzinger, 1843</small> (''ex errore'')
* ''Platysternum megacephalum'' <small>Boulenger, 1889</small>
* ''Platysternon platycephalum'' <small>Mertens, 1959</small> (''ex errore'')
* ''Platysternum megalocephalum'' <small>Stanek, 1959</small> (''ex errore'')
* ''Platysternon megacephalum megacephalum'' <small>Wermuth, 1960</small>
* ''Platysternon magacephalum megacephalum'' <small>Pritchard, 1979</small>
* ''Platysternon megacephalum tristernalis'' <small>Schleich & Gruber, 1984</small>
* ''Platysternon megacephalum tristornalis'' <small>Alderton, 1988</small> (''ex errore'')
; ''Platysternon megacephalum peguense''
* ''Platysternon peguense'' <small>Gray, 1870</small>
* ''Platysternon megacephalum peguense'' <small>Wermuth, 1960</small>
* ''Platysternon megacephalum vogeli'' <small>Wermuth, 1969</small>
* ''Platysternon megacephalum penguense'' <small>Nutaphand, 1979</small> (''ex errore'')
* ''Platysternon megacephalum penuense'' <small>Nutaphand, 1979</small> (''ex errore'')
* ''Platysternon megacephalum peguensis'' <small>Sharma, 1998</small> (''ex errore'')
; ''Platysternon megacephalum shiui''
* ''Platysternon megacephalum shiui'' <small>Ernst & McCord, 1987</small>
| synonyms_ref = <ref name="Fritz 2007">{{Cite journal |journal=Vertebrate Zoology |title=Checklist of Chelonians of the World |year=2007 |author=Fritz, Uwe |author2=Peter Havaš |volume=57 |issue=2 |pages=264–265 |doi=10.3897/vz.57.e30895 |issn=1864-5755 |doi-access=free }}</ref>
}}

The '''big-headed turtle''' ('''''Platysternon megacephalum''''') is a species of [[Biology:Turtle|turtle]] in the family '''Platysternidae''' from [[Place:Southeast Asia|Southeast Asia]] and southern {{wipe|China}}.<ref name="Rhodin107"/>

==Background==
Previously considered a distinct family placed on occasion in "[[Biology:Kinosternoidea|Kinosternoidea]]", it was later moved to the [[Biology:Emydidae|Emydidae]]. This, as well as the subfamily and the [[Biology:Genus|genus]] ''Platysternon'', are monotypic.

The big-headed turtle is named after its unproportionally large head which leads to an inability to retreat into its [[Biology:Turtle shell|shell]]. In order to protect itself it instead has an armored head and sharp beak.<ref name=":0">{{Cite web |title=The Big-headed Turtle (Platysternon megacephalum) Project |url=https://asianturtleprogram.org/big-headed-turtle-project/ |access-date=2023-04-20 |website=asianturtleprogram.org |language=en-US}}</ref>

==Distribution==
The big-headed turtle is found in Cambodia, {{wipe|China}}, Laos, Myanmar, Thailand, and Vietnam.<ref name="iucn status 15 November 2021" /><ref name="Rhodin107"/>  It is commonly found in fast flowing streams and waterfalls in rocky areas. [https://asianturtleprogram.org/big-headed-turtle-project/]

==Behaviour==
[[File:Platysternon megacephalum Hardwicke.jpg|thumb|Illustration from Indian Zoology (1830-1834) by John Edward Gray|left]]
The big-headed turtle is known to readily climb over obstacles in and around rivers and fast streams, using its tail as a prop to extend the reach of its strong [[Biology:Claw|claw]]s. It also uses its beak to assist in climbing.<ref name=Kirkpatrick>[http://www.unc.edu/~dtkirkpa/stuff/bigheads.html Kirkpatrick, David T. 1995. ''Platysternon megacephalum''. Reptile & Amphibian Magazine, November/December 1995, pages 40 – 47. C/R.] {{webarchive |url=https://web.archive.org/web/20110522230829/http://www.unc.edu/~dtkirkpa/stuff/bigheads.html |date=May 22, 2011 }} Retrieved 2012-11-25.</ref>  It has been reported to climb trees and bushes.  These turtles generally move more during the night, and are not prone to moving long distances.  They have a general daily range of 0-89.6m and males tend to move further than the females in this species.<ref>{{Cite web |url=https://meridian.allenpress.com/ccb/article-abstract/9/2/154/26989/Movements-and-Microhabitat-Use-of-Translocated-Big |access-date=2023-02-10 |website=meridian.allenpress.com}}</ref> They are not  strong swimmers, and when swimming, this species occasionally arches its tail in the manner of a scorpion.<ref name=Kirkpatrick/> The big-headed turtle cannot pull its head in its shell. That being the case, it will not hesitate to use its powerful jaws to defend itself.  Its diet consists of [[Biology:Fish|fish]], [[Biology:Snail|snail]]s and worms.<ref>{{Cite web|url=https://animaldiversity.org/accounts/Platysternon_megacephalum/|title=Platysternon megacephalum (Big-headed Turtle)|website=[[Biology:Animal Diversity Web|Animal Diversity Web]] }}</ref> It also tends to eat [[Biology:Fruit|fruit]]s like the ''[[Biology:Machilus|Machilus]]'' spp., as well as [[Biology:Insect|insect]]s, [[Biology:Crab|crab]]s and [[Biology:Mollusca|mollusks]].<ref>{{Cite journal |last1=Sung |first1=Yik-Hei |last2=Hau |first2=Billy |last3=Karraker |first3=Nancy |date=2016-01-01 |title=Diet of the endangered big-headed turtle Platysternon megacephalum |url=https://digitalcommons.uri.edu/nrs_facpubs/105 |journal=Natural Resources Science Faculty Publications |volume=4 |pages=e2784 |doi=10.7717/peerj.2784|pmid=27994979 |pmc=5157187 |doi-access=free }}</ref>

==Exploitation==
The big-headed turtle is found quite frequently in illegal wildlife trade.<ref name=":0" />  It is readily consumed in [[Earth:Asia|Asia]] and is frequently a market item. Hunters capture them on lines with baited straight pins, so this species is rapidly disappearing in the wild.<ref name=barzyk>James E. Barzyk [http://www.tortoisetrust.org/articles/asia.html Turtles in Crisis: The Asian Food Markets]. The article itself is not dated, but mostly refers to data in the range 1995-2000.</ref> The species is also threatened by its use in the pet trade.<ref name="iucn status 15 November 2021" />

==Subspecies==
*''P. m. megacephalum'', China, 1831<ref name="Rhodin107"/>
*''P. m. peguense'', Myanmar and Thailand, 1870<ref name="Rhodin107"/>
*''P. m. shiui'', Cambodia, Laos and Vietnam, 1987<ref name="Rhodin107"/>

In addition, two other subspecies, ''P. m. tristernalis'' (1984) and ''P. m. vogeli'' (1969), have been given, but may be invalid.<ref>[http://www.unc.edu/~dtkirkpa/stuff/bigheads.html ''Platysternon megacephalum''] {{webarchive |url=https://web.archive.org/web/20110522230829/http://www.unc.edu/~dtkirkpa/stuff/bigheads.html |date=May 22, 2011 }}</ref>

[[File:Platysternon megacephalum MHNT CHE 1992-19.jpg|thumb|''Platysternon megacephalum'' - MHNT|center]]

== References ==<!-- BiodiversConserv17:2037. -->
{{Reflist}}
;Bibliography
*{{Anchor|CITEREFRhodin2010}}{{cite web |url=http://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_000_checklist_v3_2010.pdf |title=Turtles of the World 2010 Update: Annotated Checklist of Taxonomy, Synonymy, Distribution and Conservation Status |date=2010-12-14 |access-date=2010-12-15 |last=Rhodin |first=Anders G.J. |author2=Paul van Dijk, Peter |author3=Iverson, John B. |author4=Shaffer, H. Bradley |archive-url=https://web.archive.org/web/20110717125632/http://www.iucn-tftsg.org/wp-content/uploads/file/Accounts/crm_5_000_checklist_v3_2010.pdf |archive-date=2011-07-17 |url-status=dead }}
*{{Anchor|CITEREFritz2007}}{{cite web |url=http://www.cnah.org/pdf_files/851.pdf |title=Checklist of Chelonians of the World |date=2007-10-31 |access-date=2010-12-29 |last=Fritz |first=Uwe |author2=Havaš, Peter |archive-url=https://web.archive.org/web/20110501060224/http://www.cnah.org/pdf_files/851.pdf |archive-date=2011-05-01 |url-status=dead }}
*Pritchard, D. 1979. Encyclopedia of Turtles. New Jersey: T.F.H. Publications, Inc. Ltd.
*"The Big-headed Turtle (Platysternon megacephalum) Project". ''asianturtleprogram.org''. Retrieved 2023-03-14

== External links ==
{{Commons}}
* [https://web.archive.org/web/20111209224040/http://www.unc.edu/~dtkirkpa/stuff/bighead2.html Big-headed turtle (Platysternidae)]
* (Chinese) [http://www.herpera.com/bigheaded.htm Big-headed turtle]
* (Spanish) [http://www.infotortuga.com/platysternon.htm ''Platysternon megacephalum''] {{Webarchive|url=https://web.archive.org/web/20160304051116/http://www.infotortuga.com/platysternon.htm |date=2016-03-04 }}

{{Taxonbar|from1=Q14566127|from2=Q754035}}

[[Category:Testudinoidea]]
[[Category:Monotypic reptile genera]]

{{Sourceattribution|Big-headed turtle}}