Platysternon megacephalum (Big-headed Turtle) Reptiles-Turtles Exotic
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Common name: Big-headed Turtle
Taxonomy: available through
www.itis.gov
Identification: Platysternon megacephalum have extremely large, flat-topped heads, half the width of the carapace and protected by a bony scute which can resemble a helmet and a poweful hooked beak. The yellowish or olive-brown carapace is elongated and flat, sometimes with a slight keel, and a powerful tail as long as the carapace (Ernst and Barbour 1989, Bonin et al. 2006). Juveniles are more brightly colored than adults, with a keeled shell and serrated posterior scutes, and may feature a colorful stripe behind the eye (Bonin et al. 2006, Rhodin et al. 2021).
Size: Carapace length up to 25.5 cm for males and 21.0 cm for females (Rhodin et al. 2021)
Native Range: Cambodia, China, Laos, Myanmar, Thailand, and Vietnam (Rhodin et al. 2021)
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Alaska |
Hawaii |
Puerto Rico & Virgin Islands |
Guam Saipan |
Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps
Nonindigenous Occurrences:
A juvenile was caught in Orange County, CA
Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Platysternon megacephalum are found here.
Table last updated 11/24/2024
† Populations may not be currently present.
Ecology: Platysternon megacephalum are largely noctural, living in cooler, high-elevation streams in Southeast Asia where they spend the day hiding in the rocky substrate and are seldom seen basking. Although poor swimmers, they are adept climbers, facilitated by their powerful jaws and strong tails. Their diet consists largely of fishes, mollusks, and crustaceans, and they may forage terrestrially along the stream bank. Females typically lay one or two white, ellipsoidal (37 x 22 mm) eggs (Ernst and Barbour 1989, Bonin et al. 2006).
Means of Introduction: This was likely an escaped pet
Status: Not known to be established in the United States
Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. Research is required to evaluate effects before conclusions can be made.
References: (click for full references)
Bonin, F., B. Devaux, and A. Dupre. 2006. Turtles of the World. The John Hopkins University Press, Baltimore, MD.
Ernst, C.H. and R.W. Barbour. 1989. Turtles of the world. Smithsonian Institution Press, Washington, D.C.
Rhodin, A.G.J., J.B. Iverson, R. Bour, U. Fritz, A. Georges, H.B. Shaffer, and P.P. van Dijk. 2021. Turtles of the world: annotated checklist and atlas of taxonomy, synonymy, distribution, and conservation status. In: Conservation biology of freshwater turtles and tortoises: a compilation project of the IUCN/SSC tortoise and freshwater turtle specialist group. Volume 8. 9th edition. Chelonian Research Foundation and Turtle Conservancy, Arlington, VT. https://iucn-tftsg.org/wp-content/uploads/crm.8.checklist.atlas_.v9.2021.e3.pdf
Author:
Jonathan Freedman
Revision Date: 3/25/2024
Citation Information:
Jonathan Freedman, 2024, Platysternon megacephalum Gray, 1831: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/Queries/FactSheet.aspx?SpeciesID=3881, Revision Date: 3/25/2024, Access Date: 11/24/2024
This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.