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The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

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Common name: Chinese softshell

Taxonomy: available through www.itis.gov

Identification: A small to medium-sized softshell having a carapace (upper shell) length averaging 112-250 mm (about 4.5 to 10 in) (Mao, 1971; Ernst and Barbour, 1989; Ernst et al., 1994). The ventral surface is pale or white in adults, but typically with a darker pattern superimposed on the plastron (lower shell) of juveniles (Smith, 1931; Mao, 1971; Pritchard, 1979; Ernst et al., 1994; McKeown, 1996; Bonin et al., 2006). The cluster of wattles (enlarged tubercles) found between the neck and carapace of Palea steindachneri (wattle-necked softshell) is lacking or greatly underdeveloped in Pelodiscus sinensis (Ernst et al., 1994; McKeown, 1996; Bonin et al., 2006). Juveniles may have dark or light spots on the carapace; they usually lack the broad, pale stripe on the side of the neck and head that is normally present in juvenile wattle-necked softshells, but other patterns can be present (Pritchard, 1979; Ernst and Barbour, 1989; Ernst et al., 1994; McKeown, 1996; Bonin et al., 2006). The Chinese softshell is illustrated in Smith (1931), Pope (1935), Mao (1971), Ernst and Barbour (1972, 1989), Nakamura and Uéno (1976), McKeown (1978, 1996), Pritchard (1979), Sengoku (1979), [Matsui], (1985), Meylan (1987), Zhao and Adler (1993), Ernst et al. (1994), Cox et al. (1998), and Bonin et al. (2006).

Size: carapace length of 112-250 mm (about 4.5 to 10 inc).

Native Range: Distributed throughout eastern China, Korea, Taiwan, extreme southeastern Russia, Japan, and northern Vietnam (Smith, 1931; Pope, 1935; Mao, 1971; Nakamura and Uéno, 1976; Pritchard, 1979; Sengoku, 1979; [Matsui], 1985, Ernst and Barbour, 1989; Webb, 1989; Iverson, 1992; Zhao and Adler, 1993; Bonin et al., 2006).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Ecology: The natural history of these softshells has been summarized by Pope (1935), Mao (1971), Ernst and Barbour (1989), Ernst et al. (1994), Cox et al. (1998), and Bonin et al. (2006). The Chinese softshell is a highly aquatic, mostly carnivorous turtle which feed on insects, crustaceans, mollusks, fish, and the seeds of marsh plants (Pope, 1935; Mao, 1971; Ernst and Barbour, 1989; Ernst et al., 1994; Cox et al., 1998; Bonin et al., 2006). Females lay clutches of 15-28 eggs, with multiple clutches per year, which are buried in moist soil (McKeown, 1996; Bonin et al., 2006).

 

Means of Introduction: These turtles were brought to Hawaii, U.S.A., and cultivated by Asian immigrants as a traditional source of food from the 1800s up till World War II (Brock, 1947; McKeown and Webb, 1982; McKeown, 1996). The same seems to be true for Maryland (U.S.A.), Guam, and parts of southeastern Asia where, in the lattermost region, this species also serves religious uses (Pope, 1935; McCoid, 1993; Cox et al., 1998; Bonin et al., 2006; Kraus, 2009). Introductions of P. sinensis in France and Spain were from the pet trade (Kraus, 2009).

Status: The Chinese softshell is established in Kauai and Oahu, Hawaii, U.S.A. (Brock, 1947; McKeown and Webb, 1982; Iverson, 1992; Ernst et al., 1994; McKeown, 1996; Kraus, 2008, 2009; Collins and Taggart, 2009), Guam (McCoid, 1993; Kraus, 2009), Spain, Japan, Timor and one of the Bonin islands (Ernst et al., 1994; McKeown, 1996; Kraus, 2009). This species is not established in New York, U.S.A., but it is unclear if the individual studied by Rahman and Warny (2011) was left in Windmill Pond. It is not established in Maryland (U.S.A.), France, Great Britain, or Madagascar (Kraus, 2009). It also is established in various countries in southeastern Asia; however, many specimens found could be turtles escaped from cultivation (Pope, 1935; Cox et al., 1998; Kraus, 2009), rendering its established, nonindigenous range determination difficult.

Impact of Introduction: Unknown; but the potential for this highly carnivorous turtle to have a negative impact on indigenous aquatic fauna in various region of introduction seems likely, if it has not occurred already. There are no freshwater turtles native to Hawaii (McKeown, 1996).

Remarks: The taxonomy the Chinese softshell has been reviewed by Meylan (1987), Zhao and Adler (1993), Bickham et al. (2007), and Collins and Taggart (2009). Recent studies have shown Pelodiscus sinensis to be a species complex comprising P. axenaria (Hunan Softshell Turtle, from southern China), P. maacki (Northern Chinese Softshell Turtle, from northern China and the Amur River basin), P. parviformis (Vietnamese Softshell Turtle, from Vietnam and southern China), and P. sinensis (Chinese Softshell Turtle, found throughout eastern China) (Stuckas and Fritz, 2011; Yang et al. 2011; Rhodin et al. 2017). In an examination of the genetic composition of introduced softshell turtles in Hawaii, Dong et al. (2016) found three species to be present: P. sinensis, P. maackii (Northern Chinese or Amur softshell turtle), and Palea steindachneri (Wattle-necked softshell turtle). Given the challenges in differentiating these species morphologically it should be assumed that some identifications may be erroneous without genetic validation.

Pelodiscus sinensis is much prized as food and as a “tonic” in China, Taiwan, and other parts of Asia where it is commonly cultivated in ponds and canals (Pope, 1935; Brock, 1947; Mao, 1971; McKeown and Webb, 1982; Cox et al., 1998; Bonin et al., 2006). It is for this reason that it has become established out of its native range.

References: (click for full references)

Bickham, J. W., J. B. Iverson, J. F., Parham, H.-D. Philippen, A. G. J. Rhodin, H. B. Shaffer, P. Q. Spinks, and P. P. van Dijk. 2007. An annotated list of modern turtle terminal taxa with comments on areas of taxonomic instability and recent change. Chelonian Research Monographs 4:173-199.

Bonin, F., B. Devaux, and A. Dupré. 2006. Turtles of the World. [English Edition.] The Johns Hopkins University Press, Baltimore. 416 pp.

Brock, V. E. 1947. The establishment of Trionyx sinensis in Hawaii. Copeia 1947(2):142.

Collins, J. T., and T. W. Taggart. 2009. Standard Common and Current Scientific Names for North American Amphibians, Turtles, Reptiles & Crocodilians. Sixth Edition. The Center for North American Herpetology, Lawrence, Kansas.  44 pp.

Cox, M. J., P. P. van Dijk, J. Nabhitabhata, and K. Thirakhupt. 1998. A Photographic Guide to Snakes and Other Reptiles of Peninsular Malaysia, Singapore and Thailand. New Holland Publishers (UK) Ltd, London. 144 pp.

Dong, C.M., T.N. Engstrom, and R.C. Thomson. 2016. Origins of softshell turtles in Hawaii with implications for conservation. Conservation Genetics 17(1):207-220.

Ernst, C. H., and R. W. Barbour. 1972. Turtles of the United States and Canada. The University Press of Kentucky, Lexington. 347 pp.

Ernst, C. H., and R. W. Barbour. 1989. Turtles of the World. Smithsonian Institution Press, Washington, D.C. and London. 313 pp.

Ernst, C. H., J. E. Lovich, and R. W. Barbour. 1994. Turtles of the United States and Canada. Smithsonian Institution Press, Washington and London. 578 pp.

Iverson, J. B. 1992. A Revised Checklist with Distribution Maps of the Turtles of the World. First Edition. John B. Iverson, Richmond, Indiana. 363 pp.

Iverson, J. [B.], P. [A.] Meylan, and M. [E.] Seidel. 2000. Testudines—turtles. Pp. 75-82. In: B. I. Crother (chair), and Committee on Standard English and Scientific Names (editors). Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Society for the Study of Amphibians and Reptiles Herpetological Circular (29):i-iii, 1-82.

Kraus, F. 2002. Personal communication—Zoologist, Bishop Museum, 1525 Bernice Street, Honolulu, Hawaii.

Kraus, F. 2008. Alien species. Pp. 75-83. In: B. I. Crother (chair), and Committee on Standard English and Scientific Names (editors). Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Sixth Edition. Society for the Study of Amphibians and Reptiles Herpetological Circular (37):1-84.

Kraus, F. 2009. Alien Reptiles and Amphibians. A Scientific Compendium and Analysis. Springer, [Dordrecht]. 563 pp. + CD-ROM.

Mao, S. H. 1971. Turtles of Taiwan. A Natural History of the Turtles. The Commercial Press, LTD, Taipei. 128 pp.

[Matsui, K.] 1985. [Amphibians and Reptiles of Japan. Shogakukau, Tokyo.] [In Japanese.] 160 pp.

McCoid, M. J. 1993. The “new” Herpetofauna of Guam, Mariana Islands. Herpetological Review 24(1):16-17.

McKeown, S. 1978. Hawaiian Reptiles and Amphibians. The Oriental Publishing Company, Honolulu. 80 pp.

McKeown, S. 1996. A Field Guide to Reptiles and Amphibians in the Hawaiian Islands. Diamond Head Publishing, Inc., Los Osos, California. 172 pp.

McKeown, S., and R. G. Webb. 1982. Softshell turtles in Hawaii. Journal of Herpetology 16(2):107-111.

Meylan, P. A. 1987. The phylogenetic relationships of soft-shelled turtles (Family Trionychidae). Bulletin of the American Museum of Natural History 186(1):1-101.

Nakamura, K., and S.-I. Uéno. 1976. Japanese Reptiles and Amphibians in Colour. Hoikusha Publishing Co., Ltd., Osaka. 215 pp.

Oliver, J. A., and C. E. Shaw. 1953. The amphibians and reptiles of the Hawaiian Islands. Zoologica (New York) 38(5):65-95.

Ota, H. 1999. Introduced amphibians and reptiles of the Ryukyu Archipelago, Japan. Pp. 439-452. In: G. H. Rodda, Y. Sawai, D. Chiszar, and H. Tanaka (editors). Problem Snake Management: The Habu and the Brown Treesnake. Cornell University Press, Ithaca. 534 pp.

Pope, C. H. 1935. The Reptiles of China. Turtles, Crocodilians, Snakes, Lizards. Natural History of Central Asia Vol. X. The American Museum of Natural History, New York. 604 pp. + 27 plates.

Pritchard, P. C. H. 1979. Encyclopedia of Turtles. T.F.H. Publications, Inc., Neptune, New Jersey. 895 pp.

Rahman, S. C., and P. R. Warny. 2011. Pelodiscus sinensis (Chinese softshell turtle). Extralimital winter survival. Herpetological Review 42(2):267-268.

Rhodin, A.G.J., J.B. Iverson, R. Bour, U. Fritz, A. Georges, H.B. Shaffer, and P.P. van Dijk. 2017. Turtles of the World Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status . Pages 1-292 inRhodin, A.G.J., J.B. Iverson, P.P. van Dijk, R.A. Saumure, K.A. Buhlmann, P.C.H. Pritchard, and R.A. Mittermeier, eds. Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group. Chelonian Research Monographs. Volume 7. 8th edition. Chelonian Research Foundation and Turtle Conservancy. Lunenburg, MA.

Sengoku, S. 1979. [Amphibians and Reptiles. Ienohikari (House of Light) Corporation, Tokyo.] [In Japanese.] 206 pp.

Smith, M. A. 1931. The Fauna of British India, Including Ceylon and Burma. Reptilia and Amphibia. Vol. I.—Loricata, Testudines. Taylor & Francis Ltd., London. 185 pp. + I-II.

Stuckas, H. and U. Fritz. 2011. Identity of Pelodiscus sinensis revealed by DNA sequences of an approximately 180-year-old type specimen and a taxonomic reappraisal of Pelodiscus species (Testudines: Trionychidae). Journal of Zoological Systematics and Evolutionary Research 49(4):335-339.

Webb, R. [G.] 1989. Pelodiscus sinensis (Wiegmann 1835). Pp. 112-113. In: F. W. King and R. L. Burke (editors). Crocodilian, Tuatara, and Turtle Species of the World. A Taxonomic and Geographic Reference. The Association of Systematics Collections, Washington, DC. 216 pp.

Yang, P., Tang, Y., Ding, L., Guo, X., and Wang, Y. 2011. Validity of Pelodiscus Parviformis (Testudines: Trionychidae) inferred from molecular and morphological analyses. Asian Herpetological Research 2(1):21-29.

Zhao, Er-mi, and K. Adler. 1993. Herpetology of China. Contributions to Herpetology 10. Society for the Study of Amphibians and Reptiles, Oxford, Ohio. 522 pp.

Other Resources:
Alien Species in Hawaii (HEAR Project)

Author: Somma, L.A., and J.A. Freedman

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.