Trionychidae
Trionychidae Temporal range:
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Chinese softshell turtle Pelodiscus sinensis
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Order: | Testudines |
Suborder: | Cryptodira |
Superfamily: | Trionychia |
Family: | Trionychidae Fitzinger, 1826 |
Subfamilies | |
The Trionychidae are a
Characteristics
They are called "softshell" because their
These turtles have many characteristics pertaining to their aquatic lifestyle. Many must be submerged in order to swallow their food.[5] They have elongated, soft, snorkel-like nostrils. Their necks are disproportionately long in comparison to their body sizes, enabling them to breathe surface air while their bodies remain submerged in the substrate (mud or sand) a foot or more below the surface.
Females can grow up to several feet in carapace diameter, while males stay much smaller; this is their main form of
Most are strict carnivores, with diets consisting mainly of fish, aquatic crustaceans, snails, amphibians,[4] and sometimes birds and small mammals.
Softshells are able to "breathe" underwater with rhythmic movements of their mouth cavity, which contains numerous processes copiously supplied with blood, acting similarly to gill filaments in fish.[6] This enables them to stay underwater for prolonged periods. Moreover, the Chinese softshell turtle has been shown to excrete urea while "breathing" underwater; this is an efficient solution when the animal does not have access to fresh water, e.g., in brackish-water environments.[7]
According to Ditmars (1910): "The mandibles of many species form the outer border of powerful crushing processes—the alveolar surfaces of the jaws", which aids the ingestion of tough prey such as molluscs. These jaws make large turtles dangerous, as they are capable of amputating a person's finger, or possibly their hand.[8]
Unlike the temperature-dependent sex determination of most turtles, Trionychids have ZZ/ZW genetic sex determination; microchromosomes play a role in determining sex.[9]
As food
In East Asia
Softshell turtles are eaten as a
Worldwide, the most commonly consumed softshell species is the Chinese softshell
Due to rising demand and overhunting, the price of Pelodiscus sinensis in China skyrocketed by the mid-1990s; large-scale turtle farming in China and neighboring countries; raising this species by hundreds of millions was the response, with prices soon returning to a more affordable level.[12][13][14]
Another species,
In the United States
In the United States, harvesting softshells (e.g.
New rules, in effect as of July 20, 2009, restrict collecting any wild turtles to one turtle per person per day, completely prohibit collection of softshells (
Some other US states, too, have already adopted strict limitations on wild turtle trade. In 2009, South Carolina passed a law (Bill H.3121) restricting interstate and international export of wild-caught turtles (both soft-shell and some other species) to 10 turtles per person at one time, and 20 turtles per person per year.[17]
Taxonomy
Family Trionychidae
- †Palaeotrionyx (fossil) Paleotrionyx jimenezfuentesi[18]
- Subfamily Plastomeninae[19] (fossil)
- Genus †Gilmoremys[20][18]
- Genus †Hutchemys
- Genus †Plastomenus[18]
- Subfamily Cyclanorbinae
- Genus Cyclanorbis
- Genus Cycloderma
- Genus Lissemys
- Subfamily Trionychinae
Past classification
- Genus Aspideretes
Phylogeny
Cladogram after Walter G. Joyce, Ariel Revan, Tyler R. Lyson and Igor G. Danilov (2009).[19]
Trionychidae |
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Gallery
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Amyda cartilaginea(juvenile)
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Apalone ferox
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Chitra indica
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Dogania subplana
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Lissemys punctata
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Nilssonia nigricans
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Pelochelys cantorii
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Pelodiscus sinensis in a Seoulmarket
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Rafetus euphraticus
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Rafetus swinhoei
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Trionyx triunguis
Notes
- ^ Chelonia.org
- S2CID 245107305.
- ^ Meylan, P.A. 1987. The phylogenetic relationships of soft-shelled turtles (Family Trionychidae). Bulletin of the American Museum of Natural History. 186: 1–101.
- ^ ISBN 978-0-12-178560-4.
- ^ About Turtles and Tortoises, Chelonians
- JSTOR 2449924.
- PMID 23053366.
- ISBN 978-1112357510.
- S2CID 14434440.
- Jenyns, Soame (1930), "The tortoise and the turtle in Kwongtung"(PDF), The Hong Kong Naturalist, 1: 161–163
- ^ Mitsukuri, Kakichi (1906), "The cultivation of marine and fresh-water animals in Japan", in Rogers, Howard Jason (ed.), Congress of arts and science: Universal exposition, St. Louis, 1904, Houghton, Mifflin and company, pp. 694–732. The Japanese variety of Pelodiscus sinensis is referred to in Mitsukuri's article under its older name, Trionyx japonicus.
- ^ Zhao Huanxin, "Low price hurts turtle breeding". China Daily 1999-06-30 (scroll to the end of the file to find that article)
- ^ Zhang Jian (章剑), Chinese soft-shelled turtle value return Archived 2011-05-26 at the Wayback Machine, Turtle news (中国龟鳖网), 13 August 2009 (appears to be a machine translation of the more comprehensible "中华鳖价值回归", at "中国龟鳖网". Archived from the original on 2010-11-18. Retrieved 2009-12-28. )
- ^
- ^ "China Gobbling Up Florida Turtles", By CRAIG PITTMAN, St. Petersburg Times. Published: Thursday, October 9, 2008
- ^ Freshwater Fish and Wildlife, Rule No. 68A-25.002: General Provisions for Taking Possession and Sale of Reptiles
- ^ (South Carolina) Legislative Update, June 5, 2009, Vol. 26, No. 16 (see Bill H.3121)
- ^ a b c d e f g h i j k "Trionychidae". Fossilworks. Retrieved 17 December 2021.
- ^ S2CID 85505337.
- S2CID 133358179.
References
- Trionychidae (all species) at The Reptile Database
- Parade of the Animal Kingdom. Hegner, Robert. 1935. the Macmillan Company.