Trionychidae is a
taxonomicTaxonomy is the practice and science of classification. The word finds its roots in the Greek , taxis and , nomos...
familyIn biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus...
which comprises a number of
turtleTurtles are reptiles of the order Testudines , characterised by a special bony or cartilaginous shell developed from their ribs that acts as a shield...
generaIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
commonly known as
soft-shell turtles. It consists of some of the world's largest
fresh waterFresh Water is the debut album by Australian rock and blues singer Alison McCallum, released in 1972. Rare for an Australian artist at the time, it came in a gatefold sleeve...
turtles, though many can adapt to living in highly brackish areas. Members of this family occur in
AfricaAfrica is the world's second-largest and second most-populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area. With a billion people in 61 territories, it accounts for about 14.8% of the...
,
AsiaAsia is the world's largest and most populous continent, located in the eastern and northern hemispheres. It covers 8.6% of the earth's total surface area and with approximately 4 billion people, it hosts 60% of the world's current human population.Asia is traditionally defined as part of the...
,
North AmericaNorth America is the northern continent of the Americas, situated in the Earth's northern hemisphere and in the western hemisphere. It is bordered on the north by the Arctic Ocean, on the east by the North Atlantic Ocean, on the southeast by the Caribbean Sea, and on the west by the North Pacific...
, and the East Indies. North American members of genus
Trionyx were fairly recently assigned the new genus name
ApaloneApalone is a North American genus in the Trionychidae family of turtles, a family whose members are commonly referred to as softshell turtles. Apalone species are native primarily to the United States, though are also found in parts of southern Canada and northern Mexico...
, though they are still listed semi-correctly as
Trionyx in some texts.
Characteristics
They are called "soft shelled" because their
carapaceA carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids as well as vertebrates such as chelonians, order Testudines, turtles and tortoises.-Crustaceans:In crustaceans, the carapace is a part of the exoskeleton...
lacks horny
scuteA scute or scutum is a bony external plate or scale, as on the shell of a turtle, the skin of crocodilians, or the feet of some birds.-Properties:Scutes are similar to scales and serve the same function...
s (scales), though the Spiny Softshell Turtle,
Apalone spinifera, does have some scale-like projections, hence its name. The carapace is leathery and pliable, particularly at the sides. The central part of the carapace has a layer of solid bone beneath it, as in other turtles, but this is absent at the outer edges. Some species also have dermal bones in the
plastronThe plastron is the nearly flat part of the shell structure of a turtle or tortoise, what one would call the belly, similar in composition to the carapace; with an external layer of horny material divided into plates called scutes and an underlying layer of interlocking bones.In certain families...
, but these are not attached to the bones of the shell. The light and flexible shell of these turtles allows them to move more easily in open water, or in muddy lake bottoms.
Females can grow up to several feet in carapace diameter, while males stay much smaller; this is their main form of
sexual dimorphismSexual dimorphism is the systematic difference in form between individuals of different sex in the same species. Examples include colour , size, and the presence or absence of parts of the body used in courtship displays or fights, such as ornamental feathers, horns, antlers or tusks.-Examples:In...
.
Pelochelys cantoriiThe Cantor's giant soft-shelled turtle is a species of fresh water turtle. The turtle has a broad head and small eyes close to the tip of its snout. The carapace is smooth and olive colored...
, found in southeastern Asia, is the largest softshell turtle on earth.
These turtles have many characteristics pertaining to their aquatic lifestyle. Like all aquatic turtles, they need to be submerged to be able to swallow food. Most are strict carnivores, with diets consisting mainly of fishes, aquatic crustaceans, snails, amphibians, and sometimes birds and small mammals. They have elongated, soft,
snorkelSnorkeling is the practice of swimming on or through a body of water while equipped with a diving mask, a shaped tube called a snorkel, and usually swimfins. In cooler waters, a wetsuit may also be worn...
-like nostrils. Their necks are disproportionately long in comparison to their body size, enabling them to breathe surface air while their bodies remain submerged in the substrate (mud or sand) a foot or more below the surface.
Like some
amphibianAmphibians , such as frogs, toads, salamanders, newts, and caecilians, are ectothermic animals that metamorphose from a juvenile water-breathing form, to an adult air-breathing form. Though amphibians typically have four limbs, the Caecilians are notable for being limbless. Unlike other land...
s and marine snakes, softshell turtles are able to extract a small amount of oxygen out of water via their skin, further enabling them to stay underwater for prolonged periods. Their feet are webbed and are three-clawed, hence the "
Tri-" in the genus name. The carapace color of each type of softshell turtle tends to match the sand and/or mud color of its geographical region, assisting in their "lie and wait" feeding methodology.
Soft-Shelled Turtles look rather helpless but are fully able to protect them-selves in time of danger. "Hidden by the lips, are a pair of mandibles remarkably keen and strong; on many specimens the mandibles form the outer border of powerful crushing processes- the alveolar surfaces of the jaws; examples thus provided feed largely on mollusks. Taken at a disadvantage, out of the water, the soft-shelled turtles are savage fighters. the head darts at an offending object like that of a snake. Large turtles are dangerous; for they can amputate a man's finger- possibly his hand."
Soft-shell turtles as food
Soft-shell turtles are eaten as a delicacy in most parts of their range, particularly in East Asia. Chinese people, in particular, enjoy eating them with
chickenThe chicken is a domesticated fowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other bird...
in
stewA stew is a combination of solid food ingredients that have been cooked in liquid and served in the resultant gravy.Ingredients in a stew can include any combination of vegetables , meat, poultry, sausages and seafood. While water can be used as the stew-cooking liquid, wine, stock, and beer are...
.
In the United States, "harvesting" them is legal in
FloridaFlorida is a state located in the southeastern region of the United States, bordering Alabama to the northwest and Georgia to the north. It was the 27th state admitted to the United States...
. Environmental groups have been advocating with the authorities for banning, or restricting, the practice. The
Florida Fish and Wildlife Conservation CommissionThe Florida Fish and Wildlife Conservation Commission is a Florida government agency charged with managing the state's fish and wildlife resources, regulating Florida's fisheries and wildlife, and enforcing related laws...
responded by introducing the daily limit of 20 turtles per day for licensed harvesters - the level which the turtles advocates consider unsustainable, as there may be anywhere between 100 to 500 hunters state-wide. While some catch is consumed locally, most is exported; the Commission estimates (2008) that around 3,000 pounds of softshell turtles are exported each week via
Tampa International AirportTampa International Airport is a major public airport located six nautical miles west of the central business district of Tampa, in Hillsborough County, Florida, United States. This airport is publicly owned by Hillsborough County Aviation Authority...
.
After meetings and discussions with a diverse group of stakeholders, Commission staff decided to propose a ban on commercial take of freshwater turtles. Further study revealed there is a potential for a commercial market to impact freshwater turtle populations through too much harvest pressure, which in turn could threaten the sustainability and the unique diversity of turtles in Florida.
Because of these potential threats, the Commission staff believes substantial monitoring would need to be conducted and data collected if commercial harvest of turtles continued. This process would be difficult and expensive. The Commission has no feasible cost-effective process for developing a monitoring program that would allow a sustainable commercial harvest. Commission staff believes an effective way to ensure sustainability of turtles is through highly restrictive conservation measures. Commissioners directed staff to finalize a draft rule that bans the commercial take or sale of wild freshwater turtles.
Taxonomy
Family Trionychidae
- Palaeotrionyx
Palaeotrionyx is an extinct genus of softshell turtle from the Paleocene epoch of western North America.Palaeotrionyx, like its modern relatives, had no scutes on its carapace, which probably had leathery, pliable skin at the sides...
(extinct)
- Subfamily Cyclanorbinae
- Genus Cyclanorbis
Cyclanorbis is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Nubian Flapshell Turtle * Senegal Flapshell Turtle...
- Genus Cycloderma
Cycloderma is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Zambezi Flapshell Turtle...
- Genus Lissemys
Lissemys is a genus of turtles of the family Trionychidae.-Species:* Lissemys punctata * Lissemys scutata...
- Subfamily Trionychinae
- Genus Amyda
Amyda is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Asiatic Softshell Turtle...
- Genus Apalone
Apalone is a North American genus in the Trionychidae family of turtles, a family whose members are commonly referred to as softshell turtles. Apalone species are native primarily to the United States, though are also found in parts of southern Canada and northern Mexico...
- Genus Aspideretes
Aspideretes is a genus of soft-shelled turtles . It has been found to be so closely related to the Burmese Peacock Softshell that it is probably better united with this species under Nilssonia, the older name...
(might belong in Nilssonia)
- Genus Chitra
Chitra is a genus of turtles of the family Trionychidae.-Species:*Chitra chitra *Chitra chitra javanensis *Chitra indica...
- Genus Dogania
Dogania is a genus of softshell turtle in the Trionychidae family.It contains the following species:* Malayan Soft-Shelled Turtle...
- Genus Nilssonia
Nilssonia is a genus of softshell turtles . In many treatments, it is monotypic, with the single species Burmese Peacock Softshell . However, the supposed other genus of peacock softshells, Aspideretes, is even closer related to N. formosa than was prevously believed...
- Genus Palea
- Genus Pelochelys
Pelochelys is a genus of turtles of the family Trionychidae.-Species:*Pelochelys bibroni *Pelochelys cantorii *Pelochelys signifera...
- Genus Pelodiscus
- Genus Rafetus
Rafetus is a genus of highly endangered softshell turtles in the Trionychidae family.It contains the following species:* Euphrates Softshell Turtle * Shanghai soft-shell turtle...
- Genus Trionyx