Overview
The Emydidae are the largest and most diverse of Testudines.
The family Emydidae includes more than 40 species in 12 genera. Members are distributed throughout North America, northern South America, Europe, northwestern Africa, and Asia. Emydids are primarily freshwater species, though some species inhabit brackish waters (Malaclemmys terrapin) or are terrestrial (Terrapene, except T. coahuila).
Anatomy
Sizes are variable and range from only 11 centimetres (4.3 in) (Clemmys) to nearly 60 centimetres (24 in) (Kachuga) in carapace length. Coloration is also quite variable. The family does not have a distinguishing suit of superficial characters, although they all have well-developed limbs with webbed feet. In most species, the carapace is low-arching, but some havea higher dome. The plastron is hinged and movable in some, while fixed in others. There are few distinctive skeletal features, but there is a lack of contact between the squamosal and parietal bones in the skull, and the the frontal bone forms part of the orbit.
Behavior
Food habits range from strictly carnivorous to strictly herbivorous. The carnivores feed on annelids, crustaceans, and fish. In several species, there is a shift from carnivory in juveniles to herbivory in adults. Small mammals, especially raccoons, are responsible for the destruction of many Emydid nests. Members of all vertebrate classes predate eggs and hatchlings. The wide range of sizes in mature animals leads to an assortment of predators. While snapping turtles are responsible for predation in some smaller species (e.g., Clemmys muhlenbergii), they cannot eatl arger species. Alligators pose a risk to adults of several species, but humans are chiefly responsible for the deaths of adults either through collection for food or the senseless shooting of basking animals.
Knowledge of reproductive behavior ranges from some of the most detailed, long-term study of any taxa (Chrysemys picta in Michigan) to a total lack of information. In many species, dimorphisms include elongated foreclaws or a concave plastron in the male. The longer claws are used in a courtship routine in which the male faces the female and fans her face. The concave plastron allows the male to mount females in species with more domed carapaces (e.g., Terrapene). Reproduction is on an annual cycle, and multiple clutches may be produced in a single season. Clutch size is quite variable, ranging from as few as two to more than 30 eggs.
Threats To the Emydidae
Emydids are the principle turtles sold through the pet trade. The pond slider (Trachemys scripta) has expanded its range through the careless release of pets into the wild. Many Asian species are threatened by over-collection of animals for sale in markets and into the pet trade. The North America species Clemmys muhlenbergii is listed as an Appendix II species by CITES and is considered threatened or endangered in many states. This status is the result of habitat degradation and over-collection.
Systematics and Evolution
The Emydidae are most closely related to the tortoises (Testudinidae) and are included along with that family in the Testudinoidea. Shared features include a lack of inframarginal scutes, the shape and muscle attachment of the ilium, and the shape of the eighth cervical vertebra (biconvex). Within the Emydidae, two subfamilies were recognized along biogeographic lines. The Emydidae as understood today contain New World species (except Emys), while the former Batagurinae, today a separate family Geoemydidae, contain Old World species (except Rhinoclemmys). Osteological characters, such as the construction of the mandible and articulations of the cervical vertebrae distinguish the two families.
The enigmatic Big-headed Turtle (Platysternon megacephalum) was for some time considered a specialized but still very primitive early offshoot of the Emydidae. But with the geoemydidae being split off it is better reinstated as its own family Platysternidae, though it seems very close to the emydid-geoemydid group.
Fossil Record
Presumed emydids are well-represented in the fossil record. Gyremys sectabilis and Clemmys backmani are both North American species that date from the Upper Cretaceous and Paleocene, respectively. These are the two oldest fossil species. Many other extinct species traditionally placed in the Emydidae are known from the Eocene of North America, Asia and Europe, but the Old World taxa are likely to be more properly Geoemydidae. The North American genus Palaeochelys and probably the trans-Atlantic Echmatemys too would seem to be Emydidae, but their precise relationship to the living genera are indeterminate.
Classification
- Subfamily Emydinae
- Genus Emys
- Genus Emydoidea
- Genus Actinemys
- Genus Clemmys
- Genus Glyptemys
- Genus Terrapene
- Subfamily Deirochelyinae
- Genus Deirochelys
- Genus Chrysemys
- Genus Graptemys
- Genus Malaclemys
- Genus Pseudemys
- Genus Trachemys
Photos
Taxonomy
The Family Emydidae is a member of the Superfamily Testudinoidea. Here is the complete "parentage" of Emydidae:
- Domain: Eukaryota
Whittaker & Margulis,1978 - eukaryotes
- Kingdom: Animalia
Linnaeus, 1758 - animals
- Subkingdom: Bilateria
(Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians
- Branch: Deuterostomia
Grobben, 1908 - Deuterostomes
- Infrakingdom: Chordonia
(Haeckel, 1874) Cavalier-Smith, 1998
- Phylum: Chordata
Bateson, 1885 - Chordates
- Subphylum: Vertebrata
Cuvier, 1812 - Vertebrates
- Infraphylum: Gnathostomata
Auct. - Jawed Vertebrates
- Superclass: Tetrapoda
Goodrich, 1930 - Tetrapods
- Class: Sauropsida
- Subclass: Anapsida
- Order: Testudines
- Turtles
- Suborder: Cryptodira
- Superfamily: Testudinoidea
- Family: Emydidae - Pond Turtles
- Superfamily: Testudinoidea
- Suborder: Cryptodira
- Order: Testudines
- Turtles
- Subclass: Anapsida
- Class: Sauropsida
- Superclass: Tetrapoda
Goodrich, 1930 - Tetrapods
- Infraphylum: Gnathostomata
Auct. - Jawed Vertebrates
- Subphylum: Vertebrata
Cuvier, 1812 - Vertebrates
- Phylum: Chordata
Bateson, 1885 - Chordates
- Infrakingdom: Chordonia
(Haeckel, 1874) Cavalier-Smith, 1998
- Branch: Deuterostomia
Grobben, 1908 - Deuterostomes
- Subkingdom: Bilateria
(Hatschek, 1888) Cavalier-Smith, 1983 - bilaterians
- Kingdom: Animalia
Linnaeus, 1758 - animals
The Family Emydidae is further organized into finer groupings including:
- Subfamily (6): Batagurinae · Coliadinae · Deirochelyinae · Emydinae · Geoemydinae · Heteroderinae
- Tribe (1): Magnolieae
- Genus (58): Actinemys · Batagur · Bridgeremys · Callagur · Chersina · Chinemys · Chniemys · Chrysemys · Clemmys · Cuora · Cyclemys · Deirochelys · Dierochelys · Dipsochelys · Echmatemys · Emydoidea · Emys · Furculachelys · Geochelone · Geoclemmys · Geoclemys · Geoemyda · Geomyda · Glyptemys · Gopherus · Graptemys · Hardella · Heosemys · Hieremys · Homopus · Indotestudo · Kachuga · Kinixys · Leucocephalon · Malaclemmys · Malaclemys · Malacochersus · Malayemys · Manouria · Mauremys · Melanochelys · Morenia · Notochelys · Ocadia · Orlitia · Planetochelys · Psammobates · Pseudemys · Pyxidea · Pyxis · Rhinoclemmys · Sacalia · Siebenrockella · Siebenrockiella · Terrapaena · Terrapene · Testudo · Trachemys
- Species: ZipcodeZoo has pages for 506 species and subspecies in the Family Emydidae.
Genera
Actinemys
Batagur
The Batagur, also called giant river turtle or mangrove terrapin (Batagur baska) is a species of riverine . It is one of the most critically-endangered turtle species according to a 2003 assessment by the IUCN. Batagur baska is a rare and endangered Asian river terrapin also called the "Royal Turtle" in Cambodia because its eggs were a royal delicacy. [more]
Bridgeremys
Callagur
The Painted Batagur, Painted Terrapin, Saw-jawed Turtle, or Three-striped Batagur (Callagur borneoensis) is a species of in the Bataguridae family. It is monotypic within the genus Callagur. [more]
Chersina
Chinemys
Chinemys is a of turtle in the family Geoemydidae (formerly Bataguridae). It is sometimes included in Mauremys, but they do not seem to be particularly close relatives. [more]
Chniemys
Chrysemys
The Painted Turtle (Chrysemys picta) is a that is common in southern Canada, the United States, and northern Mexico and is related to other water turtles such as sliders and cooters. This turtle lives in ponds, lakes, marshes, and in slow-moving rivers that have soft, muddy bottoms. The maximum carapace size, or shell length, for painted turtles is 10 inches (250 mm), or 25 cm. Its shell is used to protect it from its predators. [more]
Clemmys
Clemmys is a of turtle, comprised of one North American species, the spotted turtle (C. guttata), [more]
Cuora
Cuora, the box turtle is a genus of the family Geoemydidae comprising some 10-11 species with about the same number of subspecies. The Keeled Box Turtle/Pyxidea mouhotii is now often included in this genus but half of the authors still place it into its own Genus (Pyxidea), see discussion there. The genus occurs from Assam throughout Southeast Asia and central to southern China northeastwards to Japan, and southeastwards to the borders of the Wallacea and onto Indonesia and the Philippines. [more]
Cyclemys
Deirochelys
Dierochelys
Dipsochelys
Dipsochelys is a genus of giant restricted to Madagascar (extinct) and the Seychelles islands, containing six species: [more]
Echmatemys
Emydoidea
The Blanding's Turtle (Emydoidea blandingii) is a of semi-aquatic turtle. It is the only species in the genus Emydoidea, and is considered to be a threatened or endangered species throughout much of its range.[1] [more]
Emys
Emys is a small of turtles. Its members are: [more]
Furculachelys
Testudo is a of tortoises found in North Africa, western Asia, and Europe. Several species are under threat in the wild, mainly from habitat destruction. [more]
Geochelone
Geochelone is a of tortoises. [more]
Geoclemmys
Geoclemys
Geoemyda
Geoemyda is a of turtle in the family Geoemydidae (formerly Bataguridae). Heosemys and the Sulawesi Forest Turtle were formerly included herein. [more]
Geomyda
Glyptemys
Gopherus
Gopherus is a of tortoises commonly referred to as gopher tortoises. The gopher tortoise is grouped with land tortoises that originated 60 million years ago, in North America. A genetic study has shown that their closest relatives are in the Asian genus Manouria. [more]
Graptemys
Graptemys is a of turtles known commonly as map turtles or sometimes sawback turtles. They are aquatic, freshwater basking turtles that are found throughout the eastern half United States and into southern Canada. They superficially resemble many other species of aquatic turtle, including sliders (genus Trachemys) and cooters (genus Pseudemys), but are distinguished by a keel that runs the length of the center of their carapace, and that they don't typically grow as large. The name map turtle is given to them because of the map-like markings on their carapace. Life expectancy of the map turtle range is 15-20 years. [more]
Hardella
Heosemys
Heosemys is a of turtles in the family Bataguridae. The genus Heosemys was split out of the larger genus Geoemyda by McDowell (1964). [more]
Hieremys
Homopus
Homopus is a genus of in the Testudinidae family. It contains the following species: [more]
Indotestudo
Indotestudo is a genus of . [more]
Kachuga
Kachuga is a genus of . [more]
Kinixys
Kinixys is a genus of in the Testudinidae family. It contains the following species: [more]
Leucocephalon
The Sulawesi Forest Turtle (Leucocephalon yuwonoi) is a species of in the Bataguridae family. It is monotypic within the genus Leucocephalon. It is endemic to Indonesia. [more]
Malaclemmys
Malaclemys
The Diamondback terrapin (Malaclemys terrapin) is a of turtle native to the brackish coastal swamps of the eastern and southern United States, from as far north as Cape Cod, Massachusetts and as far south as Cape Sable, Florida. [more]
Malacochersus
Malayemys
Malayemys subtrijuga is a species of in the Bataguridae family. It was monotypic within the genus Malayemys until Brophy (2004, 2005) revalidated (based on morphology) Malayemys macrocephala (Gray, 1859) long time considered to be a synonym of M. subtrijuga. [more]
Manouria
Manouria is a genus of in the Testudinidae family. It contains the following species: [more]
Mauremys
Mauremys is a of turtle in the family Geoemydidae (formerly called Bataguridae). Ocadia and Chinemys are included here by some scientists, but not by the majority nor by hobbyists. [more]
Melanochelys
Morenia
Morenia is a genus of in the Bataguridae family. It contains the following species: [more]
Notochelys
Ocadia
Ocadia is a of turtle in the family Geoemydidae (formerly called Bataguridae). It is sometimes included in Mauremys (Spinks et al. (2004), Feldman & Parham (2004), Honad et al. (2002). It contains the following species: [more]
Orlitia
The Bornean River Turtle or Malaysian Giant Turtle (Orlitia borneensis) is a species of in the Bataguridae family. It is monotypic within the genus Orlitia. It is found in Indonesia and Malaysia. [more]
Planetochelys
Psammobates
Pseudemys
Pseudemys is a of pond turtles also known as Cooter Turtles, especially in the state of Florida. (The word "cooter" may be used to refer to snapping turtles of the Chelydridae family elsewhere in the southeastern United States.) Cooter stems from kuta, the word for turtle in the Bambara and Malinké languages, brought to America by African slaves. [more]
Pyxidea
The Keeled Box Turtle (Pyxidea mouhotii) is a of the turtle family Geoemydidae found in China (Hainan & southwestern Guangxi and possibly southern Yunnan), northern and Central Vietnam, Laos, northern Cambodia, Thailand, Myanmar and Assam in India. [more]
Pyxis
Pyxis is a minor southern introduced by Nicolas Louis de Lacaille under the name Pyxis Nautica. [more]
Rhinoclemmys
Rhinoclemmys is a of turtle in the family Geoemydidae (formerly Bataguridae). [more]
Sacalia
Sacalia is a of turtle in the family Geoemydidae (formerly called Bataguridae). Species include: [more]
Siebenrockella
Siebenrockiella
The Malaysian Black Mud Turtle, Siebenrockiella crassicollis, is a species of in the Bataguridae family. It used to be monotypic within the genus Siebenrockiella until Diesmos et al (2006) showed based on genetic studis and morphology, that the rare and recently rediscovered Philippine Pond Turtle until that time known as Heosemys leytensis actually belongs into this genus i.e. Siebenrockiella leytensis provisionally also based into a new subgenus Panayanemys. Siebenrockiella crassicollis is known by a variety of vernacular names among hobbyists, such as Black (Mud) Terrapin. Most notably, the edges of its upper jaw extend downwards in the middle, hence the popular name Smiling Terrapin. It is found in Cambodia, Indonesia, Malaysia, Myanmar, Singapore, Thailand, and Vietnam. It is threatened by habitat loss. [more]
Terrapaena
Terrapene
Terrapene is a of box turtles found in the eastern half of the United States and Mexico. [more]
Testudo
Trachemys
Trachemys is a of water turtles found in North, Central, and South America. They are commonly known as "Sliders". It includes the Red-eared slider (Trachemys scripta elegans), which is the most common turtle kept as a pet. [more]
At least 40 species and subspecies belong to the Genus Trachemys.
More info about the Genus Trachemys may be found here.
Sources
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