Cheloniidae

Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Megaclassis: Osteichthyes
Cladus: Sarcopterygii
Cladus: Rhipidistia
Cladus: Tetrapodomorpha
Cladus: Eotetrapodiformes
Cladus: Elpistostegalia
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Cladus: Archelosauria
Division: Pan-Testudines
Division: Testudinata
Ordo: Testudines
Subordo: Cryptodira
Superfamilia: Chelonioidea

Familia: Cheloniidae
Subfamiliae (3): Carettinae - Cheloniinae - †Toxochelyinae

Overview of genera

Allopleuroninae
†Allopleuron – †Glyptochelone – †Protosphargis –

Carettinae
Caretta – Lepidochelys

Cheloniinae
Chelonia – †Eochelone – Eretmochelys – †Gigantatypus – †Itilochelys – †Miocaretta – Natator – †Pacifichelys

†Syllominae
†Syllomus – †Tasbacka – †Thalassochelys – †Trachyaspis – †Zangerlchelys

Toxochelyinae
†Ctenochelys – †Osteopygis – †Porthochelys – †Prionochelys – †Thinochelys – †Toxochelys

Stem Taxa
†Argillochelys – †Ashleychelys – †Carolinochelys – †Catapleura – †Glarichelys – †Mexichelys – †Procolpochelys

Name

Cheloniidae Oppel, 1811
Vernacular names
беларуская: Марскія чарапахі
български: Морски костенурки
Deutsch: Meeresschildkröten
English: Sea Turtles
español: Tortuga Marina
suomi: Merikilpikonnat
עברית: צב ים
magyar: Tengeriteknős-félék
Bahasa Indonesia: Penyu
日本語: ウミガメ科
한국어: 바다거북과
lietuvių: Jūriniai vėžliai
Nederlands: Zeeschildpadden
polski: Żółwie morskie
svenska: Havssköldpaddor
தமிழ்: கடலாமைகள்
ไทย: เต่าทะเล
Türkçe: Deniz kaplumbağasıgiller
中文: 海龟

Cheloniidae is a family of typically large marine turtles that are characterised by their common traits such as, having a flat streamlined wide and rounded shell and almost paddle-like flippers for their forelimbs. They are the only sea turtles to have stronger front limbs than back limbs.[2] The six species that make up this family are: the green sea turtle, loggerhead sea turtle, olive ridley sea turtle, hawksbill sea turtle, flatback sea turtle and the Kemp's ridley sea turtle.[3]
Morphology

In contrast to their earth-bound relatives, tortoises, sea turtles do not have the ability to retract their heads into their shells. Their plastron, which is the bony plate making up the underside of a turtle or tortoise's shell, is comparably more reduced from other turtle species and is connected to the top part of the shell by ligaments without a hinge separating the pectoral and abdominal plates of the plastron. Sizes among the seven species of sea turtles range from 71 to 213 cm;[2] for example, the smallest turtle species in the family Cheloniidae, the Kemp's Ridley, only has a shell size of about 75 cm and a weight of 50 kg. All species have a distinct hardened shell.[4]
Reproduction and life cycle

Reproductive behaviors among the different species of sea turtles are similar, with slight differences in each of the species. The females come to shore and bury their clutch of eggs on beaches or sandy environments typically at night and well away from the high tide line of the shore. Most females nest only once every three to four years and most species have two to four egg laying time periods per nesting season, which is from spring to late fall. A common number of eggs laid in a nest is often about 100 eggs per clutch. The incubation period of some turtles can range anywhere from 50 to 60 days. The development of the eggs is dependent on the temperature of the environment that they were buried in, with warmer climates bringing about an earlier emergence by the hatchlings. The timing of sea turtle hatching tends to be almost synchronous among the whole clutch of eggs, with just about all the eggs in the nest hatching within the same time. This is thought to aid the process of the hatchlings unburying themselves from the sand and most often occurs at night time. Temperature has also been linked to the likeliness of hatching's sex, warmer temperature more likely to produce females and colder temperatures more commonly producing males.[5]
Habitat and ecology

The habitat range of sea turtles, in general, is known to be far reaching into warmer temperatures and the tropical and subtropical areas of the Pacific and Atlantic Oceans and is even also found in warmer seas such as the Mediterranean Sea.[6] Within these temperamental biomes, sea turtles frequent near by the coastlines when nesting, and spend most of their lives swimming out in waters over the continental shelf when feeding.[7] Travelling throughout the oceans has been reported in olive ridley sea turtles but more often than not, they tend to frequent bays and estuaries. The diets of all the sea turtle species, except for the Green Sea Turtle, which is only herbivorous from hatchling to juvenile, are mostly carnivorous, with some herbivorous tendencies. Sea turtles feed mainly on sea sponges, jellyfish, mollusks and barnacles, sea urchins, and even fish. The green sea turtle, on the other hand, feeds primarily on many different types of sea grasses.[8]
Conservation status and significance to humans

The conservation status of each of the seven turtle species are either endangered, threatened or data deficient (Flatback). The green and loggerhead sea turtles are categorized as endangered, olive ridley are classified as vulnerable, Kemp's ridley, and hawksbill sea turtles are critically endangered and the flatback sea turtle does not have enough data to draw an accurate conclusion on conservation status.[9]

Most do not reach sexual maturity before becoming prey to other organisms, or being caught by humans either intentionally or as bycatch by commercial fishing operations. Their slow maturity rate, which most of the time means about 10 or 15 years, does not allow the turtles which have been caught to have fully reproductively matured and to have produced hatchlings of their own. International legislation has been put into place to attempt to reduce the number of sea turtle deaths but this does not deter the demand for the consumption of turtle eggs around the world, and some are hunted for their shells.

In addition to this, turtles face another threat which has been theorized as being linked to human pollution. A growing number of turtles have been found with fibropapillomatosis, fibrous tumor growths on their skin, mouths, and even internal organs. In some areas the number of infected turtles is over 70%. It is unknown what the effects of the growths will have in the long term for sea turtle populations.[10]

Sea turtles play a very important part in marine ecosystems. They maintain the balance of health of sea grasses and reefs, which in turn benefit the likes of shrimp, lobsters, and tunas. They are also the last living members of the seafaring category of marine reptiles that have been in existence on Earth for at least the past 100 million years. They are also highly significant to multiple cultures and are also popular animals in tourism, which gives a higher importance to their conservation.[11]
Classification
Extant genera

Subfamily Carettinae
Genus Caretta
Loggerhead sea turtle (Caretta caretta)[1]
Genus Lepidochelys
Kemp's ridley sea turtle (Lepidochelys kempii)[1]
Olive ridley sea turtle (Lepidochelys olivacea)[1]
Subfamily Cheloniinae
Genus Chelonia
Green sea turtle (Chelonia mydas)[1]
Genus Eretmochelys
Hawksbill sea turtle (Eretmochelys imbricata)[1]
Genus Natator
Flatback sea turtle (Natator depressus)[1] (previously in Chelonia)

Cladogram

Below is a cladogram showing the phylogenetic relationships of living and extinct sea turtles in the family Cheloniidae based on Lynch and Parham (2003)[12] and Parham and Pyenson (2010).[13]

Pancheloniidae (=Cheloniidae sensu lato)

†Toxochelys †Mexichelys †Lophochleyinae †Euclastes †Argillochelys †Eochelone †Erquelinnesia †Pacifichelys †Puppigerus  Cheloniidae (sensu stricto)  †Syllomus †Procolpochelys Chelonia mydas Natator depressus Eretmochelys imbricata  Carettini   Lepidochelys  Lepidochelys kempii Lepidochelys olivacea Caretta caretta

Extinct genera

Genus †Allopleuron
Genus †Argillochelys[citation needed]
Genus †Cabindachelys[14]
Genus †Carolinochelys[citation needed]
Genus †Catapleura
Genus †Erquelinnesia
Genus †Gigantatypus[15]
Genus †Glyptochelone
Genus †Itilochelys[16]
Genus †Lytoloma
Genus †Osteopygis
Genus †Pampaemys
Genus †Peritresius
Genus †Porthochelys
Genus †Prionochelys
Genus †Procolpochelys[citation needed]
Genus †Retechelys
Genus †Syllomus
Genus †Tasbacka
Genus †Thinochelys
Genus †Miocaretta

Rhodin 2011, p. 000.172
Pecor, Keith. "Cheloniidae". Animal Diversity Web. Retrieved 2022-10-29.
"Cheloniidae - an overview | ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-10-29.
"Information about Sea Turtles: Leatherback Sea Turtle" Sea Turtle Conservancy https://conserveturtles.org/information-about-sea-turtles-leatherback-sea-turtle/
"Sea Turtle Species" World Wildlife https://www.worldwildlife.org/species/sea-turtle
"Seaturtles (Cheloniidae) Encyclopedia.com "http://www.encyclopedia.com/environment/encyclopedias-almanacs-transcripts-and-maps/seaturtles-cheloniidae
"Sea Turtles- Cheloniidae Over View" Encyclopedia of Life http://eol.org/pages/8123/overview
"Green Sea Turtle" National Geographic http://animals.nationalgeographic.com/animals/reptiles/green-turtle/
"Sea Turtle Threats" See Turtles http://www.seeturtles.org/sea-turtles-threats/
"Fibropapillomatosis" Florida Fish and Wildlife Conservation Commission http://myfwc.com/research/wildlife/sea-turtles/threats/fibropapillomatosis/
"Sea Turtle" World Wildlife Fund https://www.worldwildlife.org/species/sea-turtle
Lynch, S.C.; Parham, J.F. (2003). "The first report of hard-shelled sea turtles (Cheloniidae sensu lato) from the Miocene of California, including a new species (Euclastes hutchisoni) with unusually plesiomorphic characters" (PDF). PaleoBios. 23 (3): 21–35.[permanent dead link]
James F. Parham; Nicholas D. Pyenson (2010). "New Sea Turtle from the Miocene of Peru and the Iterative Evolution of Feeding Ecomorphologies since the Cretaceous". Journal of Paleontology. 84 (2): 231–247. doi:10.1666/09-077R.1. S2CID 62811400.
Myers, T.S., Polcyn M.J., Mateus O., Vineyard D.P., Gonçalves A.O., & Jacobs L.L. (2017). "A new durophagous stem cheloniid turtle from the lower Paleocene of Cabinda, Angola." Papers in Palaeontology 1-16.
H. F. Kaddumi (2006). "A new genus and species of gigantic marine turtles (Chelonioidea: Cheloniidae) from the Maastrichtian of the Harrana Fauna-Jordan" (PDF). PalArch's Journal of Vertebrate Palaeontology. 3 (1): 1–14. Archived from the original (PDF) on 2012-02-24. Retrieved 2010-02-04.

Danilov, I.G.; Averianov, A.O; Yarkov, A.A. (2010). "Itilochelys rasstrigin gen. et sp. nov., a new hard-shelled sea turtle (Cheloniidae sensu lato) from the Lower Palaeocene of Volgograd Province, Russia" (PDF). Proceedings of the Zoological Institute RAS. 314 (1): 24–41. doi:10.31610/trudyzin/2010.314.1.24. S2CID 250006012.

External links

Skaphandrus.com Cheloniidae

Bibliography
Rhodin, Anders G.J.; van Dijk, Peter Paul; Inverson, John B.; Shaffer, H. Bradley; Roger, Bour (2011-12-31). "Turtles of the world, 2011 update: Annotated checklist of taxonomy, synonymy, distribution and conservation status" (PDF). Chelonian Research Monographs. 5. Archived from the original (PDF) on 2012-01-31.