| Pancheloniids Temporal range: Late Cretaceous-Holocene, | |
|---|---|
 | |
| Ctenochelys stenoporus skeletons | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Testudines |
| Suborder: | Cryptodira |
| Clade: | Panchelonioidea |
| Clade: | Pancheloniidae |
| Subgroups | |
Pancheloniidae is a clade of sea turtles [1] It is defined as all turtles more closely related to cheloniid sea turtles than to dermochelyid ("leatherback") sea turtles. [2]
The following genera are placed here:
The following list of non-cheloniid pancheloniid species was published by Hirayama and Tong in 2003 [4]
Below is a cladogram showing the phylogenetic relationships of living and extinct sea turtles in the clade Pancheloniidae based on Lynch and Parham (2003) [9] and Parham and Pyenson (2010). [10]
| Pancheloniidae | ||||||||||||||||||||||||||||||||||||||||||||||||||||
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. 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.
Archelon is an extinct marine turtle from the Late Cretaceous, and is the largest turtle ever to have been documented, with the biggest specimen measuring 4.6 m (15 ft) from head to tail and 2.2–3.2 t in body mass. It is known only from the Pierre Shale and has one species, A. ischyros. In the past, the genus also contained A. marshii and A. copei, though these have been reassigned to Protostega and Kansastega, respectively. The genus was named in 1895 by American paleontologist George Reber Wieland based on a skeleton from South Dakota, who placed it into the extinct family Protostegidae. The leatherback sea turtle was once thought to be its closest living relative, but now, Protostegidae is thought to be a completely separate lineage from any living sea turtle.
The Cryptodira are a suborder of Testudines that includes most living tortoises and turtles. Cryptodira differ from Pleurodira in that they lower their necks and pull the heads straight back into the shells, instead of folding their necks sideways along the body under the shells' marginals. They include among their species freshwater turtles, snapping turtles, tortoises, softshell turtles, and sea turtles.
Clemmys is a genus of turtles currently containing a single extant species, the spotted turtle (Clemmys guttata).
Allopleuron is a genus of extinct sea turtle, which measured 2-to-2.5-metre long in life. The type species is Allopleuron hofmanni. It is a basal member of the clade Pancheloniidae, closely related to Protosphargis. Similar to Protosphargis, it was characterized by shell reduction.
Protostegidae is a family of extinct marine turtles that lived during the Cretaceous period. The family includes some of the largest sea turtles that ever existed. The largest, Archelon, had a head one metre (39 in) long. Like most sea turtles, they had flattened bodies and flippers for front appendages; protostegids had minimal shells like leatherback turtles of modern times.
Toxochelys is an extinct genus of marine turtle from the Late Cretaceous period. It is the most commonly found fossilized turtle species in the Smoky Hill Chalk, in western Kansas.
Euclastes is an extinct genus of sea turtles that survived the Cretaceous–Paleogene mass extinction. The genus was first named by Edward Drinker Cope in 1867, and contains three species. E. hutchisoni, was named in 2003 but has since been reassigned to the genus Pacifichelys, while E. coahuilaensis named in 2009 was reassigned as Mexichelys coahuilaensis in 2010.
Peritresius is an extinct genus of sea turtle from the Late Cretaceous deposits in the US Eastern Seaboard.
Kirgizemys is an extinct genus of turtle from Early Cretaceous of China, South Korea, Mongolia, Russia and Kyrgyzstan.
Itilochelys is an extinct genus of sea turtle in the family Cheloniidae containing the single species Itilochelys rasstrigin. The species is known only from the Early Paleocene, Danian stage Rasstrigin 2 locality, Dubovsky District, Volgograd Oblast, Russia.
Mexichelys is an extinct monotypic genus of sea turtle which lived in Mexico during the Cretaceous. The only species is Mexichelys coahuilaensis. Mexichelys was erected in 2010 as a replacement name for Euclastes coahuilaensis, a species named in 2009.
Trionyx is a genus of softshell turtles belonging to the family Trionychidae. In the past many species in the family were classified in this genus, but today T. triunguis, the African or Nile softshell turtle, is the only extant softshell still classified as Trionyx. The other species still assigned to this genus are only known from fossils. T. triunguis is a relatively large, aquatic piscivore.
Archelosauria is a clade grouping turtles and archosaurs and their fossil relatives, to the exclusion of lepidosaurs. The majority of phylogenetic analyses based on molecular data have supported a sister-group relationship between turtles and archosaurs. On the other hand, Archelosauria had not been historically supported by most morphological analyses, which have instead found turtles to either be descendants of parareptiles, early-diverging diapsids outside of Sauria, or close relatives of lepidosaurs within the clade Ankylopoda. Some recent morphological analyses have also found support for Archelosauria.
Nanhsiungchelyidae is an extinct family of land turtles known from Cretaceous deposits in Asia and North America. Nanhsiungchelyids were more terrestrial than many of their contemporaries, and may have gone extinct at the end of the Cretaceous as a result.
Paleontology or palaeontology is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 2017.
Thalassochelydia is a clade of extinct marine turtles from the Late Jurassic and earliest Cretaceous of Europe and South America. The group is defined as including Eurysternum, Plesiochelys and Thalassemys to the exclusion of Pelomedusa, Testudo and Protostega. While a clade uniting the families Eurysternidae, Plesiochelyidae and Thalassemydidae had been supported by phylogenetic evidence, a name was not given for the clade until 2017, when Jérémy Anquetin and colleagues coined Thalassochelydia.
Glossochelys is an extinct genus of sea turtles from the Pancheloniidae that has been discovered in Eocene (Ypresian) deposits in Harwich, England that was first described as a species of Lytoloma in 1842. The type species, G. planimentum, was described as a separate species in 1871 by Harry Seeley. It was possibly the same animal as Euclastes or Erquelinnesia.
Erquelinnesia is an extinct turtle genus from the Cretaceous period, which has been found in fossils. Paleontologist Louis Dollo first described this genus late 19th century from fossilized samples found in the layers of Upper Paleocene / Lower Eocene in Hainaut, Belgium,. Erquelinnesia lived between the Upper Cretaceous and Lower Paleocene ( Danian. Louis Dollo named his discovery as Pachyrhynchus gosseleti in 1886. However, in the following year, the nomenclature was changed by Dollo to Erquelinnesia gosseleti to resolve a conflict with another already existing generic name. Moreover, an additional species was attributed to the genus Erquelinnesia. The North American species called Erquelinnesia molariathat was known only from a fossilized mandible bone has subsequently re-categorized to the genus Euclastes.
Prionochelys is an extinct genus of pancheloniid from the Mooreville Chalk and Eutaw Formations of Alabama. It consists of a single species, P. matutina.