Paracryptodira

Paracryptodira Temporal range: Jurassic-Eocene
Manchurochelys liaoxiensis (Baenoidea: Macrobaenidae)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Superclass:	Tetrapoda
Class:	Sauropsida
Order:	Testudines
Suborder:	Cryptodira
Infraorder:	Paracryptodira Gaffney, 1975
Superfamilies
Baenoidea and see text
Synonyms
Pleurosternoidea

The Paracryptodira are an extinct infraorder of the Testudines, an order of reptiles which includes tortoises, turtles and terrapins. Initially treated as suborder sister to the Cryptodira,^[1] they are now known to be a very primitive lineage inside the Cryptodira according to the most common use of the latter taxon.^[2] Some less primitive prehistoric cryptodires (e.g. the "horned turtles", Meiolaniidae) as well as the living forms make up the Eucryptodira.^[3]

Paracryptodires according to the obsolete concept were made up of two Cretaceous families, the Pleurosternidae and Baenidae. The former has been found in North America, Europe, and possibly Asia, while the latter is only known to have occurred in North America. According to modern understanding however, the Macrobaenidae and the Neurankylidae are split from the Baenidae to form the superfamily Baenoidea, whose monophyly needs confirmation however. In addition, there are a number of more basal families as well as some of uncertain position with regards to the Baenoidea:^[4]

• Kallokibotiidae
• Mongolochelyidae
• Pleurosternidae
• Solemydidae

The Macrobaenidae, another prehistoric cryptodiran group that may actually be a paraphyletic assemblage, are sometimes placed entirely or partly in the paracryptodires too.

Characteristics

Paracryptodira have reduced prefrontal exposure on the dorsal surface of the skull, reduced fenestra perilymphatica, and a secondary reduced supraoccipital crest. .^[2] In the skull, the posterior foramen for the internal carotid canal is located midway along the basisphenoid-pterygoid suture.^[1]

Footnotes

References

• Gaffney, E.S. (1975): A phylogeny and classification of higher categories of turtles. Bulletin of the American Museum of Natural History 155(5): 387-436. PDF fulltext
• Haaramo, Mikko (2008): Mikko's Phylogeny Archive - Paracryptodira. Version of 2008-MAR-11. Retrieved 2008-MAY-06.
• Joyce, W.G. (2007): Phylogenetic relationships of Mesozoic turtles. Bulletin of the Peabody Museum of Natural History 48(1): 3–102. DOI:10.3374/0079-032X(2007)48[3:PROMT]2.0.CO;2 HTML abstract

External links

• [1]

Turtles portal