Placochelys

Placochelys; Temporal range: Late Triassic (Norian to Rhaetian), ; 221.5–205.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N ;
	Restored Placochelys placodonta skull at the Museum für Naturkunde, Berlin
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Superorder:	†Sauropterygia
Order:	†Placodontia
Family:	†Placochelyidae
Genus:	†Placochelys; Jaekel, 1902

Placochelys (from Greek: plax, plakos, "plate" and Greek: chelys, "tortoise")^[1] is an extinct genus of placodont reptiles erected by Otto Jaekel in 1902.

Fossil records

Fossils of Placochelys dates back to the Triassic period (age range: 221.5 to 205.6 million years ago). They have been found in Germany, Austria, Hungary and Italy.^[2]

Species

This genus includes only one species:

Placochelys placodonta Jaekel, 1902 (from Upper Ladinian of Hungary)

Description

Placochelys looked remarkably similar to a sea turtle, and grew to about 90 centimetres (3.0 ft) in length. It had a flat turtle-like carapace covered with knobbly plates, and a compact triangular skull. Its beaked skull had powerful muscles. It had only two pairs of palatal teeth, a large posterior pair, and a small rostral pair. The specialized broad teeth on the palate, were most likely used for crushing shellfish and hard-shelled prey. Its limbs were paddle-shaped for swimming, although, unlike modern sea turtles, they still had discernable toes, and it also had a short tail.^[3]

Gallery

Life restoration of Placochelys
Placochelys placodonta fossil skull, lateral view
Placochelys placodonta skull seen from below
Placochelys tooth from Adnet, Austria

Bibliography

Jaekel O. 1902. Über Placochelys n. g. und ihre Beeutung fur die Stammesgeschichte der Schildkroten: Neues Jahrbuch für Mineralogie, Geologie und Palaontologie, Abhandlungen, 1902: 127–144.
Mazin, J.-M. and Pinna, G. 1993. Palaeoecology of the armoured placodonts. Paleontologia Lombarda, N. S. 2: 83–91.
Rieppel O. and Zanon R.T. 1997. The interrelationships of Placodontia. Historical Biology: Vol. 12, pp. 211–227
Yin G., in Yin, G., Zhou, X., Cao, Z., Yu, Y, and Luo, Y., 2000, A preliminary study on the Early Late Triassic marine reptiles from Guanling Guizhou, China.
Rieppel O. 2001. The Cranial Anatomy of Placochelys placodonta Jaekel, 1902, And a Review of the Cyamodontoidea (reptilia, Placodonta) Fieldiana: Geology, New Series, No. 45:1-101.
Rieppel, O., 2002, The dermal armor of the cyamodontoid placodonts (Reptilia, Sauropterygia): morphology and systematic value: Fieldiana; Geology, new series, n. 46, p. 1-41pp.

References

^ Colbert, Edwin H. (Edwin Harris); Knight, Charles Robert (1951). The dinosaur book: the ruling reptiles and their relatives. New York: McGraw-Hill. p. 153.
^ Paleobiology Database
^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 71. ISBN 1-84028-152-9.

External links

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[1] Colbert, Edwin H. (Edwin Harris); Knight, Charles Robert (1951). The dinosaur book: the ruling reptiles and their relatives. New York: McGraw-Hill. p. 153.

[2] Paleobiology Database

[EoDP-3] Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 71. ISBN 1-84028-152-9.

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