Tuesday, 3 December 2013

Ammosaurus major

Ammosaurus major is very similar to the contemporary but smaller Anchisaurus and may be a synonym. Fairly complete fossils of this animal missing th skull (the holotype and a juvenile specimen, originally referred as A. solus) have been found in the Connecticut Valley in the Upper Portland Formation dating from the Early Jurassic. Additionnal specimens from the Navajo Sandstone, Arizona and from the McCoy Brook Formation, Nova Scotia, may or may not belong to the same species.

Ammosaurus major
(Marsh, 1889)
Meaning of generic name
Greek Ammos (sand) and Sauros (lizard)
Meaning of specific name
Rather Large
Length: 4 m, Skull length: ?
Holotype (YPM 208): posterior part of skeleton

Referred specimens: YPM 209 (type of Ammosaurus solus); MNA G2 7233 (Arizona specimen); UCMP 82961(Arizona specimen)
Age and Distribution
Horizon: Upper Portland Formation, Lower Jurassic (Plienbaschian-Toarcian?).

Locality: Connecticut River Valley, Connecticut, USA; Also possibly Navajo Sandstone, Arizona, USA.
Dinosauria Saurischia Sauropodomorpha Sauropoda Anchisauria Anchisauridae
Further Reading
Galton, P.M. 1971. The prosauropod dinosaur Ammosaurus, the crocodile Postosuchus, and their bearing on the age of the Navajo Sandstone of Northeastern Arizona. Journal of Palaeontology 45: pp. 781–795.
Anchisaurus major Marsh, 1889, Anchisaurus solus Marsh, 1892 (Juvenile), Ammosaurus solus (Marsh, 1892)

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