Machimosaurus (Thalattosuchia) in Late Jurassic of England.

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com


A new online paper:



Mark T. Young & Lorna Steel (2013)
Evidence for the teleosaurid crocodylomorph genus Machimosaurus in the
Kimmeridge Clay Formation (Late Jurassic) of England.
Historical Biology (advance online publication)
DOI:10.1080/08912963.2013.793320
http://www.tandfonline.com/doi/full/10.1080/08912963.2013.793320#.UZJQT7XvtcQ



We report the only definite specimen of the teleosaurid crocodylomorph
genus Machimosaurus from the Kimmeridge Clay Formation of England.
This specimen (an isolated tooth) is now the only evidence of
Machimosaurus in the Kimmeridge Clay Formation because a large skull
and mandible, previously considered to be of Machimosaurus mosae, was
recently shown to pertain to a metriorhynchid crocodylomorph. The
tooth described herein was originally figured in 1884 as a tooth crown
from a metriorhynchid crocodylomorph. However, its conical shape,
blunt apex and distinctive enamel ornamentation are characteristic of
the teleosaurid genus Machimosaurus. That Machimosaurus, and
teleosaurids in general, were so rare in the Kimmeridge Clay Formation
suggests that these marine crocodylomorphs did not commonly use this
seaway. Their rarity is in contrast to contemporaneous deposits from
continental Europe where teleosaurid remains, including Machimosaurus,
are far more common. These continental deposits were deposited in
shallow-marine/brackish ecosystems, suggesting that teleosaurids were
largely restricted to coastal marine environments.