Jurassic marine crocodile taphonomy

[Ben Creisler <bcreisler@gmail.com>]

From: Ben Creisler
bcreisler@gmail.com


A new online paper not yet mentioned:


Susan R. Beardmore, Patrick J. Orr, Tom Manzocchi and Heinz Furrer (2012)
Float or sink: modelling the taphonomic pathway of marine crocodiles
(Mesoeucrocodylia, Thalattosuchia) during the death–burial interval.
Palaeobiodiversity and Palaeoenvironments (advance online publication)
DOI: 10.1007/s12549-011-0066-0
http://www.springerlink.com/content/8l54506310l5842h/


A taphonomic model is erected for a dataset of 19 Steneosaurus
(Mesoeucrocodylia; Thalattosuchia) from the Toarcian
Posidonienschiefer Formation (Lower Jurassic) of Germany. These were
deposited in a quiet-water, marine, basin. Their taphonomy is compared
with that of an additional seven thalattosuchians from other Jurassic
localities (Peterborough and Yorkshire, UK; Nusplingen, Germany). The
skeletal taphonomy of the specimens is assessed in terms of the
articulation and completeness of nine skeletal units. Steneosaurus
from the Posidonienschiefer Formation exhibit variable levels of
articulation in the nine units. Completeness also varies but the head,
neck and dorsal units are complete in all specimens. Carcasses reached
the sediment–water interface shortly after death. Loss of fidelity
occurred primarily as individuals lay on the sediment, and
disarticulated elements tended to remain in the vicinity of the
carcass. Those elements absent from specimens are the smaller, more
distal, bones of the limbs and tail; these were removed preferentially
by weak bottom currents. Smaller specimens are consistently less
complete. Specimens from other localities broadly follow the same
taphonomic pathway, suggesting a consistent pattern for the skeletal
taphonomy of the carcasses of marine crocodiles. Loss of completeness
in some specimens is more exacerbated, the result of stronger current
activity at the sediment–water interface.