[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Jurassic tetrapod footprint ichnofaunas of the Western Interior, USA.

Ben Creisler

A new paper in open access:

Martin Lockley (2014)
Jurassic tetrapod footprint ichnofaunas and ichnofacies of the Western
Interior, USA.
Volumina Jurassica 12 (2): 133–150
DOI : 10.5604/17313708 .1130134

The Jurassic tetrapod track record of the Western Interior, USA, is
one of the most diverse, complete and well-studied in the world,
spanning a relatively continuous representation of Lower, Middle and
Upper Jurassic formations. Although a few of these formations, notably
the Morrison Formation, have yielded abundant body fossils, the
majority lack abundant skeletal remains and, while track-rich, are in
some cases completely barren of body fossils. Thus, the track record
assumes great importance as the most complete and representative
record of changing tetrapod faunas through time in a region where the
body fossil record is often sparse or absent. In the Lower and Middle
Jurassic, many distinctive assemblages are associated with eolian
units (Wingate, Navajo and Entrada) that are almost devoid of body
fossils. However, the former two units are rich in synapsid tracks
characterized as the Brasilichnium ichnofacies. In the Middle
Jurassic, fluctuating sea-levels exerted important controls on the
distribution of theropod and pterosaur-dominated ichnofaunas
associated with coastal plain and marginal marine settings. The
Morrison ichnofauna is a reliable reflection of the body fossil record
of that formation. Ongoing efforts to group and classify the various
tetrapod ichnofaunas into tetrapod ichnofacies and tetrapod biochron
categories have, in some cases, provoked stimulating, if sometimes
inconclusive, debate.