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Dimetropus tracks from Oklahoma + other non-dino papers

Ben Creisler

A number of recent non-dino papers that may be interest:

Eva Sacchi, Richard Cifelli, Paolo Citton, Umberto Nicosia & Marco Romano (2014)
Dimetropus osageorum n. isp. from the Early Permian of Oklahoma (USA):
A Trace and its Trackmaker.
Ichnos 21(3)175-192

A new ichnospecies is named as Dimetropus osageorum n. isp. within the
ichnogenus Dimetropus Romer and Price, 1940. The new ichnotaxon comes
from the Lower Permian Midco Member of the Wellington Formation,
cropping out near Perry, Noble Co. (Oklahoma, USA), and differs from
congeneric ichnospecies in the apparent heteropody and in the
proportionally shorter digits. The characters of the new ichnotaxon,
together with comparative analysis of footprints and of known skeletal
remains, suggest referral of the trackmaker to the Caseidae, although
edaphosaurid affinities cannot be excluded. Tracks referred to
Dimetropus exhibit wide variation, and their respective trackmakers
may be ascribed to an accordingly wide range of different zoological
taxa among non-therapsid Synapsida and not only to Sphenacodontidae as
has been generally believed. At the same time, the process of
attributing ichnotaxa, on the basis of well preserved tracks and by
comparison with known skeletal remains, is validated.

Alexander M. Dunhill, Bjarte Hannisdal & Michael J. Benton (2014)
Disentangling rock record bias and common-cause from redundancy in the
British fossil record.
Nature Communications 5, Article number: 4818
Free pdf:

The fossil record documents the history of life, but the reliability
of that record has often been questioned. Spatiotemporal variability
in sedimentary rock volume, sampling and research effort especially
frustrates global-scale diversity reconstructions. Various proposals
have been made to rectify palaeodiversity estimates using proxy
measures for the availability and sampling of the rock record, but the
validity of these approaches remains controversial. Targeting the rich
fossil record of Great Britain as a highly detailed regional exemplar,
our statistical analysis shows that marine outcrop area contains a
signal useful for predicting changes in diversity, collections and
formations, whereas terrestrial outcrop area contains a signal useful
for predicting formations. In contrast, collection and formation
counts are information redundant with fossil richness, characterized
by symmetric, bidirectional information flow. If this is true, the
widespread use of collection and formation counts as sampling proxies
to correct the raw palaeodiversity data may be unwarranted.


In open access:

Lionel Cavin and Guillaume Guinot (2014)
Coelacanths as "almost living fossils".
Frontiers in Ecology and Evolution 2: 49
doi: 10.3389/fevo.2014.00049

Since its usage by Darwin (1859), the concept of "living fossil" has
undergone multiple definitions and has been much discussed and
criticized. Soon after its discovery in 1938, the coelacanth Latimeria
was regarded as the iconic example of a "living fossil." Several
morphological studies have shown that the coelacanth lineage
(Actinistia) has not displayed critical morphological transformation
during its evolutionary history and molecular studies have revealed a
low substitution rate for Latimeria, indicating a slow genetic
evolution. This statement, however, has been recently questioned by
arguing that the low substitution rate was not real, and that the slow
morphological evolution of actinistians was not supported by
paleontological evidence. The assessment of morphological
transformation among three vertebrate lineages during a time interval
of circa 400 million years shows that the morphological disparity of
coelacanths is much more reduced than the morphological disparity of
Actinopterygii and Tetrapoda. These results support the idea that
living coelacanths are singular organisms among the living world.


An Early Triassic ichthyopterygian fossil from the Osawa Formation in
Minamisanriku Town, Miyagi Prefecture, Japan.
Palaeontological Research (advance online publication)