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Fossil and molecular dates for birds + other non-dino papers

Ben Creisler

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

Daniel T. Ksepka, Jessica L. Ware and Kristin S. Lamm (2014)
Flying rocks and flying clocks: disparity in fossil and molecular
dates for birds.
Proceedings of the Royal Society B 7 August 2014 vol. 281 no. 1788 20140677
doi: 10.1098/rspb.2014.0677

Major disparities are recognized between molecular divergence dates
and fossil ages for critical nodes in the Tree of Life, but broad
patterns and underlying drivers remain elusive. We harvested 458
molecular age estimates for the stem and crown divergences of 67 avian
clades to explore empirical patterns between these alternate sources
of temporal information. These divergence estimates were, on average,
over twice the age of the oldest fossil in these clades. Mitochondrial
studies yielded older ages than nuclear studies for the vast majority
of clades. Unexpectedly, disparity between molecular estimates and the
fossil record was higher for divergences within major clades (crown
divergences) than divergences between major clades (stem divergences).
Comparisons of dates from studies classed by analytical methods
revealed few significant differences. Because true divergence ages can
never be known with certainty, our study does not answer the question
of whether fossil gaps or molecular dating error account for a greater
proportion of observed disparity. However, empirical patterns observed
here suggest systemic overestimates for shallow nodes in existing
molecular divergence dates for birds. We discuss underlying biases
that may drive these patterns.


in open access:

Thomas Fletcher, John Altringham, Jeffrey Peakall, Paul Wignall and
Robert Dorrell (2014)
Hydrodynamics of fossil fishes.
Proceedings of the Royal Society B 7 August 2014 vol. 281 no. 1788 20140703
doi: 10.1098/rspb.2014.0703

>From their earliest origins, fishes have developed a suite of
adaptations for locomotion in water, which determine performance and
ultimately fitness. Even without data from behaviour, soft tissue and
extant relatives, it is possible to infer a wealth of palaeobiological
and palaeoecological information. As in extant species, aspects of
gross morphology such as streamlining, fin position and tail type are
optimized even in the earliest fishes, indicating similar life
strategies have been present throughout their evolutionary history. As
hydrodynamical studies become more sophisticated, increasingly complex
fluid movement can be modelled, including vortex formation and
boundary layer control. Drag-reducing riblets ornamenting the scales
of fast-moving sharks have been subjected to particularly intense
research, but this has not been extended to extinct forms. Riblets are
a convergent adaptation seen in many Palaeozoic fishes, and probably
served a similar hydrodynamic purpose. Conversely, structures which
appear to increase skin friction may act as turbulisors, reducing
overall drag while serving a protective function. Here, we examine the
diverse adaptions that contribute to drag reduction in modern fishes
and review the few attempts to elucidate the hydrodynamics of extinct


Gábor Botfalvai, Edina Prondvai & Attila Osi  (2014)
Inferred bite marks on a Late Cretaceous (Santonian) bothremydid
turtle and a hylaeochampsid crocodilian from Hungary.
Cretaceous Research 50: 304–317
DOI: 10.1016/j.cretres.2014.05.006

Pathological deformations were recognized on fossil turtle and
crocodilian bones.
Their morphology and histology suggest a crocodilian bite mark origin.
This indicates a rare predator–prey interaction between two crocodilian species.
By contrast, the turtle was most probably scavenged rather than actively hunted.
More comparative studies on extant bone pathologies and their origin are needed.

The Iharkút locality in the Bakony Mountains of western Hungary has
provided a rich and diverse assemblage of Late Cretaceous vertebrates.
Here we present two specimens of this assemblage, a plate fragment of
the bothremydid turtle Foxemys trabanti, and a partial skull roof of
the hylaeochampsid crocodilian, Iharkutosuchus makadii, that exhibit
pathological traits, such as shallow and deep pits, bisected pits, and
scores on their surface, and in the case of the skull roof, also a
hole piercing through the entire bone thickness. Morphological and
bone histological features of these pathological traits imply that
they probably represent bite marks rather than deformations due to
pre-mortem shell diseases, infections or post-mortem invertebrate
bioerosion, and microbial activity. Morphological similarities with
experimentally investigated crocodilian tooth marks suggest that both
elements bear the bite marks of a crocodilian predator with typical
conical teeth, possibly the Allodaposuchus-like crocodile, also known
from the locality. The inferred tooth marks on the dorsal surface of
the Iharkutosuchus skull roof indicate a rarely documented
predator–prey interaction between two different crocodilian taxa
rather than antagonistic behaviour over common resources.
Nevertheless, more comparative studies are needed on different
traumatic as well as non-traumatic bone pathologies that may eventuate
in bite-mark-like abnormalities.


Florian Witzmann & Sebastian Voigt (2014)
An Eryops-like interclavicle from the Early Permian of the Saar-Nahe
Basin, and a discussion of temnospondyl interclavicle characters.
Paläontologische Zeitschrift (advance online publication)
DOI: 10.1007/s12542-014-0235-3

A large, isolated temnospondyl interclavicle from Rockenhausen,
Rhineland-Palatinate, is described that is derived from the Early
Permian Meisenheim Formation of the Saar-Nahe Basin, south-western
Germany. The element resembles closely the interclavicle of the North
American genus Eryops in the following characters that justify its
assignment to an eryopid temnospondyl: (1) The broad-ovate shape with
a narrow, convex anterior margin and slightly convex or straight
anterolateral margins, and the length-to-width ratio of approximately
0.7; (2) the ventral surface with a raised triangular field and the
irregular dermal sculpture consisting of transversely oriented ridges,
furrows and pits; (3) the anteroposteriorly shortened clavicular
facets. The interclavicle from Rockenhausen represents the first
unambiguous remain of an eryopid in the Saar-Nahe Basin. In contrast
to dissorophoid and stereospondylomorph temnospondyls that constitute
autochthonous faunal elements in the lakes of the Saar-Nahe Basin,
eryopids seem to be allochthonous and might have been washed in from
more distant habitats. Comparison of the morphologies and proportions
of temnospondyl interclavicles suggests that the plesiomorphic state
for temnospondyls is a proportionally small interclavicle equal in
length and width or slightly longer than wide. Interclavicles that are
broader than long are a derived character of zatracheids, certain
dissorophoids (branchiosaurids) and Eryops and the specimen from the
Saar-Nahe Basin, but evolved convergently in these groups. The much
enlarged, elongate interclavicles appear to be a synapomorphy of