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Re: Cloudy With A Chance of New Papers
Bhullar, B.-A.S., and Bever, G.S. 2009. An archosaur-like
laterosphenoid in early turtles (Reptilia: Pantestudines). Breviora
ABSTRACT: Turtles are placed with increasing consistency by molecular
phylogenetic studies within Diapsida as sister to Archosauria, but
published gross morphologyâbased phylogenetic analyses do not recover
this position. Here, we present a previously unrecognized unique
morphological character offering support for this hypothesis: the
presence in stem turtles of a laterosphenoid ossification identical
to that in Archosauriformes. The laterosphenoid is a tripartite
chondrocranial ossification, consisting of an ossified pila antotica,
pila metoptica, and taenia medialis + planum supraseptale. It forms
the anterior border of the exit for the trigeminal nerve (V) and
partially encloses the exits for cranial nerves III, IV, and II. This
ossification is unique to turtles and Archosauriformes within
Vertebrata. It has been mistakenly dismissed as anatomically
dissimilar in these two groups in the past, so we provide a complete
description and detailed analysis of correspondence between turtles
and Archosauriformes in each of its embryologically distinct
components. A preliminary phylogenetic analysis suggests other
potential synapomorphies of turtles and archosaurs, including a row
or rows of mid-dorsal dermal ossifications.
(Thanks to Augusto Haro for having posted this earlier. I didn't have
time to respond.)
I presume the laterosphenoid isn't simply the good old pleurosphenoid...?
The osteoderms are not convincing. Turtles (*Odontochelys* included)
have one row of osteoderms dorsal to the neural spines; archosaurs have
an even number of osteoderms dorsal to the epaxial musculature, _never_
a median one dorsal to the neural spines.
Prauss, M.L. 2009. The K/Pg boundary at Brazos-River, Texas, USA --
an approach by marine palynology. Palaeogeography, Palaeoclimatology,
Palaeoecology. doi: 10.1016/j.palaeo.2009.09.024.
ABSTRACT: Two cores and one outcrop section from the
Cretaceous/Palaeogen (K/Pg) boundary interval at the Brazos-River
area, Texas, USA, have been high resolution sampled and analysed
fully quantitatively by marine palynology. The results have been
compared and integrated with data from micropalaeontology,
sedimentology and isotope-geochemistry from the same sections. Within
all three sections, the K/Pg boundary, defined as the base of the P0
foraminifera zone and the onset of a negative carbon isotope anomaly,
closely corresponds to the appearance of lowermost Danian
Keep this in mind for a moment...
[...] Thus, prominent
paleo-environmental changes and sea-level fluctuations precede and
coincide with the K/Pg boundary proper. These data are inconsistent
with a single âcatastrophicâ impact as the cause for the K/Pg
boundary eve! nt, but s uggest relative longer term environmental
stress as finally leading to End-Cretaceous crisis of the biosphere.
How so? Why can't it suggest that all those climate and sea level
changes had little impact on biodiversity? Where does the "finally
leading to" part come from? After all, there's a carbon isotope anomaly
in there, distinct from the usual ebb and flow (see above).
Roberts, E.M., O'Connor, P.M., Stevens, N.J., Gottfried, M.D.,
Jinnah, Z.A., Ngasala, S., Choh, A.M., and Armstrong, R.A. 2009.
Sedimentology and depositional environments of the Red Sandstone
Group, Rukwa Rift Basin, southwestern Tanzania: new insight into
Cretaceous and Paleogene terrestrial ecosystems and tectonics in
sub-equatorial Africa. Journal of African Earth Sciences. doi:
Progress!!! Just too bad there's no Maastrichtian or Paleocene there yet.
Ji, Q., Luo, Z.-X., Zhang, X., Yuan, C.-X., and Xu, L. 2009.
Evolutionary development of the middle ear in Mesozoic therian
mammals. Science 326:278-281. doi: 10.1126/science.1178501.
ABSTRACT: The definitive mammalian middle ear (DMME) is defined by
the loss of embryonic Meckel's cartilage and disconnection of the
middle ear from the mandible in adults. It is a major feature
distinguishing living mammals from nonmammalian vertebrates. We
report a Cretaceous trechnotherian mammal with an ossified Meckel's
cartilage in the adult, showing that homoplastic evolution of the
DMME occurred in derived therian mammals, besides the known cases of
eutriconodonts. The mandible with ossified Meckel's cartilage appears
to be paedomorphic. Reabsorption of embryonic Meckel's cartilage to
disconnect the ear ossicles from the mandible is patterned by a
network of genes and signaling pathways. This fossil suggests that
developmental heterochrony and gene patterning are major mechanisms
in homplastic evolution of the DMME.
Incredible what you miss when your institution has no access to Science
(except old issues via JSTOR) or for that matter Nature.
Elzanowski, A., and Stidham, T.A. 2009. Morphology of the quadrate in
the Eocene anseriform Presbyornis and extant galloanserine birds.
Journal of Morphology. doi: 10.1002/jmor.10799.
Does the paper say anything about *Vegavis*...?