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Baurusuchian external ears? + Kuruleufenia, new Cretaceous frog + Hesperornis attacked + more new papers
A number of recent (and not so recent) papers:
(Did baurusuchians have pinna--external ears like mammals?)
Felipe C. Montefeltro, Denis V. Andrade and Hans C. E. Larsson (2016)
The evolution of the meatal chamber in crocodyliforms.
Journal of Anatomy (advance online publication)
The unique outer ear of crocodylians consists of a large meatal
chamber (MC) concealed by a pair of muscular earlids that shape a
large part of the animal's head. This chamber is limited medially by
the enlarged tympanic membrane. Yet, the anatomy of this distinctive
and complex region is underexplored and its evolutionary history
untraced. The osteology and soft tissues of the MC in extant
crocodylians was analysed to describe it and establish osteological
correlates within this region. A broad survey of the osteological
correlates was conducted in major clades of fossil crocodyliforms to
estimate evolutionary trends of the MC. The reorganization of the MC
at the origin of crocodyliforms includes characters also present in
more basal taxa such as 'sphenosuchians' as well as unique traits of
crocodyliforms. Three major patterns are recognized in the MC of basal
mesoeucrocodylians. The distinct 'thalattosuchian pattern' indicates
that extensive modifications occurred in this clade of aquatic fossil
crocodyliforms, even when multiple alternative phylogenetic positions
are taken into account. Some traits already established in putative
closely related clades are absent or modified in this group. The
'basal notosuchian/sebecian pattern' is widespread among basal
metasuchians, and establishes for the first time characters maintained
later in neosuchians and extant forms. The 'advanced notosuchian
pattern' includes modifications of the MC possibly related to a
terrestrial lifestyle and potentially a structure analogous to the
mammalian pinna. The main variation in the MC of neosuchians is
associated with the homoplastic secondary opening of the
cranioquadrate passage. The inferred phylogenetic trends in the
crocodyliform MC suggest the great anatomical disparity in this region
followed a complex evolutionary pattern, and tympanic hearing played
an important role in the origin and diversification of
Raúl O. Gómez (2016)
A new pipid frog from the Upper Cretaceous of Patagonia and early
evolution of crown-group Pipidae.
Cretaceous Research (advance online publication)
A new pipid frog is described from the Upper Cretaceous of Patagonia.
Phylogenetic analyses place the new taxon within crown-group Pipidae.
Cranial and postcranial traits support the new taxon as a member of
A time-tree shows that main lineages of pipids have already diverged
around 100 Ma.
Western Gondwana breakup might have triggered diversification of
Pipid frogs are fully aquatic frogs that today inhabit freshwater
environments of southern continents on both sides of the Atlantic
Ocean, with a fairly good fossil record dating back to the Cretaceous.
Here I report on fossils from the Allen Formation (upper
Campanian–lower Maastrichtian), Río Negro Province, Argentina, that
are ascribed to a new genus and species of pipid. In order to assess
the evolutionary relationships of the new taxon, which is represented
by sphenethmoids, otic capsules, ilia, humeri, and vertebrae,
cladistic analyses of a data matrix of 165 osteological characters
scored for 36 taxa were performed. The results are congruent with
previous hypotheses of pipoid interrelationships and consistently
place the new taxon as part of the lineage today represented by the
African xenopodines. Temporal calibration of the phylogenetic tree
based on the fossil record imply that the origin and early
diversification of crown-group Pipidae might have occurred during the
Early Cretaceous, prior to the final breakup of western Gondwana. This
study highlights the importance of including fossils, even fragmentary
ones, directly in phylogenetic analyses in order to disentangling how,
when, and where pipid frogs diversified.
Larry D. Martin, Bruce M. Rothschild & David A. Burnham (2016)
Hesperornis escapes plesiosaur attack.
Cretaceous Research (advance online publication)
Predator-prey interactions have been a matter for speculation. It is
rare when evidence is available to actually document such an
interaction. Herein, we present documentation that a Hesperonis
survived a predation effort and identify the perpetrator.
The arrows in figure 3A identify the longitudinal position of the bite
marks, while 3B identifies their exact location.
Evidence from the Pierre Shale (Late Cretaceous) of South Dakota is
presented for an attack on a juvenile Hesperornis by a polycotylid
plesiosaur. The wound healed and the Hesperornis grew to maturity.
Evidence of survival provides our best information about predator prey
interactions in the fossil record but are rare for birds where
survival is an unlikely outcome.