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Marine tetrapod evolution and other non-dino papers

From: Ben Creisler

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

Nicholas D. Pyenson, Neil P. Kelley & James F. Parham (2014)
Marine tetrapod macroevolution: Physical and biological drivers on 250
million years of invasions and evolution in ocean ecosystems.
Palaeogeography, Palaeoclimatology, Palaeoecology (advance online publication)
doi: http://dx.doi.org/10.1016/j.palaeo.2014.02.018

The dominant consumers in today's ocean ecosystems are marine mammals,
including cetaceans, sirenians, and pinnipeds, and other marine
carnivorans. The ecological dominance of marine mammals can be traced
back to at least seven independent transitions during the Cenozoic,
when different lineages of terrestrial mammals underwent land to sea
evolutionary transformations. However, the evolution of marine mammals
represents only the most recent set of marine invasions by tetrapods
over the past 250 million years. During the Mesozoic, over a dozen
different reptile lineages (e.g., mosasaurs, ichthyosaurs, turtles,
snakes) evolved obligate marine lineages, including a few lineages
that persist to today, such as sea turtles. Birds, which are
phylogenetically nested among diapsid reptiles, have also repeatedly
adapted to marine life since the Cretaceous. Attempts to understand
the common patterns of marine tetrapod evolution, and the processes
that have shaped them, have largely been limited to individual groups.
Placed in a broad comparative view from the Mesozoic to the Cenozoic
eras, the macroevolution of marine tetrapods reveals evolutionary
drivers at different scales, along with morphological parallels,
unique evolutionary innovations, and the strong influence of
historical constraints. Major physical, environmental drivers appear
to be responsible for some patterns in marine tetrapod evolution at
some temporal and geographic scales, but these drivers are not unique
causes, as biological drivers (e.g., escalation) likely also play a
role. The culmination of this trophic ascendancy has been dramatically
altered by human hunting (especially of marine mammals), underscoring
the need for historical datasets that extend into deep time to
understand the ecological history of marine tetrapods.


Natasha S. Vitek & Igor G. Danilov (2014)
Soft-shelled turtles (Trionychidae) from the Cenomanian of Uzbekistan.
Cretaceous Research (advance online publication)
doi: http://dx.doi.org/10.1016/j.cretres.2014.01.004

Localities from the Cenomanian of Uzbekistan are the oldest in Middle
Asia and Kazakhstan to preserve two broadly sympatric species of
trionychid turtle. Material described here comes from multiple
Cenomanian formations from the Itemir locality, and from multiple
localities in the Cenomanian Khodzhakul Formation. The first taxon
from the locality, "Trionyx" cf. kyrgyzensis, has multiple
morphological similarities with the older, Early Cretaceous "Trionyx"
kyrgyzensis. In contrast, the second taxon, "Trionyx" dissolutus, has
multiple similarities with "Trionyx" kansaiensis, one of two species
of trionychid found in younger Late Cretaceous localities. "Trionyx"
dissolutus bears some superficial resemblance to other trionychid taxa
within the clade Plastomenidae because of its highly ossified plastron
with a hyoplastral lappet and an epiplastral notch. However,
Plastomenidae is diagnosed primarily through characters that are
absent or cannot be observed in the available material of "T."
dissolutus, and other shared features are plesiomorphic. In addition,
"T." dissolutus shares other synapomorphies with Trionychinae. A
heavily ossified plastron may be more homoplastric within Trionychidae
than has been previously recognized. Finally, we provide an improved
understanding of the subtle similarities and differences between
several closely related Cretaceous turtle assemblages of Middle Asia
and Kazakhstan.


Igor G. Danilov, Ren Hirayama, Vladimir B. Sukhanov, Shigeru Suzuki,
Mahito Watabe & Natasha S. Vitek (2014)
Cretaceous soft-shelled turtles (Trionychidae) of Mongolia: new
diversity, records and a revision.
Journal of Systematic Palaeontology (advance online publication)

This paper is devoted to the description and revision of material of
Cretaceous soft-shelled turtles (Trionychidae) of Mongolia. It
includes the description of seven trionychid species, six of which are
new, and two new genera: the cyclanorbine Nemegtemys conflata gen. et
sp. nov. from the Nemegt Formation (Maastrichtian), and the
trionychines Gobiapalone breviplastra gen. et sp. nov. from the Nemegt
and Barungoyot (Campanian) formations, G. orlovi from the Baynshire
Formation (Cenomanian-Santonian), 'Trionyx' baynshirensis sp. nov.
from the Baynshire Formation, 'T.' gilbentuensis sp. nov. from the
Nemegt Formation, 'T.' gobiensis sp. nov. from the Nemegt Formation,
and 'T.' shiluutulensis sp. nov. from an unknown formation
(Campanian). In addition, one shell from the ?Baynshire Formation of
Khermin Tsav is assigned to Gobiapalone sp. The type material of Amyda
menneri is considered to be Trionychidae indet. and Amyda menneri to
be a nomen dubium. Finally, we revise other available materials of
Cretaceous trionychids from 45 localities in Mongolia. Nemegtemys
conflata, if correctly assigned, is the earliest known member of
Cyclanorbinae. The two species of the new genus Gobiapalone are
included in two phylogenetic analyses of Trionychidae. In both
analyses Gobiapalone is monophyletic. In the first analysis,
Gobiapalone is placed within Apalonina. In the second analysis,
Gobiapalone is sister to Apalonina. Thus, the results of both analyses
show that Apalonina, which is a rather advanced and well-supported
trionychid clade, or its closest sister taxon (stem-Apalonina), were
present in the Late Cretaceous of Asia. These results suggest that
most other supra-generic clades of modern trionychids had been
established in Asia by the Late Cretaceous. That suggestion is
supported by the discovery of a cyclanorbine Nemegtemys conflata in
the Late Cretaceous of Mongolia. Finally we summarize the latest data
on temporal and geographical distributions of Cretaceous Trionychidae
of Asia and North America.


Agustín Scanferla1 &, Bhart-Anjan S. Bhullar (2014)
Postnatal Development of the Skull of Dinilysia patagonica
(Squamata-Stem Serpentes).
The Anatomical Record (advance online publication)
DOI: 10.1002/ar.22862

The snake skull represents a profound transformation of the ancestral
squamate cranium in which dermal skull roof bones were integrated with
the braincase, in a manner convergent with that which occurred during
the origin of mammals. However, the ontogeny of snake characters at
the origin of the clade has until now been inaccessible. Here we
describe a postnatal ontogenetic series of the Late Cretaceous stem
snake Dinilysia patagonica and compare it to that of extant lizards
and snakes. Comparative analysis indicates notable ontogenetic
changes, including advanced state of ossification, isometric growth of
the otic capsule, fusion of the stylohyal to the quadrate, and great
posterior elongation of the supratemporal. Of these transformations,
the unfused condition of braincase bones and the retention of a large
otic capsule in adults are examples of paedomorphic and peramorphic
processes, respectively. Some ontogenetic transformations detected, in
particular those present in middle ear, skull roof and suspensorium,
are strikingly similar to those present in extant snakes.
Nevertheless, Dinilysia retains a lizard-like paroccipital process
without an epiphyseal extremity, and a calcified epiphysis that caps
the sphenoccipital tubercle. Finally, the integration of the dermal
skull roof with the braincase is similar to that seen in mammals with
regard to the overall closure of the braincase, but the two
evolutionary and developmental modules appear less integrated in
snakes in that the parietal bone of the dermal skull roof
progressively overlaps the supraoccipital of the chondrocranial


Claudia Schröder-Adams (2014)
The Cretaceous Polar and Western Interior seas: paleoenvironmental
history and paleoceanographic linkages.
Sedimentary Geology 301: 26-40
doi: http://dx.doi.org/10.1016/j.sedgeo.2013.12.003

This study reviews the Cretaceous histories of the Polar and Western
Interior seas as recorded in the Canadian High Arctic Sverdrup Basin,
Beaufort-Mackenzie Basin of northwest Canada and Western Canadian
Foreland Basin. Newly emerging stratigraphic, paleoclimatic and
paleoenvironmental interpretations from the polar realm allow for a
fresh look at the response of this oceanic system to global climatic
trends and sea-level histories over 35 Ma. Sverdrup basin localities
on Axel Heiberg and Ellef Ringnes islands represent shelf to slope
environments that contrasted with the shallow water and low gradient
settings of the Canadian Western Interior Sea. Both marine systems,
connected throughout Aptian to Maastrichtian time, responded to global
transgressive-regressive cycles resulting in dynamic paleogeographic
changes. The upper Aptian to Campanian succession of the Polar Sea
shows at least two unconformable boundaries; one at the
Albian/Cenomanian transition and another within the upper Cenomanian.
The shallow basin setting and in particular the forebulge and
backbulge settings of the Western Canadian Foreland Basin are
characterized by multiple erosional surfaces throughout the Cretaceous
succession. The Upper Albian disconformity is widely discernible close
to the entrance of the Western Interior Sea to the Polar Sea. This
suggests a short-lived closure of the latest Albian Mowry Sea that
might have been responsible for the large loss of benthic
foraminiferal species at this time. Several oceanic anoxic events are
documented in these basins representing their response to global
climate dynamics. During the Late Cretaceous temperature maximum
benthic foraminiferal communities were severely restricted by bottom
water hypoxia in both basins. A stratified water column might have
been the result of increased freshwater runoff under warm, humid
conditions. These conditions supported vegetation up into the polar
latitudes that added abundant organic matter to marine shelf systems.
Conversely, the Canadian Western Interior Sea biotic communities were
controlled by watermasses of two or maybe three different sources and
physical properties including the Polar, Tethyan and a possibly third
source from the emerging Labrador Sea through the Hudson Seaway. Where
the southern and northern watermasses mixed, plankton might have been
influenced by oceanic fronts, forming mass kills through sinking of
dense waters. Migration of calcareous phyto- and zooplankton was
controlled by a temperature and salinity gradient and did not invade
northern regions. Siliceous plankton occurred and is more commonly
found in the Sverdrup Basin, but taphonomic loss through deep burial
needs to be taken into account.