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Ettling, Germany Jurassic Konservat-Lagerstätte + marine tetrapod evolution + reptile vivparity

Ben Creisler

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

Martin Ebert,  Martina Kölbl-Ebert &  Jennifer A. Lane (2015)
Fauna and Predator-Prey Relationships of Ettling, an Actinopterygian
Fish-Dominated Konservat-Lagerstätte from the Late Jurassic of
Southern Germany.
PLoS ONE 10(1): e0116140.

The newly recognized Konservat-Lagerstätte of Ettling (Bavaria), field
site of the Jura-Museum Eichstätt (JME), is unique among Late Jurassic
plattenkalk basins (Solnhofen region) in its abundant, extremely well
preserved fossil vertebrates, almost exclusively fishes. We report
actinopterygians (ginglymodins, pycnodontiforms, halecomorphs,
aspidorynchiforms, “pholidophoriforms,” teleosts); turtles; and
non-vertebrates (echinoderms, arthropods, brachiopods, mollusks,
jellyfish, sponges, biomats, plants) in a current faunal list. Ettling
has yielded several new fish species (Bavarichthys incognitus;
Orthogonikleithrus hoelli; Aspidorhynchus sanzenbacheri;
Macrosemimimus fegerti). Upper and lower Ettling strata differ in
faunal content, with the lower dominated by the small teleost
Orthogonikleithrus hoelli (absent from the upper layers, where other
prey fishes, Leptolepides sp. and Tharsis sp., occur instead).
Pharyngeal and stomach contents of Ettling fishes provide direct
evidence that Orthogonikleithrus hoelli was a primary food source
during early Ettling times. Scarcity of ammonites and absence of
vampyromorph coleoids at Ettling differ markedly from the situation at
other nearby localities in the region (e.g., Eichstätt, Painten,
Schamhaupten, the Mörnsheim beds), where they are more common.
Although the exact biochronological age of Ettling remains uncertain
(lack of suitable index fossils), many Ettling fishes occur in other
plattenkalk basins of Germany (e.g., Kelheim) and France (Cerin) dated
as Late Kimmeridgian to Early Tithonian (eigeltingense horizon),
suggesting a comparable geologic age. The Ettling deposits represent
an independent basin within the larger Upper Jurassic “Solnhofen
Archipelago”, a shallow subtropical sea containing scattered islands,
sponge-microbial and coral reefs, sandbars, and deeper basins on a
vast carbonate platform along the northern margin of the Tethys Ocean.


Free pdf:

Neil P. Kelley & Ryosuke Motani (2015)
Trophic convergence drives morphological convergence in marine tetrapods.
Biology Letters:201511 20140709;
DOI: 10.1098/rsbl.2014.0709

Marine tetrapod clades (e.g. seals, whales) independently adapted to
marine life through the Mesozoic and Caenozoic, and provide iconic
examples of convergent evolution. Apparent morphological convergence
is often explained as the result of adaptation to similar ecological
niches. However, quantitative tests of this hypothesis are uncommon.
We use dietary data to classify the feeding ecology of extant marine
tetrapods and identify patterns in skull and tooth morphology that
discriminate trophic groups across clades. Mapping these patterns onto
phylogeny reveals coordinated evolutionary shifts in diet and
morphology in different marine tetrapod lineages. Similarities in
morphology between species with similar diets—even across large
phylogenetic distances—are consistent with previous hypotheses that
shared functional constraints drive convergent evolution in marine


Benedict King and Michael S. Y. Lee (2015)
Ancestral  State  Reconstruction, Rate Heterogeneity, and the
Evolution of Reptile Viviparity.
Systematic Biology (advance online publication)


>From the text:

The evolution of viviparity (live-birth, including "ovoviviparity”)
from oviparity
(egg-laying) has long been a topic of great scientific interest,
particularly in squamate
reptiles (lizards, snakes and amphisbaenians), which show much greater
lability in
reproductive mode than do other amniotes. Studies have focused on a
range of aspects
including physiology, ecology and evolutionary history (Blackburn,
2000; Sites et al.,
2011; Shine, 2014). Viviparity is present at a variety of phylogenetic
levels within
squamates, including some reproductively bimodal species such as
Lerista bougainvillii
(Qualls and Shine, 1998) and Saiphos equalis (Smith et al. 2001). In
most taxa, viviparity
involves retention of shell-less eggs, with embryos sustained mainly
by a large yolk.
However, some skinks, including the south American genus Mabuya, and the African
genera Trachylepis and Eumecia, have chorioallantoic placentae
convergent with those
of eutherian mammals, allowing the embryos to be sustained by direct transfer of
nutrients across the placenta rather than by the yolk (Blackburn et
al., 1984; Blackburn
and Flemming, 2009).

One important aspect of the evolution of viviparity is the question of whether
oviparity can evolve from viviparity. Oviparity has been assumed to be
usually or
invariably ancestral to viviparity, given the wide distribution of
oviparity in amniotes
and the idea that reversals to oviparity are unlikely due to the need
to re-evolve complex
structures and enzymes involved in the deposition of egg-shell.