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Some very 'shelly' papers here...
Sterli, J. (2008) A new, nearly complete stem turtle from the Jurassic of
South America with implications for turtle evolution. Biology Letters.
Abstract: "Turtles have been known since the Upper Triassic (210Myr old);
however, fossils recording the first steps of turtle evolution are scarce and
often fragmentary. As a consequence, one of the main questions is whether
living turtles (Testudines) originated during the Late Triassic (210Myr old) or
during the Middle to Late Jurassic (ca 160Myr old). The discovery of the new
fossil turtle, _Condorchelys antiqua_ gen. et sp. nov. from the Middle to Upper
Jurassic (ca 160–146Myr old) of South America (Patagonia, Argentina), presented
here sheds new light on early turtle evolution. An updated cladistic analysis
of turtles shows that _C. antiqua_ and other fossil turtles are not crown
turtles, but stem turtles. This cladistic analysis also shows that stem
turtles were more diverse than previously thought, and that until the Middle to
Upper Jurassic there were turtles without the modern jaw closure mechanism."
Interestingly, the cladistic analysis tips many turtles out of the crown-group
(Testudines). Even _Meiolania_ (which lingered into the Holocene) is recovered
as a stem-turtle. _Condorchelys_ itself is close to _Kayentachelys_, also
Balanoff A.M., Norell, M.A., Grellet-Tinner, G., and Lewin, M.R. (2008)
Digital preparation of a probable neoceratopsian preserved within an egg, with
comments on microstructural anatomy of ornithischian eggshells.
Naturwissenschaften. [Epub ahead of print]
Abstract: "We describe the first known embryo of a neoceratopsian dinosaur,
perhaps the most ubiquitous Laurasian group of Cretaceous dinosaurs, which is
preserved completely enclosed within an egg. This specimen was collected from
Late Cretaceous beds of southern Mongolia, which commonly preserve fossils of
the neoceratopsian, _Yamaceratops dorngobiensis_. The small egg was scanned
using high-resolution X-ray computed tomography and digitally prepared from the
matrix. The preserved and imaged elements support a diagnosis of the embryo to
Neoceratopsia and allow preliminary observations of ontogenetic transformations
within this group. The addition of an embryo also adds another important data
point to the already impressive postnatal ontogenetic series that are available
for this clade."
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