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Frankenstein's Papers

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. 
[FirstCite] 10.1098/rsbl.2008.0022 

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 
outside Testudines.

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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