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Arvinachelys, new turtle from Kaiparowits Formation (Upper Cretaceous) of Utah



Ben Creisler
bcreisler@gmail.com


Here's the paper (already mentioned in a news link posted today):

Joshua R. Lively (2015)
A new species of baenid turtle from the Kaiparowits Formation (Upper
Cretaceous, Campanian) of southern Utah.
Journal of Vertebrate Paleontology (advance online publication)
DOI:10.1080/02724634.2015.1009084
http://www.tandfonline.com/doi/full/10.1080/02724634.2015.1009084

Newly discovered baenid turtle specimens from the middle Campanian
Kaiparowits Formation of southern Utah are described herein as a new
taxon, Arvinachelys goldeni, gen. et sp. nov. The holotype consists of
a nearly complete articulated skeleton and shell. The skull was
scanned using micro-computed tomography (μCT) to gain a better
understanding of its internal anatomy. This baenid possesses two
distinct external nares almost completely separated by a dorsal
projection of the premaxillae and a ventral extension of the nasals,
an autapomorphic feature among known baenid taxa. The skull is
wedge-shaped with a broad rostrum and laterally expanded nasals. The
importance of skull/shell associations is exemplified by Arvinachelys
goldeni, because isolated shells attributable to this taxon had
previously been assigned to the genus Plesiobaena, whereas
phylogenetic analysis of more complete material supports a sister
relationship with the Maastrichtian taxon Hayemys latifrons. These
taxa are relatively basal within the Baenodda, a nested clade within
Baenidae. The general shell morphology exhibited by Plesiobaena
antiqua, Peckemys brinkman, and Palatobaena cohen was previously
hypothesized to support a monophyletic clade that included those three
taxa, along with Cedrobaena putorius, Gamerabaena sonsalla,
Palatobaena bairdi, and Palatobaena gaffneyi. However, the inclusion
of Arvinachelys goldeni, gen. et sp. nov., in a phylogenetic analysis
of Baenidae indicates that the character states exhibited by those
taxa are representative of plesiomorphic states within Baenodda, and
the phylogenetic relationships within this clade are in need of
reevaluation.

http://zoobank.org/urn:lsid:zoobank.org:pub:A5C5717C-4962-4056-8563-2C90C3276FDF