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Tambatitanis, new titanosauriform sauropod from Lower Cretaceous of Japan (free pdf)



Ben Creisler
bcreisler@gmail.com

A new monograph in open access:

Haruo Saegusa & Tadahiro Ikeda (2014)
A new titanosauriform sauropod (Dinosauria: Saurischia) from the Lower
Cretaceous of Hyogo, Japan.
Zootaxa 3848 (1): 1–66
doi: http://dx.doi.org/10.11646/zootaxa.3848.1.1
http://www.mapress.com/zootaxa/2014/f/zt03848p066.pdf

A new genus and species of titanosauriform sauropod is erected based
on a partial skeleton found in the Lower Cretaceous  Sasayama Group of
Hyogo Prefecture, SW Japan. The new taxon is here named as
Tambatitanis amicitiae gen. et sp. nov., which is diagnosed by the
following features of the caudal vertebrae, chevrons and braincase:
the postzygapophysis and the summit of the neural spine of the
anterior caudal vertebrae are located beyond the posterior border of
the centrum, the spine of the anterior caudal vertebrae is curved
strongly anteriorly and bow-shaped in lateral view, the summit of the
neural spine is expanded and hemispherical with its anterior face
excavated by the posterodorsal extension of a deep and narrow SPRF,
the transverse process of the anterior caudal vertebrae are short and
L shaped, the anterior chevron is the longest among sauropods in
proportion to body size, the distal ends of the anterior chevrons are
rod-shaped, the distal ends of the mid chevrons are transversely thin
and anteroposteriorly long without cranial processes, and the dorsal
border of the shaft of the paroccipital process that forms the ventral
margin of the posttemporal fenestra is short mediolaterally and
V-shaped in posterior view. A phylogenetic analysis suggests that T.
amicitiae is a basal titanosauriform, possibly belonging to the East
Asian endemic clade Euhelopodidae. The caudals and chevrons are
described in detail in order to document highly autapomorphic features
of the new taxon as well as potentially phylogenetically informative
characters. The discovery of T. amicitiae suggests that East Asian
basal titanosauriforms were diverse not only in the number of the taxa
but also in the morphological variation of the caudal elements.