Futabasaurus and Trilophosaurus

[Nick Pharris <npharris@umich.edu>]

Hey, all!

Thought you might be interested to know that the May issue of 
_Palaeontology_ includes two new papers on dead sauropsids:

----------
A NEW ELASMOSAURID PLESIOSAUR FROM THE UPPER CRETACEOUS OF FUKUSHIMA, JAPAN

by TAMAKI SATO, YOSHIKAZU HASEGAWA and MAKOTO MANABE

Abstract: A new genus and species of an elasmosaurid plesiosaur, 
Futabasaurus suzukii, is described based on a partial skeleton from the 
Inoceramus amakusensis Zone (Lower Santonian, Upper Cretaceous) of the 
Irimazawa Member of the Tamayama Formation, Futaba Group, in Fukushima 
Prefecture, Japan. The new taxon is characterized by a number of 
characters such as the wide space between the orbit and external naris, 
posterior extension of the interclavicle, relatively long humerus and 
prominent femoral muscle scar. The holotype includes a partial skull 
and mandible, posterior cervicals to sacrals, ribs, clavicular arch, 
pelvic girdle and four limbs. The remains are mostly in articulation, 
and exhibit evidence of predation/scavenging by sharks. The 
distribution of elasmosaurid species in the circum-Pacific region 
remains unclear due to the lack of diagnostic materials. The occurrence 
of F. suzukii is geographically and stratigraphically significant, 
because it allows species-level comparison; as a diagnosable 
elasmosaurid specimen, F. suzukii is the first and the oldest from the 
northern Pacific.

----------
REVISION OF THE ARCHOSAUROMORPH REPTILE TRILOPHOSAURUS, WITH A 
DESCRIPTION OF THE FIRST SKULL OF TRILOPHOSAURUS JACOBSI, FROM THE 
UPPER TRIASSIC CHINLE GROUP, WEST TEXAS, USA

by ANDREW B. HECKERT, SPENCER G. LUCAS, LARRY F. RINEHART, JUSTIN A. 
SPIELMANN, ADRIAN P. HUNT and ROBERT KAHLE

Abstract: The first abundant, well-preserved fossils of the unusual 
archosauromorph reptile Trilophosaurus jacobsi Murry are from an Upper 
Triassic bonebed in the lowermost Trujillo Formation of the Chinle 
Group in Borden County, Texas. A nearly complete left side of the skull 
and incomplete but articulated mandible of a juvenile individual 
demonstrate that Trilophosaurus jacobsi Murry is referable to 
Trilophosaurus, so the putative procolophonid genus Chinleogomphius is 
a junior objective synonym of Trilophosaurus. Features of T. jacobsi 
that diagnose it from T. buettneri include asymmetrical, tricuspate 
teeth in which the central cusp is taller than the marginal cusp, 
polygonal in cross-section and displaced slightly lingually; the 
lingual cusp is low, transversely broadened and anteroposteriorly 
compressed; teeth with prominent cingula along the mesial and distal 
margins; and paired sagittal (parasagittal) crests composed of portions 
of the postfrontals and the parietals, as well as a relatively broad 
skull roof between the supratemporal fenestrae. We also re-illustrate 
and re-describe the holotypes of both Trilophosaurus buettneri Case and 
T. jacobsi Murry. T. jacobsi is primarily Adamanian in age, and the 
lowest occurrence of T. jacobsi is stratigraphically above that of T. 
buettneri. Therefore, T. buettneri is an Otischalkian?Adamanian index 
taxon, and T. jacobsi is an Adamanian??earliest Revueltian index taxon. 
Trilophosaurus teeth are readily identifiable to species and therefore 
identifiable as isolated fossils.

----------
Enjoy!

--
Nick Pharris
Department of Linguistics
University of Michigan

"Creativity is the sudden cessation of stupidity."
    --Edwin H. Land