Project

Description of proboscidean remains

Updates
0 new
0
Recommendations
0 new
0
Followers
0 new
3
Reads
0 new
105

Project log

Michael R. Pasenko
added a research item
A reanalysis of proboscidean remains from the Benson local fauna and the Curtis Ranch local fauna demonstrates that several specimens may be incorrectly identified. Stegomastodon from the younger Curtis Ranch Fauna is correctly identified, but the holotype of Anancus bensonensis, from the older Benson local fauna, may indeed represent Rhynchotherium. A. bensonensis has more recently been referred to Cuvieronius, but similarities between the closely related taxa Cuvieronius and Rhynchotherium prevent certain assignment to Cuvieronius. Several other isolated specimens from the Benson local fauna could also be either Cuvieronius or Rhynchotherium. The Pliocene age for the Benson local fauna agrees more with the temporal range of Rhynchotherium. Our review of gomphotheriids in Arizona indicates that a thorough re-analysis is needed of specimens referred to Cuvieronius and Rhynchotherium. At least two species of Stegomastodon are represented in Arizona.
Michael R. Pasenko
added a research item
A partial left and right manus of a gomphotheriid are described from earliest Pleistocene deposits of 111 Ranch in southeastern Arizona, USA. The discovery of these well preserved manuses provides a rare opportunity to describe these elements of a gomphotheriid in North America. I provide detailed descriptions and measurements as well as comparisons of the manuses with those of other extant and extinct proboscideans. Analyses of the manuses indicate it was a small gomphotheriid, possibly a small female, having morphological attributes more similar to other gomphotheriids, then ele-phantids and mammutids. The gomphotheriids Stegomastodon and Rhynchotherium have both been previously reported from 111 Ranch.
Michael R. Pasenko
added a research item
The remains of a mastodont and mammoth were recovered from Pleistocene deposits in southeastern Arizona. These new proboscidean remains have characteristics distinguishing them from their more typical late Pleistocene forms. The mastodont (Mammut americanum), has traits similar to those of other female mastodonts, but includes mandibular tusks. This may indicate an early Pleistocene Age or supports evidence that female mastodonts had mandibular tusks. The partial mammoth jaw and molar display characteristics similar to Mammuthus columbU but appears to be a variant or earlier form approaching those displayed in Mammuthus meridionalis. The presence of different proboscideans with different diets, although within the same geologic unit, cannot be confirmed as being sympatric. If so, it would indicate a partitioning of resources. Mammoths are grazers, and more common in Arizona than the browsing mastodonts.