Saturday 21 December 2013

A new species of Desmostylian Mammal from the Late Miocene of Orange County, California.

Desmostylians were an order of large, quadruped marine Mammals known from the Oligocene and Miocene margins of the northern Pacific Ocean. They were related to Elephants and Sea Cows, and were thought to have led a lifestyle similar to that of Hippopotamuses, though in marine rather than fresh water. The order is divided into two families, the Paleoparadoxiidae with larger heads and feet and low crowned rounded molars, and the Desmostylidae with smaller heads and feet and higher, more pointed molars.

In a paper published in the journal Contributions in Science on 11 September 2013, Lawrence Barnes of the Department of Vertebrate Paleontology at the Natural History Museum of Los Angeles County, describes a new species of Paleoparadoxiid Desmostylian from the Late Miocene of Orange County California.

The new species is named Neoparadoxia cecilialina, where 'Neoparadoxia' means 'New Paradoxia' (there are also genera named Archaeoparadoxia, Old Paradoxia, and Paleoparadoxia, Ancient Paradoxia; the groups being named after this latter genus), and 'cecilialina' honours Cecilia Perlstein and Alina Perlstein, the daughters of Ron and Judy Perlstein, long term supporters of the Natural History Museum of Los Angeles County. 

The species is described from an almost complete skeleton (only the second such ever found of a Desmostylian in North America), though this was only partially articulated at the time of discovery, and showed signs damage to some bones by scavenging animals (probably Sharks, a number of Shark teeth being found with the remains), and was, in addition, partially damaged at the time of its discovery, which was inadvertent, and came during the excavation a site at Laguna Niguel for construction purposes. The specimen is thought to be a subadult, and to have been about 2.44 m long when alive.

The specimen was found within the upper part of the Monterey Shale, and is thought to be early Late Miocene in age, making it 10-11 million years old. This makes it the youngest known Desmostylian.

Neoparadoxia cecilialina as mounted on display in the Age of Mammals Hall at the Natural History Museum of Los Angeles County. Barnes (2013).

Digital image of Neoparadoxia cecilialina as mounted, but with the background removed. Barnes (2013).

Reconstructive line drawing of the skeleton of Neoparadoxia cecilialina as mounted. Barnes (2013).

Reconstructive line drawing of the skeleton of Neoparadoxia cecilialina as mounted, with estimated body outline added. Barnes (2013).

Reconstructive drawing of Neoparadoxia cecilialina in life. Doyle Trankina in Barnes (2013).

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