Tuesday, December 11, 2007

New Antarctic Sauropodomorph: Glacialisaurus

Anatomy of a basal sauropodomorph dinosaur from the Early Jurassic Hanson Formation of Antarctica. 2007. Nathan D. Smith and Diego Pol. Acta Palaeontologica Polonica 52 (4): 657-674

From the press release:

The new primitive sauropodomorph Glacialisaurus hammeri from the Early Jurassic has been discovered in Antarctica. The description is based on partial foot, leg and ankle bones found on Mt. Kirkpatrick near the Beardmore Glacier in Antarctica at an elevation of more than 13,000 feet.

“The fossils were painstakingly removed from the ice and rock using jackhammers, rock saws and chisels under extremely difficult conditions over the course of two field seasons,” said Nathan Smith, a graduate student at The Field Museum. “They are important because they help to establish that primitive sauropodomorph dinosaurs were more broadly distributed than previously thought, and that they coexisted with their cousins, the true sauropods.”

Glacialisaurus hammeri was about 20-25 feet long and weighed about 4-6 tons . It was named after Dr. William Hammer, a professor at Augustana College who led the two field trips to Antarctica that uncovered the fossils. Glacialisaurus belongs to the sauropodomorph family Massopsondylidae, which may represent a secondary radiation of basal sauropodomorphs during the Early Jurassic.

The recent discovery of a possible sauropod at roughly the same location in Antarctica lends additional evidence to the theory that the earliest sauropods coexisted with their basal sauropodomorph cousins during the Late Triassic and Early Jurassic.