The 70 million year old fossil remains of a 1.5m long juvenile elasmosaur represent one of the most-complete skeletons ever recovered from Antarctica.From the press release:
The animal's stomach area was spectacularly preserved. Stomach ribs (gastralia) span the abdomen, and rather than being long, straight bones like those of most plesiosaurs, these are forked, sometimes into three prongs. Moreover, numerous small, rounded stomach stones (gastroliths) are concentrated within the abdominal cavity, indicating stomach stones were ingested even by juvenile plesiosaurs to help maintain buoyancy or to aid digestion.
The skeleton is nearly perfectly articulated as it would have been in life, but the skull has eroded away from the body. Extreme weather at the excavation site on Vega Island off the Antarctic Peninsula and lack of field time prevented further exploration for the eroded skull.
The researchers speculate volcanism may have caused the animal's death. Excavation turned up volcanic ash beds layered within the shallow marine sands at the site, and chunks of ash were found with plant material inside. Silica released from the ash allowed spectacular preservation of the skeleton.
The juvenile plesiosaur appears to be related to one discovered in New Zealand in 1874. That plesiosaur was named Mauisaurus and is characterized by a rounded end of the major paddle bone. It was confined to the southern oceans where it existed more than 5 million years.
The bones will be unveiled at the South Dakota School of Mines and Technology's Museum of Geology Dec.13, 2006. image