A fossilized vertebra collected during a 1985 expedition to Antarctica has been identified as a dinosaur tail bone, marking the first dinosaur bone ever discovered on the continent.
The specimen, initially believed to be from a large marine reptile, was stored at the British Antarctic Survey (BAS) in Cambridge for nearly four decades before being re-examined.
Discovery and Initial Storage
The 10-centimeter bone was found by geologist Dr. Mike Thomson of the British Antarctic Survey in December 1985 on James Ross Island. Thomson recorded the find in his field diary as a "vertebra of large reptile." The specimen was subsequently stored at BAS, where it remained for approximately 40 years.
Re-Examination and Identification
Paleontologist Mark Evans, a collections manager at BAS who specializes in vertebrate paleontology, later noticed the bone in the collection and suspected it might be from a dinosaur. Analysis of its shape, compared to other dinosaur remains, confirmed it was a tail vertebra from a titanosaur, a group of long-necked, plant-eating sauropod dinosaurs.
The findings were published on January 13, 2025, in the journal Acta Palaeontologica Polonica.
Context and Significance
The specimen is estimated to be approximately 82 million years old, from the Late Cretaceous period. Based on the size of the vertebra, researchers estimate the dinosaur was between 6 and 7 meters long, making it a juvenile or a relatively small individual for its group. Titanosaurs are known to have been among the largest land animals.
Antarctic dinosaur fossils are rare due to the continent's extensive ice cover. At the time the organism lived, Antarctica was forested and had a temperate climate, and was part of the supercontinent Gondwana. Researchers cited in the reports stated that the dinosaur likely died at sea, floated away from shore, sank, and was fossilized in marine sediment.
Professor Paul Barrett of the Natural History Museum in London noted that no titanosaur fossils have been found in Australia, with limited evidence in New Zealand. He added that this find suggests titanosaurs could have traveled to those regions when the landmasses were connected.
Researchers at BAS expressed the view that more dinosaur fossils may be discovered as Antarctic ice retreats.
Attribution
The identification was reported with contributions from the Natural History Museum in London and the British Antarctic Survey. Geologist Mike Thomson, who collected the fossil, died in 2020 before the identification was completed. The research was published in Acta Palaeontologica Polonica.