New fossil armoured mammal from Chile

The only reason that most people ascend to 14,000 feet is to go skiing. For a group of U.S. and Chilean scientists, however, such altitudes are ideal fossil-hunting terrain. In fact, over the past 10 years their explorations have taken them to one of the highest elevation vertebrate fossil sites in the world. The localities near Salar de Surire in Chile have yielded several hundred fossil mammal specimens.

A study led by Dr Darin Croft of Case Western Reserve University has determined that one of these specimens, a partial skeleton collected in 2004, represents a new species of armored mammal known as a glyptodont, which they have named Parapropalaehoplophorus septentrionalis.

As Dr Croft says, 'The name of this new species is a mouthful, but it does roll off the tongue nicely!'

The discovery is reported in the December issue of the Journal of Vertebrate Palaeontology.

Glyptodonts are a group of now-extinct armoured mammals most closely related to modern armadillos. Unlike armadillos, glyptodonts had shells made of mostly immovable plates and reached much larger sizes; some of the largest likely weighed two tons - the size of a small car! The new species, P. septentrionalis, is much smaller, weighing a mere 200 pounds and it documents the early history of this interesting group, which went extinct at about the same time that humans arrived in the New World. 'When we collected this fossil, we had no idea that it would turn out to be a new species,' said Croft. 'We knew that it would be an important specimen, given its completeness, but it was only after careful comparison to other known species that we realised how unusual it was.'

The new species of glyptodont is one of about 18 mammal species known from the Chucal Fauna, the collective name given to the fossils from the Salar de Surire region. Other Chucal mammals include armadillos, marsupials (opossum relatives), rodents, and a variety of extinct hoofed mammals. These mammals, along with plant fossils recovered from the same area, suggest that northern Chile had relatively few trees 18 million years ago. John Flynn, a co-author of the study said that ' Our sites are now located more than 14,500 feet above sea level, but when these animals were alive the region was at much lower elevations. That means that the Chucal fossils give us a unique insight into the timing and rate of uplift of the high Andes.'

Croft said that 'working in the Altiplano of Chile can be challenging; the air is thin, water is scarce, and the temperatures plummet as soon as night falls. On the other hand, there are hardly any bugs, you don't have to worry much about rain, and the stars are spectacular.'