Australia: The Land Where Time Began

A biography of the Australian continent 

Riversleigh Feathertail Possums

The Australian Feathertail Glider (Acrobates pygmaeus) and the New Guinea Pen-tail Possum (Distoechurus pennatus) are the 2 extant species of feathertail possum. They were previously thought to be related to pygmy possums but are now known to be not closely related to that group. Their relationships being uncertain, they were tentatively assigned to their own family, the acrbatids. Presently they are thought to be most closely related to the tarsipidids, the honey-possums.

No fossil earlier than the Pleistocene were known before their discovery in the Riversleigh deposits. When the Gotham City Deposit at Riversleigh was excavated their very tiny teeth were found when the blocks of limestone was dissolved away. There are now partial skulls, jaws and more teeth from a number of the Riversleigh deposits to study. One thing that is known about them is that they are acrobatidids. It has to be resolved whether the extinct taxon is a species of Acrobates, Distoechurus or a new taxon.

The family of the living Honey-possum (Tarsipes rostratum) is one of the few family-level groups that hasn't been found at Riversleigh. Honey-possums have small spicule-like cheekteeth. It has been suggested that ancestral forms would have had teeth that were less specialised, so not recognisable as being an ancestral tarsipidid. The same may apply to other animals with highly specialised teeth such as the numbat

Sources & Further reading

Michael Archer, Suzanne J. Hand & Henk Godthelp, Australia's Lost World: Riversleigh, world heritage Site, Reed New Holland

Links

• Riversleigh Fossils - World heritage
• Australian Fossil Mammal Site - Riversleigh World Heritage values
• ABC
• Australian Museum