Named By: Rich et al. - 1999.
Classification: Chordata, Mammalia, Monotremata, Platypoda, Steropodontidae.
Species: T. trusleri (type).
Size: Estimated at around 10 centimetres long (based upon comparison to similar mammals).
Known locations: Australia, Victoria.
Time period: Aptian of the Cretaceous.
Fossil representation: Partial left dentary (lower jaw bone).
At roughly the time when large predatory dinosaurs like Australovenator were roaming Australia, the mammals were eking out a living in the shadows. One of these, a tiny monotreme mammal (the kind that still laid eggs) was called Teinolophos and although only known from a partial jawbone, Teinolophos is considered to be one of if not the earliest relatives of the platypus. Reconstructions and size estimations of Teinolophos are usually based upon comparison to Steropodon, a related monotreme that possibly resembled a larger Teinolophos. However Steropodon itself is also only known from a jawbone and its reconstruction is more directly based upon the platypus.