Steropodon

Steropodon
Classification
Kingdom	Animalia
Phylum	Chordata
Superclass	Tetrapoda
Class	Mammalia
Order	Monotremata
Family	Steropodontidae
Genus	Steropodon
1st Species	Steropodon galmani
Other Attributes
Time Range	100.5-93.3 mya
Location	Australia
Name Meaning	Lightning tooth
Physical Dimensions	40 centimeters long
Diet	Carnivore

Steropodon is a steropodontid monotreme mammal from the Early Cretaceous of Australia. It was named in 1985 by Richard Archer, Timothy Fridjof Flannery, Alex Ritchie, and Ralph E. Molnar. It was one of the first monotremes to exist, as well as one of the largest Mesozoic mammalians from Australia.

Physiology

Not much is known about how Steropodon looked, but based on the remains of many Mesozoic mammals as well as some remains of its own, it can be assumed that it had a relatively standard mammalian body plan, with a somewhat slender, barrel-shaped body, 4 semi-erect legs, a moderately long tail, and a mid-sized head with large jaws. As well as this, based on the presence of a mandibular canal, it is possible that it may had a bill similar to that of a platypus; however, unlike platypuses, Steropodon would have had teeth. Most of its body (excluding its feet and snout) would have been covered in thick fur, while its feet and snout would have been covered in smooth skin.

Diet

Steropodon was a predator, preying on worms, crustaceans, and insect larvae. Unlike platypuses, which have keratinized ridges inside their mouth for assisting in grinding up food, Steropodon had sturdy, heavily-built teeth, and thus may have been able to feed on tougher prey.

Ecology

So far, all we know about Steropodon is that it likely would have filled an ecospace similar to that of a platypus, being a possible semi-aquatic predator that dug for prey hiding in the riverbed^[1]; however, due to its sturdy teeth, it likely would have fed on tougher prey.^[2]

In popular culture

Steropodon was featured in the 5th episode of the 1999 documentary Walking with Dinosaurs, where it is, interestingly enough, live-acted by a South American coati^[3]; although it is uncertain whether Steropodon had a beak or not, it is not very likely that it fully resembled a coati, either. In the episode itself, it tries to steal eggs from a Leaellynasaura; however, the dinosaur repels it by kicking dirt at it.

References

1. Archer, M., Flannery, T. F., Ritchie, A., & Molnar, R. E. (1985, November 28). First Mesozoic mammal from Australia-an early Cretaceous monotreme. Nature News. https://www.nature.com/articles/318363a0.

1. Musser, A. A. (2018, November 24). Steropodon galmani. The Australian Museum. https://australian.museum/learn/australia-over-time/extinct-animals/steropodon-galmani/.

1. BBC. (2003, October 3). Dinosaur Fact Files - Steropodon. Walking with Dinosaurs. https://web.archive.org/web/20031003192636/http://www.bbc.co.uk/dinosaurs/fact_files/forest/birds_mammals/steropodon.shtml.