Hello all! Welcome to Terrific Tetanurae! #8. Enjoy!

Today we take a look at one of the smallest non-avian dinosaurs. Enter the “Ashdown Maniraptoran”. In 2011, Darren Naish and Steve Sweetman published a paper describing a single, tiny, but adult vertebrae. This specimen was collected from the Lower Cretaceous Wealden Supergroup in England. Because the dinosaur is only known from a single vertebrae, it’s hard to definitively place this animal in any clade of maniraptora, but we can be pretty certain it is some sort of maniraptoran based on the morphology of the vertebrae.

The vertebrae itself is a tiny cervical. I mean a really tiny one. And because there is no neurocentral suture perceivable, we can surmise that the animal was full grown. Besides the initial description and Darren’s blog post on the animal, there really hasn’t been much literature on this guy. So I suppose it is time for me to chime in a bit.

Contrary to popular thought, I don’t believe the vertebrae came from a protoarchaeopterygid (although I should note that even those who have supposed this animal to be a protoarchaeopterygid have pronounce their judgements as highly speculative). Rather, I suppose it to be a derived oviraptorosaur, but this judgement is highly speculative as well. The X-shape of the vertebrae in dorsal view, as noted by Darren, is also found in a variety of oviraptorosaurs, namely Microvenator. The “Ashdown Maniraptoran” vertebrae is also seems more laterally compressed then that of such oviraptorosaurs as Microvenator, which is found in  the vertebrae of some derived oviraptorosaurs, namely Nomingia. However, all judgements are speculative as this specimen is just a vertebrae.

“The Ashdown Maniraptoran”, with a penny for comparison, by the author. Pencils on paper, 2015.

I hope you enjoyed Terrific Tetanurae! #8, and thanks for reading! 

References

1. Naish, D. & Sweetman, S. C. 2011. “A tiny maniraptoran dinosaur in the Lower Cretaceous Hastings Group: evidence from a new vertebrate-bearing locality in south-east England.” Cretaceous Research 32(4):464-471.

2. Makovicky, P. J. & Sues, H. D. 1998. “Anatomy and phylogenetic relationships of the theropod dinosaur Microvenator celer from the Lower Cretaceous of Montana.”  American Museum Novitates 3240:1-27.

3. Barsbold R., Osmólska, H., Watabe M., Currie, P. J. & Tsogtbaatar K.  .2000. “New oviraptorosaur (Dinosauria, Theropoda) from Mongolia: The first dinosaur with a pygostyle.” Acta Palaeontologica Polonica 45(2):97–106.

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