Ambopteryx

Type Species: Ambopteryx longibrachium

Classification: Dinosauria – Saurischia – Theropoda – Coelurosauria – Maniraptora – Paraves – Scansoriopterygidae 

Time Period: Late Jurassic

Location: China

Diet: Omnivorous? 

The non-avian theropod Ambopteryx is known from a nearly complete skeleton with preserved soft tissues. This small critter was just a foot long snout-to-tail, and it had a wing membrane preserved as a continuous brownish layer on the matrix surrounding the left hand, right forelimb, and abdomen. This thin membrane may have been reminiscent of that equipped by modern bats. Ambopteryx’s head, neck, and shoulders were coated with a dense layer of feather. Its head was short and blunt, and it had a hyper-elongated third finger. Some researchers believe that this finger was used to extract grubs from wood, but others believe it was elongated for the attachment of the patagium (wing membrane) and that, in life, their fingers were encapsulated by membranous tissue and had limited mobility. Unlike most non-avian theropods, it had a short tail that lacked a transitional point and ended in a pygostyle (a set of fused tail vertebrae to support tail feathers and musculature). The only other non-avian theropods known to have a pygostyle were a handful of oviraptosaurs and therizinosaurs. Ambopteryx’s abdominal region contained a small number of gastroliths and crushed bones, likely the remnants of its last meal. The presence of both bones and gastroliths indicate it may have been an omnivore. 

Ambopteryx belongs to the non-avian Scansoriopterygid dinosaur family. Only a few species of these scansoriopterygids are known, but these reveal that they had clear adaptations for an arboreal (tree-dwelling) lifestyle and that they likely glided from branch-to-branch, spending little time on the forest floor. These were some of the smallest dinosaurs, some no larger than a sparrow.