175 — A Feathered Dinosaur Tail with Primitive Plumage Trapped in Mid-Cretaceous Amber

Xing, McKellar, Xu, Li, & Bai et al (10.1016/j.cub.2016.10.008)

Read on 11 February 2018
#paleontology  #dinosaur  #feather  #birds  #amber  #cretaceous  #fossil 

This is another paper that made quite a stir when it was published: A beautifully preserved chunk of dinosaur tail was embedded in an amber block which — in an almost cinematic flair — was found by a native of the area and was nearly sold as a keepsake to a tourist at a Myanmar market.

Instead, a paleontologist snagged it and began researching the richest source of knowledge about dinosaur plumage ever found.

These 3cm of preserved tissue have little signs of intact soft tissue: I didn’t realize this, but apparently a Jurassic-Park-style preservation of soft-tissue is very rare in amber, since the tissue dessicates in the process. (At least… I assume so. I wonder if insect tissues dessicate the same way as animals with soft tissue on the outside…)

Scans of the microstructure showed that the feathers didn’t quite look like those of a modern bird. This Cretaceous Caelurosaur had a single rachis (the central shaft of the feather) with alternating barbs (the first-level branches from the rachis) that have symmetrical sub-branches, or barbules. This shed light on the origin of symmetrical-barb feathers common in today’s birds. Evidently, the barbs already had offshooting barbules evolutionarly before the barbs merged to form the central rachis.

The skeleton also teaches us about the origins modern birds. The vertebrae were discrete and “whip-like,” whereas modern birds’ are fused. The shape of the verebrae, which lack neural arches, also tells us that this tail was likely very long, and this was just the distal end of it. From the size of the bones, we can tell that it’s likely that this tail belonged to a juvenile dinosaur.

With such a treasure-trove of information at their disposal, I’m excited to see what other discoveries these researchers make in the upcoming months. This specimen is so information-rich. I wonder if the scans will be made public someday, for public research.