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Doug Bonderud

Apr 23rd 2021

Did Dinosaurs Have Feathers? Fossils Fuel Fuzz-First Frameworks

Mega-blockbuster “Jurassic Park” gave us the iconic image of Brachiosaurus striding across fertile plains, head held high and body devoid of feathers. Instead, it had the smooth reptilian look commonly associated with Earth’s once-dominant lifeforms. But evolving fossil research suggests that dinosaur skin wasn’t so much flat as it was feathered — which opens the door to a prehistoric world full of fuzzy, feathery dino families that challenge our notion of the familiar.

Did dinosaurs have feathers? Yes, but fossil finds still paint a fuzzy picture of how far this feathered framework fanned out.

Bird Is the Word

The idea of feathered dinosaurs isn’t new — in the 1990s, fossils from China made it abundantly clear that dinosaurs were the ancestors of modern-day birds and shared their propensity for physical featheration. But this initial group of fuzzy fossils was confined to therapods or “raptor” dinosaurs, such as the velociraptor, which offered a close evolutionary link to our modern avians.

However, according to a National Geographic piece from 2014, fossil discoveries in Siberia showcased a new species, Kulindadromeus zabaikalicus, which was similarly feathered but from a different family: the two-legged, beaked runner “ornithischian” group. These 4.5-foot-long speedsters sported thin feathers that likely evolved from scales. In fact, evidence of both scales and feathers were found in the fossils.

While this dino couldn’t fly, and it’s not known exactly what the feathers were for (though one potential explanation is insulation), its discovery gave rise to the notion that almost all dinosaurs shared a common, feathered ancestor.

Hit the Ground Running

With the direct ancestors and running cousins of the feathered family, it was only a matter of time until flight-capable creatures also got their moment in the feather fossil spotlight. As Discover notes, work from 2018 found evidence of “novel filaments” on flying pterosaurs — considered “cousins” of the more familiar dinosaurs — suggesting they were at the very least fuzzy and potentially feathered.

Analysis of well-preserved pterosaur fossils had already revealed hollow filaments known as “pycnofibers,” indicating they had some type of furry covering. But the discovery of additional pycnofiber types in other pterosaur species demonstrated a branched structure type that only occurred on the creatures’ wing membranes, which suggests that at least some pterosaurs had more familiar feather forms.

However, debate remains about the origin of feathers across multiple evolutionary groups. Some scientists suggest that dinosaurs and pterosaurs shared a common, feathered progenitor and took their cue from the anatomy of this ancestor, while others argue that these two groups developed feathers independently. Regardless of their converged or parallel past, the fact remains: Feathers are everywhere.

Facing the Feather Facts

But wait! Before we get too far off the ground, it’s worth noting that feather fossil frameworks take us only so far. According to an analysis of all known dinosaur skin specimens by Professor Paul Barnett of the Natural History Museum (NHM), it’s unlikely that feathers fanned out particularly far from theropods, ornithomimosaurs and pterosaurs — creatures that all shared bird-like characteristics. Dinosaurs such as the horned ceratopsian Triceratops, meanwhile, were almost certainly scaly.

Solving the scale-or-feather puzzle is much like dealing with the dino dental debate — it all comes down to accurately identifying examples of both in fossils of varying quality and age. As the NHM notes, true features must be made of beta-keratin, must display a branching structure and must originate from a follicle. Not surprisingly, this isn’t an easy task when dealing with multi-million-year-old skin samples.

Barnett puts it simply, “If we look at the evidence that we do have, and we combine that with evolutionary trees, what we find is that there is no evidence for the first dinosaurs being feathered.” Instead, he suggests that all dinosaurs may have had the genetic potential to produce feathers — but not all had the predisposition. Discovering why — and how — specific species sprouted feathers offers an entirely new and engaging branch of study.

Did dinosaurs have feathers? Affirmative. Did all dinosaurs have feathers? Fossil findings suggest this is a flight of fancy.

Check out Northrop Grumman career opportunities to see how you can participate in this fascinating time of discovery in science, technology, and engineering.

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