At the end of 2012, I took a moment to look back at some of the fantastically fluffy feathered dinosaurs that paleontologists had uncovered during the year. In so doing, I mentioned that researchers have been quite busy ever since Sinosauropteryx – a little theropod clothed in dinofuzz – popped onto the scientific scene in 1996. What I neglected to mention that the little compsognathid may not have been the first feathery non-avian dinosaur ever found. There were other, unconfirmed candidates before 1996, including the strange Pelecanimimus.
Even though Sinosauropteryx was the beginning of a resounding confirmation that many dinosaurs were fuzzy, if not feathery, paleontologists had been toying with the idea for decades. In fact, the Victorian anatomist Thomas Henry Huxley unintentionally anticipated the discovery of Sinosauropteryx when he rhapsodized that the closely related Compsognathus, if covered in feathers, would have looked exceptionally bird-like. Other paleontologists and artists entertained similar visions in decades to come, the most famous being Gregory S. Paul’s 1988 fan-favorite Predatory Dinosaurs of the World – a book brimming with rich black-and-white illustrations of bird-like, enfluffed dinosaurs.
But, prior to the 1990s, restorations of feathery dinosaurs were marred by the simple fact that no one had ever found direct evidence of such body coverings. Hypotheses about the relationship between birds and dinosaurs (or, in Huxley’s case, birds and as-yet-undiscovered dinosaur-like reptiles) hinted that feathers should have originated long before the origin of the first flying birds, and there were only the barest hints that this was the case. Among the enigmatic clues were what appeared to be feather imprints in stone.
In the mid 19th century, American naturalist Edward Hitchcock acquired an impression of what he thought was a resting bird, complete with feather traces around the legs and feet. Paleontologists later realized that Hitchcock’s “sandstone birds” were really Early Jurassic dinosaurs, which raised the possibility of fuzzy dinosaurs. Only, as relatively recent analyses have shown, the apparent feather imprints are actually subtle sedimentary structures the bipedal dinosaur created as it stood up off the ground.
All the same, the skeletal connections between birds and dinosaurs eventually led many paleontologists to conclude that birds are truly dinosaur descendents. Pelecanimimus had the potential to further underscore that idea.
In 1994, a paper in Nature by paleontologist Bernardino Pérez-Moreno briefly described the partial skeleton of an exceptionally-preserved theropod dinosaur with soft tissue impressions. They called the long-snouted, many-toothed animal Pelecanimimus polyodon, and the dinosaur was an archaic ornithomimosaur closely related to forms such as Harpymimus.
Included with the 128 million year old specimen, discovered in central Spain, were “subparallell fibres” found near the lower neck and the right arm. Pérez-Moreno and coauthors didn’t call these structures feathers, nor were the fibers included in the restoration of the animal created by Mauricio Antón, but the paper still counted them as “integumentary structures” that would have covered part of the dinosaur’s body.
Had protofeathers finally been find on a dinosaur? Paleontologists were cautious about the possibility. In fact, in 1997 Pérez-Moreno joined Derek Briggs and colleagues in a reassessment of the Pelecanimimus soft tissue structures that recharacterized the mysteries fibers as muscle remnants. Pelecanimimus truly did have a throat pouch and a crest atop its head, as originally envisioned, but the paleontologists concluded that the dinosaur’s skin was smooth and lacked feathers or scales. As with another small theropod fossil found in Brazil and described by Alexander Kellner the year before, the preservation of Pelecanimimus was so detailed that clear evidence of feathers would have been expected if they were truly present.
Maybe they are. Even though the 1997 study was taken as solid evidence that the sole Pelecanimimus was not preserved with feathers, the specimen deserves another look. After all, Pelecanimimus was a coelurosaur, and, as multiple studies over the past decade and a half have indicated, there was some kind of feather or dinofuzz in every branch of the coelurosaur family tree. Pelecanimimus almost certainly had feathers, and the detecting the presence of simple protofeathers on this dinosaur would alter the often-told story of how fuzzy and fluffy dinosaurs emerged on the scientific scene. Sinosauropteryx may have kicked out the Dinosaur Feather Rush, but we should not forget odd little Pelecanimimus in the history of enfluffled dinosaurs.
Previous entries in the Dinosaur Alphabet series:
O is for Ojoceratops
N is for Nqwebasaurus
M is for Montanoceratops
L is for Leaellynasaura
K is for Kileskus
J is for Juravenator
A-I at Dinosaur Tracking.
Briggs, D. Wilby, P., Pérez-Moreno, B., Sanz, J., Fregenal-Martinez, M. 1997. The mineralization of dinosaur soft tissue in the Lower Cretaceous of Las Hoyas, Spain. Journal of the Geological Society, London. 154: 587-588
Kellner, A. 1996. Fossilized theropod soft tissue. Nature. 379: 32.
Pérez-Moreno, B., Sanz, J., Buscalloni, A., Moratalla, J., Ortega, F., Rasskin-Gutman, D. 1994. A unique multitoothed ornithomimosaur dinosaur from the Lower Cretaceous of Spain. Nature. 370: 363-367
Unwin, D. 1998. Feathers, filaments and theropod dinosaurs. Nature. 391: 119-120