Pronunciation: teh-ROP-uh-liks
Meaning: Winged pelvis
Author/s: Cope (1889)
Synonyms: None known
First Discovery: Montana, USA
Discovery Chart Position: #71
Pteropelyx grallipes
It's fair to say that Pteropelyx hasn't had a smooth ride since E. D. Cope declared that its "pelvis and ischium are so slender as to be almost functionless" in its first description in 1889. And that was followed by O. C. Marsh renaming the same remains Claosaurus a year later, during the infamous bone wars, in the American Journal of Science and Arts for May 1890 on page 423—or so his nemesis thought. Barring the fact that the journal cited by Cope had ceased to run under that name by that point, being known as the shortened American Journal of Science since 1880, the only mention of Claosaurus on the stated page is Marsh assigning that name to a specimen he found himself in the Pteranodon beds near the Smokey Hill River in western Kansas and had named Hadrosaurus agilis in 1872. We'll put that down to Cope's paranoia, which is understandable given the tension between the pair at the time. Nevertheless, everyone else knew that Pteropelyx was still Pteropelyx, and they assigned fossils to it with gay abandon.
The problem is that Pteropelyx is missing a skull, and extremely fragmentary bones were being assigned to it that lacked the matching parts for direct comparison and just as likely belonged to other hadrosaurids from the same area. Some palaeontologists even hedged their bets and inserted the name, bracketed, into other "new" species, such as Lambe's Trachodon (Pteropelyx) marginatus, which would become Stephanosaurus. However, the limb and pelvic bones of Pteropelyx are indistinguishable from those of Corythosaurus, with the pair mostly thought of as synonymous, and, strictly speaking, that should make Pteropelyx the valid name by which both species are known, because it was named 15 years earlier. Unfortunately for old "Wing Pelvis", almost all palaeontologists prefer the handsome and fully skulled Corythosaurus. But they've bypassed appealing to the ICZN to officially abandon the former in favour of the latter, as suggested by Brett Surman three decades ago as of 2019, and abandoned it anyway.
The problem is that Pteropelyx is missing a skull, and extremely fragmentary bones were being assigned to it that lacked the matching parts for direct comparison and just as likely belonged to other hadrosaurids from the same area. Some palaeontologists even hedged their bets and inserted the name, bracketed, into other "new" species, such as Lambe's Trachodon (Pteropelyx) marginatus, which would become Stephanosaurus. However, the limb and pelvic bones of Pteropelyx are indistinguishable from those of Corythosaurus, with the pair mostly thought of as synonymous, and, strictly speaking, that should make Pteropelyx the valid name by which both species are known, because it was named 15 years earlier. Unfortunately for old "Wing Pelvis", almost all palaeontologists prefer the handsome and fully skulled Corythosaurus. But they've bypassed appealing to the ICZN to officially abandon the former in favour of the latter, as suggested by Brett Surman three decades ago as of 2019, and abandoned it anyway.
(Winged Pelvis. Stilt Foot)Etymology
Pteropelyx is derived from the Greek "pteron" (wing) and "pelyx" (pelvis, basin) alluding to the light construction of its pelvis, "so slender as to be almost functionless".
Cope never gave a meaning behind the name, but we're guessing that the species epithet, grallipes, is derived from the Latin "grallae" (stilt) and "pes" (foot), in reference to its long, thin legs. According to Cope, "the bones of the posterior leg are very long, and the fibula is very slender" and "its posterior legs are much longer than those of the Monoclonius crassus".
Discovery
The remains of Pteropelyx were discovered in the Judith River Formation near Cow Island, Montana, USA, by Mr. J.C. Isaac in 1876.
The holotype (AMNH 3791) is a partial, skulless skeleton, including bones from the hip (ischium, ilium, pelvis), hindlimb (thigh, shin, calf, metatarsals), a shoulder blade, and back vertebrae.
Coincidentally, there's an issue of American Museum Novitates, a peer-reviewed academic journal published by the American Museum of Natural History, with the same number as the holotype ("3791"), in which Bolzern and Platnick name Varioonops: a genus of neotropical goblin spider.
