Paleobiological inferences from paleopathological occurrences in the Arctic ceratopsian Pachyrhinosaurus perotorum

Abstract

As a key tool for understanding how animals lived in the past, paleopathology informs us about the lives and deaths of fossil animals. We identify paleopathologies within an assemblage of bones of the pachyrostran centrosaurine Pachyrhinosaurus perotorum, an Arctic ceratopsian. More than 1,000 bones of this dinosaur were collected from the Prince Creek Formation of North Slope, Alaska from fossil sites along the Colville River. Our survey shows the occurrence of paleopathology to be very low and comparable to other populations of horned dinosaurs from the lower latitudes, suggesting that the ancient Arctic environment did not impose intense hardships on these dinosaurs greater than in other environments, as expressed by paleopathological modification of the skeleton. This result may be due to the more equable mean annual temperatures in the Arctic region during the Cretaceous. Also of interest, the frequency of occurrence of paleopathology in the Arctic Pachyrhinosaurus population is very low compared to populations of fossil and historic quadrupedal artiodactyls that are recognized as long distance wanderers.

Celebrating dinosaurs: their behaviour, evolution, growth, and physiology

“…There are no terrestrial ecosystems (either extinct or extant) known that could survive the presence of hundreds or thousands of multitonne herbivores for more than very brief periods of time. Therefore, we can assume that the gigantic monodominant bonebeds of Centrosaurus, Edmontosaurus, Maiasaura, Pachyrhinosaurus (Fiorillo and Tykoski 2022), Saurolophus, Styracosaurus, and other animals represent herds of these animals that encountered catastrophic conditions when they were passing through the regions. Packs of tyrannosaurs and other carnivores may either have formed when the herds of herbivores were passing through the specific ecosystems, or may have actually been following the herds.…”

Dinosaurs of all ilks bow and pay tribute to Peter Dodson, their intrepid chronicler, in an Anatomical Record Special Issue in his honor

“…This current special, Special Issue, “Dinosaurs: New Ideas from Old Bones” (Fiorillo et al, 2023) has been meticulously Guest‐edited by three who have learned their craft upon poppa Dodson's knee as his graduate students: Anthony Fiorillo, Executive Director of the New Mexico Museum of Natural History and Science; Catherine Forster, Professor of Geology and of Biology at George Washington University; and David Weishampel, Professor of Functional Anatomy and Evolution at Johns Hopkins University. These three have themselves had extraordinary careers in the multifaceted world of dinosaur paleontology and biology, and have been referred to as “the Big Three” of PD's students (by Catherine; oy!, I can hear the growls from other PD progeny!).…”

“…Rather, to name just some, they span a glorious gamut: from detailed descriptions of unusual Therapods from New Jersey (really? hadrosaurs, Jimmy Hoffa…who knew Jersey was actually interesting; sorry, JL is a native New Yorker and has little control when commenting on New Jersey; Gallagher, 2023); reports on a new iguanodontian dinosaur from South Africa (Forster et al, 2023); new insights on evolutionary relationships from analyses of the hyolaryngeal apparatus in extant archosaurs (i.e., birds and crocodilians; Yoshida et al, 2023); new reconstructions of the pectoral girdle and forelimb musculature of Megaraptora (Rolando et al, 2023); insights from osteohistology of Dromornis stironi with implications for understanding the histology of Australian mihirung birds (Chinsamy et al, 2023); insightful observations on fracture and disease in a large‐bodied ornithomimosaur with insights into identifying unusual endosteal bone in the fossil record (Chinzorig et al, 2023); a comprehensive assessment of the history and future of the study of morphometrics in the study on non‐avian dinosaurs (Hedrick, 2023); detailed modeling to assess and predict the abundance of large carnivorous dinosaurs of the Upper Jurassic Morrison Formation and the Upper Cretaceous Dinosaur Park formation (by Peter and JL's Yale classmate, the ever‐creative James Farlow; JL is still in awe at all the super‐bright dino dudes that surrounded him at Yale “back in the day”; Farlow et al, 2023); to a number of papers—naturally—on Peter's great love, the ceratopsians, including those by lead Guest Editor Fiorillo (Fiorillo & Tykoski, 2023) and Peter's successor teaching anatomy at Penn, Ali Nabavizadeh (Nabavizadeh, 2023). Even the cover of this Special Issue has been a creative homage to Peter, lovingly created by Anatomical Record Associate Editor (and artist extraordinaire) Adam Hartstone‐Rose (Hartstone‐Rose et al, 2023).…”

Illuminating dinosaurs under the aurora borealis—A commentary on the creation of the Arctic cover for Dinosaurs: New Ideas from Old Bones

“…The nose horn of Pachyrhinosaurus was, as recommended (Hieronymus et al, 2009), reconstructed from the boss of a muskox ( Ovibos ). For the fighting dinosaurs in the background, references were used of fighting birds and lizards (there are some particularly dramatic records of Komodo dragons fighting), but several studies (Farlow & Dodson, 1975; Fiorillo & Tykoski, 2023; Sternberg, 1950) suggest more similarity to the pushing of mammalian megafauna, though whether dinosaurs pushed or crashed heads in this manner is still hotly debated (Farke, 2010; Goodwin & Horner, 2004; Moore et al, 2022; Nabavizadeh, 2023; Snively & Cox, 2008; Snively & Theodor, 2011). Although initial references of multiple taxa were used to imagine this combat, in the end, the only elements that were integrated into the actual reconstructions of the bodies came from lizards (again, mostly varanids) and bird feet (predominantly Struthio ).…”

“…Often there are tussles between animals (usually maturing juveniles) to test the subtle hierarchies in a group, but most of the time animals are doing mundane activities and generally avoiding unnecessary exertion. In fact, another paper in this volume (by Fiorillo & Tykoski, 2023) finds that Pachyrhinosaurus remains to display remarkably little evidence of pathology—suggesting a potentially even calmer lifestyle than that of other ceratopsians and modern herbivores.…”