Thomas Dudgeon

• Master of Science
• University of Toronto

Unlike mammals, reptiles typically lack large muscles and ligaments that connect the zygoma to the mandible. Dinosaur craniomandibular soft tissue reconstructions, often based on the rationale of extant phylogenetic bracketing, follow this general rule. However, descending flanges from the zygomata of hadrosaurs, heterodontosaurids, and psittacosau...

Although the neochoristodere Champsosaurus is well documented in Campanian deposits of western North America, species-diagnostic remains from these strata are restricted to the Dinosaur Park Formation of Alberta, Canada. Here, we describe an exceptionally well-preserved specimen of Champsosaurus lindoei from the Two Medicine Formation of Montana, U...

Lambeosaurine hadrosaurids exhibited extreme modifications to the skull, where the premaxillae, nasals, and prefrontals were modified to form their iconic supracranial crests. This morphology contrasts with their sister group, Hadrosaurinae, which possessed the plesiomorphic arrangement of bones. Although studies have discussed differences between...

Various morphological proxies have been used to infer habitat preferences among fossil turtles and their early ancestors, but most are tightly linked to phylogeny, thereby minimizing their predictive power. One particularly widely used model incorporates linear measurements of the forelimb (humerus + ulna + manus), but in addition to the issue of p...

For sheer complexity, braincases are generally considered anatomically conservative. However, recent research on the braincases of tyrannosaurids have revealed extensive morphological variations. This line of inquiry has its root in Dale Russell’s review of tyrannosaurids in which he established Daspletosaurus torosus — a large tyrannosaurine from...

Four neochoristoderan vertebral centra are described from the latest Cretaceous of New Jersey, USA. One specimen was recovered from the basal transgressive lag of the Navesink Formation in the area of Holmdel, New Jersey, and two others were recovered nearby and probably were derived from the same horizon. The fourth was recovered from the Marshall...

A new skeleton of the exceedingly rare, late Carboniferous eureptile Anthracodromeus longipes (Carroll and Baird, 1972), reveals the presence of a reduced phalangeal count in the manus and pedes and uniquely recurved unguals. With these data, we quantitatively evaluate the locomotor ecology of Anthracodromeus using morphometric analyses of the phal...

Rare occurrences of dinosaurian embryos are punctuated by even rarer preservation of their development. Here we report on dental development in multiple embryos of the Early Jurassic Lufengosaurus from China, and compare these to patterns in a hatchling and adults. Histology and CT data show that dental formation and development occurred early in o...

Although isolated Champsosaurus remains are common in Upper Cretaceous sediments of North America, the braincase of these animals is enigmatic due to the fragility of their skulls. Here, two well-preserved specimens of Champsosaurus (CMN 8920 and CMN 8919) are CT scanned to describe their neurosensory structures and infer sensory capability. The an...

Choristoderes are extinct neodiapsid reptiles that are well known for their unusual cranial anatomy, possessing an elongated snout and expanded temporal arches. Although choristodere skulls are well described externally, their internal anatomy remains unknown. An internal description was needed to shed light on peculiarities of the choristodere sku...

This paper presents an analysis of the faunal material obtained from the 1950s Royal Ontario Museum excavation of the shell midden at the Middle Woodland Serpent Mounds on Rice Lake, Ontario (BbGm-2). The zooarchaeological and taphonomic data presented here provide significant information for understanding subsistence activities at the site, as wel...