Triceratops has been controversial because of its unique morphological features. However, arguments based on brain and inner ear structures have been scarce. In this study, two braincases (FPDM-V-9677 and FPDM-V-9775) were analyzed with computed tomography to generate three-dimensional virtual renderings of the endocasts of the cranial cavities and bony labyrinths. Quantitative analysis, including comparison of linear measurements of the degree of development of the olfactory bulb and inner ear, was performed on these virtual endocasts to acquire detailed neuroanatomical information. When compared with other dinosaurs, the olfactory bulb of Triceratops is relatively small, indicating that Triceratops had a reduced acuity in sense of smell. The lateral semicircular canal reveals that the basicranial axis of Triceratops is approximately 45° to the ground, which is an effective angle to display their horns as well as frill, and to graze. The semicircular canals of Triceratops are relatively smaller than those of primitive ceratopsians, such as Psittacosaurus and Protoceratops, suggesting that sensory input for the reflexive stabilization of gaze and posture of Triceratops was less developed than that of primitive ceratopsians. The cochlear length of Triceratops is relatively short when compared with other dinosaurs. Because cochlear length correlates with hearing frequency, Triceratops was likely adapted to hearing low frequencies.

previously described as an indeterminate neornithischian, is here reinterpreted as a leptoceratopsid ceratopsian, Ferrisaurus sustutensis, gen. et. sp. nov. The skeleton includes parts of the pectoral girdles, left forelimb, left hindlimb, and right pes. It can be distinguished from other named leptoceratopsids based on the proportions of the ulna and pedal phalanges. This is the first unique dinosaur species reported from British Columbia, and can be placed within a reasonably resolved phylogenetic context, with Ferrisaurus recovered as more closely related to Leptoceratops than Montanoceratops. At 68.2 to 67.2 Ma in age, Ferrisaurus falls between, and slightly overlaps with, both Montanoceratops and Leptoceratops, and represents a western range extension for Laramidian leptoceratopsids.

No abstract

Triceratops has been controversial because of its unique morphological features. However, arguments based on brain and inner ear structures have been scarce. In this study, two braincases (FPDM-V-9677 and FPDM-V-9775) were analyzed with computed tomography to generate three-dimensional virtual renderings of the endocasts of the cranial cavities and bony labyrinths. Quantitative analysis, including comparison of linear measurements of the degree of development of the olfactory bulb and inner ear, was performed on these virtual endocasts to acquire detailed neuroanatomical information. When compared with other dinosaurs, the olfactory bulb of Triceratops is relatively small, indicating that Triceratops had a reduced acuity in sense of smell. The lateral semicircular canal reveals that the basicranial axis of Triceratops is approximately 45° to the ground, which is an effective angle to display their horns as well as frill, and to graze. The semicircular canals of Triceratops are relatively smaller than those of primitive ceratopsians, such as Psittacosaurus and Protoceratops, suggesting that sensory input for the reflexive stabilization of gaze and posture of Triceratops was less developed than that of primitive ceratopsians. The cochlear length of Triceratops is relatively short when compared with other dinosaurs. Because cochlear length correlates with hearing frequency, Triceratops was likely adapted to hearing low frequencies.

Adult large-bodied theropods are often found with numerous pathologies. A large, almost complete, probably adult Allosaurus specimen from the Howe Stephens Quarry, Morrison Formation (Late Kimmeridgian-Early Tithonian), Wyoming, exhibits multiple pathologies. Pathologic bones include the left dentary, two cervical vertebrae, one cervical and several dorsal ribs, the left scapula, the left humerus, the right ischium, and two left pedal phalanges. These pathologies can be classified as follows: the fifth cervical vertebra, the scapula, several ribs and the ischium are probably traumatic, and a callus on the shaft of the left pedal phalanx II-2 is probably traumatic-infectious. Traumatically fractured elements exposed to frequent movement (e.g. the scapula and the ribs) show a tendency to develop pseudarthroses instead of a callus. The pathologies in the lower jaw and a reduced extensor tubercle of the left pedal phalanx II-2 are most likely traumatic or developmental in origin. The pathologies on the fourth cervical are most likely developmental in origin or idiopathic, that on the left humerus could be traumatic, developmental, infectious or idiopathic, whereas the left pedal phalanx IV-1 is classified as idiopathic. With exception of the ischium, all as traumatic / traumatic-infectious classified pathologic elements show unambiguous evidences of healing, indicating that the respective pathologies did not cause the death of this individual. Alignment of the scapula and rib pathologies from the left side suggests that all may have been caused by a single traumatic event. The ischial fracture may have been fatal. The occurrence of multiple lesions interpreted as traumatic pathologies again underlines that large-bodied theropods experienced frequent injuries during life, indicating an active predatory lifestyle, and their survival perhaps supports a gregarious behavior for Allosaurus. Alternatively, the frequent survival of traumatic events could be also related to the presence of non-endothermic metabolic rates that allow survival based on sporadic food consumption or scavenging behavior. Signs of pathologies consistent with infections are scarce and locally restricted, indicating a successful prevention of the spread of pathogens, as it is the case in extant reptiles (including birds).