INVESTIGADORES
PAULINA CARABAJAL ariana
artículos
Título:
Two braincases of Daspletosaurus (Theropoda: Tyrannosauridae): anatomy and comparison
Autor/es:
PAULINA CARABAJAL, A.; CURRIE, P. J.; DUNGEON, T.; LARSSON, H; MIYASHITA, T.
Revista:
CANADIAN JOURNAL OF EARTH SCIENCES
Editorial:
NATL RESEARCH COUNCIL CANADA-N R C RESEARCH PRESS
Referencias:
Lugar: Otawa; Año: 2021
ISSN:
0008-4077
Resumen:
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 the Russell (1970) review of tyrannosaurids in which he established Daspletosaurus torosus ? a large tyrannosaurine from the Campanian of southern Alberta. In the wake of systematic revisions to tyrannosaurines previously assigned to Daspletosaurus, one potentially distinct species remains undescribed. This paper describes and compares a braincase referable to this species with that of the holotype for D. torosus using CT-based reconstructions. The two braincases have numerous differences externally and internally. The specimen of D. sp has a bottlenecked olfactory tract, short and vertical lagena, and a developed ascending column of the anterior tympanic recess. The holotype of D. torosus has many unusual traits, including an anteriorly shifted trochlear root, elongate common carotid canal, distinct chamber of the basisphenoid recess, asymmetry in the internal basipterygoid aperture, and laterally reduced but medially expanded subcondylar recess. This comparison also identified characters that potentially unite the two species of Daspletosaurus, including deep midbrain flexures in the endocasts. However, many character variations in the braincases are known in other tyrannosaurids to correlate with body size and maturity, or represent individual variations. Therefore, taxonomic and phylogenetic signals can be isolated from background variations in a more comprehensive approach by using additional specimens. New information on the two braincases of Daspletosaurus is consistent with the emerging view of tyrannosaurid braincases as highly variable, ontogenetically dynamic character complexes.