The rostral neurovascular system of Tyrannosaurus rex

Abstract

The study of the rostral neurovascular system using CT scanning has shed new light on phylogenetic and palaeobiological reconstructions of many extinct tetrapods. This research shows a detailed description of the rostral neurovascular canals of Tyrannosaurus rex including the nasal, maxillary (dorsal alveolar), and mandibular (ventral alveolar) canals. Extensive comparisons with published descriptions show that the pattern of these canals in Tyrannosaurus is not unusual for a non-avian theropod. As in the non-avian theropod Neovenator, the maxillary canal shows several anastomoses of its branches. Differences from the plesiomorphic sauropsid condition are concentrated within the canal for the maxillary neurovasculature, which is primitively horizontal, tubular, and connected to a single row of supralabial foramina, whereas in Tyrannosaurus the main trunk of the canal is oriented more obliquely and dorsally displaced to give room to the deep tooth alveolae. As a result, the lateral branches that provide innervation and blood supply to the skin are dorsoventrally elongated compared to non-theropod taxa, and multiple rows of supralabial foramina are present. An overview of the literature suggests that the evolution of the trigeminal canals among sauropsids only weakly supports previous hypotheses of crocodile-like facial sensitivity in non-avian theropods (except, maybe, in semiaquatic taxa). More systematic studies of the rostral neurovascular canals in non-avian theropods may help answer the question of whether lips were present or not.

Pachyosteosclerosis, rhamphotheca and enhanced sensory capabilities of the premaxillae of Hyperodapedon (Archosauromorpha, Rhynchosauria): implications for foraging at the sediment–water interface

“…2020; Bouabdellah et al . 2022), mosasaurs (Alvarez‐Herrera et al . 2020) and anomodont therapsids (Benoit et al .…”

Ultraviolet Autofluorescence Microscopy of Nanotyrannus lancensis Sections Reveals Blood Clots in Vessel Canals

“…In recent years, a non-destructive computed tomography (CT) scanning of dinosaur bones has also been employed, resulting in remarkable images of neurovascular and other canals [6,[8][9][37][38][39][40][41][42][43]. This is especially notable with respect to imaging dinosaur jaws (maxillae and mandibles) [8,40,43].…”

“…In recent years, a non-destructive computed tomography (CT) scanning of dinosaur bones has also been employed, resulting in remarkable images of neurovascular and other canals [6,[8][9][37][38][39][40][41][42][43]. This is especially notable with respect to imaging dinosaur jaws (maxillae and mandibles) [8,40,43]. Soil matrix and metal artifacts can be identified by CT scanning [37], however none of the referenced dinosaur bone CT studies have reported blood products in neurovascular canals.…”

“…Bone has a large mineral component yet is amply supplied by soft tissue neurovascular bundles [8,[42][43]. It would be expected, therefore, that a rich supply of blood vessels, veins, and nerves would have been present in dinosaur bones at death.…”

“…The immense public popularity of theropod dinosaurs has generated considerable marketing of bone and bone-replica models, books, clothing, artwork, toys, novelties, theatrical presentations, and traveling animatronic dinosaur model shows. Those who study theropods often acknowledge this popularity in their publications [1][2][3][4][5][6][7][8], and, as one worker has put it, "Nearly any five-year-old in the industrialized world knows what it is, and to many, Tyrannosaurus is the quintessential predatory dinosaur … T. rex is as common in the popular media as Tyrannosaurus." [9].…”