Tusks, the extra-oral teeth

Nasoori, Alireza

doi:10.1016/j.archoralbio.2020.104835

Cited by 5 publications

(3 citation statements)

References 157 publications

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“…In mammals, tusks are enlarged specialized anterior teeth, commonly incisors or canines, in which the crown extends beyond the mouth [1]. By definition, true tusks are continuously growing hypselodont teeth, with no root [2,3]. The continuous growth is due to a bed of epithelial stem cells at the base of the tooth continuously producing more dental tissues [4,5].…”

Section: Introductionmentioning

confidence: 99%

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A new dolphin with tusk-like teeth from the late Oligocene of New Zealand indicates evolution of novel feeding strategies

2023

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All extant toothed whales (Cetacea, Odontoceti) are aquatic mammals with homodont dentitions. Fossil evidence from the late Oligocene suggests a greater diversity of tooth forms among odontocetes, including heterodont species with a variety of tooth shapes and orientations. A new fossil dolphin from the late Oligocene of New Zealand, Nihohae matakoi gen. et sp. nov., consisting of a near complete skull, earbones, dentition and some postcranial material, represents this diverse dentition. Several preserved teeth are horizontally procumbent, including all incisors and canines. These tusk-like teeth suggest adaptive advantages for horizontally procumbent teeth in basal dolphins. Phylogenetic analysis places Nihohae among the poorly constrained basal waipatiid group, many with similarly procumbent teeth. Features of N. matakoi such as its dorsoventrally flattened and long rostrum, long mandibular symphysis, unfused cervical vertebrae, lack of attritional or occlusal wear on the teeth and thin enamel cover suggest the rostrum and horizontally procumbent teeth were used to injure and stun prey though swift lateral head movements, a feeding mode that did not persist in extant odontocetes.

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Section: Introductionmentioning

confidence: 99%

“…The continuous growth is due to a bed of epithelial stem cells at the base of the tooth continuously producing more dental tissues [4,5]. The constant growth enables compensation for wear, abrasion, and trauma, which can be common in tusked species [3].…”

Section: Introductionmentioning

confidence: 99%

A new dolphin with tusk-like teeth from the late Oligocene of New Zealand indicates evolution of novel feeding strategies

2023

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“…Crocodylians generally have overall thicker enamel than dinosaurs, with thicker regions toward the apex of the crown ( 21 ). In addition, dentine exposure is common in teeth and tusks that are exposed to the environment ( 22 ). To investigate the dental histology of large theropods in detail, we removed a functional upper maxillary tooth from a large individual of the tyrannosaurid Daspletosaurus and examined it for age and enamel ultrastructure in histological thin section under plane-polarized and cross-polarized light using a petrographic microscope (Fig.…”

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Theropod dinosaur facial reconstruction and the importance of soft tissues in paleobiology

Cullen

Larson

Witton

et al. 2023

Science

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Large theropod dinosaurs are often reconstructed with their marginal dentition exposed because of the enormous size of their teeth and their phylogenetic association to crocodylians. We tested this hypothesis using a multiproxy approach. Regressions of skull length and tooth size for a range of theropods and extant varanid lizards confirm that complete coverage of theropod dinosaur teeth with extraoral tissues (gingiva and labial scales) is both plausible and consistent with patterns observed in living ziphodont amniotes. Analyses of dental histology from crocodylians and theropod dinosaurs, including Tyrannosaurus rex , further indicate that the most likely condition was complete coverage of the marginal dentition with extraoral tissue when the mouth was closed. This changes our perceptions about the appearance and oral configuration of these iconic predators and has broad implications for our interpretations of other terrestrial animals with large teeth.

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Diagenetic Alterations to Vertebrate Mineralized Tissues – A Critical Review

Turner‐Walker¹

2023

Handbook of Archaeological Sciences

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Tusks, the extra-oral teeth

Cited by 5 publications

References 157 publications

A new dolphin with tusk-like teeth from the late Oligocene of New Zealand indicates evolution of novel feeding strategies

A new dolphin with tusk-like teeth from the late Oligocene of New Zealand indicates evolution of novel feeding strategies

Theropod dinosaur facial reconstruction and the importance of soft tissues in paleobiology

Diagenetic Alterations to Vertebrate Mineralized Tissues – A Critical Review

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