Squalicorax mutabilis

Siversson, Cook, Ryan, Watkins, Tatarnic, Downes & Newbrey, 2019


Classification: Elasmobranchii Lamniformes Anacoracidae

Reference of the original description
Siversson, M. & Cook, T.D. & Ryan, H.E. & Watkins, D.K. & Tatarnic, N.J. & Downes, P.J. & Newbrey, M.G. (2019)
Anacoracid sharks and calcareous nannofossil stratigraphy of the mid-Cretaceous "upper' Gearle Siltstone and Haycock Marl in the lower Murchison River area, Western Australia. Alcheringa, 43(1), 85–113



Description:


Citation: Squalicorax mutabilis Siversson, Cook, Ryan, Watkins, Tatarnic, Downes & Newbrey, 2019: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 11/2024

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Description
Original diagnose after Siverson et al. (2019) p. 99 [27309]: Cutting edges of cusp smooth to irregularly serrated. Distal heel lacks serrations in vast majority of teeth. Lingual neck relatively broad and generally smooth but may bear rather faint, densely spaced vertical ridges extending halfway from root/neck boundary towards neck/crown boundary. Labial overhang of the root by the crown strongly developed. Central half of basal edge of labial side of crown weakly (anterior and posterior teeth) to strongly (anterolateral and lateral teeth) scalloped. Labial face of crown strongly convex in smallest juvenile teeth but flat to very slightly concave in large teeth. Lobes of root short and broad in most full-size anterior teeth. Smallest lateral teeth, presumably from neonates, about one-fifth of width of largest lateral teeth. Minute, distally inclined cusp projects from crescent-shaped crown base in these teeth from very young individuals. Orientation of distal heel of crown changes from vertical to sub-horizontal during ontogeny.

Remarks
shark-references Species-ID=15457;
valid after Siversson et al. (2019) p. 99 [27309];


References
Guinot, G. & Condamine, F.L. (2023)
Global impact and selectivity of the Cretaceous-Paleogene mass extinction among sharks, skates, and rays. Science, 379, 802–806
DOI: 10.1126/science.abn2080
Berrell, R.W. & Boisvert, C. & Trinajstic, K. & Siversson, M. & Alvarado-Ortega, J. & Cavin, L. & Salisbury, S.W. & Kemp, A. (2020)
A review of Australia’s Mesozoic fishes. Alcheringa, 44(2), 286-311
DOI: 10.1080/03115518.2019.1701078
Siversson, M. & Cook, T.D. & Ryan, H.E. & Watkins, D.K. & Tatarnic, N.J. & Downes, P.J. & Newbrey, M.G. (2019)
Anacoracid sharks and calcareous nannofossil stratigraphy of the mid-Cretaceous "upper' Gearle Siltstone and Haycock Marl in the lower Murchison River area, Western Australia. Alcheringa, 43(1), 85–113
DOI: 10.1080/03115518.2018.1462401