Galagadon nordquistae

GATES, GORSCAK & MAKOVICKY, 2019


Classification: Elasmobranchii Orectolobiformes incert. fam.

Reference of the original description
GATES, T.A. & GORSCAK, E. & MAKOVICKY, P.J. (2019)
New sharks and other chondrichthyans from the latest Maastrichtian (Late Cretaceous) of North America. Journal of Paleontology, 93 (3): 512-530

Types
Galagadon nordquistae
Holotype: FMNH: PF 15769;

Images of types

Description:


Citation: Galagadon nordquistae GATES, GORSCAK & MAKOVICKY, 2019: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 06/2021

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Galagadon nordquistae gen. et sp. nov., holotype, labial view, FMNH PF 15769 © Gates et al. 2019

Description
Original diagnose after Gates et al. (2019) p. 517 [26956]: Orectolobiform shark possessing the following autapomorphies: central cusp with distinctly swollen lingual face forming a clearly demarcated constriction, or neck, between the cusp and the root; labial surface of central cusp ornamented with a raised ridge or closely arrayed plications, which in most cases are distributed in such a pattern as to follow the slope of the heels; convex heels, well developed both mesial and distal to the central cusp with a distinct convex angle mid-distance along slope seen in anterior teeth and some lateral teeth. This taxon is further differentiated by the following suite of shared characters: anterior teeth possess distinct, high central cusp; heels on lateral teeth slightly serrated; heels of anterior teeth and some lateral teeth do not slope gradually toward root lobes, but are instead squared-off or rounded at their terminus; one or two rounded diminutive cusplets may be present although this trait varies among individual teeth; apron is generally broadly rounded and shows a bifid habit on some but not all specimens; root lobes enlarged on lingual side of tooth compared to more constricted structure on labial side, bestowing an exaggerated heart-shape in basal view; a central foramen pierces between the root lobes with the foramen divided by thin struts in some teeth.

Remarks
type species of Galagadon Gates et al., 2019 p. 516 [26956] by monotypy (Art. 68.3 ICZN);

valid after Gates et al. (2019) p. 516 [26956];


References
WYND, B.M. & DEMAR, D.G. & WILSON, G.P. (2020)
Euselachian diversity through the uppermost Cretaceous Hell Creek Formation of Garfield County, Montana, USA, with implications for the Cretaceous-Paleogene mass extinction in freshwater environments. Cretaceous Research, 113: 104483
DOI: 10.1016/j.cretres.2020.104483
GATES, T.A. & GORSCAK, E. & MAKOVICKY, P.J. (2019)
New sharks and other chondrichthyans from the latest Maastrichtian (Late Cretaceous) of North America. Journal of Paleontology, 93 (3): 512-530
DOI: 10.1017/jpa.2018.92