Eostriatolamia paucicorrugata

Underwood & Cumbaa, 2010


Classification: Elasmobranchii Lamniformes Cretoxyrhinidae

Reference of the original description
Underwood, C.J. & Cumbaa, S.L. (2010)
Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontology, 53(4), 903–944

Types
Eostriatolamia paucicorrugata
Holotype: RSM: P2989.76;


Description:


Citation: Eostriatolamia paucicorrugata Underwood & Cumbaa, 2010: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 09/2026

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Description
Original diagnosis after Underwood & Cumbaa, 2010 [12632]: Heterodonty well developed and probably of Odontaspis ferox type. Teeth small and gracile, typically less than 10 mm high. Root and base of crown quite symmetrical in all teeth, with main cusp distally inclined or curved in presumed upper lateral files. Main cusp higher than wide in all teeth, widening towards the base, especially in lateral teeth. Lingual curvature of cusp present in anterior teeth. One or two pairs of short but robust lateral cusplets present in all teeth, clearly separated from main cusp but joined by broad labial base of crown. Cusplets sharply pointed and higher than wide in anterior teeth but similar width and height in lateral teeth. Lateral edge of outer cusplets overhangs outer edges of root, weakly in anterior teeth, strongly in lateral teeth. Base of crown extends at least half way down labial face of root lobes and does not strongly overhang the root in lateral teeth. A continuous and well-developed cutting edge extends over all cusps. Crown ornament restricted to faint and irregular corrugations at base of labial face and, in some teeth, very faint longitudinal striations on lingual face of cusps. The root is strongly bilobed with a very prominent nutritive groove in all teeth. Root lobes form basal angle of 70–140 degrees. Linguobasal face of root slightly arched and flattened.

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
Condamine, F.L. & Romieu, J. & Guinot, G. (2019)
Climate cooling and clade competition likely drove the decline of lamniform sharks. Proceedings of the National Academy of Sciences of the United States of America, 116(41), 20584–20590
DOI: 10.1073/pnas.1902693116
Ouroumova, O. & Shimada, K. & Kirkland, J.I. (2016)
Fossil Marine Vertebrates from the Blue Hill Shale Member (Middle Turonian) of the Upper Cretaceous Carlile Shale in Northeastern Nebraska. Transactions of the Kansas Academy of Science, 119(2), 211–221
DOI: 10.1660/062.119.0213
Underwood, C.J. & Cumbaa, S.L. (2010)
Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontology, 53(4), 903–944
DOI: 10.1111/j.1475-4983.2010.00969.x
Cumbaa, S.L. & Shimada, K. & Cook, T.D. (2010)
Mid-Cenomanian vertebrate faunas of the WesternInterior Seaway of North America and their evolutionary, paleobiogeographical, and paleoecological implications. Palaeogeography, Palaeoclimatology, Palaeoecology, 295(1–2), 199–214
DOI: 10.1016/j.palaeo.2010.05.038