Megalolamna paradoxodon

Shimada, Chandler, Lam, Tanaka & Ward, 2017


Classification: Elasmobranchii Lamniformes Otodontidae

Reference of the original description
Shimada, K. & Chandler, R.E. & Lam, O.L.T. & Tanaka, T. & Ward, D.J. (2017)
A new elusive otodontid shark (Lamniformes: Otodontidae) from the lower Miocene, and comments on the taxonomy of otodontid genera, including the ‘megatoothed’ clade. Historical Biology, 29(5), 704–714

Synonyms / new combinations and misspellings
Cretalamna bassanii

Types
Megalolamna paradoxodon
Holotype: UCMP: 112146;


Description:


Citation: Megalolamna paradoxodon Shimada, Chandler, Lam, Tanaka & Ward, 2017: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 04/2024

Please send your images of "Megalolamna paradoxodon" to info@shark-references.com

Megalolamna paradoxodon Shimada, Chandler, Lam, Tanaka & Ward, 2017 collection and © Jean-Marie Canevet

Description
Original diagnose after Shimada et al. (2017) p. 706 [24480]: Lamniform differing from all known species of otodontids (sensu this paper; see Discussion) by the following combination of characters: tooth consisting of a sharply-pointed, relatively tall, triangular main cusp, one prominent pair of triangular lateral cusplets, and strongly bilobed root; main cusp erect, slightly inclined distally, or gently curved distally; lingual crown face very convex without ornamentation; labial crown face flat or subtly convex except center of base with weak depression; height and width of each lateral cusplet nearly equal with tendency to point outward; both mesial and distal cutting edges of main cusp and lateral cusplets smooth and razor-like, and continuous from apex to base; main cusp and lateral cusplets nearly erect to gently curved lingually; concave crown base and distinct tooth neck on lingual face; prominent tooth neck also on labial face in tall teeth, forming rounded ledge with thin enameloid layer that grades into enameloid of main cusp and lateral cusplets; bilobed root with rounded basal tips and moderately tight basal concavity in between; root overall robust but particularly at lingual protuberance that generally exhibits one or two prominent and a few smaller nutritive foramina; root width slightly wider than total crown width; osteodentine tooth histology.

Remarks
shark-references Species-ID=14704;
type species of Megalolamna Shimada et al., 2016 p. 706 [24480] by original designation (Art. 68.2 ICZN);

valid after Shimada et al. (2017) p. 706 [24480];



References
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A Review of the Paleobiology of Some Neogene Sharks and the Fossil Records of Extant Shark Species. Diversity, 16(3), Article 147
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New geographic and stratigraphic occurrences of the enigmatic extinct lamniform shark, Megalolamna (Lamniformes: Otodontidae), from the eastern USA. Historical Biology, in press
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DOI: 10.1073/pnas.1902693116
Shimada, K. & Chandler, R.E. & Lam, O.L.T. & Tanaka, T. & Ward, D.J. (2017)
A new elusive otodontid shark (Lamniformes: Otodontidae) from the lower Miocene, and comments on the taxonomy of otodontid genera, including the ‘megatoothed’ clade. Historical Biology, 29(5), 704–714
DOI: 10.1080/08912963.2016.1236795