Megalolamna paradoxodon
Shimada, Chandler, Lam, Tanaka & Ward, 2017
Classification: Elasmobranchii Lamniformes Otodontidae
Reference of the original description
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
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
Cretalamna bassanii
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
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.
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];
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
A Review of the Paleobiology of Some Neogene Sharks and the Fossil Records of Extant Shark Species. Diversity, 16(3), Article 147
DOI: 10.3390/d16030147
New geographic and stratigraphic occurrences of the enigmatic extinct lamniform shark, Megalolamna (Lamniformes: Otodontidae), from the eastern USA. Historical Biology, in press
DOI: 10.1080/08912963.2023.2282664
Trophic relationships in the Early Miocene Upper Marine Molasse of Baden-Württemberg, Southwest Germany, with special emphasis on the elasmobranch fauna. Palaeontologia Electronica, 26(3), Article a46
DOI: 10.26879/1233
Feeding ecology has shaped the evolution of modern sharks. Current Biology, 31(23), 5138–5148
DOI: 10.1016/j.cub.2021.09.028
Diversity and paleoenvironmental implications of an elasmobranch assemblage from the Oligocene–Miocene boundary of Ecuador. PeerJ, 8, Article e9051
DOI: 10.7717/peerj.9051
The early Miocene elasmobranch assemblage from Zamaca (Chilcatay Formation, Peru). Journal of South American Earth Sciences, 91, 352–371
DOI: 10.1016/j.jsames.2018.08.004
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
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
A Review of the Paleobiology of Some Neogene Sharks and the Fossil Records of Extant Shark Species. Diversity, 16(3), Article 147
DOI: 10.3390/d16030147
New geographic and stratigraphic occurrences of the enigmatic extinct lamniform shark, Megalolamna (Lamniformes: Otodontidae), from the eastern USA. Historical Biology, in press
DOI: 10.1080/08912963.2023.2282664
Trophic relationships in the Early Miocene Upper Marine Molasse of Baden-Württemberg, Southwest Germany, with special emphasis on the elasmobranch fauna. Palaeontologia Electronica, 26(3), Article a46
DOI: 10.26879/1233
Feeding ecology has shaped the evolution of modern sharks. Current Biology, 31(23), 5138–5148
DOI: 10.1016/j.cub.2021.09.028
Diversity and paleoenvironmental implications of an elasmobranch assemblage from the Oligocene–Miocene boundary of Ecuador. PeerJ, 8, Article e9051
DOI: 10.7717/peerj.9051
The early Miocene elasmobranch assemblage from Zamaca (Chilcatay Formation, Peru). Journal of South American Earth Sciences, 91, 352–371
DOI: 10.1016/j.jsames.2018.08.004
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
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