Ptychodus rhombodus
Underwood & Cumbaa, 2010
Classification: Elasmobranchii incert. sedis Ptychodontidae
Reference of the original description
Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontology, 53(4), 903–944
Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontology, 53(4), 903–944
Description:
Citation: Ptychodus rhombodus Underwood & Cumbaa, 2010: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 09/2026
Description
Original diagnosis after Underwood & Cumbaa, 2010 [12632]: Teeth small and low. Strong heterodonty, symphyseal teeth quite square in occlusal view, all other teeth asymmetrical and rhombic to some degree. Dentition with many more files of small, rhombic, compressed lateral teeth than larger and more square anterior teeth. Crown low and outer part of crown flat, with small but conspicuous raised ‘cusp’ towards centre of anterior teeth, inclined to posterior in lateral teeth. Ornament continues across all of occlusal face with no clearly defined marginal area. Ornament of four to 15 subparallel ridges (typically 6–10 in lateral teeth, 8–14 in anterior teeth), rarely bifurcating other than close to edge, breaking up to tubercles at edges and often towards labial margin of larger teeth. Root low and strongly lingually inclined. Foramina below root-crown junction on all sides, especially conspicuous on labial root face.
Original diagnosis after Underwood & Cumbaa, 2010 [12632]: Teeth small and low. Strong heterodonty, symphyseal teeth quite square in occlusal view, all other teeth asymmetrical and rhombic to some degree. Dentition with many more files of small, rhombic, compressed lateral teeth than larger and more square anterior teeth. Crown low and outer part of crown flat, with small but conspicuous raised ‘cusp’ towards centre of anterior teeth, inclined to posterior in lateral teeth. Ornament continues across all of occlusal face with no clearly defined marginal area. Ornament of four to 15 subparallel ridges (typically 6–10 in lateral teeth, 8–14 in anterior teeth), rarely bifurcating other than close to edge, breaking up to tubercles at edges and often towards labial margin of larger teeth. Root low and strongly lingually inclined. Foramina below root-crown junction on all sides, especially conspicuous on labial root face.
References
Microvertebrate faunal assemblages of the Favel Formation (late Cenomanian-middle Turonian) of Manitoba, Canada. Peerj, 11, Article e15493
DOI: 10.7717/peerj.15493
Stratigraphic, Geographic, and Paleoecological Distribution of the Late Cretaceous Shark Genus Ptychodus within the Western Interior Seaway, North America. New Mexico Museum of Natural History and Science, Bulletin, 81, 1–94
A New Late Cretaceous Marine Vertebrate Assemblage from the Lincoln Limestone Member of the Greenhorn Limestone in Southeastern Colorado. Transactions of the Kansas Academy of Science, 115(3–4), 107–116
DOI: 10.1660/062.115.0303
Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontology, 53(4), 903–944
DOI: 10.1111/j.1475-4983.2010.00969.x
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
Microvertebrate faunal assemblages of the Favel Formation (late Cenomanian-middle Turonian) of Manitoba, Canada. Peerj, 11, Article e15493
DOI: 10.7717/peerj.15493
Stratigraphic, Geographic, and Paleoecological Distribution of the Late Cretaceous Shark Genus Ptychodus within the Western Interior Seaway, North America. New Mexico Museum of Natural History and Science, Bulletin, 81, 1–94
A New Late Cretaceous Marine Vertebrate Assemblage from the Lincoln Limestone Member of the Greenhorn Limestone in Southeastern Colorado. Transactions of the Kansas Academy of Science, 115(3–4), 107–116
DOI: 10.1660/062.115.0303
Chondrichthyans from a Cenomanian (Late Cretaceous) bonebed, Saskatchewan, Canada. Palaeontology, 53(4), 903–944
DOI: 10.1111/j.1475-4983.2010.00969.x
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
