''Petalodus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of cartilaginous fish from the Pennsylvanian to the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last ...

,Fossils (Smithsonian Handbooks) by David Ward (Page 198) known from subtriangular to rhomboidal teeth. The genus was named by Richard Owen in 1840 and the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specime ...

is ''Petalodus hastingsii''.Report on the Geology of the County of Londonderry, and of Parts of Tyrone and Fermanagh. Memoirs of the Geological Survey of the United Kingdom, district mem. Geol. Surv. Ireland, Dublin, xxxi + 784 pp., A. Milliken, 1843, 784ppPetalodus hastingsii OWEN, 1840: In: Database of fossil elasmobranch teeth www.shark-references.com, World Wide Web electronic publication, Version 07/2020 Case 3779 – Petalodus Owen, 1840 (Chondrichthyes, Petalodontiformes, Petalodontidae): proposed conservation of usage by designation of a neotype for its type species ''Petalodus hastingsii'' Owen, 1840. Bulletin of Zoological Nomenclature, 75: 241-246A synopsis of the classification of the British Palæozoic rocks, with a systematic description of the British Palæozoic fossils in the Geological museum of the

University of Cambridge The University of Cambridge is a public collegiate research university in Cambridge, England. Founded in 1209 and granted a royal charter by Henry III in 1231, Cambridge is the world's third oldest surviving university and one of its most pr ...

. In: Sedgwick, A. (ed), A synopsis of the classification of the British Palæozoic rocks, London :J.W. Parker and Son; tc.1855. The only

dubious Doubt is a mental state in which the mind remains suspended between two or more contradictory propositions, unable to be certain of any of them. Doubt on an emotional level is indecision between belief and disbelief. It may involve uncertainty ...

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

within this genus is ''P. securiger''.Handbook of Paleoichthyology, Vol. 3D: Chondrichthyes Paleozoic Elasmobranchii: Teeth Verlag Dr. Friedrich Pfeil, pp. 168, 154 fig., 4 Tab.

Sources

Petalodontiformes Carboniferous fish of Asia Permian fish of Asia Paleozoic fish of Europe Fossil taxa described in 1840 {{paleo-cartilaginous-fish-stub