Synonyms: Cestracion duponti, Dasyatis duponti, Raja aff. duponti, Raja cf. duponti, Raja duponti
Original description species: (Winkler, 1874)
Genus: Jacquhermania Cappetta, 1982
Family: Gymnuridae Fowler, 1934
Order: Myliobatiformes
Superorder: Batomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Carcharias robustus africanus, Hypotodus africanus, Odontaspis robusta africana, Odontaspis robustus africanus, Odontaspis (Synodontaspis) robusta africana
Original description species: (Arambourg, 1952)
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Otero, Oyarzún, & Soto-Acuña, Yury-Yáñez, Gutierrez, Le Roux, Torres & Hervé, 2014
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Glikman, 1964
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Carcharodon cavidens, Otodus cavidens
Original description species: (Neugeboren, 1850)
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Jaekelotodus jaekelii
Original description species: Zhelezko, 1994
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: (Glikman, 1964)
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Jaekelotodus londonensis londonensis
Original description species: Zhelezko, 1994
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Jaekelotodus minor minor
Original description species: Glikman, 1964
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Carcharias robustus, Hypotodus robustus, Jaekelotodus cf. robustus, Odontaspis robusta, Odontaspis (Synodontaspis) robusta, Synodontaspis robusta
Original description species: (Leriche, 1922)
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Odontaspis speyeri, Odontaspis (Odontaspis) speyeri, Palaeohypotodus speyeri
Original description species: (Darteville & Casier, 1943)
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Hypotodus triangonalis, Hypotodus trigonalis, Iekelotodus trigonalis, Jaekelotodus cf. trigonalis, Odontaspis cf. trigonalis, Odontaspis trigonalis, Odontaspis (Odontaspis) trigonalis, Odontaspis (Synodontaspis) cf. trigonalis, Odontaspis (Synodontaspis) trigonalis, Otodus trigonalis
Original description species: (Jaekel, 1895)
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Zhelezko in Zhelezko & Kozlov, 1999
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Zhelezko in Zhelezko & Kozlov, 1999
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Glikman, 1964
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Glikman, 1964
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Glikman, 1964
Genus: Jaekelotodus Menner, 1928
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Phoebodus australiensis
Original description species: (Long, 1990)
Genus: Jalodus Ginter, 1999
Family: Jalodontidae Ginter, Hairapetian & Klug, 2002
Order: Jalodontiformes
Subclass: Elasmobranchii

Original description species: Branson, 1916
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Acrodus larva, Byzenos latipinnatus, Dictaea striata, Dictea striata, Janassa angulata, Janassa dictea, Janassa humboldii, Janassa humboldtii, Trilobites bituminosa
Original description species: (Schlotheim, 1820)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Climaxodus brevis
Original description species: (Newberry, 1856)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Janassa cf. clarki
Original description species: Lund, 1989
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Chomatodus clavatus, Chomatodus truncatus, Chomatodus (Petalodus) truncatus
Original description species: M'Coy, 1855
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Thoracodus emydinus
Original description species: (Cope, 1883)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Strigilina gurleiana
Original description species: (Cope, 1877)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Climaxodus imbricatus, Janassa ordiana
Original description species: (M'Coy, 1848)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Original description species: Nielsen, 1932
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Ctenoptychius korni
Original description species: (Weigelt, 1930)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Climaxodus linguaeformis, Climaxodus oratus, Climaxodus vermiformis, Janassa minutus, Janassa processus
Original description species: (Atthey, 1868)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Original description species: Eastman, 1903
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Cymatodus oblongus
Original description species: (Newberry & Worthen, 1870)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Synonyms: Strigilina linguaformis
Original description species: (Cope, 1881)
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Original description species: Eastman, 1903
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Original description species: Eastman, 1903
Genus: Janassa Münster, 1839
Family: Janassidae Jaekel, 1899
Order: Petalodontiformes
Subclass: Euchondrocephali

Original description species: Klug, Tütken, Wings, Pfretzschner & Martin, 2010
Genus: Jiaodontus Klug, Tütken, Wings, Pfretzschner & Martin, 2010
Family: Lonchidiidae Herman, 1977
Superfamily: Hybodontoidea
Order: Hybodontiformes
Cohort: Euselachii
Subclass: Elasmobranchii

Genus: Jiaodontus Klug, Tütken, Wings, Pfretzschner & Martin, 2010
Family: Lonchidiidae Herman, 1977
Superfamily: Hybodontoidea
Order: Hybodontiformes
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Klug, Tütken, Wings, Pfretzschner & Martin, 2010
Genus: Jiaodontus Klug, Tütken, Wings, Pfretzschner & Martin, 2010
Family: Lonchidiidae Herman, 1977
Superfamily: Hybodontoidea
Order: Hybodontiformes
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: Zangerl, 1979
Genus: Jimpohlia Zangerl, 1979
Family: incert. fam.
Subclass: Subterbranchialia

Original description species: Siverson, 1996
Genus: Johnlongia Siverson, 1996
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Synonyms: Johnlongia cf. parvidens, Odontaspis parvidens
Original description species: (Cappetta, 1973)
Genus: Johnlongia Siverson, 1996
Family: Odontaspididae Müller & Henle, 1839
Order: Lamniformes
Superorder: Galeomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii

Original description species: (Brotzen, 1934)
Genus: Jolepis Burrow & Turner, 2018
Family: incert. fam.
Order: incert. sedis
Subclass: Elasmobranchii

Original description species: Roelofs, Konigshof, Trinajstic & Munkhjargal, 2021
Genus: Junggarensis Roelofs, Konigshof, Trinajstic & Munkhjargal, 2021
Family: incert. fam.
Order: Ctenacanthiformes
Superorder: Cladodontomorphi
Subclass: Elasmobranchii

Original description species: Thies, 1982
Genus: Jurobatos Thies, 1983
Family: Rhinobatidae Bonaparte, 1835
Order: Rhinopristiformes
Superorder: Batomorphii
Subcohort: Neoselachii
Cohort: Euselachii
Subclass: Elasmobranchii