Semionotiformes

Semionotiformes is an order of ray-finned fish known from the Middle Triassic (Anisian) to the Late Cretaceous (Maastrichtian). Their closest living relatives are gars (Lepisosteidae), with both groups belonging to the clade Ginglymodi within the Holostei. The group includes both freshwater (Semionotidae) and marine (Callipurbeckiidae, Macrosemiidae) adapted forms. Many members of the family Macrosemiidae (which are usually included in Semionotiformes but sometimes placed in their order), had elongated dorsal fins, often associated with an adjacent area of skin which was free of scales. These fins were likely undulated for use in precision swimming. The body morphology of macrosemiids suggests that they were slow swimmers who were capable of maneuvering around complex topography, such as reef environments.

Classification

• Order †Semionotiformes <small>Arambourg & Bertin 1958 sensu López-Arbarello 2012</small>
• Genus ?†Orthurus <small>Kner 1866</small>
• Genus †Sangiorgioichthys <small>Tintori & Lombardo 2007</small>
• Genus †Luoxiongichthys <small>Wen et al. 2011</small>
• Genus †Aphanepygus <small>Bassani 1879</small>
• Genus †Austrolepidotes <small>Bocchino, 1974</small>
• Genus †Corunegenys <small>Wade, 1942</small>
• Genus †Placidichthys <small>Brito 2000</small>
• Family ?†Hadrodontidae <small>Thurmond and Jones, 1981</small> (alternately considered a pycnodont)
• Genus ?†Hadrodus <small>Leidy, 1857</small> (alternately considered a pycnodont)
• Family †Pleurolepididae <small>Lütken 1871</small>
• Genus †Pleurolepis <small>Agassiz 1863 non Quenstedt 1852</small>
• Family †Macrosemiidae <small>Wagner 1860a corrig. Cope 1889 sensu Murray & Wilson 2009</small> [Macrosemii <small>Wagner 1860a</small>]
• Genus †Eusemius <small>Vetter 1881</small>
• Genus †Blenniomoeus <small>Costa 1850</small> [Calignathus <small>Costa 1853</small>]
• Genus †Enchelyolepis <small>Woodward 1918</small>
• Genus †Palaeomacrosemius <small>Ebert, Lane & Kolbl-Ebert 2016</small>
• Genus †Voelklichthys <small>Arratia & Schultze 2012</small>
• Genus †Notagogus <small>Agassiz 1833-1844</small> [Neonotagogus <small>Bravi 1994</small>]
• Genus †Agoultichthys <small>Murray & Wilson 2009</small>
• Genus †Histionotus <small>Egerton 1854</small>
• Genus †Propterus <small>Agassiz 1833-1844</small> [Rhynchoncodes <small>Costa 1850</small>]
• Genus †Macrosemiocotzus <small>González-Rodríguez, Applegate & Espinosa-Arrubarrena 2004</small>
• Genus †Legnonotus <small>Egerton 1853</small>
• Genus †Macrosemius <small>Agassiz 1833-1844</small>
• Family †Semionotidae <small>Woodward 1890 sensu López-Arbarello 2012</small>
• Genus †Semionotus <small>Agassiz 1832</small> (Usually considered a wastebasket taxon)
• Genus †Sargodon <small>Plieninger 1847</small>
• Family †Callipurbeckiidae <small>López-Arbarello 2012</small> [Paralepidotidae <small>Hadding 1919 ex Lund 1920</small>]
• Genus †Occitanichthys <small>López-Arbarello & Wencker 2016</small>
• Genus †Semiolepis <small>Lombardo & Tintori 2008</small>
• Genus †Paralepidotus <small>Stolley 1919</small>
• Genus †Macrosemimimus <small>Schröder, López-Arbarello & Ebert 2012</small>
• Genus †Tlayuamichin <small>López-Arbarello & Alvarado-Ortega 2011</small>
• Genus †Callipurbeckia <small>López-Arbarello 2012</small>

Timeline of genera

References