Tornoceras Hyatt, 1884

Korn, Dieter & Bockwinkel, Jürgen, 2022, The tornoceratid ammonoids from the Roteisenstein Formation of Dillenburg (Cephalopoda, Ammonoidea), European Journal of Taxonomy 806, pp. 32-51 : 36

Genus Tornoceras Hyatt, 1884

Type species

Goniatites uniangularis Conrad, 1842 ; by original designation.

Diagnosis

Genus of the subfamily Tornoceratinae with compressed conch, umbilicus closed in the pre-adult stage but slightly opened in the juvenile stage. Usually without ventrolateral grooves. Growth lines biconvex, without ribs. Sutural formula E A L I; adventive lobe broadly rounded, asymmetric with steep dorsal flank.

Included species

Tornoceras aequilobum Söte, Becker, Herd & Bockwinkel, 2021 , Rhenish Mountains; Tornoceras (Tornoceras) uniangulare var. aldanense House, 1965 , New York; Tornoceras (Tornoceras) amuletum House, 1965 , New York; Tornoceras simplex Mut. angustelobata Holzapfel, 1895, Rhenish Mountains; Tornoceras (Tornoceras) arcuatum House, 1965 , Michigan; Tornoceras (Tornoceras) arkonense House, 1965 , Ontario; Goniatites Astarte Clarke, 1885 , New York; Tornoceras baldisi Leanza, 1968 , Argentina; Tornoceras Bertrandi Frech, 1902 , Montagne Noire; Tornoceras (Tornoceras) bolivianum Kullmann, 1980 , Bolivia; Tornoceras uniangulare var. compressum Clarke, 1899: 116 ; New York; Tornoceras (Tornoceras) concentricum House, 1965 , New York; Tornoceras (Tornoceras) contractum Glenister, 1958 , Western Australia; Tornoceras Edwin -Halli Clarke, 1899, New York; Tornoceras Frechi Wedekind, 1918 , Rhenish Mountains; Tornoceras fundibulum Korn, 2021 , Rhenish Mountains; Linguatornoceras holwilli House, 2002 , Devon; Goniatites Hughesii Whidborne, 1890 , Devon; Tornoceras (Tornoceras) iowaense Miller, 1938 , Iowa; Gomi -monomeroceras (Tornoceras) kielcense Sobolev, 1914, Holy Cross Mountains; Tornoceras Lewinskii Dybczynski, 1913 , Holy Cross Mountains; Tornoceras uniangulare var. obesum Clarke, 1899 , New York; Tornoceras occasus Korn, 2021 , Anti-Atlas; Tornoceras ortus Korn, 2021 , Anti-Atlas; Tornoceras postsimplicius Pajchlowa, 1972 ; Tornoceras radialis Becker, 1993 , Rhenish Mountains; Tornoceras subacutum Makowski, 1991 , Holy Cross Mountains; Gomi - monomeroceras (Tornoceras) sublentiforme Sobolev, 1914, Holy Cross Mountains; Goniatites retrorsus var. typus Sandberger & Sandberger, 1851 , Rhenish Mountains; Goniatites uniangularis Conrad, 1842 , New York; Tornoceras varicatum Grüneberg, 1925 , Rhenish Mountains; Tornoceras Verae Frech, 1902 , Montagne Noire; Tornoceras vretterense Korn, 2021 , Rhenish Mountains; Tornoceras Whidbornei Foord & Crick, 1897 , Devon; Tornoceras (Tornoceras) uniangulare var. widderi House 1965 , Ontario; Tornoceras wunderlichi Bockwinkel & Korn, 2015 , Rhenish Mountains;

Remarks

Tornoceras is a genus that has long been used as a taxon to group together most involute Late Devonian ammonoids with a simple suture line. Even after the revisions by House (1965) and Becker (1993) and their separation of a number of new genera, there is a long list of species assigned to the genus ( Korn & Klug 2002). Most of these species are morphologically very similar and a detailed description of the ontogenetic development of the conch is lacking. A revision of the genus would require a careful description of the ontogeny, suture lineage and growth lineage of the material from the different geographical regions and stratigraphic units ( Korn 2021a).