Symmorium

Symmorium is an extinct symmoriiform cartilaginous fish from the Devonian and Carboniferous of the United States (Illinois)^[1][2] and Russia.^[3] The type species, Symmorium reniforme, was named by Edward Drinker Cope in 1893,^[4] with other species assigned to the genus having since been reclassified into other genera such as Petalodus. Symmorium bears close similarity in size and appearance to Stethacanthus^[5] but lacks the "spine-brush complex" in place of the first dorsal fin.^[6] Some paleontologists think that the two forms represented the males and females of related species, while other scientists think they were distinct genera.^[6][7]

Symmorium Temporal range: Devonian-Carboniferous, Famennian–Moscovian PreꞒ Ꞓ O S D C P T J K Pg N
Fossil specimen (FMNH PF 2202) of S. reniforme, Field Museum of Natural History
Life restoration of S. reniforme
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Chondrichthyes
Order:	†Symmoriiformes
Family:	†Symmoriidae
Genus:	†Symmorium Cope, 1893
Species:	†S. reniforme
Binomial name
†Symmorium reniforme Cope, 1893

Tooth assigned to Symmorium