Symmorium

Symmorium
Temporal range: Devonian-Carboniferous, Famennian–Moscovian
Fossil specimen (FMNH PF 2202) of S. reniforme, Field Museum of Natural History
Life restoration of S. reniforme
Scientific classification Edit this classification
Domain: Eukaryota
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

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]

  1. ^ E. D. Cope. 1894. New and little known Paleozoic and Mesozoic fishes. Journal of the Academy of Natural Sciences Philadelphia (Series 2) 9:427-448
  2. ^ M. E. Williams. 1985. The "Cladodont level" sharks of the Pennsylvanian black shales of central North America. Palaeontographica Abteilung A 190:83-158
  3. ^ A. Ivanov. 1999. Late Devonian - Early Permian chondrichthyans of the Russian Arctic. Acta Palaeontologica Polonica 49(3):267-285
  4. ^ E. D. Cope. 1893. On Symmorium, and the position of cladodont sharks. American Naturalist 27:999-1001
  5. ^ "Hierarchical Taxonomy of the Class Chondrichthyes". comenius.susqu.edu. Archived from the original on 27 September 2007. Retrieved 12 January 2022.
  6. ^ a b M. Ginter, O. Hampe, and C. J. Duffin. 2010. Chondrichthyes, Paleozoic Elasmobranchii: Teeth. In H.P. Schultze (ed.), Handbook of Paleoichthyology 3D:1-168
  7. ^ Coates, Michael I.; Gess, Robert W.; Finarelli, John A.; Criswell, Katharine E.; Tietjen, Kristen (2017). "A symmoriiform chondrichthyan braincase and the origin of chimaeroid fishes". Nature. 541 (7636): 208–211. Bibcode:2017Natur.541..208C. doi:10.1038/nature20806. ISSN 0028-0836. PMID 28052054. S2CID 4455946.