HIERARCHICAL CLASSIFICATION OF THE CLASS ACANTHODII+

EUKARYA>UNIKONTA>OPISTHOKONTA>ANIMALIA>BILATERIA>DEUTEROSTOMATA>VERTEBRATA>GNATHOSTOMATA>ACANTHODII

CLASS ACANTHODII LINKS

The following descriptions come from Benton (2005) and Nelson (2006). The structure of the following system is also based, in part, on the phylogenetic treatment by Mikko’s Phylogeny Web (from the Finnish Museum of Natural History). Taxa in red are extinct.

CLASS ACANTHODII+
- These were small fish that were lightly armored. They had numerous in-line fins (upper and lower). In addition, they had paired pectoral fins and paired rows of spines that supported fins. The scales that covered the fish were of bone and dentine and showed concentric growth rings. Generally, acanthodians were toothless, though they may have taken whole prey that were secured by back-pointed gill rakers. Most had very large eyes and may have occupied deep water.
- Upper Ordovician to the Upper Permian
- ORDER CLIMATIIFORMES
  - Dermal bone with ornamentation in shoulder region; two dorsal fins; each supported by a spine; numerous (up to 6) paired spines between pectoral and pelvic girdles. Teeth absent; or present but not fused to the jaws.
  - Mid Silurian to Pennsylvanian (North and South America, Greenland, Europe, Asia, Australia, Antarctica).
  - FAMILY CLIMATIIDAE
  - Brachycanthus, Climatius, Parexus, Vernicomacanthus.
  - FAMILY CULMACANTHIDAE
  - Culmacanthus.
  - FAMILY DIPLACANTHIDAE
  - Diplacanthus, Gladiobrachus,Uraniacanthus, Tetranopsyrus.
  - FAMILY GYRACANTHIDAE
  - Gyracanthides.
  - FAMILY EUTHACANTHIDAE
  - Euthacanthus.
  - Incertae Sedis: Nostolepis.
- ORDER ACANTHODIFORMES
  - One dorsal fin with spine; no teeth; gill rakers well developed, likely for filter-feeding; prepelvic spines absent.
  - Lower Devonian to lower Permian (North America, Europe, Asia, South Africa, Australia, Antarctica).
  - FAMILY MESACANTHIDAE
  - Mesacanthus, Melanoacanthus.
  - FAMILY CHEIRACANTHIDAE
  - Carycinacanthus, Cheiracanthus, Homalacanthus.
  - FAMILY ACANTHODIDAE
  - Acanthodes, Acanthodopsis, Howittacanthus, Traquairichthys.
- ORDER ISCHNACANTHIFORMES
  - Two dorsal fins, each with a spine; teeth firmly attached to bony jaws; no prepelvic spines.
  - Upper Silurian to Pennsylvanian (North and South America, Europe, Australia, Antarctica, Asia).
  - FAMILY ISHNACANTHIDAE
  - Atopacacanthus, Ishnacanthus, Marsdenius, Xylacanthus.
  - FAMILY PORACANTHODIDAE
  - Poracanthodes.

LITERATURE CITED

Benton, M. J. 2005. Vertebrate Paleontology. Third Edition. Blackwell Publishing, Malden, MA.

Janvier, P. 1996. Early Vertebrates. Oxford University Press, Oxford.

Nelson, J. S. 2006. Fishes of the World. 4th edition. John Wiley and Sons, Inc. New York.

Wilson, M. V. H., G. F. Hanke, and T. Märss. 2007. Paired fins of jawless vertebrates and their homologies across the “agnathan”-gnathostome transition. In: J. S. Anderson and H.-D. Suess, eds. Major Transitions in Vertebrate Evolution. Indiana University Press. Bloomington. pp. 122-149.

By Jack R. Holt. Last revised: 01/17/2013

HIERARCHICAL CLASSIFICATION OF THE CLASS ACANTHODII+

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