Iniopterygiformes ("Nape Wing Forms") is an

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

chimaera Chimaeras are cartilaginous fish in the order Chimaeriformes , known informally as ghost sharks, rat fish, spookfish, or rabbit fish; the last three names are not to be confused with rattails, Opisthoproctidae, or Siganidae, respectively. At ...

-like

cartilaginous fish Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissue ...

that lived from the

Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

periods (345–280 million years ago).

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s of them have been found in Montana, Indiana, Illinois, and Nebraska. The Iniopterygians are characterized by large pectoral fins, wing-like projections on their backs, mounted high on the body and denticulated bony plates on the head and jaws. Iniopterygian sharks were small, and their average length was about . The elongated pectoral fins had denticles along the leading edge which may have had a role in mating. They are thought to have been able to move their pectorals in a vertical plane, ”flying” through the water much like modern-day

flying fish The Exocoetidae are a family of marine fish in the order Beloniformes class Actinopterygii, known colloquially as flying fish or flying cod. About 64 species are grouped in seven to nine genera. While they cannot fly in the same way a bird do ...

. The majority of iniopterygians are placed within the family Sibyrhinchidae. Members of this family include '' Sibyrhinchus denisoni'', '' Inioptera richardsoni'', and '' Inioxyele''. Ironically, '' Iniopteryx rushlaui'', the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

, has not yet been assigned to a specific family, though some experts place it in its own monotypic family, "Iniopterygidae." The closest modern-day relatives of the Iniopterygii are the Chimaeras ( Chimaeriformes) also known as ghost sharks, rabbit fish or rat fish. These fish had several unusual features: massive skulls with huge eye sockets, shark-like teeth in rows, tails with clubs, enormous pectoral fins that were dorsalized or placed almost on their backs, and bone-like spikes or hooks on the tips of their fins. Most iniopterygians were fairly small, ranging from about in length, with the largest approaching sizes of at most.

Bibliography

* Richard Lund and Eileen D. Grogan: ''Relationships of the Chimaeriformes and the Basal Radiation of the Chondrichthyes'', Reviews in Fish Biology and Fisheries 7: 65-123. 1997 * Rainer Zangerl: ''Handbook of Paleoichthyology 3 A. Chondrichthyes I. Paleozoic Elasmobranchii.'' Gustav Fischer Verlag, New York 1981 (unveränderte Neuauflage Januar 2004) * Rainer Zangerl and Gerard Ramon Case: ''Iniopterygia: a new order of Chondrichthyan fishes from the Pennsylvanian of North America.'' Fieldiana Geology Memoirs, v. 6, Field Museum of Natural History, 197
Biodiversity Heritage Library
(Volltext, engl.) * Joseph S. Nelson: ''Fishes of the World''. John Wiley & Sons, 2006,

External links

AMNH article

Scientists snare 3-D image of oldest fossil brain
{{Taxonbar, from=Q148509 Devonian cartilaginous fish Carboniferous cartilaginous fish Prehistoric cartilaginous fish orders Late Devonian taxonomic orders Mississippian taxonomic orders Holocephali Devonian first appearances Carboniferous extinctions