Edited by oilshale
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Allenypterus montanus Melton, 1969
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By oilshale (edited)
Taxonomy
Coelacanth
Kingdom: Animalia
Phylum: Chordata
Class: Sarcopterygii Romer 1955
Order: Coelacanthiformes
Family: Hadronectoridae Lund and Lund 1984
Genus: Allenypterus
Species: Allenypterus montanus
Author Citation Melton, 1969
Geological Time Scale
Eon: Phanerozoic
Era: Paleozoic
Period: Carboniferous
Sub Period: Mississippian
Epoch: Late
International Age: Serpukhovian
Stratigraphy
Big Snowy Group
Heath Formation
Provenance
Acquired by: Purchase/Trade
Dimensions
Length: 25 cm
Location
Bear Gulch
Fergus County
Montana
United States
Comments
Allenypterus montanus was first described by Melton as a Dorypterid; in 1977 this fish was recognized by Lund as a Coelacanth.Taken from "Fossil Fishes of Bear Gulch" by Lund, Richard, and Grogan, E.D., 2005, Bear Gulch web site, www.sju.edu/research/bear_gulch, 1/11/2016 (last update from 2/1/2006):
Allenypterus montanus is a coelacanth of relatively primitive skull osteology but with a unique, teardrop-shaped body form. They range in size from about 25 mm (1 inch) to 150 mm (6 1/4 inches) in length.Like other coelacanths, Allenypterus had a complete covering of thin, rounded, overlapping scales, and webbed fins with few, widely spaced rays. No teeth, thick lips, and a very small gape of the mouth show that this fish was a suction feeder on small prey. The body is very high relative to length. The paired fins are large with delicate webbing. The paired fins, second dorsal and anal fins are supported on long muscular lobes by segmental bony axes that are covered with fine rounded scales. There is a long, continuous dorsal lobe of the webbed caudal fin. The combination of all these fins, webs, and lobes indicates a superb maneuverer in weedy, sheltered environments but a fish that could not outswim any predator. It is noteworthy that the belly was armored, suggesting that Allenypterus may have swam and fed on and close to the bottom.
The body form of Allenypterus is unique among known coelacanths — all others differ subtly only in proportions. The skull of Allenypterus is among the most primitive coelacanth skulls known.
Line drawing from Lund & Lund 1985, p.242:
References:Melton, W. G. 1969. A new dorypterid fish from central Montana. Northwest Science 43:196-206
Glickman W. L. 1977: Allenypterus montanus (Crossopterygii: Coelacanthiformes) from the Bear Gulch Limestone of Montana. Adelphy University, 1977.
Lund, R. & Lund, W. 1984: New genera and species of coelacanths from the Bear Gulch Limestone (Lower Carboniferous) of Montana (U.S.A.) Geobios, Volume 17, issue 2, p. 237-244.
Lund, R., and W.L. Lund, 1985. "Coelacanths from the Bear Gulch Limestone (Namurian) of Montana and the evolution of the Coelacanthiformes." Bull. Carnegie Mus. Nat. Hist. 25: 1-74.
Lund, W. L., R. Lund and G. Klein, 1985. "Coelacanth feeding mechanisms and the ecology of the Bear Gulch coelacanths." Compte Rendu, Neuvième Congrès International de Stratigraphie et de Géologie du Carbonifère, 5: 492-500.
Friedman, M. & Coates, M. 2006: A newly recognized fossil coelacanth highlights the early morphological diversification of the clade Proc. R. Soc. B (2006) 273, 245–250.
Hagadorn, J.: Bear Gulch: An Exceptional Upper Carboniferous Plattenkalk
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