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Pentanogmius (Bananogmius) evolutus


Copyright © 2007-2012 by Mike Everhart

Page created  05/29/2007 - Updated 05/21/2012





LEFT: Painting of Pentanogmius evolutus adapted from an original work (Plate 30) by Deb Bennett (1983) as published in Kansas Geology, Rex Buchanan (ed.), University of Kansas Press, 1983.


Pentanogmius (Bananogmius) evolutus is featured in the National Geographic IMAX movie, Sea Monsters CLICK HERE


Pentanogmius evolutus (Cope) is one a diverse family of plethodids from the Western Interior Sea ( Late Cretaceous) of Kansas. The remains of plethodids are a fairly common in the Smoky Hill Chalk. The family Plethodidae includes the genera: Pentanogmius (originally "Anogmius" evolutus, then Bananogmius), Ferrifrons, Niobrara, Zanclites, Luxilites, Syntegmodus, Bananogmius, Martinichthys, Thryptodus, and Plethodus. The species "Bananogmius evolutus" was removed from the genus Bananogmius and renamed Pentanogmius evolutus by Taverne (2001).

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Pentanogmius was a medium to large sized fish (4 to 6+ feet) with a narrow, but deep body (somewhat like a modern Angel fish) and jaws that had small, comb-like teeth. Most of the skeleton was bone and preserves well. A commonly found fossil is the palatine bone from the roof of the mouth. These have a pebbled surface that served as the base for hundreds of small, sharp teeth.


E.D. Cope originally named the genus "Anogmius" in 1877, but that genus name had already been used (e.g. pre-occupied).


LEFT: DMNS 57159 - A large and nearly complete Pentanogmius evolutus (Cope) in the Denver Museum that was discovered by Chuck Bonner near Monument Rocks in the Smoky Hill Chalk of western Kansas. The tail is reconstructed.

DMNS 57159-01a.jpg (28934 bytes) LEFT: DMNS 57159 is probably the best preserved, most complete example known of Pentanogmius evolutus. Shown here in right lateral view.  See more photos on the Keystone Gallery site

RIGHT: The skull of DMNS 57159 in right lateral view.

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LEFT: A close up of the dorsal fin (sail) of DMNS 57159, showing some of the scales preserved with the specimen.

RIGHT: A close-up of the jaws of DMNS 57159 showing the hundreds of tiny teeth that covered the jaw plates.

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LEFT: The exhibit specimen of Bananogmius (Pentanogmius) evolutus (FHSM VP-2182) in the collection of the Sternberg Museum. Although not fully displayed in this photograph of the reconstruction, the fish had a large, sail-like dorsal fin.  Detail of the anterior portion of the specimen, including scales is shown here.

LEFT: Bananogmius (Pentanogmius) evolutus  FHSM VP-2117) from the Smoky Hill Chalk in the collection of the Sternberg Museum of Natural History. Collected by Marion Bonner. The caudal fin (tail) is reconstructed. A close up view of the skull is HERE. A view of the teeth on the lower jaw of another specimen is HERE.

VP-2117Ga.jpg (19324 bytes) LEFT: The oddly crushed skull of FHSM VP-2117.

RIGHT: Close-up of one of the tooth bearing elements (left lower jaw?) of FHSM VP-2117 (note that teeth are missing).

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KUVP27815a.jpg (20632 bytes) LEFT: The skull of a large Bananogmius (Pentanogmius?) evolutus - KUVP 27815 in left lateral view collected from the Pierre Shale in 1971 by the Orville Bonner party.  

RIGHT: The type specimen of Bananogmius ellisensis, preserved uncrushed in an ironstone concretion from the Blue Hill Shale Member of the Carlile Shale, Ellis County, Kansas (Middle Turonian in age).

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KUVP 445Ca.jpg (39104 bytes) LEFT: KUVP 445 - Right lateral view of a large Bananogmius (Pentanogmius?) specimen collected from a concretion in the Fairport Chalk Member (Middle Turonian) of the Carlile Shale, Russell County, KS. A detailed view of the skull is here.
The most recent discovery (2012) of a reasonably complete specimen of Pentanogmius evolutus was made in the upper chalk of western Logan County by Fred Ackerman. Unfortunately the held of the fish was already eroded out and mostly destroyed, and the tail was missing. The specimen would have measured almost 4 feet long if complete and the dorsal fin (sail) extended 20 inches above the vertebral column. 

LEFT: Headless and tailless, the specimen preserves a nearly complete dorsal fin.

RIGHT: This close-up of the dorsal fin shows two large scales (circled).


Plethodid fossils: The most common plethodid fossils collected in the Smoky Hill Chalk are the parasphenoid bones... a flat, roughly rectangular bone on the roof of the mouth that is has hundreds of small pits.... These pits held small teeth when the fish was alive.


LEFT: The parasphenoid of a large plethodid fish in ventral (top) and dorsal views.  In life, each of the tiny pits would have held a small tooth that helped keep small prey from escaping from the fish's mouth.

RIGHT: Fragments of a plethodid parasphenoid bone.

LEFT: A fragment of a plethodid parasphenoid bone showing the distinctive pitted oral (occlusal) surface.

RIGHT: The fragmented skull of a plethodid - Pentanogmius evolutus. Note that the jaw fragments show the same pitted texture as the parasphenoid...and in fact have the same kind of villiform teeth....




Other Oceans of Kansas webpages on Late Cretaceous fish:


Field Guide to Sharks and Bony Fish of the Smoky Hill Chalk



Kansas Shark Teeth

Cretoxyrhina and Squalicorax




Bony Fish


Pycnodonts and Hadrodus












Saurodon and Saurocephalus


Suggested references:

Cope, E. D. 1877. On some new or little known reptiles and fishes of the Cretaceous No. 3 of Kansas. Proceedings of the American Philosophical Society 17(100): 176-181. (Anogmius and Stratodus)

Fielitz, C. and K. Shimada, 1999. A new species of Bananogmius (Teleostei; Tselfatiformes) from the Upper Cretaceous Carlile Shale of western Kansas. Journal of Paleontology 73(3): 504-511.

Loomis, F. B. 1900. Die anatomie und die verwandtschaft der Ganoid- und Knochen-fische aus der Kreide-Formation von Kansas, U.S.A. Palaeontographica, 46: 213-283.

Taverne, L. 2001. Révision du genre Bananogmius (Teleostei, Tselfatiiformes), poisson marin du Crétecé supérior d'Amérique du Nord et d'Europe. Geodiversitas 23(1):17-40. (Revision of the genus Bananogmius (Teleostei, Tselfatiiformes), marine fish from the Upper Cretaceous of North America and Europe).

Taverne, L. 2003. Redescription critique des genres Thryptodus, Pseudothryptodus et Paranogmius, poissons marins (Telostei, Tselfatiiformes) du Crétecé supérior des Etats-Unis d’ Egypte et de Libye. Belgian Journal of Zoology 133(2):163-173.