''Holoptychius'' (from el, όλος , 'whole' and el, πτυχή 'fold') 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 ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

porolepiform Porolepiformes is an Order (biology), order of prehistoric lobe-finned fish which lived during the Devonian geological period, period (about 416 to 359 million years ago). The group contains two family (biology), families: Holoptychiidae and Poro ...

lobe-finned fish from the Middle Devonian to

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 ...

( Mississippian) periods. It is known from fossils worldwide. The genus was first described by

Louis Agassiz Jean Louis Rodolphe Agassiz ( ; ) FRS (For) FRSE (May 28, 1807 – December 14, 1873) was a Swiss-born American biologist and geologist who is recognized as a scholar of Earth's natural history. Spending his early life in Switzerland, he rec ...

in 1839.

Description

''Holoptychius'' was a streamlined predator about long (though largest specimen could grew up to ), which fed on other

bony fish Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartilag ...

. Its rounded scales and body form indicate that it could have swum quickly through the water to catch prey. Similar to other

rhipidistia Rhipidistia, also known as Dipnotetrapodomorpha, is a clade of lobe-finned fishes which includes the tetrapods and lungfishes. Rhipidistia formerly referred to a subgroup of Sarcopterygii consisting of the Porolepiformes and Osteolepiformes, a d ...

ns, it had fang-like

teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

on its palate in addition to smaller teeth on the jaws. Its asymmetrical tail sported a

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

on its lower end. To compensate for the downward push caused by this fin placement, the

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

s of ''Holoptychius'' were placed high on the body.

Species

Of the genus ''Holoptychius'' the following species have been described:Species ''Holoptychius''
/ref> * ''H. americanus'' * ''H. andersoni'' * ''H. bergmanni'' (Downs et al, 2013) from the

Frasnian The Frasnian is one of two faunal stages in the Late Devonian Period. It lasted from million years ago to million years ago. It was preceded by the Givetian Stage and followed by the Famennian Stage. Major reef-building was under way during th ...

-aged

Fram Formation The Fram Formation is an Upper Devonian (Frasnian) sequence of rock strata on Ellesmere Island that came into prominence in 2006 with the discovery in its rocks of examples of the transitional fossil, ''Tiktaalik'', a sarcopterygian or lobe-finne ...

Ellesmere Island Ellesmere Island ( iu, script=Latn, Umingmak Nuna, lit=land of muskoxen; french: île d'Ellesmere) is Canada's northernmost and List of Canadian islands by area, third largest island, and the List of islands by area, tenth largest in the world. ...

, Arctic CanadaDowns, Jason P.; Daeschler, Edward B.; Jenkins, Farish A.; Shubin, Neil H. (2013-03).
Holoptychius bergmannisp. nov. (Sarcopterygii, Porolepiformes) from the Upper Devonian of Nunavut, Canada, and a Review ofHoloptychiusTaxonomy
. Proceedings of the Academy of Natural Sciences of Philadelphia. 162 (1): 47–59. doi:10.1635/053.162.0104. ISSN 0097-3157. * ''H. flemingi'' * ''H. giganteus'' * ''H. halli'' * ''H. hopkinsii'' * ''H. nobilissimus'' * ''H. quebecensis'' * ''H''. sp. indet. from the Kennebecasis Formation of New Brunswich,

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. * ''H.'' sp. indet. from the

Cuche Formation The Cuche Formation ( es, Formación Cuche, Cc) is a geological formation of the Floresta Massif, Altiplano Cundiboyacense in the Eastern Ranges of the Colombian Andes. The sequence of siltstones, shales, and sandstone beds dates to the Late Devo ...

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

, known from an isolated tooth (UN-DG-PALV86) and preserved scales (UN-DG-PALV50-51).

Distribution

Fossils of ''Holoptychius'' have been found in the Mississippian of the United Kingdom and the Devonian of Belgium, Colombia (

, Boyacá),Janvier & Villarroel, 1998 Norway, Canada, the Russian Federation, and the United States (Pennsylvania).''Holoptychius''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org

Gallery

File:Holoptychius andersoni.jpg, ''H. andersoni'' File:Holoptychius sp. 2.jpg, Life restoration of ''Holoptychius'' sp. File:Holoptychius nobilissimus.jpg, ''H. nobilissimus'' and scale

References

Bibliography

* Porolepiformes Late Devonian fish Carboniferous fish Devonian fish of Europe Devonian fish of North America Prehistoric fish of South America Devonian animals of South America Devonian Colombia Fossils of Colombia Fossil taxa described in 1839 Taxa named by Louis Agassiz {{paleo-lobefinned-fish-stub