''Onchopristis'' is an extinct

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 ...

of sclerorhynchoid from the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

North Africa North Africa, or Northern Africa is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region, and it is sometimes defined as stretching from the Atlantic shores of Mauritania in ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

, and

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. Its name is derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''ónkos'' ( ὄγκος, 'barb') and ''prístis'' ( πρίστις, 'saw' or 'sawfish'). It contains two valid species, ''O. numida'' and ''O. dunklei''. ''Onchopristis'' first appeared in the

Barremian The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 129.4 ± 1.5 Ma (million years ago) and 121.4 ± 1.0 Ma). It is a subdivision of the Early Cretaceous Epoch (or Lower Cretaceous Series). It is precede ...

and its latest occurrence dates to the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous Epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campanian s ...

, making it one of the oldest and longest-lived sclerorhynchoid genera.

Description

Specimens of ''O. numida'', IPUW 353500 and IGR 2818, suggest a length estimate of and , respectively; such individuals would have weighed . Like other sclerorhynchoids, it had a long

rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * Ros ...

with large denticles similar to sawfishes and sawsharks. This feature was

convergently evolved Convergent evolution is the independent evolution of similar features in species of different periods or epochs in time. Convergent evolution creates analogous structures that have similar form or function but were not present in the last com ...

and its closest living relatives are actually skates. Isolated rostral denticles are the most common fossils of ''Onchopristis'', but rostra, chondrocrania, jaws, oral teeth, vertebrae, and dermal denticles have also been found.

Taxonomy

'' Gigantichthys numidus'' was named by

Émile Haug Gustave Émile Haug (19 June 1861 - 28 August 1927) was a French geologist and paleontologist known for his contribution to the geosyncline theory. Career Émile Haug was born on 19 June 1861. In 1884 he received his doctorate in natural scie ...

in 1905 for fragmentary rostral denticles from the

Continental intercalaire The Continental intercalaire, sometimes referred to as the Continental intercalaire Formation, is a term applied to Cretaceous strata in Northern Africa. It is the largest single stratum found in Africa to date, being between thick in some places. ...

Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , relig ...

. Haug also named ''Platyspondylus foureaui'' for vertebrae from the same formation. Articulated specimens have confirmed that the rostral denticles and vertebrae belong to the same species. In 1917,

Ernst Stromer Ernst Freiherr Stromer von Reichenbach (12 June 1871 in Nürnberg – 18 December 1952 in Erlangen) was a German paleontologist. He is best remembered for his expedition to Egypt, during which the first known remains of ''Spinosaurus'' we ...

named the new genus ''Onchopristis'' with "''G''". ''numidus'' as the type species. Although the spelling "''Onchopristis numidus''" is commonly used, it is grammatically incorrect and has been emended to ''O. numida''. Oral teeth from the

Bahariya Formation The Bahariya Formation (also transcribed as Baharija Formation) is a fossiliferous geologic formation dating back to the early Cenomanian, which outcrops within the Bahariya depression in Egypt, and is known from oil exploration drilling across ...

Egypt Egypt ( ar, مصر , ), officially the Arab Republic of Egypt, is a transcontinental country spanning the northeast corner of Africa and southwest corner of Asia via a land bridge formed by the Sinai Peninsula. It is bordered by the Mediter ...

were named '' Squatina aegyptiaca'' by Stromer in 1927, and were later renamed as the separate genus ''Sechmetia'' by Christa Werner in 1989. Again, articulated specimens confirmed that these teeth belong to ''O. numida''. In 1935, Wilhelm Weiler named ''Peyeria libyca'' for what he thought were sawfish rostral denticles from the Bahariya Formation. An associated specimen of '' Ischyrhiza mira'', a close relative of ''Onchopristis'', indicates that "''Peyeria''" are actually dermal denticles from ''O. numida''. A second valid species from the

Woodbine Formation The Woodbine Group is a geological formation in east Texas whose strata date back to the Early to Middle Cenomanian age of the Late Cretaceous. It is the producing formation of the giant East Texas Oil Field (also known as the "Black Giant") fr ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

, ''Onchopristis dunklei'', was named by Charles McNulty, Jr. and Bob Slaughter in 1962. In 1971, John Thurmond named the subspecies ''O. dunklei praecursor'', but it is probably not distinct from ''O. dunklei''. Rostral denticles from

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

formerly referred to "''O. d. praecursor''" have been reassigned to their own genus and species, '' Australopristis wiffeni''.

References

Prehistoric cartilaginous fish genera Cretaceous cartilaginous fish Prehistoric fish of Africa Sclerorhynchoidei {{paleo-cartilaginous-fish-stub