Onchopristis is an extinct
genus of
sclerorhynchoid from the
Cretaceous of
North Africa,
Europe, and
North America. Its name is derived from the
Ancient Greekónkos (
ὄγκος, 'barb') and prístis (
πρίστις, 'saw' or 'sawfish').[2] It contains two valid species, O. numida and O. dunklei, though some researchers argue that both may be considered a single taxon with variation in morphology caused by a wide geographical range.[12] Specimens of Onchopristis have been discovered in coastal and fluvial deposits dated from the
Barremian to the
Cenomanian age,[13][1] making this genus one of the oldest and longest-lived sclerorhynchoid genera.
Description
Specimens of O. numida, IPUW 353500 and IGR 2818, suggest a length estimate of 2.94–4.25 m (9.6–13.9 ft) and 2.21–3.15 m (7.3–10.3 ft), respectively; such individuals would have weighed 70–150 kg (150–330 lb).[1] Like other sclerorhynchoids, it had a long
rostrum with large
denticles similar to
sawfishes and
sawsharks. This feature was
convergently evolved and its closest living relatives are actually
skates.[1] Isolated rostral denticles are the most common fossils of Onchopristis, but rostra,
chondrocrania, jaws, oral teeth, vertebrae, and dermal denticles have also been found.[1][14] An isolated fish vertebra, tentatively referred to Onchopristis, has been associated with the tooth alveolus of a possible specimen of Spinosaurus.[15] Similarly, the dentary fragment of Spinosaurus aegyptiacus, MPDM 31, is associated with the rostral tooth of Onchopristis.[16]
Taxonomy
Restoration of O. numida
Gigantichthys numidus was named by
Émile Haug in 1905 for fragmentary rostral denticles from the
Continental intercalaire of
Algeria. Haug also named Platyspondylus foureaui for vertebrae from the same formation.[3] Articulated specimens have confirmed that the rostral denticles and vertebrae belong to the same species.[1][14] In 1917,
Ernst Stromer named the new genus Onchopristis with "G". numidus as the type species.[2] Although the spelling "Onchopristis numidus" is commonly used, it is grammatically incorrect and has been
emended to O. numida.[17]
Oral teeth from the
Bahariya Formation of
Egypt were named Squatina aegyptiaca by Stromer in 1927, and were later renamed as the separate genus Sechmetia by Christa Werner in 1989.[10][7] Again, articulated specimens confirmed that these teeth belong to O. numida.[1][14] In 1935, Wilhelm Weiler named Peyeria libyca for what he thought were sawfish rostral denticles from the Bahariya Formation.[6] An associated specimen of Ischyrhiza mira, a close relative of Onchopristis, indicates that "Peyeria" are actually dermal denticles from O. numida.[18]
A second valid species from the
Woodbine Formation of
Texas, Onchopristis dunklei, was named by Charles McNulty, Jr. and Bob Slaughter in 1962.[4] In 1971, John Thurmond named the subspecies O. dunklei praecursor, but it is probably not distinct from O. dunklei.[11][19] Rostral denticles from
New Zealand formerly referred to "O. d. praecursor" have been reassigned to their own genus and species, Australopristis wiffeni.[20][12] An uncritical summary of 70 vertebrate taxa found in the
Aguja Formation reports the presence of O. dunklei based on two fragmentary specimens, though the authors acknowledge the skepticism regarding the
Campanian-
Maastrichtian occurrence of this genus.[21] Subsequent studies have identified these specimens as Columbusia deblieuxi.[22][23]
References
^
abcdefgVillalobos-Segura, E.; Kriwet, J.; Vullo, R.; Stumpf, S.; Ward, D.J.; Underwood, C.J. (2021). "The skeletal remains of the euryhaline sclerorhynchoid †Onchopristis (Elasmobranchii) from the 'Mid'-Cretaceous and their palaeontological implications". Zoological Journal of the Linnean Society. 193 (2): 746–771.
doi:
10.1093/zoolinnean/zlaa166.
^
abMcNulty, C.L. Jr.; Slaughter, B.H. (1962). "A new sawfish from the Woodbine Formation (Cretaceous) of Texas". Copeia. 1962 (4): 775–777.
doi:
10.2307/1440678.
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^
abWerner, C. (1989). "Die Elasmobranchier-Fauna des Gebel Dist Member der Bahariya Formation (Obercenoman) der Oase Bahariya, Ägypten". Palaeo Ichthyologica. 5: 1–112.
^
abMartill, D.M.; Ibrahim, N. (2012). "Aberrant rostral teeth of the sawfish Onchopristis numidus from the Kem Kem beds (?early Late Cretaceous) of Morocco and a reappraisal of Onchopristis in New Zealand". Journal of African Earth Sciences. 64: 71–76.
Bibcode:
2012JAfES..64...71M.
doi:
10.1016/j.jafrearsci.2011.11.009.
^dal Sasso, C.; Maganuco, S.; Buffetaut, E.; Mendez, M.A. (2005). "New information on the skull of the enigmatic theropod Spinosaurus, with remarks on its sizes and affinities". Journal of Vertebrate Paleontology. 25 (4): 888–896.
doi:
10.1671/0272-4634(2005)025[0888:NIOTSO]2.0.CO;2.
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^Greenfield, T. (2021). "Corrections to the nomenclature of sawskates (Rajiformes, Sclerorhynchoidei)". Bionomina. 22 (1): 39–41.
doi:
10.11646/bionomina.22.1.3.
S2CID239067365.
^Sternes, P.C.; Shimada, K. (2019). "Paleobiology of the Late Cretaceous sclerorhynchid sawfish, Ischyrhiza mira (Elasmobranchii: Rajiformes), from North America based on new anatomical data". Historical Biology. 31 (10): 1323–1340.
doi:
10.1080/08912963.2018.1452205.
S2CID90291295.
^Rowe, T.; Cifelli, R.L.; Lehman, T.M.; Weil, A. (1992). "The Campanian Terlingua local fauna, with a summary of other vertebrates from the Aguja Formation, Trans-Pecos Texas". Journal of Vertebrate Paleontology. 12 (4): 472–493.
Bibcode:
1992JVPal..12..472R.
doi:
10.1080/02724634.1992.10011475.
^Kirkland, J.I.; Eaton, J.G.; Brinkman, D.B. (2013). "Elasmobranchs from Upper Cretaceous freshwater facies in southern Utah". In Titus, A.L.; Loewen, M.A. (eds.). At the Top of the Grand Staircase, the Late Cretaceous of Southern Utah. Bloomington: Indiana University Press. pp. 153–194.
ISBN978-0253008831.
^Schubert, J.A.; Wick, S.L.; Lehman, T.M. (2017). "An Upper Cretaceous (middle Campanian) marine chondrichthyan and osteichthyan fauna from the Rattlesnake Mountain sandstone member of the Aguja Formation in West Texas". Cretaceous Research. 69: 6–33.
Bibcode:
2017CrRes..69....6S.
doi:
10.1016/j.cretres.2016.08.008.
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