Captorhinus
Captorhinus | |
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Two C. aguti specimens, Cisuralian (299-270 Ma), Oklahoma, United States | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Family: | †Captorhinidae |
Genus: | †Captorhinus Cope, 1895 |
Type species | |
†Captorhinus aguti Cope, 1895
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Synonyms | |
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Captorhinus (from
Description
While there are several forms of Captorhinus, there are three main species that are the best known. The previously mentioned Captorhinus aguti is the type species of Captorhinus, but there is also a fair amount of material collected on Captorhinus magnus and Captorhinus laticeps.[2]
The most distinguishable trait of Captorhinus is its namesake: the hooking of the snout from prominent ventral angulation of the premaxillary process. Other notable characteristics include the dorsally positioned alary process of the jugal on the medial surface and flushed with the orbital margin, the retroarticular process longer anteroposteriorly than broad, and the anteriormost dentary tooth strongly procumbent. The posterior teeth are either chisel-shaped or ogival. Until the late 1990s, Captorhinus was diagnosed by the presence of multiple rows of marginal teeth on the maxillary and dentary bones. However, single-rowed captorhinid elements have been discovered, proving this hypothesis incorrect.[3]
Captorhinus aguti
C. aguti was a small captorhinid reptile that lived during the Permian Period[4] 286 MYA to 245 MYA when the continents were still connected as Pangea.[5] An abundance of fossils have been found in Oklahoma,[6] and Texas,[7] including a skull,[4] hindlimb bones,[8] spinal vertebra, ribs, and forelimb bones.[7] The entire skeleton of C. aguti resembles a modern lizard.[7]
Although a subfamily of Captorhinidae,
The vertebral structure in C. aguti is that commonly possessed by primitive reptiles. The centra are
Similarly to
Preserved skin is known from the neck of the species, which preserves corneous epidermal bands.[15]
Captorhinus magnus
Captorhinus magnus has thus far been identified from only the Richards Spur locality in Oklahoma, a site that also produced the remains of C. aguti. Fossils of C. magnus are found predominately in the deeper regions of the fissure complex, whereas in the upper, younger sediments of the fillings, C. magnus remains are extremely rare. This suggests the ecological replacement of C. magnus by the smaller, multiple-rowed C. aguti during the Early Permian.[16]
The skeletal elements of Captorhinus magnus possess a nearly identical morphology to those elements of Captorhinus aguti, with the lone exception of the size difference. Captorhinus magnus averaged about twice as large as C. aguti. Another important difference between the two species is that the teeth are arranged in a single row. Captorhinus magnus possesses ogival check teeth, where the distal tips of the teeth exhibit a triangular shape when viewed in anterior view. Unlike C. aguti, the femur of C. magnus possesses a concave proximal articular surface in both immature and mature individuals. This allows for distinction between similar-sized femora of C. aguti and C. magnus, regardless of the
Captorhinus laticeps
C. laticeps is distinguished from C. aguti by the lack of multiple tooth rows, but is very similar in all other aspects. Captorhinus laticeps is considerably smaller than C. magnus, and possesses chisel-shaped teeth instead of ogival teeth on the posterior portion of the maxilla and dentary.[18]
Other remains
Possible remains of Captorhinus have been reported from the Pedra de Fogo Formation, Piauí, Brazil, but they are fragmentary and cannot be assigned to the genus with confidence.[19]
History of discovery
In 1882, Edward Cope described a fragmentary skull from the Lower Permian of Texas collected by W. F. Cummins at Coffee Creek as Ectocynodon aguti. The name had then been revised several times by different paleontologists as more genera were discovered. In 1911, paleontologist Ermine Cowles Case revised the recently discovered species. He decided to refer P. (Ectodynodon) aguti, P. aduncus, and P. isolomus to Captorhinus, and established a new family, Captorhinidae.[20]
Named by Cope from the Latin word, “captor,” meaning “one who catches something,” and the Greek word, “rhino,” meaning, “of the nose.” This is based on the theory that the characteristically curved premaxilla of Captorhinus may have been used to catch prey.[21]
Paleobiology
Diet
Possible prey from the known fauna of the early Permian of both Texas and Oklahoma may have included other small amniotes, small dissorophid
Palaeoecology
Captorhinus is known from the
References
- ^ Colbert, Edwin H. (Edwin Harris); Knight, Charles Robert (1951). The dinosaur book : the ruling reptiles and their relatives. New York: McGraw-Hill. p. 146.
- ^ Canoville 2010
- ^ Kissel 2002
- ^ ISSN 2296-701X.
- PMID 31966109.
- ^ Richards, E.J. (2016). "The Ontogenetic Osteohistology of the Eureptile Captorhinus aguti (Reptilia: Captorhinidae) and the Community Histology of the Early Permian Fissure-Fill Fauna Dolese Quarry, Richards Spur, Oklahoma". ProQuest.
- ^ a b c Fox, Richard; Bowman, M. (1966). Osteology and Relationships of Captorhinus Aguti (Cope) (Reptilia: Captorhinomorpha). The University of Kansas Paleontological Institute. pp. 1–79.
- ^ Holmes, R.B. (2003). "The hind limb of Captorhinus aguti and the step cycle of basal amniotes". NRC Research Press.
- ^ Fox 1966
- S2CID 218627600.
- ^ Fox 1966
- ^ Kissel 2002
- ^ Holmes 2003
- ^ Kissel 2002
- PMID 38215745.
- ^ Kissel 2002
- ^ Kissel 2002
- ^ Kissel 2002
- PMID 32185112.
- ^ Fox 1996
- ^ Fox 1966
- ^ Kissel 2002
- ^ Friedman 1996
- ^ Modesto 1996
- ^ Modesto 2007
- ^ Gaffney 1979
Sources
- Fox, Richard C.; Bowman, Merton C. (January 31, 1966). "Osteology and relationships of Captorhinus aguti (Cope) (Reptilia: Captorhinomorpha)". University of Kansas Paleontological Contributions. Vertebrata (Article 11): 1–79. hdl:1808/3815.
- Gaffney, Eugene S.; Mc Kenna, Malcolm C. (October 30, 1979). "A Late Permian Captorhinid from Rhodesia" (PDF). American Museum Novitates (2688): 1–15. Archived from the original (PDF) on April 2, 2015. Retrieved 22 February 2015.
- Kissel, Richard A.; Dilkes, David W.; Reisz, Robert R. (September 1, 2002). "Captorhinus magnus, a new captorhinid (Amniota: Eureptilia) from the Lower Permian of Oklahoma, with new evidence on the homology of the astragalus". Canadian Journal of Earth Sciences. 39 (9): 1363–1372. doi:10.1139/e02-040.
- Holmes, Robert B. (April 1, 2003). "The hind limb of Captohinus aguti and the step cycle of basal amniotes". Canadian Journal of Earth Sciences. 40 (4): 515–526. doi:10.1139/e02-039.
- Modesto, Sean P.; Scott, Diane M.; Berman, David S.; Muller, Johannes; Reisz, Robert R. (February 1, 2007). "The skull and the palaeoecological significance of Labidosaurus hamatus, a captorhinid reptile from the Lower Permian of Texas". Zoological Journal of the Linnean Society. 149 (2): 237–262. .
- Seltin, Richard J. (October 22, 1959). "A Review of the Family Captorhinidae". Fieldiana: Geology. 10 (34): 461–505.
- Canoville, Aurore; Laurin, Michel (June 1, 2010). "Evolution of humeral microanatomy and lifestyle in amniotes, and some comments on palaeobiological inferences". Biological Journal of the Linnean Society. 100 (2): 384–406. .
- Modesto, S. P. (February 1996). "A Basal Captorhinid Reptile from the Fort Sill Fissures, Lower Permian of Oklahoma". Oklahoma Geology. 56 (1): 4–14.
- Friedman, Gerald M. (February 1996). "A Note on Metamorphism in the World's Deepest Boreholes in Sedimentary Strata: Anadarko Basin, Oklahoma". Oklahoma Geology. 56 (1): 15–17.