Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-28T00:14:45.106Z Has data issue: false hasContentIssue false

Two different vertebral forms in the axial column of Labidosaurus (Captorhinomorpha: Captorhinidae)

Published online by Cambridge University Press:  14 July 2015

Stuart Shigeo Sumida*
Affiliation:
Department of Biology, University of California, Los Angeles 90024

Abstract

The axial column in Labidosaurus is thoroughly described. Two different vertebral “morphs” are found to occur in this genus. One type is that which is classically illustrated for Labidosaurus, while the other shows alternation in height and construction of the neural arches and neural spines. A brief description of the modifications of muscle attachments in alternating forms is outlined. Analysis shows that such a structural modification probably allowed (more) efficient dorsiflexion and lateral flexion of the vertebral column. The occurrence of alternation of neural spine and arch structure is probably a primitive characteristic, but becomes variously modified in different forms. The variability observed in the axial column suggests that Labidosaurus may have been sexually dimorphic, or that the genus may consist of two different species.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Brinkman, D. B., Berman, D. S. and Eberth, D. A. 1984. A new araeoscelid reptile, Zarcasaurus tanyderus, from the Cutler Formation (Lower Permian) of north-central New Mexico. New Mexico Geology: Science and Service, 6:3439.CrossRefGoogle Scholar
Broili, F. 1904. Permische Stegocephalen und Reptilien aus Texas. Paleontographica, 51:1120.Google Scholar
Broili, F. 1908. Ein montiertes skelet von Labidosaurus hamatus Cope, einem Cotylosaurier aus dem Perm von Texas. Zeitschrift deutschlandische geologische Gesellschaft, 60:6367.Google Scholar
Carroll, R. L. 1968. The postcranial skeleton of the Permian microsaur Pantylus. Canadian Journal of Zoology, 46:11751192CrossRefGoogle Scholar
Carroll, R. L. and Gaskill, P. 1978. The Order Microsauria. Memoirs of the American Philosophical Society, 126, 211 p.Google Scholar
Case, E. C. 1911. A revision of the Cotylosauria of North America. Publications of the Carnegie Institute of Washington, 122 p.CrossRefGoogle Scholar
Clark, J. and Carroll, R. L. 1973. Romeriid reptiles from the Lower Permian. Bulletin of the Museum of Comparative Zoology, 144:353407.Google Scholar
Cope, E. D. 1896. Labidosaurus Cope. Proceedings of the American Philosophical Society, p. 185.Google Scholar
Fox, R. C. and Bowman, M. 1966. Osteology and relationships of Captorhinus aguti (Cope) (Reptilia: Captorhinomorpha). University of Kansas Paleontological Contributions, Vertebrata, 11, 79 p.Google Scholar
Heaton, M. J. 1979. Cranial anatomy of primitive captorhinid reptiles from the Late Pennsylvanian and Early Permian, Oklahoma and Texas. Oklahoma Geological Survey Bulletin, 127:184.Google Scholar
Heaton, M. J. and Reisz, R. R. 1980. A skeletal reconstruction of the Early Permian captorhinid reptile Eocaptorhinus laticeps (Williston). Journal of Paleontology, 54:136143.Google Scholar
Moss, J. L. 1972. The morphology and phylogenetic relationships of the Lower Permian tetrapod Tseajaia campi Vaughn (Amphibia: Seymouriamorpha). University of California Publications in Geological Sciences, 98, 72 p.Google Scholar
Olson, E. C. 1936. The dorsal axial musculature of certain primitive Permian tetrapods. Journal of Morphology, 59:265311.CrossRefGoogle Scholar
Olson, E. C. 1937. A mounted skeleton of Labidosaurus Cope. Journal of Geology, 45:95100.CrossRefGoogle Scholar
Olson, E. C. 1984. The taxonomic status and morphology of Pleuristion brachycoelous Case; referred to Protocaptorhinus pricei Clark and Carroll (Reptilia: Captorhinomorpha). Journal of Paleontology, 58:12821295Google Scholar
Peabody, F. E. 1952. Petrolacosaurus kansensis, a Pennsylvanian reptile from Kansas. University of Kansas Paleontological Contributions, Vertebrata, 1, 41 p.Google Scholar
Reisz, R. R. 1981. A diapsid reptile from the Pennsylvanian of Kansas. Special Publications of the Museum of Natural History, University of Kansas, 7, 74 p.Google Scholar
Reisz, R. R., Berman, D. S. and Scott, D. 1984. The anatomy and relationships of the Lower Permian reptile Araeoscelis. Journal of Vertebrate Paleontology, 4:5767.CrossRefGoogle Scholar
Romer, A. S. 1956. Osteology of the Reptiles. University of Chicago Press, Chicago, Illinois, 772 p.Google Scholar
Romer, A. S. and Price, L. I. 1940. Review of the Pelycosauria. Geological Society of America Special Paper 28, 538 p.CrossRefGoogle Scholar
Vaughn, P. P. 1966. Seymouria from the Lower Permian of southeastern Utah, and possible sexual dimorphism in that genus. Journal of Paleontology, 40:603612.Google Scholar
Vaughn, P. P. 1970. Alternation of neural spine height in certain Early Permian tetrapods. Bulletin of Southern California Academy of Sciences, 69:8086.Google Scholar
Vaughn, P. P. 1972. More vertebrates, including a new microsaur from the Upper Pennsylvanian of central Colorado. Contributions in Science, Natural History Museum of Los Angeles County, 223, 30 p.Google Scholar
von Huene, F. 1913. The skull elements of the Permian tetrapods in the American Museum of Natural History, New York. Bulletin of the American Museum of Natural History, 32:315386.Google Scholar
Williston, S. W. 1910. The skull of Labidosaurus. American Journal of Anatomy, 10:6984.CrossRefGoogle Scholar
Williston, S. W. 1917. Labidosaurus Cope, a Lower Permian cotylosaur reptile from Texas. Contributions of the Walker Museum, 2:4557Google Scholar