Variation in the shell elements of Chrysemys picta bellii (Gray 1831)
DOI:
https://doi.org/10.18435/vamp29390Keywords:
osteology,, carapace, plastron, shell characters, emydidAbstract
Variation in the Shell Elements of Chrysemys picta bellii (Gray 1831)
Assignment of fossil turtle shell elements to a specific taxon is often difficult because the range of variation within the population is usually not well characterized. In addition, it is sometimes not clear whether the fossil forms actually differ from their extant counterparts because often the range of shell element variation in modern species has not been determined. The emydid turtles are no exception, with confusion often arising in the identification of isolated fossil elements and sometimes intact shells representing Emys, Pseudemys, Malaclemys, and Graptemys, as well as the deirochelyids Chrysemys, Clemmys, Deirochelys, and Trachemys. In order to begin providing a database with modern counterparts of the deirochelyid turtles, I have photographed and illustrated seven extant Chrysemys picta bellii shells, six of which were collected at a single pond in Nebraska and one from Ladd Marsh in Union County, Oregon . Photographs and detailed illustrations indicate a broad range in the shapes of many characters. Side by side comparisons of some key elements show that there is significant variation in several important characters (nuchal shape/sulci, entoplastron shape/sulci, and pygal shape/sulci). I also conducted a limited morphometric analysis of several sulcus/suture distance ratios, showing substantial variation between individuals in some cases. Covariance and correlation analysis of this variation suggests that allometry is not involved in most cases. In summary, this work provides a visual and morphometric dataset for aid in identifying and assigning shell elements of fossil emydid turtles.
Downloads
References
Adler, K. 1968. Synonymy of the Pliocene turtles Pseudemys hilli Cope and Chrysemys limnodytes Galbreath. Journal of Herpetology 1:32−38.
Bishop, S.C., F.J.W. Schmidt, and W.H. Osgood. 1931. The painted turtles of the genus Chrysemys. Field Museum of Natural History 18:123−139.
Clark, J. 1937. The stratigraphy and paleontology of the Chadron formation in the Big Badlands of South Dakota. Annals of the Carnegie Museum 25:261−350.
Corsini, J.A., and H. Chamberlain. 2009. Characterization of modern turtle death sites for comparison with late Eocene and early Oligocene turtle sites. The American Midland Naturalist 161:96−109.
Delfino, M., and F. Chesi. 2009. Shell morphology of the Egyptian tortoise, Testudo kleinmanni Lortet, 1883, the osteologically least-known Testudo species. CINECA IRIS Institutional Research Information System 48:850−860.
Ernst, C.H. 1971. Chrysemys picta. Catalogue of American Amphibians and Reptiles (CAAR).
Fritz, U., P.H. Širokýkami, and M. Wink. 2005. Environmentally caused dwarfism or a valid species—Is Testudo weissingeri Bour 1996 a distinct evolutionary lineage? New evidence from mitochondrial and nuclear genomic markers. Molecular Phylogenetics and Evolution 37:389−401.
Fritz, U., A.K. Hundsdörfer, P. Široký, M. Auer, H. Kami, J. Lehmann, L.F. Mazanaeva, and O. Türkoza. 2007. Phenotypic plasticity leads to incongruence between morphology-based taxonomy and genetic differentiation in western Palaearctic tortoises (Testudo graeca complex; Testudines, Testudinidae). Amphibia-Reptilia 28:97−121.
Gray, J.E. 1856. Catalogue of the shield reptiles in the collection of the British Museum. Part 1. Testudinata (tortoises).
Hay, O.P. 1908. The fossil turtles of North America. Carnegie Institution of Washington. Publication No. 75.
Holman, J.A., and C.J. Clausen. 1984. Fossil vertebrates associated with paleo-indian artifact at Little Salt Spring, Florida. Journal of Vertebrate Paleontology 4:146−154.
Holman, J.A., and R.L. Richards. 1993. Herpetofauna of the Prairie Creek Site, Daviess County, Indiana. In Proceedings of the Indiana Academy of Science 102:115−132).
Hutchison, J.H. 1996. Testudines; pp. 337−353 in D.R. Prothero and R.J. Emry (eds.), The Terrestrial Eocene-Oligocene Transition in North America. Cambridge University Press, USA.
Jackson, D.R. 1976. The status of the Pliocene turtles Pseudemys caelata Hay and Chrysemys carri Rose and Weaver. Copeia 1976:655−659.
Jackson, D.R. 1988. A re-examination of fossil turtles of the genus Trachemys (Testudines: Emydidae). Herpetologica 44:317−325.
Jasinski, S.E. 2018. A new slider turtle (Testudines: Emydidae: Deirochelyinae: Trachemys) from the late Hemphillian (late Miocene/early Pliocene) of eastern Tennessee and the evolution of the deirochelyines. PeerJ 6:4338. https://peerj.com/articles/4338/
Gardner, J.D. and A.P. Russell. 1994. Carapacial variation among soft-shelled turtles (Testudines: Trionychidae), and its relevance to taxonomic and systematic studies of fossil taxa. (With 8 figures and 12 tables in the text). Neues Jahrbuch fur Geologie und Palaontologie-Abhandlungen, 193(2):209−244.
Gemel, R., and H. Grillitsch. 2008. Hydrochelys picta WAGLER, 1821: a junior synonym of Chrysemys picta picta (SCHNEIDER, 1783). Herpetozoa 20:187−189.
Germano, D.J. 1993. Shell morphology of North American tortoises. American Midland Naturalist 129:319−335.
Gray, J.E. 1831. A synopsis of the species of the class Reptilia. Whittaker, Treacher, and Company.
Mautner, A.K., A.E. Latimer, U. Fritz, and T.M. Scheyer. 2017. An updated description of the osteology of the pancake tortoise Malacochersus tornieri (Testudines: Testudinidae) with special focus on intraspecific variation. Journal of Morphology 278:321−333.
McDowell, S.B., 1964. Partition of the genus Clemmys and related problems in the taxonomy of the aquatic Testudinidae. Proceedings of the Zoological Society of London 143(2):239−278.
Mosimann J.E. 1958. An analysis of allometry in the chelonian shell. Revue Canadienne de Biologie 17:137−228.
Parmley, D., J.H. Hutchison, and J.F. Parham. 2006. Diverse turtle fauna from the late Eocene of Georgia including the oldest records of aquatic testudinoids in southeastern North America. Journal of Herpetology 40:343−350.
Parmley, D., R, Chandler, and L. Chandler. 2019. Turtles of the early Pleistocene Santa Fe River 1B Locality. Georgia Journal of Science 77, No.2, Article 9.
Preston, R.E. 1979. Late Pleistocene Cold-Blooded Vertebrate Faunas from the Mid-Continental United States. I. Reptilia; Testudines, Crocodilia. Claude W. Hibbard Memorial, Volume VI.
Seidel, M.E., and H.M. Smith. 1986. Chrysemys, Pseudemys, Trachemys (Testudines: Emydidae): Did Agassiz have it right? Herpetologica 42:242−248.
Seidel, M.E., and C.H. Ernst. 1996. Pseudemys. Catalogue of American Amphibians and Reptiles (CAAR). 625:1−7.
Starkey, D.E., H.B. Shaffer, R.L. Burke, M.R. Forstner, J.B. Iverson, F.J. Janzen, and G.R.Ultsch. 2003. Molecular systematics, phylogeography, and the effects of Pleistocene glaciation in the painted turtle (Chrysemys picta) complex. Evolution 57:119−128.
Tucker, J.K., F.J. Janzen, and G.L. Paukstis. 1998. Variation in carapace morphology and reproduction in the red-eared slider Trachemys scripta elegans. Journal of Herpetology 32:294−298.
Vitek, N.S. 2018. Delineating modern variation from extinct morphology in the fossil record using shells of the Eastern Box Turtle (Terrapene carolina). PloS one 13: e0193437. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0193437
Weller, W.F., S.J. Hecnar, D.R. Hecnar, G.S. Casper, and F.N. Dawson. 2010. Quantitative assessment of intergradation between two subspecies of painted turtles, Chrysemys picta bellii and C. p. marginata, in the Algoma district of west central Ontario, Canada. Herpetological Conservation and Biology, 5(2):166−173.
Zangerl, R. 1969. The turtle shell. Biology of the Reptilia 1:311−339.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2022 Joseph Corsini
![Creative Commons License](http://i.creativecommons.org/l/by/4.0/88x31.png)
This work is licensed under a Creative Commons Attribution 4.0 International License.
Submission of an article to Vertebrate Anatomy Morphology Palaeontology will be taken to mean that the article is an original work and not previously published or under consideration for publication elsewhere.
If the article is accepted for publication, it will be published on-line under Creative Commons Attribution 4.0 International (CC By 4.0) meaning:
Attribution — You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
No additional restrictions — You may not apply legal terms or technological measures that legally restrict others from doing anything the license permits.