|Scientific Name:||Pseudemys gorzugi|
|Species Authority:||Ward, 1984|
Pseudemys concinna (LeConte, 1830) subspecies gorzugi Ward, 1984
|Taxonomic Notes:||Elevated to full species status by Ernst (1990) and Seidel (1994) from initial status of subspecies of Pseudemys concinna.|
|Red List Category & Criteria:||Near Threatened ver 3.1|
|Assessor/s:||van Dijk, P.P.|
|Reviewer/s:||Horne, B.D., Mittermeier, R.A., Philippen, H.-D., Quinn, H.R., Rhodin, A.G.J., Shaffer, H.B. & Vogt, R.C|
|Contributor/s:||Lavin, P., Hammerson, G.A. & Mendoza-Quijano, F.|
Pseudemys gorzugi has a large extent of occurrence (along the Pecos-lower Rio Grande basin, from New Mexico, US to Tamaulipas, Mexico). However, the area of occupancy is much smaller (perhaps less than 2,000 km2). The habitat is declining due to pollution and water control and diversion along the length of the main river. The species is also collected for the pet trade, and the population may be declining as a direct result of this.
Pseudemys gorzugi is assessed as Near Threatened on the basis that it nearly meets Vulnerable under criterion B1. However, further research is urgent to determine whether a threatened status is appropriate for this species, based on reported population fragmentation and decline.
Pseudemys gorzugi inhabits the Pecos-lower Rio Grande basin from New Mexico through Texas, USA, and Coahuila, Nuevo Leon and Tamaulipas, Mexico (Iverson 1992, Seidel 1994). Not recorded from the Rio Grande at or above the Big Bend region, nor from the San Fernando.
Native:Mexico (Coahuila, Nuevo León, Tamaulipas); United States (New Mexico, Texas)
|Range Map:||Click here to open the map viewer and explore range.|
Scant information is available on population status, densities, or population trends; it has been noted as locally common in the Mexican part of its range (P. Lavin pers. comm. 2005). Forstner et al. (2006) carried out range-wide surveys and found populations of the species concentrated in only a few stretches of the U.S. tributaries, whereas the species has minimal genetic structure across its range (Bailey et al. 2008).
|Habitat and Ecology:||
Restricted to the mainstream of the Pecos and Rio Grande, and the lowermost few miles of tributaries (Ward 1984). Occurs as high as 1,082 m altitude in New Mexico (Degenhardt and Christiansen, in Ernst et al. 1994). Apparently absent from the Texas side of the lower Rio Grande (Ward 1984).
Animals reach up to 37.2 cm carapace length (CL) (Ernst and Lovich 2009). Limited information is available on reproduction: a clutch size of nine eggs has been reported; whether females produce multiple clutches remains unknown. Age and size at maturity remain unrecorded.
An apparent absence of the species over a 160-km stretch of the lower Pecos was attributed to river pollution by natural gas and oilfield runoff (Ward 1984). Water diversion, runoff interception, groundwater pumping and other intensive water usage in the basin mean that the Rio Grande frequently runs dry before reaching the sea, while floodplain lake habitat has been lost after the construction of flood mitigation dams and infrastructure. These processes fragment populations and impede repopulation of depleted populations and gene flow.
The species is also considered to be under potentially serious threat from collection for the pet trade and wanton killing by fishermen (Forstner pers. comm. 2005, Bailey et al. 2008). Bailey et al. (2008) also reported an apparent absence of juveniles in the Texas populations of P. gorzugi, whereas their searches for juveniles in New Mexico were successful; they expressed their concerns for future population dynamics of Texas populations.
Turtles in general are protected from exploitation under Mexican wildlife and natural resource legislation. The species may occur, but has apparently not been confirmed, in the Bitter Lakes Wildlife Refuge of New Mexico. Surveys for the species in the Big Bend NP - Maderas del Carmen FFPA - Rio Grande National Scenic River – Amistad NRA, and the Lower Rio Grande Valley NWR, areas are desirable. Surveys of the Canon de Santa Elena FFPA have failed to record the species (MX Red List Workshop participants 2005).
Studies of its natural history and conservation status are warranted. Based on study results, the species may warrant specific legal protection in the USA. Commercial pet trade demand for the species can probably be met through captive breeding.
Bailey, L.A., Dixon, J.R., Hudson, R. and Forstner, M.R.J. 2008. Minimal Genetic Structure in the Rio Grande Cooter (Pseudemys Gorzugi). Southwestern Naturalist 53(3): 406-411.
Ernst, C.H. 1990. Pseudemys gorzugi. Catalogue of American Amphibians and Reptiles 461: 1-2.
Ernst, C.H. and Lovich, J.E. 2009. Turtles of the United States and Canada. Second edition. Johns Hopkins University Press, Baltimore.
Ernst, C.H., Lovich, J.E. and Barbour, R.W. 1994. Turtles of the United States and Canada. Smithsonian, Washington, DC. 578 pp.
IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.1). Available at: http://www.iucnredlist.org. (Accessed: 16 June 2011).
Iverson, J.B. 1992. A Revised Checklist with Distribution Maps of the Turtles of the World. Richmond, Indiana. (Privately published).
Seidel, M.E. 1994. Morphometric analysis and taxonomy of cooter and red-bellied turtles in the North American genus Pseudemys (Emydidae). Chelonian Conservation and Biology 1(2): 117-130.
Ward, J.P. 1984. Relationships of Chrysemys Turtles of North America. Special Publications, the Museum, Texas Tech University: 1-50.
|Citation:||van Dijk, P.P. 2011. Pseudemys gorzugi. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 10 March 2014.|
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