Literaturdatenbank |
Selman, W. , Geographic variation in population structure, shape morphology, and sexual size dimorphism in graptemys flavimaculata. Unpublished paper presented at 9th Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles.
Added by: Sarina Wunderlich (06 Jul 2014 16:17:20 UTC) |
Resource type: Conference Paper BibTeX citation key: anon2011.16481 View all bibliographic details |
Categories: General Keywords: Emydidae, Graptemys versa, Habitat - habitat, Morphologie - morphology, Nordamerika - North America, Schildkröten - turtles + tortoises Creators: Selman Collection: 9th Annual Symposium on the Conservation and Biology of Tortoises and Freshwater Turtles |
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Abstract |
Graptemys flavimaculata (Yellow-blotched Sawback) is a small, highly aquatic turtle that is endemic to the rivers and large creeks of the Pascagoula River system of southeastern Mississippi, USA. Even though its range is relatively small, little is known about geographic variation in population structure, shape morphology, and sexual size dimorphism (SSD) across its range. Graptemys flavimaculata were captured and measured from three sites in 2005 and 2006, while also conducting field work at two of these sites in 2008 for female head width analysis. Results indicate that body size, as well as population structure, varies across a geographic gradient; turtles from the lower Pascagoula River site were generally larger (both body mass and plastron length) relative to the Leaf and Chickasawhay River sites which were in more upstream localities. Additionally, body shape varies among populations in females, with Pascagoula River females having a more domed architecture relative to upstream sites which have turtles with more streamlined shapes; there was little difference in male shapes among sites. SSD was pronounced in all three populations with females attaining greater sizes relative to males, with varying degrees of SSD across sampling localities. Secondary sex characteristics such as female head width was significantly different across sites (Pascagoula > Leaf), while there was no difference among sites for male claw length. Presumably multiple factors in concert influence population structure, shape morphology, and sexual size dimorphism in Graptemys flavimaculata including: 1) food availability, 2) presence of competitors, 3) thermal environment, 4) presence of alligators, and 5) fluvial conditions.
Added by: Sarina Wunderlich |