Morphometric data for five freshwater turtles in south, central, and west Texas.

From 2008 to 2013, we sampled freshwater turtle populations at 66 sites in south, central, and west Texas, USA. Sampling sites included ponds, lakes, resacas (oxbow lakes), canals, and rivers. We sampled turtle populations using baited hoop nets (66 sites) and basking traps (3 sites), and captured turtles by hand opportunistically in terrestrial habitat. We measured carapace length and width, plastron length and width, body depth, and weight of captured turtles. Excluding recaptures, we measured 356 Apalone spinifera emoryi (Texas Spiny Softshell), 24 Chelydra serpentina (Snapping Turtle), 20 Kinosternon flavescens (Yellow Mud Turtle), 47 Trachemys gaigeae (Big Bend Slider), and 1070 Trachemys scripta elegans (Red-eared Slider). Carapace length of Apalone spinifera emoryi ranged from 85 to 426 mm (mean = 182 mm). Carapace length of Chelydra serpentina ranged from 74 to 320 mm (mean = 233 mm). Carapace length of Kinosternon flavescens ranged from 64 to 147 mm (mean = 114 mm). Carapace length of Trachemys gaigeae ranged from 54 to 203 mm (mean = 141 mm). Carapace length of Trachemys scripta elegans ranged from 30 to 328 mm (mean = 171 mm). These data are useful for assessing spatial and temporal variation in size and body condition of freshwater turtles.

An evaluation of the use of pentosidine as a biomarker for ageing turtles.

Concentrations of the biomarker pentosidine have been shown to be useful measures of age for a number of avian and mammalian species. However, no study has examined its usefulness as an age marker in a long-lived ectotherm despite the fact that such a marker could prove useful in understanding age distributions of populations subject to conservation programmes. Therefore, we evaluated pentosidine concentrations in the interdigital webbing of 117 female yellow mud turtles (Kinosternon flavescens) at a 35 year study site in western Nebraska where nearly all turtles are of known age. Pentosidine concentrations were extraordinarily low and positively correlated with age in this turtle, but concentrations were too variable to permit precise estimates of age for turtles of unknown age. These results may reflect the remarkable physiological adaptations of this turtle to low temperatures and oxygen deprivation in a highly seasonal environment requiring prolonged hibernation. Whether pentosidine concentrations in other ectotherms occupying less seasonal environments would be more highly correlated with age remains to be determined. However, our results suggest that patterns of accumulation of pentosidine in ectotherms may be fundamentally different from those in endotherms.