Habitat diversity and seasonal variations on the frequency of Caspian pond turtle, (Mauremys caspica) and determination of sex indexes grouping of specimens in Golestan province

The Caspian Pond Turtle, Mauremys caspica, is a terrapin belonging to family Geoemydidae. Testudines have different habitats in different stages of their life cycles. Terrapins have a limited locomotion that changes their population density in certain seasons. Totally 134 specimens (65 males, 69 females) were collected from 14 different aquatic habitats in Golestan province in 2016 – 2017. 25 morphometric characters were measured. Sex ratios of males to females were nearly 1:1. All morphometric characters showed normal distribution (P>0.001) except weight in females (p=0.001). Four characters (W, PL1, PFLW and PHLW) did not show normal distribution in males (P<0.001). Comparison of the parametric characters showed, mean values of characters TL1 (p<0.000), AnSL (p<0.005) and TL2 (p<0.005) were significantly different between the sexes. None of the four nonparametric characters showed significant differences between males and females (p>0.66). The ratio Tail length2 (TL2)to Tail length1 (TL1) and TL1 to Right bridge length (RBrL)are fast and simple grouping index to determine sex of the specimens. The most and the lowest number of specimens were collected in summer (n=52) and fall (n=6) respectively.