Morphological Analysis of the Carapace of the African Sideneck Turtle (Pelusios castaneus)

Abstract

The morphological analysis of the carapace of the African sideneck turtle (Pelusios castaneus) was carried out using twenty adult turtles comprising twenty females and forty males picked up at different times in various river banks in lbadan, Nigeria with the view to providing baseline information that could be useful in the comparative osteology of sea and freshwater turtles as well as in the identification of the shell of the turtle in paleontological and archaeological investigations. The average body weight of the turtles used for the study was 0.82 [plus or minus] 0.03kg. The curved carapace and plastron lengths of the turtles were 26.4 [plus or minus] 1.87cm and 19.3 [plus or minus] 1.13cm, respectively. The carapace of the turtles varied from dark brown to dark in colour, had five vertebral, four pairs of costal and twelve pairs of marginal scutes with the infra-marginal scute forming the bridge between the carapace and plastron. The turtle had seven neural bones flanked on each side by eight pairs of pleurals, while eleven pairs of peripheral bones surrounded the pleurals. The basic anatomy of the shell of this animal is similar to those of earlier reports on shell morphology of the chelonians.