Plastral deossification zones in the Endangered Spiny Hill Turtle Heosemys spinosa (Testudines: Geoemydidae) on Borneo

Studies of the evolution turtle shell morphology have raised numerous questions. In this study, five adult females and two males Endangered Spiny Hill Turtle Heosemys spinosa from localities in western Sarawak East Malaysia (Borneo) were examined for presence plastral deossification zones, reported as indicative kinesis earlier studies. A total 52 (34 females, 18 males) radiographs demonstrated distinct poorly-ossified areas across hyo-hypoplastral hypo-xiphiplastral junctures straight carapace length (SCL) 143.4–211.4 mm. The feature is here interpreted a permanent hinge, which was not observed either examined. smallest female with weak but discernible line at contact these bones had SCL 125 mm, suggestive minimum size maturity population.