Anomalies of the vertebral and pleural scutes in the Middle Jurassiс turtle <em>Annemys variabilis</em> (Xinjiangchelyidae) from the Berezovsk coal mine (Krasnoyarsk Territory, Russia)

Abstract

The anomalies of the vertebral and pleural scutes in the Middle Jurassiс turtle Annemys variabilis (Xinjiangchelyidae) from the Berezovsk coal mine (Krasnoyarsk Territory, Russia) have been studied based of more than 1000 isolated neural plates. Symmetric and asymmetric abnormal scute patterns have been found. Comparison of the anomalies as well as their frequencies in Annemys variabilis and extant turtles demonstrates similar abnormal scute patterns. It is assumed that the high level of the scute variation of Annemys variabilis is caused by the instability of the developmental mechanisms, which are common for all turtles.