Sexual Dimorphism in a New Species of Cassiduloid Echinoid, Pygaulus baghinensis, from the Aptian Strata of Baghin Area, West of Kerman, Iran

A new species of cassiduloid echinoids, Pygaulus baghinensis is reported for the first time from Aptian sediments of Baghin area, west of Kerman, Iran. The diagnostic features of the species are centrally positioned of the apical disc and approximately low profile of the test. Variation in gonopore size in different individuals allows to conclude that P. baghinensis is sexually dimorphic. Specimens with large gonopores can be considered to be females, while other specimens whose gonopores diameter is small, can be considered to be males. One of the specimens has one large and three small gonopores on its apical disc. This difference may be due to hermaphroditic feature of the specimen.