Two new species of Arbacioid echinoids (genus Goniopygus) from the Aptian sediments of Baghin area (Kerman, Iran)

Two new species of an Arbacioid echinoid, genus Goniopygus, are reported for the first time from Aptian sediments of Baghin area, Kerman, Iran. The main features of the species lie in apical disc and peristome diameter. In Goniopygus triangularis sp. nov., the periperoct is triangular in shape with three small, sunken tubercles, located alternatively adjacent to the periperoct, while Goniopygus annularis sp. nov. is characterized by having a circular periperoct without any sunken tubercle. Also, Goniopygus triangularis has a wider peristome than Goniopygus annularis. In both species sexual dimorphism is not conspicuous. They lived in restricted to low - moderate energy environments.