Cambrian rhynchonelliform nisusioid brachiopods: phylogeny and distribution

A comprehensive review and phylogenetic analysis of genera and species presently assigned to the rhynchonelliform superfamily Nisusioidea and family Nisusiidae suggests that this short-lived but important group of brachiopods first appeared in peri-Gondwana during the second half of the Cambrian Series 2, before going extinct by the end of Drumian time. Nisusiides achieved their maximum morphological disparity and geographical distribution during Wuliuan age, and most likely Laurentia was the major center of dispersal. The new phylogenetic analysis suggests an early separation between the lineages of spinose and non-spinose nisusiids. The non-spinose nisusiids probably evolved in Laurentia by the end of Cambrian Series 4. The new nisusiid genus Bellistrophia is described. The new species Nisusia multicostata represents the first documented rhynchonelliform (kutorginide) brachiopod from the Miaolingian (Drumian) of Alborz Mountains.