Abstract

The middle Ordovician brachiopod faunas of Kazakhstan provide one of the most complete records of the evolution and radiation of some of the oldest known spire-bearing brachiopods. By contrast with North Americanfaunas, Kazakhstanian atrypide taxa mostly belong to the suborders Atrypidina and Lissatrypidina, whereas the suborder Anazygidina is completely absent. Kazakhstanian species referred previously to Zygospiraand Kuzgunia are reassigned toSulcatospira, which appeared in the CaradocDiplograptus multidens and Climacograptus clinganibiozones (Sulcatospira praecursor and Sulcatospira primasp. nov.). Primitive, and possibly the oldest known Athyridida also appeared in Kazakhstan sometime during the Caradoc (Kellerella misiusisp. nov.) and became widespread in brachiopod assemblages developed in carbonate mud mounds. Phylogenetic analysis suggests the early divergence of the Anazygidina, Atrypidina and Athyridida, which probably evolved independently from variousprimitive smooth Lissatrypidina. The new atrypide subfamily Pectenospirinae and two new atrypide genera (Rozmanospiragen. nov. and Pectenospiragen. nov. with P. pectenat asp. nov. as type species) are erected.