Article: The earliest atrypides and athyridides (Brachiopoda) from the Ordovician of Kazakhstan
Leonid E. Popov, Igor F. Nikitin and Elena V. Sokiran
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 American faunas, Kazakhstanian atrypide taxa mostly belong to the suborders Atrypidina and Lissatrypidina, whereas the suborder Anazygidina is completely absent. Kazakhstanian species referred previously to ZygospiraKuzgunia are reassigned to Sulcatospira, which appeared in the Caradoc Diplograptus multidensClimacograptus clingani biozones (Sulcatospira? praecursor and Sulcatospira prima sp. nov.). Primitive, and possibly the oldest known Athyridida also appeared in Kazakhstan sometime during the Caradoc (Kellerella misiusi sp. 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 various primitive smooth Lissatrypidina. The new atrypide subfamily Pectenospirinae and two new atrypide genera (Rozmanospira gen. nov. and Pectenospira gen. nov. with P. pectenata sp. nov. as type species) are erected.