A new Early Devonian palaeozygopleurid gastropod from the Prague Basin (Bohemia) with notes on the phylogeny of the Loxonematoidea

Abstract

A new palaeozygopleurid gastropod, Palaeozygopleura vaneki sp. nov., is described from the Emsian Chýnice Limestone (Novakia elegans Zone, upper part of the Zlíchov Formation; late Early Devonian) of the Prague Basin (Bohemia). The phylogeny of the superfamily Loxonematoidea and the origin of planktotrophy are briefly discussed. It is suggested that the large protoconchs of the Palaeozygopleuridae and Loxonematidae might represent a grade before the inception of planktotrophy.