Kloedenellids: morphology and relation to non-myodocopide ostracodes

Abstract

This paper demonstrates, for the first time, the existence of an inner partition (limen) in females of Kloedenella Ulrich and Bassler, 1908, and the presence of a juvenile carapace in the brood chamber of Poloniella tertia Kroemmelbein, 1953. These facts indicate that the Kloedenellidae Ulrich and Bassler, 1908, and the living platycopes are closely related. Thin sections of female carapaces in kloedenellids, some cytherellids and a geisinid-like form, indicate that their posteriorly inflated valve walls are only half as thick as the remaining parts. This suggests that the feature developed in different lineages and had a pure adaptable character. A historical and critical survey of the kloedenellid literature is included. The latter involves a discussion of phylogenetic relationships between this group and other non-myodocopide ostracodes. In light of new facts and data reported earlier, revised diagnoses for the Kloedenellidae and Paleozoic Cytherellidae Sars, 1866, are presented.