Phylogeny of Branchiopoda (Crustacea) - character evolution and contribution of uniquely preserved fossils

Abstract

Phylogeny of Branchiopoda (Crustacea) has received intensive attention the last decade and a widely accepted full resolution of the relationships between the major branchiopod taxa is close. Various well-preserved fossil branchiopods (e.g., Castracollis, Lepidocaris, Kazacharthra, Leptodorosida) combine characters from major recent taxa and are therefore necessary for a full understanding of branchiopod phylogeny and evolution. Here is presented a morphology-based phylogenetic analysis of Branchiopoda, which combines recent taxa with the most well-preserved and informative fossils. The analysis results in support of the following clades: Branchiopoda, Sarsostraca (= Anostraca + Lepidocaris), Phyllopoda, Calmanostraca (= Kazacharthra + Notostraca), an unnamed clade consisting of Castracollis and Calmanostraca, Diplostraca, an unnamed clade consisting of Spinicaudata and Cladoceromorpha, Spinicaudata, Cladoceromorpha, Cladocera, and Gymnomera. The character support for all clades is presented, which provides a basis for a discussion of aspects of branchiopod evolution.