The clam shrimp genus Eulimnadia Packard, 1874 is the most speciose and widely distributed in the Spinicaudata. Taxonomic determinations based on morphology have been controversial because of intraspecific variability in many of the characters used to date. Most recently, egg shell morphology has been the preferred source of species specific characters.We explore the phylogenetic relationships of 19 Eulimnadia species and assess previously proposed synonymies of E. diversa based on egg shell morphology. Phylogenetic studies

were based on cytochrome b and elongation factor 1α, and were analyzed using Maximum Likelihood and Bayesian Inference approaches. Phylogenetic analyses support the monophyly of Eulimnadia, yet a large amount of polyphyly exists for species identified via morphology. Specimens of Eulimnadia diversa s.l. were highly unresolved and polyphyletic. Overall, species level phylogenetic resolution was low, emphasizing the great need for a systematic revision of Eulimnadia.