Phylogenetic position, systematic status, and divergence time of the Procarididea (Crustacea: Decapoda)

Ever since discovery of the anchialine shrimp, Procaris ascensionis Chace & Manning 1972, there has been debate as to its systematic position in relationship to other shrimp-like decapods. Several morphological characters have suggested a close affinity among Procarididae, Dendrobranchiata and Stenopodidea, whereas other physical features unite Procarididae with Caridea. Few molecular studies have examined the phylogenetic position of procaridid shrimp due to limited available material for genetic analyses. Those studies show procaridids as sister to carideans but lack sufficient taxon and locus sampling to validate the relationship. Here, we present a molecular phylogeny of selected individuals across decapod infraorders and superfamilies to clarify the phylogenetic position of procaridid shrimp. One mitochondrial (16S) and three nuclear genes (18S, 28S, H3) have been chosen to elucidate relationships. We used Bayesian molecular dating methods implemented in multidivtime to estimate and compare the divergence times among procaridids and other lineages. Findings secure the placement of the procaridids as a sister clade to carideans. Results provide evidence for the recognition of procaridids as a separate infraorder (Procarididea Felgenhauer & Abele 1983) within the Decapoda on the basis of molecular and morphological data.