Distinguishing Long-Discussed Cryptic Species of the Epibiotic Goose-Neck Barnacle of the Genus Conchoderma (Thoracicalcarea: Lepadidae) with Integrative Taxonomy

Abstract

Naked goose neck barnacles Conchoderma can grow on a wide variety of marine organisms. The taxonomic status of two of its species—C. virgatum and C. hunteri—are currently controversial. Some studies suggest that C. hunteri is a subspecies, variety or growth forms of C. virgatum, because both have great morphological variations, but other studies consider C. hunteri and C. virgatum to be distinct species. The present study examines the morphology and sequence divergence of the COI gene in C. virgatum, C. hunteri and other closely related species. There are consistent morphological differences between C. virgatum and C. hunteri in the tergum, carina and fifth teeth of the mandible. Phylogenetic analysis based on the divergence in the COI gene revealed that C. virgatum and C. hunteri form sister clades with high bootstrap values. The K2P distances within C. hunteri and C. virgatum are 0.034 ± 0.008 and 0.002 ± 0.001 for the COI sequences, respectively. The K2P distance between C. hunteri and C. virgatum is 0.097 ± 0.016. Morphological and molecular evidence confirm that C. hunteri is a valid species.