Contrasting morphological and DNA barcode-suggested species boundaries among shallow-water amphipod fauna from the southern European Atlantic coast

Abstract

In this study we compared DNA barcode-suggested species boundaries with morphology-based species identifications in the amphipod fauna of the southern European Atlantic coast. DNA sequences of the cytochrome c oxidase subunit I barcode region (COI-5P) were generated for 43 morphospecies (178 specimens) collected along the Portuguese coast which, together with publicly available COI-5P sequences, produced a final dataset comprising 68 morphospecies and 295 sequences. Seventy-five BINs (Barcode Index Numbers) were assigned to these morphospecies, of which 48 were concordant (i.e., 1 BIN = 1 species), 8 were taxonomically discordant, and 19 were singletons. Twelve species had matching sequences (<2% distance) with conspecifics from distant locations (e.g., North Sea). Seven morphospecies were assigned to multiple, and highly divergent, BINs, including specimens of Corophium multisetosum (18% divergence) and Dexamine spiniventris (16% divergence), which originated from sampling locations on the west coast of Portugal (only about 36 and 250 km apart, respectively). We also found deep divergence (4%-22%) among specimens of seven species from Portugal compared to those from the North Sea and Italy. The detection of evolutionarily meaningful divergence among populations of several amphipod species from southern Europe reinforces the need for a comprehensive re-assessment of the diversity of this faunal group.

A genetic fingerprint of Amphipoda from Icelandic waters – the baseline for further biodiversity and biogeography studies

“…com.). It is worth noting that similar results were recently observed in the case of some other North Atlantic amphipod species reported as having wide distribution range for six out of the 68 identified morphospecies (Lobo et al 2017). In their case study the incongruence between the morphological identification and genetic variability was explained by geographic distance in four of the disparate morphospecies.…”

“…The latter is commonly used for species delimitation in arthropods and particularly in Amphipoda (e.g. Hebert et al 2003, Costa et al 2007, 2009, Raupach et al 2015, Lobo et al 2017). Both uncorrected p-distance and K2P were used to calculate species distances.…”

Deep segregation in the open ocean: Macaronesia as an evolutionary hotspot for low dispersal marine invertebrates

“…Taking COI data as a benchmark for comparison of genetic distances among crustacean species (Costa et al, ; Lobo et al, ), even the shortest distances between D. edwardsi complex MOTUs (3.79%) would fall beyond the recorded distribution of intraspecific distances in numerous well‐established morphospecies, including this study's results for the other two congeneric species D. bidentata and D. magnitorata (maximum 1.54% and 2.65%, respectively; Table ). On the other hand, the highest average distance observed between the nine MOTUs within D. edwardsi complex (21.92%) surpasses the average distance between D. bidentata and D. magnitorata (16.55%).…”

Macaronesian islands as promoters of diversification in amphipods: The remarkable case of the family Hyalidae (Crustacea, Amphipoda)

“…Studies addressing the biology of Hyalidae are scarce (Dubiaski‐Silva & Masunari, ; Hiwatari & Kajihara, ; Tsoi & Chu, ), and in the NEA focused mostly on habitat and food preferences (Guerra‐García, Ros, Izquierdo, & Soler‐Hurtado, ; Torrecilla‐Roca & Guerra‐García, ; Vinagre et al, ). The only Hyalidae species investigated in NEA from the genetic viewpoint was Apohyale prevostii (Lobo et al, ; Raupach et al, ), but no molecular data were previously reported for the Macaronesia region.…”