No abstract

Although there are several nuisance species of serpulids reported worldwide, the present study shows that some of them have been overlooked even in geographic areas that are considered well studied. We report for the first time in Majorca the invasive species Ficopomatus enigmaticus and the first records for the Balearic Islands of the also non-native species Hydroides dianthus, H. dirampha, H. elegans and H. nigra. The most abundant species were F. enigmaticus, found at higher densities in Portixol (with up to 280 ind. m–2), and H. elegans, found at highest densities in the port of Palma (with up to 270 ind. m–2). Species have been identified after morphological examination and corroborated by mitochondrial DNA sequence data: cytochrome c oxidase subunit 1 (COI) and cytochrome b (Cytb). Molecular data show that the same haplotypes have been found in distant and disjoint biogeographic areas worldwide, which is only explicable by unintentional translocation of specimens through vectors (i.e. ship hulls or ballast water). Species delimitation analyses support previous findings that species complexes are common in both Ficopomatus and Hydroides. In fact, only among the Majorcan samples were we able to detect three species of the F. enigmaticus species complex, two of the H. elegans species complex and two of the H. dianthus species complex. The genetic distances between members of the F. enigmaticus species complex are 8.7% to 16.7% in COI sequences. The species of Hydroides hold 5.4% to 47.6 % genetic divergence between species of the same complex.

Sedentarian annelids are a diverse and heterogeneous group of marine worms representing more than 8600 species gathered in ca. 43 families. The attention brought to these organisms is unevenly distributed among these families, and the knowledge about them sometimes scarce. We review here the current knowledge about the families Acrocirridae, Cirratulidae (including Ctenodrilidae), Cossuridae, Longosomatidae, Paraonidae, and Sternaspidae in terms of biodiversity as well as the evolution of the taxonomy and systematics of each group. We present the challenges faced when studying these organisms and compare methodologies across groups and perspectives in future research.

Using molecular markers and species delimitation analyses, a high diversity of bi-tentaculate Cirratulidae was discovered from the North-East Atlantic. Five new species are described: Chaetozone pseudosetosasp. nov., Chaetozone quintasp. nov., Chaetozone barentsensissp. nov., Chaetozone monteverdiisp. nov., and Chaetozone chambersaesp. nov. Several morphogroups are also described, even though the presence of cryptic diversity prevented naming of individual species. For each species presented, a molecular diagnostic is given from the universal barcode COI and, when available, the D1–D2 domains of the 28S rRNA. This increases the number of species in Chaetozone in northern European waters from ten to at least 17 species, the exact number of species remaining uncertain as taxonomic issues with older names remain unresolved.