Saccocirridae (Annelida) from the Canary Islands with descriptions of a new species

Two species of Saccocirrus, S. slateri sp. nov., and S. parvus Gerlach 1953, are recorded from samples collected in nine sandy beaches throughout the Canary Islands. Detailed descriptions combining live observations with light and electron scanning microscopical analyses are provided for each species; as well as an updated molecular phylogeny of the genus including all described European species. Saccocirrus slateri sp. nov. was found in sediments exposed to strong wave action in beaches and peers at two islands, Tenerife and La Palma; while S. parvus was found in three islands: Tenerife, La Palma, and Lanzarote, in more sheltered subtidal environments. Saccocirrus slateri sp. nov. resembles the European S. papillocercus, but it differs in possessing a longer trunk, more segments, and hooked chaetae. Saccocirrus parvus from Canary Island fits the description of S. parvus from the type locality, but it differs in the presence of unequal prongs in the longest chaeta, and minor details regarding the arrangement of the gonads. These differences are considered as intraspecific variation given that the available DNA sequences are identical. The description of S. slateri sp. nov. increases the number of species of Saccocirridae to 23. We discuss the habitat preferences of the species of Saccocirrus in the light of this newly available information