First insights into the phylogeography and demographic history of the common hermit crab Pagurus bernhardus (Linnaeus, 1758) (Decapoda: Anomura: Paguridae) across the Eastern Atlantic and North Sea

The common hermit crab Pagurus bernhardus (Linnaeus, 1758) is an abundant and ecologically important benthic crustacean in the northeastern Atlantic Ocean. While this species has been intensively studied in terms of its ecology, physiology, behavior, and larval development, knowledge about its population structure and demographic history is still lacking. We examined, for the first time, the genetic variability of P. bernhardus by analyzing two mitochondrial gene fragments (CO1 and 16S) from more than 150 specimens collected from various locations from the Iberian Peninsula to Norway. Our results provide evidence for a significant genetic structure according to the sampled regions for both genetic markers. Furthermore, a comprehensive demographic history reconstruction, mainly based on neutrality tests and a Bayesian Skyline Plot (CO1), revealed a recent demographic expansion of P. bernhardus that preceded the Last Glacial Maximum. Such pattern of retrieved demographic trend could have been likely a successive process to historical contraction of the species into potential climate refugia within the surveyed geographic spectrum.

In situ observations of predatory feeding behaviour of the galatheid squat lobster Munida sarsi using a remotely operated vehicle

During remotely operated vehicle operations on the UK continental shelf to the west of Shetland (60°6′N 4°4′W) at a depth of 400 m, Munida sarsi, a common benthic crustacean was observed actively preying on the northern krill Meganyctiphanes norvegica. Video footage shows the individual using its chelipeds to catch prey items as they swarm around its burrow. These initial observations indicate that predation forms a new feeding strategy for a species previously believed to be an active scavenger.