First and repeated records of the tropical-temperate crab Asthenognathus atlanticus Monod, 1932 (Decapoda: Brachyura) in the eastern part of the Bay of Seine (eastern English Channel, France)

International audienceAsthenognathus atlanticus Monod, 1932, has been reported for the first time from the eastern part of the bay ofSeine (eastern english Channel). A total of 30 specimens were collected between the years 2008 and 2011, along thenormandy coast from ouistreham to Antifer, mainly on mud and muddy sand habitats, between 10 and 25 m depth. thedistribution range of A. atlanticus has been previously known to cover eastern Atlantic coasts from Angola to the westernenglish Channel, where it reached its northern limits. it is also present in the western part of the Mediterranean Sea. thechanges in the sediment composition of the eastern bay of Seine have probably led to the development of a potentiallyfavorable habitat for this species. However, the data collected have not yet been sufficient to ascertain the origin, and themethod of introduction of the eastern english Channel specimens. in the discussion, we ponder if they might haveoriginated from the western english Channel populations, and was transported as larvae in the eastern english Channel;they could have originated from a more distant population, and have been brought to the eastern english Channel throughhuman activities. each hypothesis is possible in theory