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Alien amphipods in a sea of troubles: cryptogenic species, unresolved taxonomy and overlooked introductions

Marchini, Agnese, Cardeccia, Alice
Marine biology 2017 v.164 no.4 pp. 69
Amphipoda, biogeography, cryptogenic species, geographical distribution, humans, introduced species, invasive species, inventories, oceans, records, species identification, uncertainty
The large amount of information available on marine alien species distribution can be synthesized into inventories. These are essential tools for management: they allow for the identification of most invasive species and most invaded areas which facilitate management decisions and horizon-scanning initiatives. Here we present an inventory of marine alien amphipods worldwide, with a focus on the quality of available data and on the uncertainty that affects species identity or alien status of amphipod species records. Amphipod records from different world ocean zones were cross-checked and the species with wide disjunct distributions that could be related to human transport were extracted. These were carefully examined for validity of species identification and assessment of alien status. One hundred and five amphipod species were studied. Of these, 55 species are verified aliens at least in one geographical region; the remaining are affected by uncertainty and further investigation is required before they are included in inventories of marine alien species. Many knowledge gaps affect our understanding of the global distribution of marine alien amphipods, as well as many other marine invertebrate groups, and it is possible that our current picture is largely underestimated.