Disembarking in port: Early detection of the ascidian Ascidiella scabra (Müller, 1776) in a SW Atlantic port and forecast of its worldwide environmental suitability

We performed morphological analyses on Ascidiella individuals collected on artificial substrates deployed at Puerto Madryn (Argentina) and individuals from collections. We test the validity of traditional characters, used previously to evaluate differences between two congeneric Ascidiella species. The study reveals A. scabra in a port area of the SW Atlantic for the first time, and represents the second record of the species outside its native range. The species could have arrived to South America as biofouling in ship hulls, having established itself in ports, but ignored for a time, confused with its congener A. aspersa, also non-indigenous species for the study area. Ecological Niche Model approaches display potential risk of introduction in high suitable areas worldwide, highlighting these located far away from the native distribution, such as the NW Atlantic and the SW Pacific. The spread along coastal areas of the SW Atlantic could also be expected.