(21) Crassicorophium bonellii (H. Milne Edwards, 1830)

Status in U.K. – cryptogenic.

Crassicorophium bonellii has a widely reported distribution but the identity of the species is problematic and it is possible that a species complex is involved (Marchini and Cardeccia 2017). Chapman (2007) considered that C. bonellii was indistinguishable from Monocorophium acherusicum . In the current sampling programme C. bonellii has been found at Vanguard in 2013 and from a scrape sample at Gutter Sound in 2016 but it has also been recorded in MNCR surveys in 1995 and 1997 (Murray et al. 1999).

Its widespread nature and association with human vectors makes establishing the native range of the species problematic (Marchini and Cardeccia 2017) and we consider it to be a cryptogenic species in the U.K.