Arion obesoductus Reischütz, 1973  

External: Slug whitish yellow with light greyish brown dorsal band and dark greyish brown lateral bands; mantle with small and irregular tubercles; head and tentacles greyish blue foot and sole orange or yellowish; mucus yellowish.

Internal: Epiphallus's internal papilla flat; free oviduct long.

Differs from juvenile A. subfuscus in its yellowish mucus. A. intermedius has a short free oviduct and A. distinctus has a conical epiphallus papilla, in contrast to A. obesoductus's flat papilla and long oviduct.

Has previously been confounded with Arion alpinus Pollonera, 1887. Was previously called Arion alpinus Pollonera, 1887, which was described from Piemonte and Lombardia, and it seems that A. obesoductus does not live sympatrically with A. intermedius. Falkner et al. 2002 argued that specimens from Piemonte belonged to this species, but the arguments were not based on published results of anatomical studies that would have enabled Manganelli et al. 2010 to verify the identity of those specimens.