Porcellio Latreille, 1804

Kashani, Ghasem M., Ahdiyeh, Abedini & Zahra, Hatami, 2017, Terrestrial isopods of the genus Porcellio Latreille, 1804 (Isopoda; Oniscidea) in Iran, with a description of a new species, Zootaxa 4311 (1), pp. 129-136 : 130

Genus Porcellio Latreille, 1804

Type species: Porcellio scaber Latreille, 1804

Diagnosis. A member of the genus Porcellio can be diagnosed by the enlarged pleon-epimera constituting continuous outline with the pereon; pereon-epimera I with cocave posterolateral margins; head with welldeveloped lateral lobes; eyes with more than 20 ommatidia; telson triangular with concave lateral margins; pleopod exopodites I–II with monospiracular covered lungs and no conglobation ability ( Schmalfuss & Ferrara 1978, Schmalfuss 1992).

Remarks. The genus Porcellio is a large taxonomic group that cannot be defined by a single character. Indeed, none of the above mentioned features satisfactorily diagnose the genus ( Schmalfuss 1992). Schmalfuss (1998) considered Porcellio as a paraphyletic group including two different linages that have been united due to convergent evolution. According to him, “the north African laevis-hoffmannseggi -group defined by elongated male pleopod exopodites, probably should be considered a separate genus which then must be called Rogopus Budde- Lund, 1908”. The northern Mediterranean scaber-obsolotus -group is diagnosed by short pleopod exopodites that includes also west Asian species ( Schmalfuss 1992). Obviously, a revision of the genus Porcellio is required to be divided to more natural genera.