Sluggish cousins

The slug Lehmannia valentiana (Férussac, 1822) is an Iberian peninsular species which has been spread inadvertently as far as Australia, and fairly recently it has also been recorded from Malta (Beckmann, 2003; Mifsud et al., 2003). These animals are imported mostly through plant nurseries, and are so far restricted to damp anthropogenic habitats like flowerbeds and potted plants. The following example is one of a few dozen individuals found beneath humid compost at a garden in Santa Venera. As can be seen, distinguishing features include a symmetrical pair of very dark bands on the dorsal side with a fainter one in the middle, over a light-brown or yellow body colour. It seems that fully adult specimens are highly unusual, probably because of pesticidal and meteorological interference. The population from which this individual came contained slugs of about 20-35mm length (in full extension).

Its close relative Lehmannia melitensis (Lessona & Pollonera, 1882) is, on the other hand, native to Malta and Italian islands. In Malta*, this can be distinguished from L. valentiana by an ash-grey colour, considerably clearer bands and a larger size (up to 55mm). In addition to this, it also seems to prefer more open spaces and minimal human presence. The typical specimen below originates from the countryside surrounding Mdina, where it seems to be relatively commoner than in other areas.

*Sicilian forms of this same species have a yellowish colour.

References:

Beckmann K.H. (2003). Kurze Mitteilungen - Neunachweis von Lehmannia valentiana für die Maltesischen Inseln. Heldia, 5 (1/2): 37-40.

Giusti F., Manganelli G. & Schembri P.J. (1995). The non-marine molluscs of the Maltese Islands. Monografie Museo Regionale di Scienze Naturali, Torino, 15: 1-608.

Mifsud C., Sammut P. & Cachia C. (2003). On some alien terrestrial and freshwater gastropods (Mollusca) from Malta. The Central Mediterranean Naturalist, 4 (1): 35-40.

Welter-Schultes F. (2009). Species summary for Lehmannia melitensis. In AnimalBase Project Team, 2005-2009. AnimalBase - Early zoological literature online, University of Göttingen. Retrieved 14th January 2010 from http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase/home/species?id=2634

Welter-Schultes F. (2009). Species summary for Lehmannia valentiana. In AnimalBase Project Team, 2005-2009. AnimalBase - Early zoological literature online, University of Göttingen. Retrieved 14th January 2010 from http://www.animalbase.uni-goettingen.de/zooweb/servlet/AnimalBase/home/species?id=2637