Ctenoscia minima ( Dollfus, 1892 )

Taiti, Stefano & Rossano, Claudia, 2015, Terrestrial isopods from the Oued Laou basin, north-eastern Morocco (Crustacea: Oniscidea), with descriptions of two new genera and seven new species, Journal of Natural History 49 (33), pp. 2067-2138 : 2077-2081

Ctenoscia minima ( Dollfus, 1892)

( Figures 6–8)

Chaetophiloscia dorsalis Verhoeff, 1928, p. 137 , Figures 34, 37, 38, syn. nov. Ctenoscia minima ; Vandel, 1961, p. 256

Material examined

2 ♂♂, 16 ♀♀, 1 juv., St. 8, leg. S. Taiti and C. Rossano, 28 April 2004 ( MZUF 9464 ) ; 4 ♂♂, 14 ♀♀, St. 10, leg. S. Taiti and C. Rossano, 26 April 2004 ( MZUF 9465 ) ; 1 ♀, St. 12, leg. C. Rossano, 26 April 2004 ( MZUF 9466 ) ; 12 ♂♂, 20 ♀♀, St. 14, Phillyrea wood, leg. S. Taiti, 27 April 2004 ( MZUF 9467 ) ; many ♂♂ and ♀♀, St. 15, sieved ground near stream, leg. S. Taiti, 27 April 2004 ( MZUF 9468 ) ; 1 ♀, St. 17, leg. S. Taiti, 29 April 2004 ( MZUF 9469 ) ; 1 ♀, St. 18, cork-oak wood, leg. S. Taiti, 29 April 2004 ( MZUF 9470 ) ; 1 ♂, 2 ♀♀, St. 21, leg. S. Taiti and C. Rossano, 30.IX.2005 ( MZUF 9471 ) ; 2 ♀♀, St. 24, cork-oak wood, leg. S. Taiti, 29 April 2004 ( MZUF 9472 ) .

Remarks

Ctenoscia minima was originally described by Dollfus (1892) from Grenada, Spain, and later recorded for several localities in Spain, including the Canary and Balearic islands, Portugal (see Schmalfuss 2003 for previous citations), and Morocco ( Vandel 1961). This species has been illustrated by Vandel (1946) and Rodríguez and Barrientos (1993). The genus Ctenoscia also includes another species, C. dorsalis ( Verhoeff, 1928) , originally described from San Remo and Grimaldi (Liguria, Italy), and later recorded from several localities in mainland Spain and the Balearic Islands, Corsica, Italy including Sardinia and Sicily, Malta (see Schmalfuss 2003 for previous citations), and Tunisia ( Achouri et al. 2008b).

According to the descriptions, C. minima differs from C. dorsalis in having the distal part of the male pleopod 1 endopod bent outwards instead of straight, while all the other characters are identical in the two species. The examination of many specimens of Ctenoscia from the Oued Laou valley showed that C. dorsalis has to be considered as a junior synonym of C. minima . In fact, the distal part of the male pleopod 1 endopod is straight or bent outwards according to the size of the specimens. In the population from St. 14 (Tirinesse), 4 mm long males show the endopod bent outwards as in C. minima ( Figure 8D), while in 4.5 mm long males this appendage is straight as in C. dorsalis ( Figure 8C), showing that this character varies according to the age and size of the specimens. For the same reason also the distal margin of the male pleopod 1 exopod is more or less convex.

Ctenoscia minima is here fully illustrated to facilitate its identification ( Figures 6–8).

Distribution

Portugal, Spain (including Canary and Balearic islands), Corsica, Italy (including Sardinia, Sicily and surrounding islands), Malta, Morocco and Tunisia. New record for the Rif region.