A TAXONOMIC AND CLADISTIC-ANALYSIS OF THE WEST-EUROPEAN GENUS MONOBELLA (COLLEMBOLA, NEANURIDAE)

The genus Monobella Cassagnau, 1979 (Collembola) is redefined. Four ne w species and one new subspecies are described from Pyrenees and Ceven nes (France) on the basis of labrum morphology, tubercle arrangement o n tergites and chaetotaxy of somites: Monobella calva sp. n., Monobell a edaphica sp. n., Monobella grassei minor ssp. n., Monobella jau sp. n., and Monobella rousseti sp. n. The subspecies Monobella grassei dub ia Deharveng, 1986 is reassigned to specific level. A key to the 14 sp ecies and subspecies of Monobella is given. Except M. g. minor ssp. n, which is present in the Pyrenees and the Massif Central and the wides pread M. g. grassei (Denis, 1923), all Monobella species and subspecie s are narrow endemics of the Pyrenean range; their distribution is map ped in details. A phylogenetic analysis is performed, laking into acco unt the high level of polymorphism of some characters and the incomple te genetic isolation between certain subspecies, indicated in the held by the presence of narrow hybrid zones. Though obtained under differe nt assumptions and constraints, the most parsimonious cladograms exhib it only slight differences, and the proposed phyletic reconstruction c an be considered as robust. It adequately reflects the known distribut ion of the species in the Pyrenees, it confirms the monophyly of the s pecies M. grassei and supports, in agreement with field distribution d ata, the idea that reticulate evolution might have occurred in this ta xon. (C) The Norwegian Academy of Science and Letters.