Further karyosystematic investigation of the Stictotarsus griseostriatus (De Geer) group of sibling species (Coleoptera: Dytiscidae)

Abstract

Karyological analysis has been carried out on Stictotarsus griseostriatus strandi (Brinck, 1943) from the Varangerfjord, Norway, S. griseostriatus (De Geer, 1774) from near Inari in Finnish Lapland, S. multilineatus (Falkenström, 1922) from Northern Ireland and S. macedonicus (Georgiev, 1959) from the Šar Planina Mountains of Macedonia. The karyotype of S. griseostriatus strandi is shown to be identical with that of typical S. griseostriatus from the Swedish Baltic coast, and material from Finnish Lapland, although of the paler more distinctly striped pattern associated with S. multilineatus, is also shown to be S. griseostriatus. S. multilineatus from Northern Ireland has a karyotype identical with those of Scottish and Swedish material. S. macedonicus, from three lakes in the Šar Planina Mountains, has a karyotype indistinguishable from that of S. creticus Dutton et Angus, 2007, syn. n. and S. creticus is therefore placed in the synonymy under S. macedonicus. The description of S. griseostriatus var. nigrescens (Favre, 1890), from the Swiss Alps is noted. S. griseostriatus does not occur in the Alps, and S. griseostriatus var. nigrescens must be the valid name for either S. alpestris Dutton et Angus, 2007 or S. inexpectatus Dutton et Angus, 2007 but in the absence of chromosomally identified material from the type locality of S. griseostriatus var. nigrescens (Alps of Chandolin near Bella Tola), its true identity remains unknown.