Mediterranean species of the Medetera plumbella species group with description of a new peculiar species from Morocco (Diptera: Dolichopodidae)

摘要

The Medetera plumbella species group in the Mediterranean Region is reviewed. It comprises seven species and one subspecies including a new species Medetera varvara Grichanov & Vikhrev sp. nov. from Morocco. The species is peculiar in its fore leg decoration and sand dune habitat. A check list and revised key to species of this species group are provided. The genus Medetera Fischer von Waldheim, 1819, numbers now about 330 mostly Holarctic species, but we think hundreds of undescribed species populate tropical and subtropical belts of the World. Medetera plumbella species group was originally recognized as the genus Oligochaetus by Mik (1878) with the type species Medeterus plumbellus Meigen. Bigot (1890) later considered Oligochaetus a synonym of Medetera. Subsequent Old World workers treated the name as a subgenus of Medetera (e.g., Becker 1917) or an independent genus (e.g., Stackelberg 1937; Parent 1938), including in the latter genus the plumbella, senicula, micacea and annulitarsa species groups. Negrobov (1966) did not find any significant generic characters to distinguish Oligochaetus from Medetera, but he nevertheless coined the subgenera Asioligochaetus Negrobov, 1966, and Lorea Negrobov, 1966, for some of the Central Asian Oligochaetusspecies. Negrobov & Stackelberg (1972) published a key that incorporated all Palearctic species of Medetera. Bickel (1985, 1987) considered all the subgenera as no more than species groups of Medetera, and he placed the subgenera Asioligochaetus and Lorea in synonymy with Medetera. Members of the former Oligochaetus are also present in the Afrotropical Region (Grichanov 1997a, 1999). They have some relations to North American petulca group of species (Bickel 1985). Only one species of the plumbella group s.s. (M. plumbella) inhabits Europe, ranging from southern regions to the Scandinavian countries. Several species of this group were described from desert and semidesert areas of the Old World including North Africa, with some species collected from rodent holes (Stackelberg 1937; Grichanov et al. 2007).