Morphology of juvenile stages and ontogeny of three species of Damaeidae (Acari: Oribatida)

Abstract

The morphology of juvenile stages and ontogeny of Belba corynopus (Hermann, 1804), Metabelba parapulverosa Moritz, 1966 and Metabelbella interlamellaris Pérez-Íñigo, 1987 were investigated. The juveniles of these species differ from each other mainly by the shape of seta ex in all juveniles, the presence of seta h 3 and shape of setae c 1, da and dm in the larva, shape of seta p 1 and location of cornicle in the nymphs. Moreover, the larva of B. corynopus carries only humus mass, the nymphs and most adults of this species carry the exuviae of previous instars and humus mass, while the nymphs of other species carry only the exuviae. The formulae of setae on genua and tibiae I–IV of tritonymphs (number of setae on leg segments I–IV) are the same for all these species and those in the literature, but the differences occur on femora I–IV and trochanters III and IV. The setal formula of femora I–IV clearly separates Belba von Heyden, 1826 from Metabelba Grandjean, 1936 and Metabelbella Bulanova-Zachvatkina, 1957, whereas the formula of trochanters III and IV separates Belba from Metabelbella. The differences in the number of setae on these leg segments between Metabelba and Metabelbella are indistinct. In contrast, the setal formula of tibiae I–IV in the adults is specific for each genus (4-5-3/4-4 in Belba, 4-5-5-4 in Metabelba and 4-4-4-4 in Metabelbella), has generic value and is consistent with Miko (2006. Damaeidae. In: Weigmann G., editor. Hornmilben (Oribatida) [Oribatid mites (Oribatida)]. Keltern (Germany): Goecke & Evers; p. 179–207. (Die Tierwelt Deutschlands [The fauna of Germany]; part 76. Dahl, F, series founder). whereas the formula of femora I–IV separates Belba from Metabelba and Metabelbella, and formula of trochanters III and IV separates Belba from Metabelbella, as in the tritonymphs.