External morphology and ontogeny of three species of Damaeidae (Acari: Oribatida)

Abstract

The morphology of juvenile stages and ontogeny of Belba compta (Kulczynski, 1902), Epidamaeus bituberculatus (Kulczynski, 1902) and Spatiodamaeus verticillipes (Nicolet, 1855) were described and illustrated for the first time. The juveniles of these species have 12 pairs of gastronotal setae (larva has 12 pairs, protonymph loses d-series setae and gains p-series, and 12 pairs remain in this and other nymphs). They differ mainly by the length of setae c ₁ and la in the larva, which are relatively long in E. bituberculatus, short in S. verticillipes and of medium size in B. compta. The nymphs of the latter species have long seta c ₃, whereas other species have this seta short. In the nymphs of B. compta, adanal setae are smooth; in E. bituberculatus, these setae have long barbs; but in S. verticillipes, they have short barbs. Ontogeny of leg setae is similar in all species, except for famulus (ϵ), which is emergent in the juveniles of B. compta and sunken in other species; the adults of all species have it emergent. Belba compta and E. bituberculatus lose seta c ₃ in the adult, and 11 pairs of notogastral setae remain, whereas S. verticillipes loses seta c ₃ and one seta of h-series, which is unique in Damaeidae. The diagnoses of B. compta, E. bituberculatus and S. verticillipes are modified and enriched in the morphological characters of juveniles, and systematic values of some morphological characters of juveniles of Belba von Heyden, 1826, Damaeus CL Koch, 1836, Epidamaeus Bulanova-Zachvatkina, 1957, Kunstidamaeus Miko, 2006, Metabelba Grandjean, 1936, Metabelbella Bulanova-Zachvatkina, 1957 and Spatiodamaeus Bulanova-Zachvatkina, 1967 are discussed.

Keywords:

• Oribatid mites
• Belba compta
• Epidamaeus bituberculatus
• Spatiodamaeus verticilipes
• juveniles
• ontogeny
• leg setation