External morphology of Oppiidae (Acari: Oribatida) in the light of the ontogeny of three species and genera

Abstract

External morphology of juveniles and ontogeny of Oppia denticulata (R. & G. Canestrini, 1882), Multioppia laniseta Moritz, 1966 and Oppiella uliginosa (Willmann, 1919) are described and illustrated for the first time. The juveniles of these species are unpigmented and have a soft body, with smooth integument that is covered with microtuberculate cerotegument; they also have a similar number of setae on the prodorsum, gastronotum and in the anal, anogenital and epimeral regions. They differ mainly by the length of seta c₂ in all juveniles, length of setae in and ex in the larva and seta le in the nymphs, and leg setation. The juveniles of Op. uliginosa have coupled seta d at some leg solenidia (σ on leg I, σ and φ on legs II and III, and φ on leg IV), whereas those of other species and the adults of all species lack this seta. The juveniles of O. denticulata and M. laniseta have sunken famulus ε on tarsus I, whereas those of Op. uliginosa and the adults of all species have it emergent. All instars of these species have setal pair p on tarsus I, and lack this pair of setae on leg tarsi II–IV. The adult Op. uliginosa has seta c₂ on the notogaster, whereas other species lack it, but O. denticulata has an alveolus of this seta. The adult of M. laniseta has all setae of d-series, whereas those of other species lack them. Morphological characters of Oppia C.L. Koch, 1836; Multioppia Hammer, 1961; and Oppiella Jacot, 1937 are compared.

Keywords:

• Oribatid mites
• Oppia denticulata
• Multioppia laniseta
• Oppiella uliginosa
• juvenile stages
• ontogeny
• leg setation

Acknowledgements

We thank the anonymous reviewers, especially Reviewer 2, for a thorough review of this manuscript and all professional suggestions that considerably improved the scientific value of this paper, and Dr. David Evans Walter, Editor-in-Chief of International Journal of Acarology, for all helpful scientific and editorial suggestions and a nice cooperation.