Ontogeny of South African intertidal oribatid mite species (Acari, Oribatida, Ameronothroidea) and supplements to adult morphology.

Abstract

Information about larva and nymphal stages as well as additional descriptions of adults of four littoral species of the families Fortuyniidae, Selenoribatidae and Podacaridae found around the coast of South Africa are provided. Juveniles of Fortuynia elamellata micromorpha are well in accordance with the morphology of other known juveniles of Fortuynia, but the larva of the former shows distinctly barbed rostral setae, a trait which lacks in all the other species. Adults of the South African Selenoribates divergens are similar in morphology to the Egyptian specimens, except for the presence of small rostral humps, anterior notogastral tubercles and the position of lyrifissure ih. These differences are presently considered to be only geographic variation. Juveniles of Sel. divergens can be easily distinguished from juveniles of other known Selenoribates species by the presence of a spinose clavate bothridial seta and branched notogastral setae in deuto- and tritonymph. Due to the loss of type specimens of Schusteria ugraseni, a neotype was designated. The juveniles of this species are very similar to those of Schusteria littorea and Schusteria melanomerus, but differ in amongst others the anoadanal and leg setation. Adults of Halozetes capensis show strong variation in the length of dorsal setae and juveniles of this species differ significantly from others in the number of prodorsal and gastronotic porose sclerites. Finally, a table is provided listing all ameronothroid species with known juvenile stages.