The discovery of Scutovertex ianus sp. nov. (Acari, Oribatida) – a combined approach of comparative morphology, morphometry and molecular data

Based on morphological, morphometric and genetic data Scutovertex ianus sp. nov. is described as a new oribatid mite species. The traditional comparison with the morphologically most similar congeneric S. minutus and S. sculptus demonstrated that the new species shares certain characters with both species, but can be clearly identified by indistinct cuticular notogastral foveae in combination with short spiniform notogastral setae. Furthermore the eggs of S. ianus exhibit a different fine structure of the exochorion. The morphometric analysis of 16 continuous morphological variables separated the three species, S. minutus, S. sculptus and S. ianus with a certain overlap indicating minor size and shape differences in overall morphology. The molecular phylogenetic analysis of mitochondrial COI gene sequences supported the monophyly of all three investigated species and confirmed S. ianus as separate species with high bootstrap values. Each performed analysis approves the discreteness of S. ianus and the results contradict the formerly supposed large intraspecific variability of the representatives of the genus Scutovertex. The records of S. ianus are as yet restricted to the Eastern part of Austria and to one location in Germany, but findings of intermediary Scutovertex specimens from other European countries may refer to this new species

Distribution patterns of intertidal oribatid mites (Acari, Oribatida) from South African shores and their relationship to temperature

A faunistic study of the intertidal oribatid mite fauna of South Africa’s coastline revealed the presence of four species from three families, showing specific biogeographic patterns. Their occurrences show a clear east–west divide, with a small gap near East London between the Podacaridae and the other two families, the Selenoribatidae and Fortuyniidae, clearly coinciding with suggested marine biogeographic ecoregions. The podacarid Halozetes capensis is confined to the cooler warm-temperate Agulhas Ecoregion; the fortuyniid Fortuynia elamellata micromorpha and the selenoribatid Schusteria ugraseni to the warmer subtropical Natal Ecoregion; and the selenoribatid Selenoribates divergens to the tropical Delagoa Ecoregion. These distributions are an indication that the oceanic climate may be the primary factor shaping their biogeography, particularly the seawater temperatures along the coast, which are in turn affected by the Agulhas and the Benguela currents. A mean monthly sea surface temperature of approximately 22 °C apparently represents the climatic border of the distributions, with the podacarid persisting only below this temperature, and the fortuyniid and selenoribatids only above it. Global warming will certainly change these geographic ranges, and in South Africa the warm-adapted fortuyniid and selenoribatids can be expected to expand their distributions southwards, while the occurrence of the cold-adapted podacarid might be reduced to a few southwestern coastal areas in the next few decades