Carolinea 77

Carolinea 77 (2019): 145-180, 17 Abb.; Karlsruhe, 16.12.2019 145 Discovery of Belba sculpta M ihel č i č , 1957 (Acari, Oribatida, Damaeidae) in an aeolian sand habitat of the Upper Rhine Rift Valley R aymond A. L amos Abstract Belba sculpta was found in a xerothermic habitat on late Pleistocene aeolian sand deposits in the Dossen- wald near Mannheim in Southern Germany. This oriba- tid mite species is so far unknown from Central Europe. The taxon is redescribed on the basis of the new ma- terial, and the larva and nymphs are documented for the first time. Aspects of the taxonomy, evolutionary sy- stematics and ecology of Belba sculpta are discussed. The Belba sculpta species group is introduced. Kurzfassung Entdeckung von Belba sculpta M ihel č i č , 1957 (Acari, Oribatida, Damaeidae) in einem Flugsandhabitat im Oberrheingraben Belba sculpta wurde in einem xerothermen Habitat auf Pleistozänen Flugsandböden im Dossenwald bei Mannheim in Süddeutschland entdeckt. Diese Oriba- tidenart ist in Mitteleuropa bisher unbekannt. Die Be- schreibung des Taxons wird auf der Basis des neuen Fundmaterials ergänzt, wobei die Larven- und Nym- phenstadien zum erstenmal beschrieben werden. Ei- nige Aspekte der Taxonomie, evolutionären Systematik und Ökologie von Belba sculpta werden diskutiert. Die Belba sculpta -Artengruppe wird vorgestellt. Author R aymond A. L amos , Rosenstraße 21, 68199 Mannheim, E-mail: cicindela127@protonmail.com 1 Introduction Belba von H eyden , 1826, is a genus within the species-rich oribatid mite family Damaeidae B er ­ lese , 1896. In the present publication, the disco- very of Belba sculpta M ihel č i č , 1957, in a xero- thermic habitat on late Pleistocene aeolian sand deposits of the Upper Rhine Rift Valley is noted and commented on. This species has up to now not been known to occur in Central Europe ( M iko 2006, W eigmann et al. 2015, B eck et al. 2018) and is so far only reliably known from Spain, where it typically occurs in very warm, relatively dry habitats and has been recorded from Madrid ( M ihel č i č 1957), from the semiarid Sabinares Al- bares vegetation zone of the provinces Huesca and Valencia ( A rribas et al. 1984), from diverse locations in Andalusia ( K ahwash et al. 1992) as well as from La Gomera of the Canary Islands ( M oraza & P eña 2005). Belba sculpta was initially described together with two other species, B . ignota M ihel č i č , 1957, and B . aberrans M ihel č i č , 1957, in the same pub­ lication. Subsequently P érez -Í ñigo (1970) re-exa- mined the original material of M ihel č i č deposited at the Museo Nacional de Ciencias Naturales in Madrid and concluded that the latter two species were synonyms of Belba sculpta . The account of the species by P érez -Í ñigo (1970, 1997) is still incomplete, however. In the present paper, the existing description of adults of Belba sculpta is supplemented on the basis of the new collection material. The juvenile stages are described for the first time, and some facets of the morphology, ecology and systema- tics of the species are commented on. The Belba sculpta species group is introduced and con- trasted with the monophyletic cluster containing B . corynopus ( H ermann , 1804), the type species of the genus. A new diagnosis of the genus Bel­ ba is provided and a determination key to Belba species of the world is presented. 2 Material and methods Specimens of Belba sculpta (27 adults, 3 tri- tonymphs, 1 deutonymph, 2 protonymphs, 2 lar- vae) were collected during May and June 2018 in the Dossenwald near Mannheim, Germany. The mites were predominantly collected from sandy soil in sun-exposed areas with a sparse vegeta- tion cover. Some were also taken from ground dwelling foliose lichens, mostly Cladonia porten­ tosa ( D ufour ) C oem . living on shallow sandy soil next to a stand of Scots pine ( Pinus sylvestris L . ). Mites were obtained from the soil samples with a combination of Berlese apparatus extraction using the sun as a heat and light source, and sand flotation. Specimens were fixed in ethanol, macerated with lactic acid and observed under a light microscope.