Carolinea 74

54 Carolinea 74 (2016) The heterogeneous species composition of Belba has been mentioned by several authors ( N orton 1979a, W ang & N orton 1995), and the polyphyly of the genus is likely. More than half a century ago V an der H ammen and S trenzke had already noted that Belba compta ( K ulczy ń ski , 1902) differs from Belba corynopus ( H ermann , 1804) in epimeral setation and instead shows a close resemblance to representatives of Meta­ belba G randjean , 1936, in general appearance. They make special mention of the Metabelba -like shape of the solenidion φ of tibia IV of this spe- cies, and suggest that “a detailed redescription of B compta might prove interesting, as there are also striking differences from B corynopus ( H ermann , 1804 ), the type of the genus Belba ” ( V an der H ammen & S trenzke 1953, p. 152). In the present contribution, a morphologically highly distinct, monophyletic group of species, which includes Belba compta , is removed from Belba and transferred to a new genus. 2 Material and methods The specimens of Tokukobelba compta (42 adults, 3 tritonymphs, 1 deutonymph, 2 proto­ nymphs, 2 larvae) were collected by the author on 6.9.2010 and 5.7.2012 on the Königstuhl hill near Heidelberg, Germany, from moist moss on rocks. Representatives of Belba coryno­ pus (20 adults, 4 tritonymphs, 2 deutonymphs, 1 protonymph) were obtained by the author on 7.5.2009 in the Waldpark forest near Mannheim, Germany, from moss on a decaying tree stump. Ten adults of each species were deposited as voucher specimens in the acarology collection of the Department of Zoology of the State Museum of Natural History Karlsruhe in Germany. Various other oribatids from the author´s own collection and from that of the State Museum of Natural History Karlsruhe were studied for comparative purposes. Mites were fixed in ethanol, macerated with lactic acid and observed under a light micro- scope. Unmacerated and living specimens were also examined. Descriptions, measurements of structures, and illustrations are based on intact or dissected specimens mounted in temporary cavity slides or on permanent slides. Unless spe- cifically mentioned all descriptions refer to the adult stage. The conventions of measurement used fol- low B ehan - P elletier & N orton (1983, 1985) and B ayartogtokh (2000). Dimensions of body structures are given in micrometers, with the mean value followed by the range in parenthe- ses where based on a sample of 10 individu- als. Adult setal length measurements are based on at least 3 specimens. Ventral body length is measured in lateral view from the tip of the ros- trum to the posterior edge of the ventral plate. Maximum notogastral width is determined in dorsal view. Prodorsal width is measured from the left margin to the right margin of the prot- erosoma at the level of the acetabulae in dorsal perspective. Length of notogaster is measured from its anterior to its posterior margin. Noto- gastral thickness is determined in lateral view from the ventral to the dorsal notogastral border. Leg length is measured on whole legs in lateral aspect from the proximal margin of the trochant- er to the base of the claw. Length of single leg segments is determined in lateral view from the most proximal sclerotized point to the most dis- tal and includes the part inserted in the follow- ing, more proximal segment. Distance between an adanal seta and the genital plate is meas- ured between the setal insertion point and the closest point on the border of the genital plate. Distances between setae of prodorsum and of notogaster are determined between their cen- tral insertion points. An explanatory list of the abbreviations used in the text follows the list of references. Leg setation formulae give the number of setae present on a specific segment of legs I-IV. Leg associated setal formulae refer to the presence (1) or absence (0) of setae paired with solenidia on a specific segment of legs I-IV. Leg solenidial formulae give the number of solenidia present on the genu, tibia and tarsus of a given leg. Pal- pal setation formulae give the number of setae present on the palp in the sequence: trochanter- femur-genu-tibia-tarsus. Epimeral setation for- mulae show the number of setae present unilat- erally on epimeres I-IV. The general morphological terms used in this pa- per derive from B ehan - P elletier & N orton (1983, 1985), and N orton & B ehan - P elletier (2009). The nomenclature of the epimeral enantiophys- es largely follows G randjean (1960a) and N orton (1978b), while that of the leg chaetotaxy is based on N orton (1977b). The term centroprodorsal groove is introduced and refers to the furrow situ- ated anteriad the bothridia and posteriad the sig- illae of the cheliceral retractor muscles, between the prodorsal apophyses Aa and Ap where these are present.