LABIDOSTOMATIDAE OUDEMANS, 1904

Three specimens from the Baltic, ing the mid-Tertiary., 2013, M, Acarologia 53 (1), pp. 25-39 : 25-39

FAMILY LABIDOSTOMATIDAE OUDEMANS, 1904 GENUS Sellnickiella FEIDER & VASILIU, 1969

Feider and Vasiliu (1969) proposed the genus Sellnickiella for Labidostoma brasiliense Sellnick, 1922 and some African and Australian species described by Womersley (1935) and Atyeo and Crossley (1961a and b). Sellnickiella differs from the other genera by the absence of an anterolateral projection of the dorsal shield, and especially by the absence of lateral pustules (or gland-like organs). Today, this genus is, as far as we know, is present today only in the southern Hemisphere, namely in Australia, South Africa and South America - i.e. it has a typical "Gondwanan" distribution ( Bertrand and Theron, 1992; Bertrand, 1997). The genus is discriminated mainly by the combination of lacking a lateral pair of pustules (gland-like organs) and having a famulus that is is bifid in the eponymous subgenus Sellnickiella , which has eight described species, and simple in Dicastriella ( Feider and Vasiliu, 1970) , the second (monobasic) subgenus. Most species of the genus Sellnickiella are characterized by having a slim, elongated body and lengthened leg tibiae, especially those of the first pair.

The specimen found in amber was provisionally assigned to the genus Sellnickiella essentially on the basis of the absence of the lateral pustules combined with the presence of eyes. Proportions of visible characters correspond to the definition given by Fei- der and Vasiliu (1970) for Sellinickiella: (i) posterior trichobothria quasi as long as the distance bop-gm, (ii) "collier antØrieur" of dorsal shield (characteristic of the subgenus Dicastriella ) is absent, (iii) tibia I long, more than 100 µm. Difficulties in obtaining complete and reliable observations (especially for the famulus) prevent us from assigning the species to either of the subgenera, i.e. Sellnickiella and Dicastriella .