Thyasella mandibularis Lundblad, 1924

Sabatino, Antonio Di, Gerecke, Reinhard, Gledhill, Terence & Smit, Harry, 2009, On the taxonomy of water mites (Acari: Hydrachnidia) described from the Palaearctic, part 2: Hydryphantoidea and Lebertioidea, Zootaxa 2266, pp. 1-34 : 7

Thyasella mandibularis Lundblad, 1924

Thyasella mandibularis torrenticola Schwoerbel, 1958 nov. syn.

Material examined: Germany, Berchtesgaden National Park, Priesberger Moos (site 812) (1/0/0), Herrenroint springs (site 304) (0/1/1). Black Forest, ex coll. Schwoerbel "7 Ufergrabung Thyasella ", uncertain site and date, remnants of at least 5 damaged adult specimens.

Discussion: Thyasella mandibularis torrenticola was introduced as a subspecies of a Scandinavian species, based on a single male from the Black Forest, with the following characters considered as diagnostic: (1) median eye weakly developed, but recognizable; (2) terminal extension of P-4 shortened (½ L of P-5) and truncated; (3) excretory pore with a strongly sclerotized ring.

A revision of a population from the Bavarian Alps indicates that under all of the three points of view, maintaining this subspecies is not reasonable: (1) As in several other species of various genera of Hydryphantidae , development of the median eye is age-dependant. Specimens with an area of weakened sclerotization in the central frontal shield and without any trace of a frontal eye can be found in the same population; (2) the terminal extension of P-4 is broken or misshapen in the holotype. All other specimens from the Black Forest show the typical, long and pointed P-4-extension; (3) also sclerotization of the excretory pore is age dependent, it may appear completely smooth in weakly sclerotized specimens, or developed, to a different degree, as a pair of crescent-shaped rods or a complete ring.