Parhypochthonius aphidinus Berlese

van der Hammen, L., 1959, Berlese's Primitive Oribatid Mites, Zoologische Verhandelingen 40, pp. 1-93 : 10-11

Parhypochthonius aphidinus Berlese , 1904

Parypochthonius aphidinus Berlese, 1904b, p. 25, pl. 2 fig. 42.

Parhypochthonius aphidinus , Lombardini, 1936, p. 46.

The original description of P. aphidinus , which is accompanied by an elementary drawing, gives a rough impression of the species. Berlese failed to observe two pairs of notogastral hairs (probably c3 and d1); cp appears to be of medium length; the sensilli are figured as symmetrical. The measurements of the mite are said to be 0.450 X 0.200 mm.

In the Berlese Collection several slides of the species are present, mainly with specimens from Florence; preparation no. 80/19 from Florence is designated as type. Only one preparation, viz. 110. 214/35 (Florence, Cascine) shows dissymmetry of the sensilli. All specimens originate from decaying chestnut-wood.

Willmann (1931, p. 98, fig. 18) described a var. germanicus of the species; differential characters are not precisely mentioned, but I think that the variety is founded on the remarkable dissymmetry of the sensillus: the 8 pectmations of the left sensillus are directed backwards, those of the right forwards. The measurements mentioned by Willmann are 0.470 X 0.225 mm.

Grandjean (1932a, p. 425) mentions that he collected Parhypochthonius aphidinus in France; his specimens are smaller (length 0.350-0.385 mm) than those described by Berlese. In 1934b (p. 423, figs. 1-4) he dealt with material from the same locality (medium length 0.380 mm), and observed also a dissymmetry of the sensillus; because of the smaller length he now named the specimens Parhypochthonius sp.

I suppose that the specimens described by Berlese, Willmann, and Grandjean belong to one species, but that there is variation in measurements as well as in position of the right sensillus (especially in slides).

Matters stand slightly different in Parhypochthonius aphidinus octofilamentis Jacot (1938, p. 647, fig. 1). Although the distinguishing characters mentioned by this author are of minor importance, his fig. 1 shows that a3 (= cp) is distinctly longer than in P. aphidinus ; I remark that the same character is found in P. urticinus .