Meristacarus rubescens

van der Hammen, L., 1959, Berlese's Primitive Oribatid Mites, Zoologische Verhandelingen 40, pp. 1-93 : 60

Meristacarus rubescens (Canestrini, 1897)

Hermannia rubescens Canestrini , 1897, pp. 461, 467; 1898, p. 393 (sep. p. 9), pl. 24 fig. 4.

? Lohmannia rubescens , Berlese, 1916a, p. 176.

The type-material of Hermannia rubescens Canestrini originates from Seleo (Berlin Harbor, Territory of New Guinea); I do not know if it is still in existence.

Canestrini published two descriptions of the species, which are nearly exactly similar; the second description is accompanied by a superficial figure of the ventral surface, which strongly reminds of a Meristacarus . The outline of the body is elliptic. The prae-anal plate is distinct. The genital plates are not divided; Canestrini probably overlooked the separate anals. The data mentioned about the structure of the mandible agree with those known in other Lohmanniidae , with the exception of the fact that Canestrini did not observe the fourth (paraxial) tooth of the fixed finger. The sensillus is described as filiform, but Canestrini probably overlooked the pinnate structure. The exorbitant measurements (2.20 X 1.00 mm) are exactly two times as large as in the type-species of the genus Meristacarus ; it is not impossible that Canestrini made a mistake in his calculation.

I myself repeatedly collected a Meristacarus species in New Guinea, which is closely related to M. porcula . When studied in air, in reflected light, at a faint enlargement, the ventral surface of this species shows a distinct similarity to Canestrini's figure 4.

As mentioned above Canestrini described rubescens as a Hermannia , without any explication; Berlese (1916a) added the species to the genus Lohmannia .

In the Berlese Collection several preparations labelled as L. rubescens are present; none of these originates from New Guinea, and I do not know if Berlese indeed compared his specimens with the type. I studied slide no. 137/14 from Semarang, Java; this preparation strongly reminds of M. porcula , but the barbules of the notogastral hairs are distinctly longer.

A study of the variability of my own Meristacarus specimens will certainly be helpful in solving this problem.