Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 62. (Budapest 1970)
Mahunka, S.: Ergebnisse der zoologischen Forschungen von Dr. Z. Kaszab in der Mongolei. 227. Acari: Pygmephoroidea
Merîstoplaxa gcu. n. (Derivation of generic name: fxEQiaroç = subdivided 4-7rA<x£ opiate) Stigmata opening on anterior margin of propodosoma, bothrydia situated latero-inferiorly (thus invisible in a superior view). Propodosoma with 3 pairs or hairs above and with 4 (24-2) ones below. The basis of some ventral hairs guttately incrassate. Yentrum subdivided into transverse sternites, 1 pair of caudal hairs arising near vulva, and 2 pairs on preceding sternite. Tarsus of legs II, III, IV similar to one another, trochanter of leg III triangular, that of leg IV elongately quadrangular. Type-species : Merîstoplaxa precipiia sp. n. Remarks : By our present information, the exact relationship of the new taxon is very difficult to determine, since it differs in some essential characters from all known Pyemotoid or Pygmephoroid taxa. The general habits and certain similarities in chaetotaxy as well as the configuration of the legs would refer it to the Siteroptids, but the shape of the trochanter of leg IV raises some problems in assignment, being transitional between the triangular (Pyemotid) and the quadrangular (Pygmephoroid) trochanters; it seems to approach that of certain Acarophenacid types, though indubitably more evolved. Merîstoplaxa precipua sp. n. Length: 250 p, width: 151 p. Dorsal side (Fig. 1): Propodosoma extraordinarily wide, rostrum undeveloped, rounded. Stigmata opening on anterior margin of propodosoma, peritrema short and sacculiform. Bothrydia situated on latero-inferior surface of body, sensillus rounded, aciculate. Scapular hairs originating along a common transverse line, inner ones quite short, thin, outer ones robust. Vertical pair of hairs also small, arising near margin of propodosoma. Humeral hairs arising adjacent to one another, outer lumbal and outer sacral hairs short, all other setae considerably longer and reaching points of origin of rearward hairs. Ventral side (Fig. 2): Circumgnathosomatic foramen deep, closed from ventral side, thus sacculately embracing basal section of gnathosoma. Anterior sternal plate large, its apodeme 1 undeveloped, thus sternum terminating free anteriorly. Apodeme 2 and apodeme of posterior margin well developed. Anterior margin of posterior sternal plate enlarged, strongly arcuate, covering a part of anterior sternal plate. Its posterior margin also convexely projecting between or behind legs IV. Hairs short, basally incrassate, spiniform. Ventrum subdivided into sternites, median one bearing median and exterior pairs of caudal hairs ; former one short and incrassate, latter one long and normal. Caudal hairs adjacent to vulva also simple. Legs : Leg I (Fig. 3) consisting of 5 distinct joints. Femur emitting 1, trochanter 1, femur 5, hairs. Tibial rp solenidia of approximately equal size, tarsal co L large, but OJ 2 minute, hardly discernible. Claw minute, thin. Tarsi of legs II (Fig. 4) and 111 also with thin claws, but enclosed pulvillus very large. Shape and chaetotaxy of leg IV shown in Fig. 5. Type-material: 1 ex. (Holotype: T-1185 p-69): As-99. Remarks: As already pointed" out in the description of the genus, the new species is apparently unrelated to any known species.
