Atractides

Gerecke, Reinhard, 2003, Water mites of the genus Atractides Koch, 1837 (Acari: Parasitengona: Hygrobatidae) in the western Palaearctic region: a revision, Zoological Journal of the Linnean Society 138, pp. 141-378 : 252

ATRACTIDES RECTIPES ( WALTER, 1947; NEC SOKOLOW, 1934) = ATRACTIDES DENTIFERUS

K. VIETS 1949

Megapus rectipes Walter, 1947

preocc., A. dentiferus nom. nov. K. Viets, 1949

Syn. to A. latipalpis ( Motaş & Tanasachi, 1946) : Schwoerbel, 1959c

Type series: Lectotype ♀, here designated, NHMB Megapus rectipes ♀ Walter Kaltbrunnental 24.10.1943 Coll. Walter; Typus; Kaltbrunnental Kiesbank 36/ 1943 24.10.1943; XV/41. Pasted over: Megapus rectipes Wtr. DIIIb55, Pr. 1541 Typ ♀. State of conservation: perfect, idiosoma complete, right I-L separate, gnathosoma separated, in oblique position, chelicerae and palps separate, lateral, palps crushed . Paralectotype ♂: as lectotype, but XV/42; Pr. 1542 Typ ♂. State of conservation: idiosoma with right IV-L-3–6 missing, left I-L separate, lateral, Gsk separate, damaged, gnathosoma isolated, lateral, both chelicerae and both palps separate, palps badly damaged and distorted.

Discussion: When Walter described this species, he had no knowledge of A. latipalpis . Schwoerbel (1956) was the first to notice the morphological agreement between these two species, and all further authors followed his proposal to synonymize A. dentiferus with A. latipalpis . Reexamining the types is difficult due to the poor state of conservation of the mouthparts. The male specimen agrees with measurements from Central European specimens attributed to A. latipalpis (e.g. Cx-1 + 2 mL 94, lL 154, W, 190, I-L-5 dL 105, vL 87, I-L-6 L 102 Mm). The thicker palp and I-L segments are an artefact caused by crushing of the mounted appendages. As regards the dimensions of the genital field (L/W 100/98 Mm), it is in agreement with a specimen from Luxembourg and differs both from the published data of the type of A. latipalpis , and from specimens from the Black Forest ( Schwoerbel, 1961a) with larger genital fields. As regards the low L ratio I-L-5/6 of 1.03, it agrees with the original description. Also the female agrees with the dimensions published in Schwoerbel’s bibliography, with the exception that proportions of leg and palp segments are altered due to mounting artefacts. Some measurements are: coxal field L 252, Cx-3 W 275, Cx-1 + 2 mL 112, lL 178, W 218, genital field L/W 153/153, chelicera L 204, L/H 5.10, basal segment/claw 2.34, palp total L 307, I-L-5 dL 121, vL 105, S-1 L 70 (L/ W 14.0), S-2 L 56 (L/ W 14.0), I-L-6 L 90 Mm. Only the L ratio I-L-5/6 of 1.34 differs strongly from the original description and and would result in a surprisingly high range of variability of 1.04–1.34. However, the other investigated specimens from Central Europe are intermediate in this character. A. latipalpis is here considered a variable species, with A. dentiferus a junior synonym. However, improved knowledge of the range of variability of south-eastern European populations could result in the resurrection of this name for Central European populations with relatively short I- L-6.