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 : 208-209

ATRACTIDES BORCEAI ( MOTAŞ, 1928)

Megapus borceai Motaş, 1928

Syn. to A. walteri (K. Viets, 1925) : syn. nov.

Type series: Missing. Locus typicus: torrent du Bruyant (massif du Vercors, 8 juillet, 1927, T. 7∞5; dans les Oxyrrhynchium rusciforme , 1 ♂. Altitude environ 900 m.

Description. Male (original description, female unknown): idiosoma total L 462, W 330 mm, oval in shape, but with protruding anterolateral edges; integument relatively thick (13 mm) with finely striated surface, but reticulated in the inferior strata; glandularia diameter 36 mm; coxal field total L 264, W 314, Cx-1 L, 192 mm, Cx-4 with a border of secondary sclerotization, Vgl-3 not fused to Cx-4; I-IV-L total L: 447, 364, 390, 624 mm; I-L-5 dL 114, HB 39, S-1 L 60, S-2 L 55 mm; I-L-6 dL 86, HC 26 mm; a small unpaired sclerite anterior from the genital field, genital field L 104, W 130 mm, surrounded by a narrow border of secondary sclerotization, anterior margin convex, posterior margin incised, gonopore L 68 mm; Ac subtriangular, each forming a pointed tip directed towards the centre of the gonopore; distance Ac-1–3 large, distance Cx-4 to genital field 99 mm; Vgl-1 fused to Vgl-2, excretory pore unsclerotized; gnathosoma with short rostrum, L 104, W 52 mm; chelicera total L 177, H max. (error in original description ‘longeur maxima’) 36, claw L 49 mm. Palp segments L/H P-1–5 21/–, 52/ 39, 62/34, 91/31, 26/– mm; ventral margin of P-2 straight, without ventrodistal protuberance, P-4 1: 1: 1, sword seta inserted between the levels of the ventral hairs, nearer the distoventral hair.

Discussion: A. borceai has not been reported since the original description. Probably in view of the small overall dimensions and the similar integument structure, Motaş compared A. borceai with A. coriaceus , and mentioned only two differences: in A. coriaceus , dimensions are larger, and the border of secondary sclerotization of Cx-4 is more extended, including Vgl-3. In the meantime, A. coriaceus has been recognized as a synonym of A. walteri , a rather small species with age-dependent variation in integument structure and extension of secondary sclerotization. From a comparison of the measurements published for A. borceai and my data from A. walteri , there is conformity in dimensions and shape of idiosoma and appendages. Comparison of the detailed figures by Motaş with the morphology of A. walteri provides no clue that might contradict the taxonomic identity of these two species. Obviously, A. borceai was based on a specimen with reduced integumental papillosity, as they are found regularly in populations of A. walteri . Thus A. borceai is a synonym of the latter species.