Atractides robustus (Sokolow, 1940)

Gerecke, Reinhard, 2014, The water mites of the genus Atractides Koch, 1837 (Acari, Hydrachnidia: Hygrobatidae) in Corsica and Sardinia, Zoosystema 36 (4), pp. 735-759 : 754

Atractides robustus (Sokolow, 1940)

Atractides nodipalpis sensu Angelier, 1955 (partim): 64 ff.

MATERIAL EXAMINED. — Corsica. Ang 38, 1 ♂, 2 ♀♀ ; F 78, 1 ♂; F 81, 1 ♂, 1 ♀, 1 dn; F 93, 1 ♂, 1 ♀, 1 dn) ( MNHN) .

Corsica. HM 07 , 1 ♂ ; HM 11 , 1 ♂ (Coll. HM) ; F 68 , 1 ♂, 2 dn ; F 81, 4 ♂♂, 1 ♀, 14 dn; F 93, 2 ♂♂, 4 ♀♀; F 94, 3 ♂♂, 1 ♀; F 96, 3 ♂♂, 2 ♀♀.

Sardinia. I 373, 3 ♂♂, 6 ♀♀ ; I 381, 1 ♂, 1 ♀; I 387, 1 ♂ (Coll. RG) .

UNCERTAIN RECORDS ( BASED ON FEMALES). — Corsica. Ang 4, 2 ♀♀ ; Ang 7, 1 ♀ – unpubl. specimen); Ang 10, 1 ♀; Ang 20, 7 ♀♀; Ang 21, 3 ♀♀; Ang 24, 2 ♀♀; Ang 36, 1 ♀; Ang 37, 1 ♀; Ang 44, 3 ♀♀; F 30b, 1 ♀; F 41c, 1 ♀; F 43b, 2 ♀♀; F 43c, 2 ♀♀; F 43f, 1 ♀; F 44a, 1 ♀; F 44d, 2 ♀♀; F 44e, 1 ♀; F 44f, 6 ♀♀; F 44h, 1 ♀; F 55, 1 ♀; F 71, 1 ♀; F 73f, 1 ♀; F 99, 1 ♀; F 103, 1 ♀; F 104, 1 ♀ ( MNHN) ; HM 10 , 3 ♀♀, HM 26 , 1 ♀, HM 29 , 1 ♀ ( Coll. HM). Sardinia. I 352, 4 ♀♀, 1 dn ; I 359, 1 ♀, 1 dn; I 378, 1 ♀; I 379, 1 ♀, 2 dn ( MNHN). PUBLISHED RECORDS. — benf 54, 3 ♂♂, 3 ♀♀ ; benf 55, 1 ♂, 12 ♀♀, 1 dn; benf 56, 2 ♂♂, 2 ♀♀, 8 dn; benf 57, 1 ♂, 3 ♀♀, 1 dn; benf 58, 3 ♂♂, 6 ♀♀, 4 dn; benf 59, 2 ♂♂, 5 ♀♀; benf 75, 1 ♂, 4 dn; benf 78, 1 ♂; benf 82, 1 ♂; benf 87, 3 ♂♂, 1 ♀; benf 90, 11 ♂♂, 11 ♀♀; benf 171, 2 ♀♀; benf 172, 1 ♂, 2 ♀♀ ( Gerecke & Di Sabatino 2013, MCSNV); (under the name “ A. nodipalpis ”) : Ang 1, 1 ♀; Ang 4, 1 ♂, 1 ♀; Ang 10, 1 ♀; Ang 20, 8 ♀♀; Ang 20 I, 1 ♂, 3 ♀♀; Ang 21, 1 ♂, 4 ♀♀; Ang 24, 4 ♀♀; Ang 36, 1 ♀; Ang 37, 1 ♀; Ang 38, 1 ♂´, 2 ♀♀; Ang 44, 3 ♀♀ ( Angelier 1954b, partim MNHN) ; Porto , middle course(200-1000 m) (no specimen numbers specified) ( Santucci 1971) .

DISTRIBUTION. — Most parts of Europe (not reported from the British Isles and Northern Fennoscandia), Asia Minor, Iran. First records from the area covered.

HABITAT. — Rhithrobiont. Middle order streams, in the area covered from 100 to 1800 m, most records from middle elevations.

REMARKS

In his general list, Angelier (1954b) published various records of A. nodipalpis , but without discussing the species. The only male deposited under this name in his collection (idiosoma only), as well as all other nodipalpis species-group males available from the area covered with a smooth excretory pore, show clearly the IV-L characters of A. robustus . An unambiguous separation of the latter species from A. nodipalpis is impossible in the female sex. However, in view of the taxonomic homogeneity of the documented males, I attribute most females from the area covered combining a finely striated integument, unsclerotized excretory pore, separate Vgl-1/2 and an I-L-5 with pointed, distanced setae S-1/2 to A. robustus . The only exception is made for three females under the name “ A. nodipalpis ” in coll. Angelier which are characterized by an excretory pore sclerite and represent A. ruffoi Gerecke & Di Sabatino, 2013 (see below). The presence of A. nodipalpis on Corsica is not confirmed. The arrangement of the acetabula is rather variable in these specimens, in most cases with the medial margin indented anterior and posterior to the medially rounded, subtriangular Ac-2. The range of the distance S-1-2 is 18-40, in most specimens 20-30 (mean 26), the S-1 is bluntly pointed, generally with a tiny, mediallydirected denticle, the range of the L ratio I-L-5/6 is 1.38-1.68 (mean 1.55), the L/H ratio IV-L-5 is 3.1-3.5 (mean 3.4), of I-L-6, 6.3-8.0 (mean 7.0).