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 : 340

ATRACTIDES GIBBERIMARGINATUS

(K. VIETS, 1955)

Atractides acutirostris gibberimarginatus K. Viets, 1955a

Syn. to Atractides acutirostris Motaş & Angelier, 1927 : syn. nov.

Type series: Holotypus ♂ SMF 7704 Atractides acutirostris gibberimarginatus ♂ Viets Type; Harz Okertal Düsterntal 8.10.52 Husmann coll. 7704.

Material examined: CSM, Donauversickerung Möhringen 11.9.60 1 ♂, 1 ♀, ‘ 19.7.1960 ’ 1 ♂. In all three specimens mouthparts badly crushed and desiccated, but idiosoma well conserved .

Discussion: Viets positioned this taxon as a subspecies to A. acutirostris , a species described from France, but in the male sex known only from Hungary at that time ( Szalay, 1935b), and provided a table with the characters which were, in his opinion, diagnostic. In fact, A. gibberimarginatus agrees in most important features with A. acutirostris . A dorsal inflation of P-4 and P-5 (after which the taxon is named) can also be observed in specimens belonging to the Sicilian population of A. acutirostris . The dorsal margin of these two segments may be inflated, mainly in juvenile, slightly sclerotized specimens. Several further characters, such as the shape of the posterior idiosoma margin, the thickness of the integument, and minor differences in measurements, are surely agedependent and of no taxonomic value. The apodemes of Cx-2 are in fact directed more caudally in the type of A. gibberimarginatus and more laterally in A. acutirostris . However, the three specimens published by Schwoerbel under the name of A. gibberimarginatus agree from this point of view with Szalay’s description of A. acutirostris . One of the I-L of the holotype of A. gibberimarginatus is misshaped: apart from the strange asymmetric extension at the base of one I-L-6 mentioned by Viets, the duplication of S-1 and -2 on I-L-5 is a developmental aberration. Therefore, the quite distal position of the ventral seta (distance insertion to distal edge 22 Mm) of this segment cannot be considered as taxonomically relevant. In fact, the other I-L is normal in this regard (distance 36 Mm). The differences in the dimensions of the genital field (relatively long in A. acutirostris ) are surely due to its nonhorizontal position in the type of A. gibberimarginatus . Last but not least, the diverging measurements of palp segments (in A. acutirostris L P- 2 = P-3, in A. gibberimarginatus L P-2 <P-3) are the result of Szalay’s measurement errors – in his figures, P-2 is clearly shorter than P-3. There is no serious taxonomic basis to this taxon, and A. gibberimarginatus is considered a junior synonym of A. acutirostris .

ATRACTIDES IBERICUS ( LUNDBLAD, 1956)

( FIG. 86K,L )

Atractides lacustris ibericus Lundblad, 1956

Type series: Holotype ♂ SMNH 4551 , Atractides lacustris f. ibericus ♂ Typus , Portugal, Santa Gomba, Bäck, 2.9.1935.

Material examined: Gerecke E 113, Andalucia, Parque Los Alcornocales, Jimena de la Frontera, Rio Hozgarganta , 40 m, TF 79 34, 01.04.1994 1 ♂ .

Description:

General features

Holotype, female unknown dorsal integument: striated; muscle attachments: extended dorsal shield including postoc and Dgl-3–5, extended ventral shield including genital field, all ventralia and Vgl, but excluding the excretory pore coxal field: completely fused I-L: setae S-1/2 slightly distanced, distally truncate excretory pore: smooth; Vgl-1: fused with Vgl-2 palp: P-4 ventral margin 3: 2: 2, sword seta enlarged, between ventral hairs,

P-5 without cheeks

Male

Holotype genital field: included into ventral shield; genital setae: 26

idiosoma L/W 460/363; glandularia –

coxal field L 286; Cx-3 W 306; Cx-1 + 2 mL 117, IL 204, W 231

I-L-5 dL 108, vL 85, dL/vL 1.27, HA-HC 26, 32, 35, dL/HB 3.38

S-1 L 38, L/ W 12.7, S-2 L 42, L/ W 10.5, interspace 4, L S-1/2 0.9

I-L-6 L 99, HA-HC 23, 23, 26, dL/HB 4.3; L I-L-5/6 1.09

genital field L/W 85/114, Ac-1–3 L ca. 20, 20, 20

gnathosoma vL 149; chelicera L 219, L/H 9.5, bS/claw 2.42

Figures

Figure 86. A–I Atractides lacustris, A–C, E–H, holotype ♂ SMNH; D, I paratype ♀. SMNH. A, ♂ coxal field; B, ♂ genital and postgenital field, partial view; C, ♂ frontal platelet with Dgl-1/2 and prefrontalia; D, ♀ genital field, E, ♂ I-L-5 and -6; F, ♂ chelicera; G, ♂ palp, medial view; H, ♂ gnathosoma, lateral view (with left P-1 in situ, directed rostrally), I ♀ P-4/5. K, L Atractides ibericus ♀ Gerecke E113. K palp, medial view, L I-L-5 and -6. Scale bars = 100 µm.