Atractides dubius, (SOKOLOW, 1940)

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 : 234

ATRACTIDES DUBIUS ( SOKOLOW, 1940)

Megapus spinipes var.? Sokolow, 1927

Megapus spinipes dubius Sokolow, 1940

Syn. to A. arcuatus ( Thor, 1914) : syn. nov.

Type series: Holotype ♀ ZISP 418 Type ♀ Megapus [cancelled: nodipalpis Thor var.I] spinipes var. caucasica n.v. I.Sokolow det.; Kaukas. 8.XI.24 Rugenj. W.Tr.G. 9.1.07 Wlduk. (No.13) Tarnogradskij leg.; comparison with figure 159 in Sokolow (1940) indicates that the description of A. dubius was based on this specimen. The name caucasica was not published by Sokolow, possibly in view of the already existing name kaukasiensis Thor, 1914 . State of conservation: idiosoma with separate dorsum, ventrum strapped in two areas, genital field separate from coxal field, all left legs missing or heavily damaged; gnathosoma separate, lateral, with palps and chelicerae in situ; two eggs.

Description: see under A. arcuatus .

Discussion: At the time when this taxon was described, the morphology of A. spinipes was poorly understood. Sokolow characterized it by unfused, paired genital plates in males (thus, a character of misshaped intersexual specimens) and P-3 and P-4 equal in L in females (a character within the range of variability of A. nodipalpis ). Furthermore, as also done by Halbert (1911), Sokolow attributed to A. spinipes the presence of swimming hairs on legs, a character within the subgenus restricted to A. ovalis .

Atractides dubius differs from all specimens pooled by various authors at that time under the name of A. spinipes due to the lineated integument. From this point of view, it is probably similar to the little known A. arcuatus , a species described from the Caucasus as well, of which the type material is lost. If we compare the available information, there is agreement in dimensions and arrangement of Ac, and in shape and setation of palp. Regarding idiosoma and palp measurements, A. dubius exceeds the values provided for A. arcuatus , but the measurement differences could be examples of normal intraspecific variability. No useful information is available on the morphology of the female I-L-5 and - 6 in A. arcuatus . In male A. arcuatus , I-L-5 is more slender than in the type of A. dubius , but in this regard we observe sexual dimorphism also in other Atractides species. The I-L-5/6 L ratio (1.31) is identical in the male A. arcuatus and the female A. dubius . The available information suggests that A. dubius is a synonym of A. arcuatus , a species that merits a detailed redescription.

ATRACTIDES ROBUSTUS ( SOKOLOW, 1940)

( FIGS 42A–H , 43H )

Megapus nodipalpis robustus Sokolow, 1940

Type series: Syntypes ♂, ZISP 1 /889 [red] N 392 type ♂ Megapus nodipalpis var. robustus n.var.; Kuban [..] 15.VIII.32 Tarnogradskij [..] 2 ♂ on one slide. Lectotype: the specimen near the species label. State of conservation: dorsum separate, coxae longitudinally fractured (measurement impossible), gnathosoma and left I-L separate, chelicerae and right palp isolated, P-3 broken, Gsk missing. Paralectotype: the specimen near the collecting site label. State of conservation: idiosoma broken in two parts, genital field missing, gnathosoma and both I-L in situ, one palp separate. Paralectotype: ♀, ZISP 2 /890 [red] N 397 Type ♀ Megapus nodipalpis S.Thor var. robustus n.var.; [..] 6.IX.32 Tarnogradskij [..] 1 ♀. State of conservation: dorsum separate, gnathosoma in situ, both palps and left I-L separate, right I-L- missing. Locus typicus: Caucasus, widely distributed in affluents of Kuban river . Further collecting area mentioned in the first description: Kolskij peninsula, Warsuga river (coll. W. I. Schadin) .

Material examined: ZISP 393, 398, 400, 410, all labelled Megapus nodipalpis S.Thor var. robustus nov. var. and Kuban [..] Tarnogradskij, collecting dates VIII/ IX 1932; SMF KOViets 1521 ‘Harz Kellwasser’ 1 ♂, 1 ♀.

Description:

General features dorsal integument: striated (9/10); muscle attachments: unsclerotized genital field: Ac in triangular arrangement

I-L: I-L-5 with diverging ventral and dorsal margins, S-1–2 with blunt tips, S- 1 longish, slender, S-2 thickened in basal third; I-L-6 curved, slender, maximum height basally genital field: Ac large, in a triangle excretory pore: smooth; Vgl-1: not fused to Vgl-2

palp: strong sexual dimorphism; P-4 1: 1: 1, sword seta long, near proximoventral hair

IV-L-4/5 distally swollen and with pointed sheaths covering the base of the following segment

Males

Lectotype genital field: anterior margin indented, posterior margin deeply indented, with a small medial extension in the posterior bay, Ac-3 long, distally narrowed; genital setae: 70

palp: ventral margin P-2 with strongly pointed ventrodistal protrusion, separated by a small longitudinal sulcus from a convexly rounded lateral area, P-3 concave, P-4 strongly thickened near proximoventral hair, sword seta proximal to proximoventral hair idiosoma L/W 1000/730; glandularia 27

coxal field L 450; Cx-3 W –; Cx-1 + 2 mL 139, Il 338, W 448

I-L-5 dL 270, vL 193, dL/vL 1.40, HA-HC 67, 81, 92, dl/HB 3.33

S-1 L 132, L/ W 14.7, S-2 L 100, L/ W 9.1, interspace 29, L S-1/2 1.32

I-L-6 L 193, HA-HC 36, 22, 31, dL/HB 8.77; L I-L-5/6 1.40

genital field L/W 189/224, Ac-1–3 L 55-68-87

gnathosoma vL 224; chelicera L 323, L/H 5.98, bS/claw 2.26

Figures

Figure 42. Atractides robustus. A–D, lectotype ♂ ZISP 1/889; E–H paralectotype ♀ ZISP 2/840. A, ♂ palp, lateral view; B, ♂ palp, medial view; C, ♂ I-L-5 and -6; D, ♂ genital field, E, ♀ mediocaudal edge of Cx-1 + 2; F, genital field; G, ♀ I-L-5 and -6; H, ♀ palp, medial view; Scale bars = 100 µm.

Figure 43. A–G, Atractides maderensis. A–C, paratype ♀ SMNH 2919; D–F, holotype ♂ SMNH 2918; G, paratype ♂ SMNH prep. Gerecke. A, ♀ I-L-5 and -6; B, ♀ palp, medial view; C, ♀ genital field (without right genital plate); D, ♂ genital field, E, ♂ excretory pore and Vgl-1/2; F, ♂ coxal field; G, ♂ palp, medial view. H, Atractides robustus lectotype ♂ ZISP 1/ 889 IV-L-3–5; I (for comparison) A. nodipalpis, S Germany; D, 459, IV-L-3–5. Scale bars = 100 µm.