Aturus intermedius Protz, 1900

Gerecke, Reinhard, 2014, Studies on European species of the water mite family Aturidae Thor (Acari: Hydrachnidia), Zootaxa 3841 (1), pp. 1-46 : 10-12

Aturus intermedius Protz, 1900

Figs 1 , 7

Aturus oudemansi Besseling, 1932 , nov. syn.

Material examined. Type series: Syntypus ♂ SMF 42858, " Aturus intermedius Protz ♂ Co-type, Ost-Preußen, Omaza-Fließ bei Heiligenbeil. 9.1900 Protz leg. 1444". SMF 42920/21, same site and date without species identification, 42920 ♂, 42921 2 ♂♂.

France: Corsica, FR 69 (1/0/0). Italy: Lazio, I 888 (1/1/0); Sardinia, I 1162 (2/2/0); Sicily, I 133 (2/1/0), I 168 (1/0/0), I 180 (1/1/0), I 181 (2/3/0), I 237 (2/2/0); Spain: Aragon, E 131a (2/6/0), E 131b (0/4/0), E 131c (0/1/0); Alabacete, E 166 (1/1/0); SMNH NHRS-GULI 0 0 0 0 0 2768, ♂ " Aturus intermedius Protz ♂. " Fjällback 30 km nordost Granada. 12.6.1935. Leg. O. Lundblad.", NHMB 4546 ♂; Sweden: SMNH NHRS-GULI 0 0 0 0 0 2769, 2 ♂♂ " Aturus intermedius Protz ♂. Skåne. Brösarp, Värkeån 18.5.1936. Leg. O. Lundblad."; Switzerland: " Aturus intermedius ♂ Protz, 1900 Lützel, Moos Coll. Schiess."; NHMB 4547 , ditto ♀.

Uncertain records. France: Corsica, F 46 (0/5/0), F 81 (0/4/0); Italy: Calabria, 1083 (0/1/0); Lazio, I 1291 (0/ 2/0); Sardinia, I 340 (0/9/0), I 349 (0/6/0), I 373 (0/2/0), I 381 (0/5/0), I 382 (0/1/0), I 390 (0/1/0), I 391 Int (0/1/0); Sicily, I 177 (0/3/1), I 214 (0/1/0), I 618 (0/1/0).

Aturus oudemansi Besseling, 1932 , type series: Lectotype, here designated: Naturalis Biodiversity Center, Leiden, " Aturus oudemansi Besseling ♂ Geul bij Tergraat, Epen, Prov. Limburg, Nederland, IVII 1949 leg. Besseling", undissected in Koenike's fluid.

First record from Corsica.

Redescription. The original description of this species is incomplete from many points of view and considers several character states now known to be of little significance for species definition in Aturus . Following Protz (1900), revision of the syntype and investigation of additional material, male A. intermedius show the following morphological characteristics: Idiosoma with subparallel lateral margins, posteriorly equally rounded, without projections flanking the gonopore slit. Posterior part of dorsal shield flattened, in the transition area to ventral field on each side an anteriorly-directed bowed line of fine setae (medially very dense and converging anteriorly, in the lateral part more curved and directed upwardly) embracing an oval field with fine hair-like setae. Dgl-1 with strong bi- or trifurcated setae, setae of all other Dgl simple, long. Lgl in the dorsal furrow, close together or Lgl-1 distanced from the remaining gland platelets. Lgl-3 and -4 side by side or fused; setae Lgl-1 and –2 strong, bifurcated, Lgl-3 and –4 short and simple, hair-like. All setae situated along the posterolateral and posterior margin particularly fine and densely-arranged; except for a few longer ones at the posterolateral edges, equal in size from the upwardly-bent ventral shield flanks up to the gonopore area, none of them with "onion-like" basal inflation. Gonopore flanked by two pairs of enlarged, club-shaped setae; genital field with 10–15 pairs of Ac (2–3 flanking the gonopore and directed ventrocaudally). Leg claws with dorsal and ventral clawlet. A particular elongated distal seta on III-L-4 of specimens from Switzerland and Spain, but not in the holotype (possibly lost by damage). III-L- 5 with about 25 setae; most of them strong, but simple, arranged in a dense longish group over the distal 2/3 of the ventral margin, three (slightly thickened and distally curved) located together on a flat posteroventral projection, and two strongly thickened, elongated and whip-like at posterior side of distal margin. IV-L-4 dorsal and ventral margin gradually diverging from base to tip, distal margin with two long ventral sword setae (one distinctly more enlarged than the other), six long, slender and pointed, three of them slightly set off from ventrodistal edge. IV-L-5 curved, proximally with a convex or bluntly pointed inflation surrounded by 4–5 leaf-like setae with strongly denticulate margins, and a line of 5–6 equally-distanced slender and simple setae; distal margin bearing about 8 setae, most of them simple, fine and short or normal in size, one irregularly-curved, long and flattened.

Females collected together with male A. intermedius (NHMB 4547, coll. GER – attribution often uncertain due to coexistence of several congeners) are characterized as follows: Idiosoma rather slender (L/W 400–450/300–350, maximum width in centre, posterior margin parabola-shaped, medially indented. Dorsal shield L/W 350–390/ 280–310, with steep lateral edges; Dgl-4 far distanced from Dgl-3 at posterolateral margin (distance ratio Dgl-3–4/ 4–5, 2.8–4.1), posterior area of secondary sclerotization trapezoidal in shape, including excretory pore (directed posteriorly) and Dgl-6 (directed posterolaterally); Vgl at the line separating primary from secondary sclerotization. Acetabular plates close to posterior margin of ventral shield, bearing 1–2 fine setae near medial edge and 8–12 pairs of Ac, some of which distinctly larger than the remaining, lateral Ac partly in double or triple rows. Palp measurements: P-1, 21–22/17–20; P-2 (excluding pointed distoventral projection) 54–58/40–47; P-3, 33–36/ 29–33; P-4, 76–84/25–28; P-5, 35–37/13–14.

The lectotype of A. oudemansi agrees in all details described here with the syntypes of A. intermedius , and is obviously its junior synonym.

Figures

FIGURE 1. Aturus intermedius (I 181), SEM photographs. A. – E. male; A. IV-L posterior; B. IV-L- 4 – 5 anteroventral; C. IV-L- 4 – 5 posteroventral; D. IV-L- 4 – 5 ventral; E. posterior dorsum with balloon-like perigenitalsetae; F. – G., female; F. posterior dorsum; G. genital field posterolaterally. Scale bars: A: 50 µm; B – G 20 µm.

FIGURE 7. Aturus intermedius, male. A. IV-L- 4 – 5 anterior; B. IV-L- 4 – 5 posterior; C. dorsum; D. III-L- 4 – 5. Scale bars = 100 µm.