Atractides (Polymegapus)

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 : 341-342

SUBGENUS POLYMEGAPUS K. VIETS, 1926

Diagnosis: Integument with a robust, irregular lineation, dorsum and ventrum with sclerotized muscle attachments; I-L-5 ventrally projecting (vL> dL), its distal margin calyciform, setal interspace narrow, S-1 and -2 strongly heteromorphic and partly embracing each other; whip-like seta long and fine; I-L-6 stout, very thick at its base, with distally strongly converging dorsal and ventral margins; Cx-4 with triangular laterocaudal extensions of secondary sclerite, Ac minute, 3–10 pairs; excretory pore sclerotized; gnathosoma short and robust, palp without ventral extensions on P-2 and -3, sword seta on P-4 very strong, finger-like, inserting proximal to proximoventral hair, P-5 long and slender.

Discussion: In the definition presented here, Polymegapus is a rather isolated taxon not connected by intermediate species with Atractides s.s. Future studies of larval morphology and behaviour should make clear if its placement as a subgenus in Atractides reflects phylogenetic relationships, or whether Polymegapus has evolved independently from Atractides - like ancestors. Because of their position on the same level, S-1 and S-2 cannot be recognized with certainty. As S-1, in most species of the other subgenera placed more proximally, is generally the longer and more slen- der one, in all species of the subgenus Polymegapus the longer and more slender seta is designated S-1.

ATRACTIDES POLYPORUS (K. VIETS, 1922)

( FIGS 84D–F , 90A–D )

Megapus polyporus K. Viets, 1922

Type series: Lectotype ♂, here designated, slide-mounted together with 3 paralectotype ♀, SMF 2768 , Atractides polyporus (Viets) ♂ ♀ Type; Vogler Breitegrund 59/60 Quelle 21.7.1920 [= Vogler 4] Viets leg. 2768. State of conservation: mounting fluid with precipitations, lectotype idiosoma in toto, gnathosoma separate, laterally, left palp, both chelicerae and right I-/IV-L separate, genital skeleton lacking. Further paralectotypes: SMF 2758 Atractides polyporus (Viets) ♂ ♀ Type Vogler Quelle i. Kohlhai 65/66 20.7.1920 [= Vogler 3] Viets leg. 2758 4 ♂, 2 ♀. Further loci typici: Vogler 2, zw. Riehenberg 55 u. Kohlhai 65 290 m 9.4∞C 20.7.1920; Vogler 5 Sickerquelle Breitegrund 61 – Fisenke 62, 10.0∞C, 300 m, 21.7.1920 ( Niphargus ); Vogler 11 Quelle (Ausfluss der unterirdischen Entwässerung einer höher gelegenen Weide) an der Chaussee Oelkassen-Scharfeldendorf, 11∞C, 23.7.1920; Vogler 12 Sickerquelle Kohlhai 65 Abhang nach dem Hüttebach , gegenüber Fuchsloch , 68/ 69, 250 m, 14∞C 24.7.1920; Ith 2, 1.5 km E Dielmissen im Forst am Ithalhange (Vordere Ith 32/33 – Mittl. Ith 34) 220 m, 13∞C, 23.7.1920; Ith 3 Quelle im Eschengrund , Vord. Ith 32/ 33, 220 m, 10.7∞C-11.5∞C, 23.7.1920; Ith 4, Quelloch Chaussee Scharfeldendorf-Kapellenhagen zw. km 3.9 M 3.8, 250 m, 13∞C, 23.7.1920; Ith 5, Qu. unterh. Rothestein-Höhle, 260 m, 11.5– 13∞C, 23.7.1920, Hüttebach, 20.7.1920.

Material examined: (in coll. Gerecke) Italy, Peloritani ( ME), DePietro & LaRocca: Idp48, Frascianida, Sta Venera del Bosco, 450 m, WC1909, 23.06.1995 1 ♀, Idp67, Gualtieri Sicaminò, sorgente pressi Cascate Cataolo, 210 m, WC2920, 29.05.1996 2 ♂, 4 ♀ ( SEM) .

Description:

General features

Lectotype, in parentheses paralectotype dorsal integument: striated; muscle attachments: sclerotized, prefr, postoc, Dgl-3 and D-1 on paired triangular plates, D-2, -3, and -5 as extended, paired irregular plates, D-4 medially fused to a rhombic medial plate, Dgl- 4, -5, and -6 with extended sclerite margins; ventrally a round median plate anterior from the genital field, V-1 fused with Vgl-3, V-3 with Vgl-4, V-2 separate coxal field: mediocaudal margin Cx-1 + 2 equally rounded, Cx-3 medially pointed, medial margin of Cx-3 + 4 formed exclusively by Cx-4

genital field: with 14–20 acetabula

I-L: S-1 distally ending in a fine, flagellum-like tip excretory pore: sclerotized; Vgl-1: fused to Vgl-2

palp: ventral margin P-4 3: 1: 3

Males

Lectotype, in parentheses paralectotype genital field: with extended secondary sclerite; anterior margin equally rounded, excretory pore sclerite and Vgl-1 + 2 fused to the posterior margin;

genital setae: 58 idiosoma L/W 480/400 (460/360); glandularia 40

coxal field L 246 (238); Cx-3 W 302 (293); Cx-1 + 2 mL 100 (108), IL 172 (193), W 237 (238)

I-L-5 dL (110), vL (116), dL/vL (0.95), HA-HC (31, 43, 43), dL/HB (2.56)

S-1 L (48), L/W (8.0), S-2 L (47), L/W (3.9), interspace 0, L S-1/2 (1.02)

I-L-6 L (61), HA-HC (23, 13, 10), dL/HB (4.69); L I-L-5/6 (1.80)

genital field L/W 128/161 (123/165), Ac L 9–20

gnathosoma vL 100; chelicera –

Figures

Figure 84. Morphology of the subgenera Tympanomegapus and Polymegapus. A–C, A. acutirostris ♀ (Sicily 1079 g). A, Cx- 1 + 2 and gnathosoma, oblique ventral view, Scale bar = 100 µm; B, P-5 lateral view, Scale bar = 10 µm; C, P-5 dorsally, Scale bar = 20 µm; D–F, A. polyporus (Sicily dp67); D, I-L-5 and -6, Scale bar = 10 µm; E, dorsum, Scale bar = 100 µm; F, Dgl-4, Scale bar = 20 µm.

Figure 90. Atractides polyporus, A, B, lectotype ♂ SMF 2768; C, D, paralectotypes SMF 2768, 2758. A, ♂ ventrum, partial view; B, ♂ gnathosoma and right palp, medial view; C, ♂ I-L-5 and -6; ♀ genital field. Scale bars = 100 µm.