Discourella helvetica, Kontschán & H-, 2011

Kontschán, Jenó, 2011, New Uropodina records from Switzerland (Acari: Mesostigmata) with the description of Discourella helvetica n. sp., Revue suisse de Zoologie 118 (1), pp. 99-106 : 103-106

Discourella helvetica sp. n. Figs 1-10

HOLOTYPE: MHNG, without registration number; female; Switzerland, Ticino, Ascona, Monte Veritá , 450 m, from dead leaves and soil; 5.XI.1982; leg. C. Besuchet.

PARATYPES: MHNG, without registration number; two females in alcohol; HNHM, without registration number; one female with gold-palladium coating and stored on aluminium stub; all with same data as for holotype .

DIAGNOSIS: All dorsal, marginal and postdorsal setae needle-like. Postdorsal and marginal shields lacking, postdorsal setae are placed on small platelets. Genital shield of female linguliform, situated between coxae II and IV, with irregular pits on its surface and bearing a crown-like process on its anterior margin.

DESCRIPTION OF FEMALE: Length of idiosoma 610-620 µ m, width 430-440 µ m (n=4). Body shape oval, posterior margin rounded.

Dorsal aspect of idiosoma (Fig. 1): All dorsal setae short, smooth and needlelike. Dorsal shield with irregular pits (Fig. 2), marginal shield lacking. Margins of idiosoma bearing needle-like setae. Postdorsal shield lacking, postdorsal setae similar to dorsal setae and placed on small and rounded platelets.

Ventral aspect of idiosoma (Figs 3, 7): Ornamentation of sternal shield lacking, all sternal setae short, smooth and needle-like. Ventral shield bearing an irregularly formed depression near basal part of genital shield. All ventral setae short, smooth and needle-like. Metapodal lines well developed, surface near metapodal lines (Fig. 10) and between metapodal lines covered by large irregular pits (Fig. 11), central part of ventral shield without sculptural pattern. Stigmata situated near coxae III. Peritremes straight. Genital shield of female linguliform, placed between coxae II and IV, with small irregular pits and with crown-like process on its anterior margin (Fig. 8).

FIGS 1-6

Discourella helvetica n. sp., female holotype. (1) Body in dorsal view. (2) Ornamentation of dorsal shield. (3) Body in ventral view. (4) Ventral view of gnathosoma. (5) Epistome. (6) Chelicera. Scale bars: 100 µm (1, 3), 20 µm (2, 4-6).

Gnathosoma (Figs 4, 9): Corniculi horn-like, internal malae long and apically serrate. Hypostomal setae: h1 long, smooth, setiform bearing spines basally; h2 0.25% of h1, smooth and setiform; h3 two times longer than h2 and apically bifurcated; h4 as long as h2, their margins serrate. Epistome basally serrate and apically pilose (Fig. 5). Tritosternum with narrow basis, apically subdivided into three visible branches. Chelicerae without nodes, fixed digit longer than movable digit (Fig. 6).

FIGS 7-11

Scanning micrographs of Discourella helvetica n. sp., female paratype. (7) Body in ventral view. (8) Genital region. (9) Ventral view of gnathosoma. (10) Ornamentation on lateral side of body. (11) Body in lateral view. Scale bars: 100 µm (7, 11), 20 µm (8-10).

Legs. Coxae of legs ornamented with alveolar pits, surface of other leg segments smooth. All legs bearing ambulacral claws and smooth and needle-like setae. Male, nymphs and larva unknown.

ETYMOLOGY: The species name, an adjective, refers to the Latin name of

Switzerland (Helvetia).

REMARKS: The new species belongs to the stammeri -species group (see

Hirschmann 1972). Four known species were previously placed in this group; their common character is the absence of the marginal shield. Only one of these species is known from Europe (D. stammeri Hirschmann & Zirngiebl-Nicol, 1969), one species was described from Japan (D. fumiakii Hiramatsu, 1980), another one was found in Mongolia (D. kaszabi Hirschmann, 1972), and the occurrence of the fourth species (D. eustructura Hirschmann, 1972) is unknown. The most important differences between these four species and the new species are summarized in Table 1.

TABLE 1. Distinguishing characters of the species in the Discourella stammeri species group

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