Aprionus styloideus Mamaev & Berest, 1990

Jaschhof, Mathias & Jaschhof, Catrin, 2017, New species of Aprionus (Diptera, Cecidomyiidae, Micromyinae) from Sweden and other parts of the Palearctic region, European Journal of Taxonomy 378, pp. 1-38 : 21-23

Aprionus styloideus Mamaev & Berest, 1990

Fig. 12

Aprionus styloideus , originally described from Ukraine, was previously thought to be synonymous with A. paludosus , based on the misapprehension that the holotype was just a slightly aberrant specimen (see Jaschhof & Jaschhof 2009: 244). Specimens now at our disposal, more than 20 from different localities in Sweden and Germany, display exactly the same morphological peculiarities found in the

holotype of A. styloideus . This we think is convincing evidence that A. styloideus is a species distinct from A. paludosus .

Diagnosis

The most important distinction is the shape of the gonostylus, which is only slightly convex and narrow basally, then evenly tapered towards the apex, and without a broadening at the base of the apical tooth (↓, Fig. 12A ); altogether this results in a slender appearance. The size of the gonostylar tooth is subject to some variation, but may also depend on the viewing angle. The tegmen is 2.5 times as long as wide, thus shorter than in most other group members, with the greatest width found at about the midlength; the 1–2 large and 1–2 small finger pairs are essentially posteriorly oriented, so that fingers intersect only slightly (↓) or not at all; the tegminal apex is rounded (↓), occasionally blunt-ended. The minimum observed in our specimens is 1 pair each of large and small, non-intersecting fingers, which is exactly the condition in the holotype. The sclerotizations at the anterior corners of the subanal plate are large and commashaped (↓). The gonocoxal apodemes are so short that the dorsal bridge, which is broadly rounded, extends only slightly, or not at all, beyond the ventroanterior gonocoxal edge (↓). The postfrons bears a single pair of setae; antennal translucent sensilla are single-pointed; the neck of the fourth flagellomere is longer than the node ( Fig. 12B ); the palpus may be either 3- or 4-segmented; and postocular bristles number 6–7.

Material studied

SWEDEN (10 specimens in NHRS, 9 in DEI): 1 ♂, Öland, Mörbylånga, Stora Dalby forest NR, 56.47° N, 16.45° E, mixed broadleaf forest, MT, MCJ leg., 8 Jun.–8 Jul. 2015 (no. CEC 309); 3 ♂♂, Mörbylånga, Vickleby ädellövskog NR, 56.59° N, 16.43° E, mixed broadleaf forest, MT, MCJ leg., 15 Jul.–3 Oct. 2015 (nos CEC 310– CEC 312); 1 ♂, Mörbylånga, Gamla Skogsby, 56.61° N, 16.51° E, mixed broadleaf forest, MT, MCJ leg., 15 Jul.–17 Aug. 2015 (no. CEC 313); 6 ♂♂, Mörbylånga, Kalkstad NR, 56.60° N, 16.50° E, mixed broadleaf forest, MT, MCJ leg., 28 May–27 Jun. 2014 (nos CEC 314– CEC 319); 1 ♂, same data, but 31 Jul.–27 Aug. 2014 (no. CEC 320); 1 ♂, Öland, Borgholm, Rönnerum-Abbantorp NR, 56.75° N, 16.62° E, mixed broadleaf forest, MT, MCJ leg., 16 Jul.–21. Aug. 2015 (no. CEC 321); 2 ♂♂, Östergötland, Ödeshög, Omberg, Stocklycke, 58.18° N, 14.37 ° E, broadleaf forest, MT, SMTP (trap 14, collecting event 1651), 28 May–15 Jun. 2005 (nos CEC 322– CEC 323); 4 ♂♂, same locality, but meadow, MT, SMTP (trap 13, collecting event 1647), 2–23 Aug. 2005 (nos CEC 324– CEC 327).

GERMANY: 4 ♂♂, Mecklenburg-Vorpommern, Karbow, 15 km SE of Greifswald, swamp forest of alder and ash, ground emergence trap, MJ leg., 2–16 Jun. 1995 ( DEI, nos A2322–A2325).

Distribution and phenology

Sweden (Öland, Östergötland), Germany (Mecklenburg-Vorpommern), Ukraine. Adults were collected from June to August in various broadleaf forests, often with a considerable proportion of ash trees.

Species of the halteratus group unassigned to subgroup

Gathered here are Aprionus whose male morphology fits the definition of the halteratus group, but does not suggest a closer affinity to any of the subgroups. Besides the new species described below, Aprionus brachypterus and A. fennicus Jaschhof, 2009 are placed here.

Figures

Fig. 12. Aprionus styloideus Mamaev & Berest, 1990, ♂, specimen from Öland (Sweden). A. Genitalia, ventral. B. Fourth flagellomere, lateral. Scale lines: 0.05 mm. Arrows indicate diagnostic characters.