Aprionus thori, Jaschhof & Jaschhof, 2017

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 : 12-14

Aprionus thori sp. nov.

urn:lsid:zoobank.org:act:80B22178-C33B-4E10-938D-3DF5E6819571

Fig. 6

Diagnosis

A typical representative of the insignis group, Aprionus thori sp. nov. is distinguished by the following male genitalic characters in combination ( Fig. 6A ): the gonostylus, which is strongly convex posteriorly, has a flat depression subapically above the tooth (↓); the tegmen, with 3–4 large finger pairs, is bluntended (↓); and the gonocoxal projections are prominent (↓).

Etymology

Thor, the god of thunder, is the son of Odin and his mistress, Jörd.

Material examined

Holotype

SWEDEN: ♂, Småland , Nybro , Bäckebo, Grytsjön Nature Reserve, 56.92° N, 16.10° E, tall coniferous forest with aspen trees, Malaise trap, M. and C. Jaschhof leg., 17 Jul.–21 Aug. 2015 ( NHRS, no. CEC283 ).

Paratypes

SWEDEN: 1 ♂, same data as for the holotype ( NHRS, no. CEC 284); 1 ♂, same data, but 17 Jul.– 11 Aug. 2014 ( NHRS, no. CEC 285).

Other material studied

SWEDEN: 2 ♂♂, Uppland, Uppsala, Fiby NR, 59.88° N, 17.34° E, swampy mixed taiga, near aspen log, MT, MCJ leg., 9 Jun.–23 Jul. 2010 ( DEI, nos CEC 286– CEC 287).

Differential diagnosis

Aprionus insignis , a species similar to Aprionus thori sp. nov., differs as follows: the gonostylus has no depression above the apical tooth; the tooth is smaller and flattened like a fingernail, not solid; the gonocoxal projections are smaller; and the tegmen, with only 2 finger pairs, is rounded apically (see Jaschhof 1998: fig. 161a–c).

Other characters

Body size 1.3 mm.

HEAD. Eye bridge 3 ommatidia long dorsally. A dense row of 8–9 postocular bristles. Neck of fourth flagellomere shorter than node; 3–4 thick, simply hair-shaped translucent sensilla ( Fig. 6B ). Palpus with 3 segments, first segment slightly swollen, apical segment longest of all.

WING. ApicR 1 2–3 times as long as Rs.

LEGS. Claws subrectangular, 2 fine teeth. Empodia rudimentary.

TERMINALIA ( Fig. 6A ). Ninth tergite subrectangular, anterior margin fully sclerotized, slightly concave medially. Gonocoxites slightly pointed ventroposteriorly; dorsal bridge massive, subrectangular. Gonostylus: basolateral apophysis conspicuously large; apical tooth solid, long, slightly curved; about 4 bristles subapicomedially, 0–1 bristles subapicoposteriorly. Tegmen with slightly intersecting large fingers, additionally 1–3 tiny, non-intersecting finger pairs. Subanal plate with dark markings both laterally and medially on posterior edge, less clearly on anterior edge.

Distribution and phenology

Sweden (Småland, Uppland). Adults were collected from June to August; the circumstances of collecting suggest the larval habitat of this species might be rotting aspen wood.

2) The styloideus subgroup of the halteratus group

Aprionus styloideus Mamaev & Berest, 1990 , previously considered to belong to the brachypterus subgroup ( Jaschhof & Jaschhof 2009: 243), is shown here to be a complex of several, morphologically distinct species that are better classified in a subgroup of their own, the styloideus subgroup. As this renders Aprionus brachypterus Edwards, 1938 the only remaining member of the brachypterus subgroup, this subdivision is abandoned here, with A. brachypterus left unassigned to subgroup within the halteratus group (see Jaschhof & Jaschhof 2009: 254).

Species of the styloideus subgroup, of which most are extremely similar to each other, share the following characters: the elongate gonostyli are flattened to various extents; the tegmen has either 1–3 posteriorly oriented finger pairs or no fingers; the subanal plate is extremely weak posteriorly, with only the anterior corners clearly visible as dark, mostly comma-shaped areas dorsolateral of the tegmen; and antennal translucent sensilla are either simple or branched. Besides the species treated below, the styloideus subgroup contains Aprionus cardiophorus Mamaev, 1963 (a species classified by Jaschhof & Jaschhof (2009) in the smirnovi group) and an unnamed species, of which our material is not sufficient for description. This subgroup is remarkable for including species that either possess or lack tegminal fingers, which indicates the weakness of this character as an indicator of relatedness.

Figures

Fig. 6. Aprionus thori sp. nov., holotype, ♂. A. Genitalia, ventral. B. Fourth flagellomere, lateral. Scale lines: 0.05 mm. Arrows indicate diagnostic characters.