Trichosiopsis vilkamaai

Taxonavigation

Ordo: Diptera
Familia: Sciaridae
Genus: Trichosiopsis

Name

Trichosiopsis vilkamaai  unpublished

Type material

Holotype: ♂, 23.08.2014, Malaise trap, leg. Salmela, ZFMK-TIS-2567749 in ZFMK

Type locality

Finland, Lapland, Rovaniemi, Sorvanulkki, 66.4925 N 25.6939 E

Other material studied

Finland: 1 ♂, LK, Parikkala, Lake Siikalahti: birch/alder swamp forest, sweep netting, Jaschhof, 24.06.2004, PKHH 6422; Germany: 3 ♂, Baden-Württemberg, Bad Buchau, Federsee nahe Bannwald, Malaise trap, Doczkal, 24.5.-14.07.2003, PKHH 4504/4805. DD 18; Sweden: 1 ♂, Småland, Bäckebo, Grytsjöns naturreservat, Old moisty haymaking meadow in forest edge, Malaise trap, Swedish Malaise Trap Project, 18.5.-15.06.2006, PKHH 6872.

Description (male)

Head. Eye bridge 4–5 rows of facets. Antenna unicolour. LW-index of 4^th flagellomere 2.1–2.5; neck 0.3–0.45 × segment width; transition of basal part to neck pronounced. Colour of neck unicolour. Antennal setae shorter than segment width; of normal strength. Sensillae present. Antennal setae salient. Palpus darkened; of normal length; palpomeres 3. First palpomere of normal shape; with 1–4 setae; with only sparse sensilla. Second palpomere short and oval. Third palpomere as long as first. Thorax. Colour brown. Notum unicolour. Thoracic setae long and strong, or normal; brown. Posterior pronotum setose. Postpronotal setae 2–5; strong. Mesothoracic sclerites bare. Legs. Colour brown. Hind coxa of same colour as femora. Setae on front coxa black. Front tibial organ as patch of setae; dark; front tibial organ not bordered. Tibial setae on hind legs normal, shorter than tibial width. Tibial spurs of equal length. Claws untoothed. Wing. Wing slightly darkened; with weakly developed anal lobe. Wing membrane without macrotrichia. Wing venation weak, with faint stM. M-fork of normal shape. R₁ ending at or slightly before base of m-fork; posterior veins with macrotrichia; stM with a few macrotrichia; CuA₁ and CuA₂ mostly with macrotrichia; bM bare; r-m mostly setose; bM:r-M 0.6–0.9; st-Cu:bM 0.2–0.5; R₁:R 1.5–1.9; c:w 0.7–0.78. Halter darkened; of normal length. Abdomen. Abdominal setae strong; dense; on tergites black; on sternites black. Hypopygium concolour with abdomen; LW-index 0.6–0.7. Base of gonocoxites with weak setae; gonocoxites broadly separated; inner margin of gonocoxites typically U-shaped; inner membrane of hypopygium scarcely setose; ventral margin of gonocoxite with short setae. Gonostylus elongate; LW-index 1.5–1.85; Inner margin concave; apex equally rounded. Apical tooth present; without internal structure; strong; LW-Index 2.5–4. Awl-like setae long; beneath apical tooth absent. Megasetae absent. Whiplash-hair absent. Tegmen 0.55–0.75 × longer than broad; rectangular with rounded edges, or rectangular with sharp edges; without special features; central process absent. Length of ejaculatory apodeme/hypopygium 24–38 %; base of ejaculatory apodeme absent. Field with aedeagal teeth inconspicuous. Measurements. Body size 2.8–3.8 mm. Hind tibia 1.3–1.6 mm. Wing length 2.8–3.3 mm.

Diagnosis

The species is most similar and very closely related to Trichosiopsis illustris. The main difference is the shape of the gonostylus, which is thicker and less concave in Tr. vilkamaai. For comparison with other related species see under Tr. illustris.

DNA Barcoding

The COI sequence is assigned to BIN BOLD:ADG4437 (n=1, K2P: 3.7%).

Etymology

The name of the new species is dedicated to Dr. Pekka Vilkamaa (Helsinki), in honour for his eminent contributions to the knowledge of Sciaridae during the past decades.

Discussion

It has first been considered to rank this taxon only as subspecies of Tr. illustris, because the genetic distance of less than 4% is quite low in comparison with most other species of Trichosiopsis. Also, only one single barcoded specimen is available at the moment, it is not certain, whether the different shaped gonostylus is really species specific. The other material shows some variation in the width and concavity of the gonostylus. This character is also often difficult to see, as it depends much on the mounting position of the gonostylus. Particularly the three specimens from Germany cannot be assigned with certainty to this species and may belong to just another species or subspecies.

Distribution

Finland, Germany, Sweden.

Images

Figure 1. Trichosiopsis vilkamaai male, habitus, scale 1.0 mm  Figure 2. Trichosiopsis vilkamaai male, hypopygium (holotype), scale 0.1 mm  Figure 3. Trichosiopsis vilkamaai male, gonostylus (holotype), scale 0.1 mm