Platypalpus tuberculatus Jonassen, 2021

Jonassen, Terje, Andersen, Trond, Salmela, Jukka, Suuronen, Anna & Vaesoja, Matti, 2021, Six new species of Empididae and Hybotidae (Diptera, Empidoidea) from Fennoscandia, Norwegian Journal of Entomology 68, pp. 174-186 : 184-185

Platypalpus tuberculatus Jonassen sp. n.

( Figure 6A–B )

Type material. Holotype ♂, FINLAND: Lkor , Savukoski, Törmäoja, N67.8357° E29.4540°, 10 July–16 August 2012, Malaise trap, J. Salmela ( LMM: MH-EMPI-2012-0107).

DIffEREntIAL dIAgnOsIs. The combination of two pairs of vertical bristles, dusted mesonotum, moderately long and pointed mid-tibial spur,

biserial acrostichals and yellow thoracic bristles suggest an affinity to Platypalpus balticus Kovalev, 1971 , but P. tuberculatus sp. n. appears to have smaller palpus and lacks the sharply defined annulations of the tarsi. There are also differences in the terminalia, including a notched right margin of the left epandrial lamella in P. balticus (see Kovalev 1971: p. 119), this margin being rather straight in P. tuberculatus .

Description. Male. Body length 2.5 mm, wing length 2.0 mm.

Head. Black, greyish dusted. Frons about as broad as the distance between hind ocelli, only slightly narrowing in front. Face slightly narrower than frons, greyish dusted. Clypeus polished black. With 2 pairs of vertical bristles, postocular pubescence light brownish to whitish. Antenna black. Palpus yellow, very small and oval. Proboscis brownish black.

Thorax. Black, mesonotum completely dusted, pleura largely dusted, but sternopleuron with anterior polished patch. Acrostichals small, biserial, distance to dorsocentrals somewhat longer than distance between the rows of acrostichals. Dorsocentrals small, not longer than acrostichals, seemingly multiserial, some pubescence similar in size to the dorsocentrals continuing to the sides of mesonotum. With 1 humeral bristle and 2 notopleural bristles, the latter surrounded by some longish pubescence. Scutellum with four bristles. All bristles on mesonotum light brownish.

Legs. Yellow including coxae, tarsi darker towards apex in all legs. Fore femur slightly thickened. Mid femur not very broad, but clearly more swollen than fore femur, with two rows of spine-like bristles ventrally. Row of whitish posteroventral bristles present, about as long as 1/3 of the thickness of femur. Mid tibia with sharply pointed apical spur, slightly longer than width of apex of mid tibia. Mid trochanter ending in a blunt, flattened, spine-like tubercle at the point where it joins the coxa, about as long as the spine on mid tibia.

Wing. Slightly brownish with light brown veins. Crossveins closing basal cells separated for about twice the length of vein r-m. Veins R 4+5 and M straight, almost parallel, but slightly converging at wing tip. Halter pale, squama yellow with pale hairs.

Abdomen. Brownish black, shining, with some slight dusting laterally on the tergites. Abdominal pubescence pale.

Terminalia ( Figure 6A–B ) of moderate size. Left epandrial lamella with dense row of longish hairs along entire straight hind margin.

Female. Unknown.

DNA barcoding. The DNA barcode clearly separate the new species from other barcoded members of the genus Platypalpus . It is the unique member of BIN BOLD: ADD3085 and the distance to the nearest Hybotidae species is 11.69 %. However, far from all Platypalpus species in Europe have been barcoded.

Etymology. From Latin tuberculatus , meaning with bulb, referring to the tubercle-like protrusion at the base of mid trochanter.

Remarks. The species is only known from a damaged type specimen, which has third segment of both antennae and the legs on the right side missing. There is also some damage to the bristling on the head and thorax.

Distribution and habitat. The type locality in Törmäoja conservation area, is a spring-fed headwater stream with luxuriant riparian vegetation like Norwegian angelica (Angelica archangelica) and numerous other herbs, grasses and sedges. The bedrock is calcareous. Törmäoja stream is flowing in a deep valley, bordered by coniferous forests and barren boulder fields. The type locality is situated in the River Tuuloma catchment area, a river flowing northwards through Russia towards the Barents Sea.

Acknowledgments. We are indebted to Sven Hellqvist, Umeå, Sweden, for providing us with specimens and information on the Swedish material, and to Dr. Luiz de Pinho, Federal University of Santa Catarina, Florianópolis, Brazil, for help with the final preparation of Anna Suuronen's illustrations. Our thanks also go to Dr. Rüdiger Wagner, Universität Kassel, Germany, for checking and confirming the validity of the new Clinocera species, as well as for his important comments on its description. Further thanks go to Dr. Patrick Grootaert, Royal Belgian Institute of Natural Sciences, Brussels, Belgium, for checking the Platypalpus descriptions. The Norwegian material was collected during projects funded by grants from the Norwegian Taxonomy Initiative. We thank FINBoL project, led by Marko Mutanen (University of Oulu, Finland), for the funding of the DNA barcoding of Finnish empidoids.

Figures

FIGURE 6. Details of Platypalpus tuberculatus Jonassen sp. n., male. A. Terminalia, dorsal view.B. Terminalia, ventral view.