Platypalpus infectus ( Collin, 1926 )

Grootaert, P., van der Weele, R., Oboňa, J. & Kustov, S. Yu., 2020, Description of a peculiar new species of the genus Platypalpus Macquart, 1827 (Diptera: Hybotidae) from the Caucasus, Caucasian Entomological Bulletin (Caucas. entomol. bull.) 16 (1), pp. 85-90 : 88-89

Platypalpus infectus ( Collin, 1926)

( Figs 7–11)

Tachydromia infecta Collin, 1926: 157 (type localities: Newmarket, Suffolk; Brighton, Sussex ( UK)); Collin, 1961: 151 (diagnosis, fig. 52c (head)).

Platypalpus infectus : Chvála, 1975: 176 (redescription, figs 133 (antenna), 222 (mid femur and tibia), 437–440 (male terminalia), 723 (wing); Chvála, 1989: 314 (diagnosis); Grootaert, Chvála, 1992: 38 (key); Kustov et al., 2015: 456 (misidentification).

Material. Belgium: 4♂, 5♀ ( RBINS), Melle , Malaise trap in meadow, 27.05– 3.06.1986 (M. Pollet); 16♂, 13♀ ( RBINS), Melle , Malaise trap in meadow, 10– 17.06.1986 (M. Pollet); 15♂, 4♀ ( RBINS), De Blankaart , Malaise trap, 16.06.1986 (B. Goddeeris); 18♂, 13♀ ( RBINS), Melle , Malaise trap in meadow, 26.06– 1.07.1986 (M. Pollet); 3♂ (1♂ dissected and figured ( Figs 7–11)), 2♀ ( RBINS), West-Flanders , De Blankaart , Malaise trap, 31.07.1986 (B. Goddeeris). In addition 299 specimens (178♂, 121♀) are present at RBINS from 13 localities all over Belgium.

Sweden: 2♀ ( SH), Medelpad, Torpshammar, Boda , pan trap, 26.06– 16.07.2012 (S. Hellqvist) ; 1♀, 2♂ ( SH), Skåne, Simrishamn , Ö Herrestad , pan trap, 20.07– 5.08.2012 (E. Nilsson) ; 1♂ ( SH), Ånge, Nyänget , pan trap, 4.07– 3.08.2018 (F. Olofsson) ; 1♀ ( SH), Gotland, Buttle, Nordkalk , Malaise trap, 10.07– 1.08.2018 (N. Johansson) .

Netherlands: 1♀ (RvdW), Zeeland, Sirjansland , 51°40ʹ47.1″N / 4°0ʹ54.0″E, 27.07.2011 (W. van Steenis) ; 1♀ ( RvdW), Zeeland, Middelburg , 51°29ʹ23.1″N / 3°35ʹ21.8″E, Malaise trap, 25.07.2012 (E. de Bree) ; 1♀ ( RvdW), Zeeland, Rilland , 51°25ʹ19.7″N / 4°13ʹ16.5″E, 12.06.2015 (N.- J. Dek) ; 1♂ ( RvdW), Groningen, Warffum , 53°23ʹ49.3″N / 6°33ʹ15.2″E, 16.09.2013 (R. van der Hout) .

Diagnosis. A medium-sized black species (2.9–3.4 mm) of the P. pallidiventris-cursitans group with a single pair of yellowish vertical bristles, close together (about 1.5 times as wide as frons below anterior ocellus). Antenna black with third antennal segment 2.5 times as long as wide, arista at least 1.5 times as long as third segment. Mesonotum thinly dusted with all hairs and bristles pale. Humeral bristle present. Acrostichals biserial. Usually a distinct anterior notopleural bristle present. Legs yellow including all coxae. Tarsi weakly annulated brownish. Male with fore tibia spindle-shaped dilated ventrally with fine ventral bristles, shorter than tibia is wide. Fore tibia in female only weakly dilated. Mid femur much thickened with long pale posteroventral bristles, half as long as femur is wide. Mid femur lacking a ventral black stripe upon which the double row of spinules are inserted. Mid tibia with a long pointed spur. Abdomen shiny black but tergites 1 and 2 with a small grey dusted patch at base. Tergites and sternites with pale bristles. Male terminalia globular ( Figs 7–11), but more elongated than in P. pilifer sp. n. Right cercus with a slender pointed apex, left cercus digitiform, with a rather rounded tip, with a few long bristles at right side well below the apex. Left epandrial lamella with a lobe on the right side ( Figs 8, 11: rl) and a long basal lobe at the base ( Fig. 9: bl). This lobe is set of the rest of the left epandrial lamella with a weakly melanised area and bears very long bristles with entangled tips. Right surstylus bearing numerous small spinules at the interior side of the apex ( Figs 10, 11).

Notes. Platypalpus infectus is a smaller species than P. pilifer sp. n. It differs in many characters from the new species as discussed above. The presence of tooth-like spinules on the apex of the right surstylus in addition of some short bristles ( Fig. 11) is remarkable and perhaps unique in Platypalpus . The left epandrial lamella bears a lobe at the right side (facing the left cercus Figs 8, 11: rl). Such lobe was also figured by Chvála [1975: fig. 439] and is also probably quite unique in Platypalpus . Both these structures are not present in P. pilifer sp. n. The right surstylus has a curious fold as shown as well by Chvála [1975: fig. 438] and here in Fig. 10. No such bent is present in the new species. The left epandrial lamella bears a lobe at the base of the left side. Such a lobe is not figured by Chvála [1975: fig. 440] but this is probably due to the position when drawing. This lobe was present in the numerous specimens from Belgium which we studied. In P. pilifer sp. n. the basal lobe is not present, however there is a small protuberance on the left side of the left epandrial lamella that is not distinctly set-off.

Distribution. The species from lowland is known with certainty from western Europe [ Chvála, 1975]. The records from the eastern part of Europe might be doubtful and need verification. All the records of P. infectus in Kustov et al. [2015] are P. pilifer sp. n., they are considered as paratypes of the new species and included in the type series.