Platypalpus silvahumidus, Bartak, Miroslav & Kubik, Stepan, 2015

Bartak, Miroslav & Kubik, Stepan, 2015, Three new species of European Platypalpus (Diptera, Hybotidae), ZooKeys 470, pp. 145-155 : 150-153

Taxon classification Animalia Diptera Hybotidae

Platypalpus silvahumidus sp. n. Fig. 9

Material examined.

Holotype: female, Czech Republic, Podyjí, Devět mlýnů, floodplain wood, MT (= Malaise trap), 270 m, 48°49'07"N, 15°58'17"E, 29.iv.-21.v.2004, M. Barták & Š. Kubík. Paratypes: 2 females, same data as holotype; 1 female, same locality as holotype, 21.v.-12.vi.2004; 2 females, Podyjí NP, pod Šobesem, wetland nr. river, MT, 48°48'48"N, 15°58'51"E, 26.iii.-8.v.2002, M. Barták & Š. Kubík; 2 females, same locality, 8.-22.v.2002; 1 female, Podyjí NP, Faltýskův mlýn, wetland nr. river, MT, 48°50'43"N, 15°54'08"E, 29.iv.-21.v.2004, M. Barták & Š. Kubík; 1 female, Vykáň, floodplain wood, sweeping, 190 m, 50°07'00"N, 14°48'33"E, 1.v.2007, M. Barták. Holotype and paratypes are deposited in the collection of the Czech University of Life Sciences Prague.

Diagnosis.

Black species of Platypalpus hackmani group with 2 pairs of vertical setae, black antennae with broad postpedicel; thorax microtrichose including katepisternum, most setae black; legs dark to brownish yellow, mid femur narrower than fore femur, with only slightly developed ventral setae, mid tibia without apical spur; abdomen lustrous.

Description.

Female. Head black, brownish grey microtrichose. Frons ≈ 0.09 mm broad just above antennae and ≈ 0.13 mm broad in the level of fore ocellus. Face ≈ 0.06 mm broad at middle. Clypeus microtrichose. Gena microtrichose and broad. Antenna black, postpedicel broad (≈ 0.10 mm), 2.2 –2.6× longer than broad and 1.1 –1.7× longer than stylus. Palpus brown, narrow and short (about 1/3 as long as proboscis), with long black subterminal seta. Both pairs of ocellar setae black and long, anterior one ≈ 0.15 mm long, posterior one only slightly shorter. Two pairs of black vertical setae, inner very long (≈ 0.25 mm) and strong. Occiput sparsely and black setose including lower part. Proboscis 2/3 as long as head, brownish black.

Thorax brownish black, entirely brownish grey microtrichose including katepisternum. All setae black. Chaetotaxy: postpronotal seta long and strong (several additional much smaller setae present), posthumeral seta similarly long and strong (not anterior notopleural but true posthumeral seta); acrostichals biserial, slightly divergent (more on posterior part), moderately long (≈ 0.10 mm in middle of rows), about 6-9 setae in one row; dorsocentrals slightly longer (≈ 0.15 mm in middle of row), uniserial, 7-10 setae in one row, last 1-2 pairs strong and long (several acrostichals and/or dorsocentrals in some specimens distinctly longer and more bristle-like); notopleuron with 2 long setae on posterior part and an additional smaller seta; 1 long postalar and 2 pairs of scutellar setae.

Wing clear with brownish yellow veins. Veins R4+5 and M1 nearly straight and almost parallel. Crossveins contiguous. Vein Cu slightly bowed but not S-shaped, proximal part of anal vein almost invisible. Two (sometimes 3) unusually long and strong black costal setae. Squama yellow with pale fringes. Halter pale yellow.

Legs black setose, rather dark yellow including fore coxa, mid femur, mid tibia and tarsi of fore and mid legs; mid and hind coxae, hind femur apically, hind tibia and hind tarsus brownish yellow. Fore femur strongly thickened (≈ 0.25 mm at broadest point), with two rows of setae ventrally up to half as long as depth of femur. Fore tibia distinctly thickened, with 2-3 black bristly setae dorsally. Mid femur narrower than fore femur, ventral rows consisting of relatively fine and short hairs only slightly stronger than remaining setation. Mid tibia without apical spur. Hind femur short setose. Hind tibia thin, with 2 antero- and 2 posterodorsal black and strong setae slightly longer than depth of tibia.

Abdomen blackish brown, lustrous, including dorsum of tergite 1, sides of tergites 7-8 and mostly also sternite 7; microtrichose parts: sides of tergite 1, dorsum of tergites 7 and 8, sternite 8, also tergites 2-3 with narrow anterior microtrichose stripes; abdomen sparsely covered with short dark setae.

Male. Unknown.

Length. body 2.5-2.7 mm, wing 2.4-2.9 mm.

Etymology.

The specific epitheton originated from two Latin words depicting typical biotope of this species (silva = forest, humidus = damp) and should be treated as adjective (i.e. silvahumida, silvahumidum).

Distribution.

Czech Republic.

Remarks.

The species described above belongs to the Platypalpus hackmani group. In spite we have no male at our disposal, we don’t hesitate to describe it because this species is very different from all other species by characters which are probably not sexually different (it may be even parthenogenetic). According to Shamshev and Grootaert (2012) and Grootaert and Stark (1997), in the Palaearctic the Platypalpus hackmani group includes six species that share distinct humeri, a posthumeral bristle, usually dusted katepisternum, a more or less dusted abdomen, with a very thickened fore femur, while the mid femur is slender with only fine bristles ventrally instead of the usual double row of spine-like bristles and lacking a row of posteroventral bristles, and lacking the apical spur on the mid tibia. Apparently not all these characters are conclusive to distinguish this species group. It is difficult to place the species into the comprehensive key by Grootaert and Chvála (1992). The whole section of the key starting from number 195 is confusing due (in part) to description of two species of Platypalpus hackmani group with long antennae ( Platypalpus canariensis Grootaert & Chvála, 1992 and Platypalpus hallensis Grootert & Stark, 1997, see also note below the latter species). We propose to adapt this section of the key as follows: