Eumerus druk
| Notice: | This page is derived from the original publication listed below, whose author(s) should always be credited. Further contributors may edit and improve the content of this page and, consequently, need to be credited as well (see page history). Any assessment of factual correctness requires a careful review of the original article as well as of subsequent contributions.
If you are uncertain whether your planned contribution is correct or not, we suggest that you use the associated discussion page instead of editing the page directly. This page should be cited as follows (rationale):
Citation formats to copy and paste
BibTeX: @article{Smit2020ZooKeys906, RIS/ Endnote: TY - JOUR Wikipedia/ Citizendium: <ref name="Smit2020ZooKeys906">{{Citation See also the citation download page at the journal. |
Ordo: Diptera
Familia: Syrphidae
Genus: Eumerus
Name
Eumerus druk Smit sp. nov. – Wikispecies link – ZooBank link – Pensoft Profile
Type locality
Bhutan, Thimphu.
Diagnosis
Body golden-coppery, except t2 and t3 medially and t4 basomedially: shiny black amplified by short adpressed black pile. Basoflagellomere rectangular, with a rounded posterior corner. Male: abdomen t3 and t4 laterally with long, silvery, ventrally directed pile; s4 without an incision posteriomedially but medial part of sternite less sclerotized. Basotarsomere of metaleg simple, equal in length to the rest of the tarsomeres. Male terminalia: posterior surstyle lobe with a tuft of long pili just anterior to the bifurcation.
Description
Male. Length of body (excluding antennae) 7.5–8.5 mm, length of the wing 5.5–6.5 mm. Head. Eyes holoptic, eye contiguity 9–10 ommatidia long, ommatidia near eye contiguity conspicuously larger than those in the posterior part (Fig. 1E). Eye margins ventrally slightly divergent. Eye covered with dense white pile; posterior eye margin bare. Face with dense, silvery-white pollinosity and white pile. Frons with golden-yellow pile, intermixed with black pile or even predominantly black pilose on the ocellar triangle. Ocellar triangle isosceles; distance between anterior ocellus and posterior ocelli compared to the distance between both posterior ocelli 1:0.55. Frons with a small pollinose macula anterior to anterior ocellus. Occiput with dense white pollinosity up to about 3/4 dorsally; dorsal part shiny black, with coppery luster. Antenna black; basoflagellomere rectangular (Fig. 2D), with a rounded posterior corner. Arista entirely black. Scape and pedicel black, with white pile; black pile dorsally; dorsal pile much shorter than ventral pile. Thorax. Entirely shiny black, with golden luster (Fig. 1D). Mesonotum with a pair of white pollinosity vittae covering 3/4 of scutal length. Mesonotum and scutellum covered with golden-yellow pile; clearly longer near the posterior margin of the mesonotum and scutellum. Notopleural suture absent. Scutum next to wing base with a row of strong black setae. Scutellum with a broad rim, somewhat granular. Anepisternum and anepimeron with the same golden luster; katepisternum pollinose, with a small shiny spot dorsally, posterior to tuft of long white pile, ventrally with a few long white pili. Legs. All black, except for the tibiae, which are red on the basal third. Tarsi black, claws bicoloured, red basally, and black apically. Metafemur moderately swollen, slightly curved, with two rows of black setae apicoventrally, 11 on anterior ridge and 11–13 on posterior ridge, long white pile dorsally, about half as long as the maximum width of the femur and even longer white pile ventrally, the longest ones slightly more than 3/4 the maximum width (Fig. 1B). Metatibia with a flange of adpressed setae on the basal half, ventrally, followed by a shallow notch, apicoposteriorly with a single row of long light pile, longer than the maximum width of the metatarsus. Basotarsomere of metaleg simple, equal in length to the rest of the tarsomeres. Wings. Hyaline, pterostigma light brown, entirely microtrichose.
Abdomen. Entirely black, parallel sided, t2–4 with oblique maculae of white pollinosity, those on t3 and t4 longer and clearly lunulate (Fig. 1A). t2 and t3 shiny black medially, as well as t4 basomedially, laterally with golden-coppery luster (Fig. 1D). The black colour in the middle of the tergites is amplified by the short adpressed black pile, light on the pollinose maculae as well as on the lateral sides and the majority of the t4. Abdomen with conspicuous long, silvery, ventrally directed, white pile on the lateral sides of the t3 and t4 (Fig. 1C). s4 with long silvery-white pile laterally, distinctly shorter medially, posteromedially without incision, but medial part of sternite less sclerotized (Fig. 2E).
Terminalia (Fig. 2A–D). Posterior lobe of sursylus bifurcate, with a tuft of long light pile just anterior to bifurcation.
Description of female
Similar to male except for the normal sexual dimorphism (Fig. 1F). Length of body (excluding antennae) 7 mm, length of the wing 6 mm. Head. Frons with some pollinosity alongside the eye-margin, from the antennae up to the anterior ocellus. Ocellar triangle isosceles, distance between anterior ocellus and posterior ocelli compared to the distance between both posterior ocelli 1:0.88. Abdomen. t3 and t4 laterally with slightly longer, silvery and ventrally directed, pile.
Etymology
The specific epithet ‘druk’ is Dzongkha (the Sino-Tibetan language spoken in Bhutan) for dragon and refers to the official name of the kingdom: Druk yul (country of the Dragon people, or the Land of the Thunder Dragon). It should be treated as a noun in apposition.
Distribution
This species is only known from the type series collected at the Royal Botanical Garden in Thimphu, Bhutan, but it likely has a wider distribution in the Himalayas. This is the only Eastern Palaearctic species of the bactrianus subgroup of the strigatus species group.
Examined material
Type material. Holotype Bhutan • male; Thimphu, Royal Botanical garden; 27.425N, 89.650E, 2400 m a.s.l.; 26 April 2018; J.T. Smit & Th. Zeegers leg.; RMNH.INS1092470.
Paratypes Bhutan • 4 males; same collection data as for holotype • 1 female; same data as for holotype; RMNH.INS1092471.
The holotype is in good condition and is deposited, together with one male and female paratype in the National Biodiversity Center, Bhutan (NBCB). The remaining three paratype males, as well as the DNA material are stored in the collection of Naturalis Biodiversity Center, the Netherlands (NBC).
Remarks
The male of Eumerus druk Smit, sp. nov. is easily distinguished from all other species in the bactrianus subgroup by the long, silvery, ventrally directed, pile on the lateral sides of t3 and t4. Eumerus banaticus has some longer pile on the lateral sides of t4, but this is shorter, not ventrally directed, and not present on t3. Furthermore E. banaticus is easily distinguished by the lack of pollinose maculae on t4 and by the shape of st4 and the terminalia. Eumerus hungaricus Szilády, 1940 and E. pulchellus Loew, 1848, which have similar long, ventrally directed pile on t3 and t4, are superficially similar but the pile is much more dense. Eumerus druk Smit sp. nov. can easily be distinguished by the bifurcate posterior surstyle lobe. E. hungaricus and E. pulchellus furthermore lack the golden-coppery luster on the thorax and abdomen of E. druk. Eumerus pulchellus is a more slender built species, with a more bluish luster, a relatively slender metafemur, the pro- and mesotarsi predominantly light brown, the basoflagellomere orange. Eumerus hungaricus is a more black species with less luster, especially on the abdomen, which is predominantly black pilose; s3 is very slender, about 2.5 times longer than wide, and t4 has a yellow posterior margin, medially.
Original Description
- Smit, J; Zeegers, T; Dorji, P; 2020: A new species of Eumerus (Diptera, Syrphidae) from the Kingdom of Bhutan, the easternmost representative of the bactrianus subgroup ZooKeys, 906: 141-151. doi
Images
|
![Figure 2. Eumerus druk Smit, sp. nov., male holotype A epandrium, lateral view B surstyle lobe, ventral view C hypandium, lateral view D hypandrium, ventral view E fourth sternum. Eumerus bactrianus Stackelberg, 1952, male F antenna, lateral view. Eumerus druk sp. nov. G antenna, lateral view. Eumerus turanicola Stackelberg, 1952, male H antenna, lateral view, after (Stackelberg 1952[1]). Eumerus turanicus Stackelberg, 1952, male I antenna, lateral view, after (Stackelberg 1952[1]).](/wiki/File:Zookeys-906-141-g002.jpg)
