Chaetonerius kotrbae, Sepúlveda & De Carvalho, 2019

Sepúlveda, Tatiana A. & De Carvalho, Claudio J. B., 2019, Chaetonerius Hendel (Neriidae: Diptera) from the East African islands with description of four new species from Madagascar and the Comoros, Zootaxa 4567 (1), pp. 130-146 : 142-143

Chaetonerius kotrbae sp. n.

urn:lsid:zoobank.org:act:351BCABF-717A-4D92-B279-03E3CBA9772

Diagnosis. Antennal base absent. Several setulae between anterior margin of frons and anterior fronto-orbital seta. Face yellow. Thorax dorsally with median V-shaped brown stripe partially divided medially by one gray pruinose narrow stripe; postsutural dorsocentral yellow stripe present. Proepisternal lobe with anterodorsal protuberance. Katepisternum brown. Katatergite yellow. Fore and hind coxae yellow; mid coxa at least partially brown. Surstylus slightly shorter than cercus; cercus linear slightly tapering towards apex.

Male. Body length 6.1 mm; mostly brown with partially yellow head, thorax dorsal, pleuron and abdomen ( Fig. 20 ).

Head. Anterior margin of frons slightly concave; fronto-orbital plate sub-shiny yellow and narrow; three equidistant fronto-orbital setae, increasing in size posteriorly ( Fig. 13 ); anterior fronto-orbital seta nearly half length of posterior fronto-orbital seta; short setulae between anterior fronto-orbital seta and anterior margin of fronto-orbital plate; frontal vitta mostly brown, except for median yellow stripe narrowing towards ocellar triangle; vertex blackish-brown, bordered laterally by yellow stripe extending from fronto-orbital plate to occipital foramen, delineating the brown median occipital sclerite; vertex and median occipital sclerite not meeting at a right angle; area around insertion of outer vertical seta, slightly inflated. Occiput brown with median yellow stripe; two long and two short postocular setae; three occipital setae; yellow postgenal setulae laterally and black setulae near occipital foramen are sparse. Frontogenal suture extends anteriorly beyond the parafacial, almost reaching the antennal socket. Palpus yellow. Antennae. Arista brown with base white, covered by short and sparse pubescence; arista inserted sub-apically; first flagellomere ovate; scape and pedicel short, length together almost as long as first flagellomere.

Thorax. Scutellum trapezoid with curved margins; length of distal margin between scutellar apical setae, half the distance between prescutellar dorsocentral setae; median yellow stripe as wide as thoracic median yellow stripe; discal scutellar seta equal to anterior notopleural seta. Pleuron mostly brown with yellow stripe from dorsal proepisternal lobe to notopleura, dorsal anepisternum, anterior half of anepimeron, katatergite, katepimeron and dorsal meron. Proepisternum brown dorsally and yellow on ventral half, with yellow setulae; ventral margin with two brown setula and one seta shorter and thicker than anterior notopleural seta; proepisternal lobe with no anterodorsal protuberance. Anepisternum and katepisternum with yellow setulae posteriorly. Wing. Slightly infuscate around reaching point of veins R 2+3 and C; length 5.0 mm and width 1.5 mm. Legs. Fore coxa yellow with two anterolateral spine-like setae; hind coxa yellow and mid coxa pale brown. Femora brown with diffuse yellow ring on distal third; fore femur with anteroventral spine-like setae that vary in size, with some longer setae standing out every 3¯4 short ones.

Abdomen. Tergites brown with two wide dorsal longitudinal yellow stripes divided by a narrow brown stripe; sternite 6 brown and visor-shaped, expanded over proximal third of epandrium ( Fig. 24 ). Distal margin of epandrium reaching posterior half of fourth abdominal segment ventrally; surstylus linear, cercus as long as one third epandrium; outer margin of phallapodeme with dark triangular sclerotized area on distal third; pregonite linear; postgonite rounded with rows of 4¯5 spines; distiphallus sclerotized with median area membranous and distal half medially divided by narrow membranous area, terminating in membranous bulb bearing two short sclerotized spikes and one longer membranous tube.

Variation. Body length 4.4–6.4 mm. Wing length 3.8–5.4 mm and width 1.2–1.6 mm. Postocular setae asymmetrical in size and number. Fore coxa with three anterolateral setae. Sternite 6 yellow.

Female. Body length 4.8–5.4 mm. Fore coxa with one single anterolateral seta. Femora darker with diffuse rings, especially on anterior femur and in several cases, those rings are inconspicuous; fore femur without anteroventral spine-like setae, with two or more anteroventral longer setae on distal third. Abdomen almost completely brown, with one dorsomedial narrow yellow stripe. Oviscape completely yellow, slightly darkened at apex.

Type Material (18 specimens) HOLOTYPE, Chaetonerius kotrbae ♂ Comoren , Moheli, Bach beiNioumachoua, leg. M.Kotrba, 20.ix.2002 [ZSM, 2249]. PARATYPES, 1♀, Grand Comore, Bahani, Weg zur Grotte des Cpt. Dubois , 600–800m, leg. M.Kotrba, 12.iv.2002 [ ZSM, 2254] ; 1♂, M´vouni, ix.69 Grande Comore, Brunhes réc. [ USNM, 1633 (dissected)] ; 3♀, Comoren, Moheli, Hoani, Weg zum Chalest St. Antoine urngefall, Baumstamm , 400m, leg. M.Kotrba, 21.iv.2002 [ ZSM, 2255, 2256, 2257] ; 4♂ 1♀, Comoren, Moheli, Bach beiNioumachoua, leg. M.Kotrba, 20.ix.2002 [ ZSM, 2258, 2259 (dissected), 2260, 2261, 2250] ; 3♀, Moheli, April. 2002, M.Kotrba [ ZSM, 2252, 2253, 2262 (dissected)] ; 1♂, Comoren, Moheli, Bach beiNioumachoua, leg. M.Kotrba, 20.iv.2002 [ ZSM, 2249] ; 2♂ 2♀, Comoren, Moheli Wald Bach bei Ouallah , leg. M. Kotrba 20.iv.2002 [ ZSM, 2244, 2243 (dissected), 2242, 2245] .

Etymology. This species is named after the entomologist Marion Kotrba for collecting the type material and for her valuable contributions to the knowledge of Diptera .

Distribution. Comoros (Grande Comore, Mohéli).

Figures

FIGURES 16–20. Male habitus of Chaetonerius of the East African islands. 16. C. kirkspriggsi (HT); 17. C. ebejeri (HT); 18. C. alluaudi [BMSA, 1858]; 19. C. madagasikara (HT); 20. C. kotrbae (HT). Abbreviation: HT, holotype.

FIGURES 11–15. Head lateral of the holotypes of the new species of Chaetonerius. 11. C. ebejeri, detailed area below the scape showing the underdeveloped antennal base pointed by the arrow; 12. C. ebejeri; 13. C. kotrbae; 14. C. kirkspriggsi; 15. C. madagasikara.

FIGURES 21–25. Male genitalia of Chaetonerius of the East African islands, lateral and ventral views, square showing the zoomed apex of distiphallus (out of scale). 21. C. alluaudi [SANC, 1604]; 22. C. ebejeri [CSCA, 2246]; 23. C. kirkspriggsi [CSCA, 2241]; 24. C. kotrbae [USNM, 1633]; 25. C. madagasikara [USNM, 466].