Dirhinus gigasetosus Delvare,

Delvare, Gérard & Copeland, Robert S., 2018, Four-horned wasps, description of some remarkable Dirhinus (Hymenoptera, Chalcididae) from Kenya, with a discussion of their taxonomic placement, Zootaxa 4374 (3), pp. 301-349: 329-333

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Dirhinus gigasetosus Delvare

sp. nov.

Dirhinus gigasetosus Delvare  sp. nov.

( Figs 3, 8View FIGURES 3–8, 43View FIGURES 43–52, 61, 66View FIGURES 61–68, 119–131) ( Tables 3 and 4)

Registered in ZooBank,


Material examined. Holotype ♀. KENYA: Rift Valley Province, Olorgesailie National Monument , 1.57930°S 36.44566°E, 982 m, 02-16.X.2011, Malaise trap, Acacia-Commiphora savannah, R. Copeland leg. [F06] [ NMK]GoogleMaps  . Paratypes. KENYA: Eastern Province, Kasaala area , 733 m, 2.07836°S 38.22517°E, Malaise trap, just inside isolated woodland patch, R. Copeland leg. (1 ♀) [F07] [ BMNH]GoogleMaps  ; same locality, Malaise trap, just inside isolated woodland patch, collected on 30.X-13.XI.2014, R. Copeland leg. (1 ♂) [M01] [ NMK]GoogleMaps  ; Kasaala area , 740 m, 2.07486°S 38.22530°E, 6 m Malaise trap, woodland and grass, 28.XI-04.XII.2013, J. Bukhebi & R. Copeland leg. (1 ♂) [M02] [ BMNH]GoogleMaps  ; base of Endau Mtn. 531 m, 1.30026°S, 38.52805°E, Malaise trap in indigenous forest, 28.xi-12.xii.2016, R. Copeland leg. (1 ♂) [M03] [ ICIPE]GoogleMaps  ; Rift Valley Province, Matthews Range , 1006 m, 1.00661°N, 37.38631°E, Malaise trap, Sarara campsite, shrubland, 29.xi-12.xii.2015, R. Copeland leg. (1 ♀) [F09] [ ICIPE]GoogleMaps  .

Condition of holotype. Specimen complete, glued on rectangular card. Left wings, mid and hind leg glued separately.

Etymology. The name refers to the extremely long setation on various parts of the body of the female.

Description of female holotype. Body length 3.5 mm. Identical with D. quadrhinus  except as follows.

Body with extremely long and thin setae on following parts: labrum, mandibles, strip along antennal scrobes, gena posteriorly, pronotal collar laterally (Fig. 120), propodeum laterally on spiracular tooth, adscrobal area of mesepisternum, metepimeron dorsally, procoxa anteroapically (Fig. 120), metacoxa at margin between dorsal and ventral surfaces, margin of metatrochanter, and pro- and metafemora on outer side (Fig. 124). Setation thin and shorter on other body parts.

Head as long as wide and 0.99× as long as high, with somewhat sparse puncturation, the punctures subcircular. Inner horn length (IHL) 4.07× as long as distance from end of scrobal depression to median ocellus and 1.65× as long as ocular-ocellar distance (Fig. 121); inner edges of inner horns diverging at an angle of approximately 30°. Frontovertex 2.26× as wide as IHL. Distance from end of scrobal depression to median ocellus very short, only as long as diameter of median ocellus. Distance between median and lateral ocellus longer than ocellar diameter. Horns, viewed laterally, sloping markedly anteriorly; without coriaceous admarginal strip on dorsal surface of inner horn. Puncturation of gena progressively sparser towards inner surface and leaving a smooth strip in the malar space. Adscrobal area with preorbital and admarginal rows of punctures and sparse points on interspaces but without preorbital ridge. Clypeus with only 1 seta on either side, the setae about as long as procoxa. Outer groove of mandible with 4 long setae, inner groove with 8 setae; labrum with 4 long setae on either side and with 2 shorter setae dorsally. Supraclypeal area with 2 or 3 setae on either side.

Antenna (Fig. 122). Pedicel 1.59× as long as wide. Second flagellomere 0.84× as long as wide, 8th segment 0.7× as long as wide and 1.18× as wide as 2nd flagellomere.

Mesosoma relatively short, 1.44× as long as wide with mesoscutellum 0.65× as long as wide (Fig. 119). Pronotum with 2 transverse rows of punctures on collar. Mid lobe of mesoscutum with anterior two fifths smooth, then regularly punctured posteriorly. Lateral lobe smooth except an admarginal row of punctures along scutal carina. Axilla entirely punctured. Mesoscutellum punctured along anterior margin and with 2 rows of punctures in front of posterior margin, hence widely smooth on disc. Propodeum with strong secondary areolation (Fig. 123); anteromedian areola wider than long; spiracular tooth sharp, raised upwards; subcoxal tooth on posterior margin of metepimeron sharp. Procoxa bearing about 10 long setae at base of apical flange. Metacoxa and metafemur respectively 1.49× and 1.63× as long as wide (Fig. 124). Metafemur and metatibia with very sparse punctulation; disc of femur completely smooth on centre. Metatibia with a wide groove tapering apically in addition to tarsal sulcus; tibia with a row of 10 long, thin and suberect setae along edge of carina that margins tarsal sulcus (Figs 126, 127). Fore wing 2.56× as long as wide; marginal vein 0.88× as long as costal cell.

Metasoma. Petiole with dorsal surface 1.72× as wide as long, rising upwards and strongly emarginate anteriorly, with incomplete submedian carinae delimiting median sulcus (Fig. 125). Gaster 1.99× as long as wide with first gastral tergite 0.65× as long as gaster, the tergite with 6 primary longitudinal ridges and 5 secondary. Posterior margin of 2nd tergite concave.

Description of male paratype M01 (except for antenna, described from male paratype M02). Body length 3 mm. Identical with female except as follows. Colour: fore wing somewhat brownish at base, behind marginal vein and even beyond venation, the infumation progressively fading towards apex of wing. Setation of hind wing entirely white. Body without extremely long setae as described for female.

Head 1.09× as wide as long and 0.89× as high as long. Setation and puncturation as for female. Scrobal depression much wider than in female in contrast with inner horns which are much narrower (Fig. 128). Frontovertex twice as wide as length of scrobal fissure. Distance from end of scrobal depression to median ocellus shorter than ocellar diameter, interocellar distance longer than ocellus diameter. Distance between apices of inner horns twice as long as that between edges of scrobal depression at base, these edges subparallel. Puncturation on gena coarser than in female, with narrow interspaces between punctures. Outer horn widely rounded in frontal FIGURES 119–125. Dirhinus (Dirhinus) gigasetosus  . 119, 122, 123, 124, holotype ♀ (F06). 120, 121, 125, paratype ♀ (F07). 119. Habitus in dorsal view. 120. Head and mesosoma in lateral view. 121. Head in dorsal view. 122. Antenna. 123. Propodeum. 124. Hind leg. 125. Petiole in posterodorsal view. Abbreviation. mo, median ocellus.

FIGURES 126–131. D. gigasetosus  (continued). 126, 127, paratype ♀ (F07). 128, 131, paratype ♂ (M01), 129, 130, paratype ♂ (M02). 126, 127. Metatibia respectively in laterodorsal and dorsal views. 128, 129. Head respectively in dorsal view and frontal views. 130. Antenna. 131. Propodeum and base of metasoma.

view; inner horn with sharp apex. Scrobal margin not quite reaching apex of outer horn; lateral margin of scrobal depression concave in frontal view. Mandibles narrower than in female and narrowly rounded at apex, without long setae (Fig. 129). Labrum narrow with 2 dorsal setae on each side. Only 1 relatively long seta on either side of clypeus. Subantennal surface irregularly punctured, delimited on each side by a ridge continuing from lateral margin of antennal scrobe.

Antenna (Fig. 130). Pedicel 1.18× as long as wide. Second flagellomere 1.30× as long as wide, 8th segment 0.6× as long as wide and 1.17× as wide as 2nd flagellomere.

Mesosoma 1.43× as long as wide with mesoscutellum 0.66× as long as wide. Pattern of puncturation and setation as in female but punctures larger. Mesoscutellum more convex. Mesodiscrimen not very wide, tapering dorsally.

Metasoma. Petiole with dorsal surface rugulose and with lateral, incomplete submedian carinae; anterior margin emarginate mesally (Fig. 131); basoventral tooth moderately sharp, posterior to areolate rugulose ventral surface. Gaster 1.40× as long as wide; first gastral tergite 0.85× as long as gaster with 4 primary and 8 secondary longitudinal ridges, the lateral ridges straight (Fig. 131); 2nd tergite with posterior margin somewhat concave, but posterior margin of other tergites straight. First sternite basally with 3 crests on either side.

Diagnosis of female. Body bearing extremely long setae on various parts. Median ocellus close to end of scrobal depression. Preorbital ridge absent. Mesosoma, mesoscutellum and gaster relatively short. Puncturation on metafemur and metatibia quite sparse.

Recognition. The very long setae of this species and the location of the median ocellus close to the end of the scrobal depression immediately differentiates the female from other quadrhinus  group members. Additionally, in contrast to the other species, the puncturation of the metafemur is very sparse. The male cannot be compared to that the other species are this sex is unknown for them but the extremely long setation and relative position of the median ocellus were assumed to be diagnostic characters for this sex as well.

Distribution. The species is known only from Kenya.

Host(s). Unknown, but probably Diptera  based on the behaviour of other species in the subfamily to which it belongs.


National Museums of Kenya