Nadus overlaeti ( Navás, 1931 )

Dobosz, Roland, Ábrahám, Levente & Bąkowski, Marek, 2024, Nadus overlaeti (Navás, 1931) redescribed-new to the fauna of Mozambique, Namibia and Tanzania (Neuroptera: Myrmeleontidae), Zootaxa 5529 (3), pp. 583-592 : 584-591

Nadus overlaeti ( Navás, 1931)

Nesoleon overlaeti Navás, 1931: 125

Nadus overlaeti ( Navás, 1931) — Stange 2004: 294 (Mon, Comb).

Nadus sudanensis Navás, 1935: 43 —Odescr, Whittington 2002: 384 (Dist), Stange 2004: 295. (Mon), Syn. n.

Type locality: The Democratic Republic of the Congo ( DRC): Katanga, Kafakumba .

Type material examined:

MRAC // Holotype // Typus // Museé do Congo / Katanga: Kafakumba / iii 1929 / G.F. Overlaet // Nesoleon / Overlaeti / P. Navás S. J. det // MRAC-Tervuren / Database No. / MRAC 00032 // ( Fig 1A ) .

MNHN: // Type // Museum Paris / Soudan franc / Koulouba / Waterlot 1929 // Nadus / sudanensis Nav. / det Navás S.J. // Lectotype // Nadus sudanensis / Navás, 1935 / Lectotype / J. Legrand dét 1992 //( Fig 1B )

Additional material examined:

SCMK: 1female — South Africa Limpopo Prov. 68 km NW of Mokopane Palala river 23°57’32,22”S 28°22’38,64”E 5–9.II.2019 leg: S.A. Knyazev ( NeuMyr2341 ) ; 1male — RSA Limpopo Prov. Lephalale envir. 831m 23°43,323’S 27°45,677’E 05.XI.2013, leg. L. Prepsl (NeuMyr537) ; 1male — Tanzania, 11 km NE Bwawani 30.12.2015, leg. S. Prepsl (NeuMyr2891) .

USMB: 1male —N Malawi, Nkhorongo Mzuzu, Mzimba distr., 11°23’S 33°59’E, 2.11.2008, leg. R.J. Murphy ( USMB 5858 /29115); 1female — Zimbabwe, Lukosi Mission, 15 km S Hwange, 3.12.1990, leg. R. Miller & L. Stange ( USMB 5858/29187 ); 1female — Mozambique, Cabo Delgado, Prov. Ancuabe district : Quirimbas National Park , Taratibu Hills 12°48’58.4”S; 39°41’43.5”E, 336 m asl., 04–08. 04. 2022, leg. Marek Bąkowski ( USMB 5858/22081 ) .

EFMEA: 1male 1female — Namibia, Erongo, Uis , 20 km NW, 21°04’S 14°41’E, 530 m, 24.03.2014, leg. J. Halada

Diagnosis: Sexual dimorphism insignificant, females usually larger than males. General colour brown to dark brown with yellow marks. Wing shape broadly oval. Hind wing with 7 cross-veins before origin of radial sector. Tarsal segment 1 as long as tarsal segments 2–4 combined. In males, ectoproct not longer than ventral margin in lateral view. In females, caudal margin of sternite 7 modified with two small processes laterally in ventral view.

Redescription: ( Fig. 2 )

Measurements: Males (4 exx.) Antenna length: 4 mm, Fore wing length: 22–23 mm, width: 4.5–6 mm, Hind wing length: 19–20 mm, width: 4–5 mm, Body length: 18–19 mm, Abdomen length: 13–14 mm.

Females (4 exx.) Antenna length: 4–5 mm, Fore wing length: 25–29 mm, width: 6–8 mm, Hind wing length: 22–26 mm, width: 5–6.5 mm, Body length: 20–24 mm, Abdomen length: 13–17 mm.

Head: ( Figs. 3A–B ). Vertex arched in frontal view; yellow with two narrow parallel transversal black bands curving towards each other in middle and touching in dorsal view; triangular black spot in middle of vertex caudally. Short, sparse, black hairs on vertex. Frons shiny brown to black, gena shiny yellow on lower side and predominantly shiny brown near eye. Shiny brown to yellow clypeus with two lateral dark spots laterally, hairless. Labrum yellow with brown lower margin and short, dark brown hairs directed towards mandible on lower margin. Mandible predominantly yellow with dark brown apices and inner margin. Maxillary palps yellow basally, last two segments brown. Last segment of labial palps as long as width of clypeus, spindle-shaped, brownish, apical segment with slit-like sensory pit and acute apices. Eye large and shiny brown. Scape brownish, pedicel black, flagellar segments brown with yellow ring basally and completely dark brown distally, club black. Segments with very short black setae.

Thorax: ( Fig. 3B ). Pronotum slightly longer than wide, yellow with two narrow lateral, and wide central brown stripes; lateral stripes do not reach anterior margin; with short sparse, and black hairs dorsally. Small brown dots at origin of black hairs. Lateral margins with long, stiff, white hairs pointing anteriorly. Meso- and metanotum yellow with wide dark-brown marks and dense brown dots. Mesoprescutum with only moderately long black hairs; mesoscutum with short black hairs dorsally and white hairs laterally. Metascutum with large oval and reddish-brown spots on each side, almost bare. Thorax in lateral view, dark brown with longitudinal narrow, yellow line directly below wings, covered with short, sparse, white hairs.

Wings: ( Fig. 3D and Fig. 4A–D ). Fore wing, costal area narrow with simple cross-veins basally, then widening distally; beyond origin of radial sector, cross-veins become predominantly bifurcated. Longitudinal veins C, Sc, R, Mp, Cua, Cua 1, Cua 2 and Anal veins pale, alternating with dark brown sections. Brown sections at ends of cross-veins. Membrane discoloured in subcostal area, another characteristic pattern in wing as in Fig. 4A . Pterostigma brown basally and yellowish white distally with 5–6 cross-veins. 9–10 usually simple or divided cross-veins (especially in females) before origin of radius sector. Forewing covered with conspicuously long microtrichia.

Hind wing with characteristic brown discolouration at both ends of hypostigmatic cell and in rhegma area. Pterostigma brown basally and whitish yellow distally with 4–5 cross-veins. In subcostal area, faint brown colouration in some places. With 9–10 cross-veins before origin of radius sector.

Legs: ( Fig. 3C ). Long and slender. Coxae dark brown with sparse white hairs. Trochanters yellow. Fore femur predominantly dark brown with short white hairs on basal surface, and stiff black or white bristles on ventral surface. Femur longer than tibia. Tibia with short black hairs and sparse, erect, stiff, black bristles. Middle and hind femora entirely dark brown with short black hairs, and sparse upright black bristles. Femora as long as tibiae. Hind femur without row of upright bristles. Tibial spurs always shorter than tarsal segment 1. Tarsal segment 1 yellow, as long as tarsal segments 2–4 combined and equal in length to tarsal segment 5. Segments 2–5 dark brown. Tarsi with black hairs and short, sparse, stiff bristles. Claws slightly curved, conspicuously short.

Abdomen: Tergites brown with indistinct broad yellow bands laterally, but pattern occasionally variegated with only small yellow distal spots. Caudal margins of segments with narrow yellow rings. Intersegmental membrane also with yellow spots. Sternites predominantly brown with narrow longitudinal yellow stripe and with yellow rings on caudal margins in ventral view. Abdomen densely covered with short white hairs.

Male terminalia and genitalia ( Fig. 5A and B ): Ectoproct long, oval-like, with blunt postventral lobe, dark brown proximally, yellow distally covering black bristles and small brown spots at origin of bristles, not extending beyond margin of sternite 9 in lateral view. Sternite 9 pentagonal, brown with indistinct yellow median band and yellow caudal margin. In ventral view, caudal margin with long brown setae. Gonocoxites 9+11 as in Figs. 5C (lateral view) and Fig. 5D (ventral view).

Female terminalia: ( Fig. 5E and F ). In lateral view, ectoproct oval with brown hairs distally. In ventral view, caudal margin of sternite 7 with two small lateral processes as in Fig. 5F ; Gonocoxite 8 short, thumb-shaped, covered with long brown hairs. Gonocoxite 9 slightly protruded with stout curved digging setae.

Morphological variability: ( Fig. 4A–D ). There is no significant sexual dimorphism within the species, the body length of females is slightly shorter than that of males. The wing venation can differ, even varying from one specimen to another. In the costal area, the cross-veins are not only bifurcated but also interconnected by additional veins. This feature can also be observed in the fore wing before the origin of the radial sector; these cells are mostly irregular. In this area, the number of cross-veins varies according to the type of vein connection. Fewer irregular cells are seen in males. There are also differences in the wing pattern. In males, the shaded radial gradate veins in the apical area are usually shorter and form a wider angle with the wing margin than in females, but this pattern is not always constant.

Distribution: Mali ( Navás 1935), Democratic Republic of the Congo ( Stange 2004), Kenya, Zimbabwe ( Whittington 2002), Malawi, Zimbabwe ( Dobosz 2021) Republic of South Africa, new to Mozambique, Namibia and Tanzania ( Fig. 6 ).

Habitat: ( Fig. 7 ). Its habitats are known from wet savannah areas or around river valleys.

Figures

FIGURE 1. Habitus of holotype of Nadus overlaeti (Navás, 1931) (photo: Mervin Mansell) (A) and Nadus sudanensis Navás, 1935 (photo: Yuchen Zheng) (B)

FIGURE 2. Habitus of male from Malawi (A) and female from Mozambique (B) Nadus overlaeti (Navás, 1931) preserved in coll. USMB. Scale bar: 10 mm.

FIGURE 3. Nadus overlaeti (Navás, 1931) Head in frontal view (A); Vertex and prothorax in dorsal view (B); Legs in lateral view (C).

FIGURE 4. Variability of forewing venation, male from Malawi (A), females: from Zimbabwe (B), from Mozambique (C), male from RSA (D). Abbreviations: C—Costa, Sc—Subcosta, R—Radius, Mp1—Media posterior 1, Cua—Cubitus anterior, Cup+A1—Cubitus posterior+Anal 1, ps—pterostigma, hsc—hypostigmatic cell, rgv—radial gradate veins.

FIGURE 5. Nadus overlaeti (Navás, 1931) Male terminalia in lateral view (A); the same in ventral view (B); Male genitalia in lateral view (C); the same in caudal view (D); Female terminalia in lateral view (E); Female terminalia in ventral view (F). Abbreviations: T8, T9—tergites 8 & 9; S7, S8, S9—sternites 7, 8 & 9, ep—ectoproct, gx—gonocoxites, gx9 & gx11—gonarcusparameres complex [in male], gx8—posterior gonopophysis, gx9—lateral gonopophysis [in female].

FIGURE 6. Nadus overlaeti (Navás, 1931) distribution map. The new records are marked with blue asterisk.

FIGURE 7. Habitat of Nadus overlaeti (Navás, 1931) in the Taratibu Hills (Quirimbas National Park, Mozambique) (Photo: M. Bąkowski).