Megistoleon ritsemae

Badano, Davide, 2013, Description of Megistoleon thaumatopteryx sp. nov. with notes on the genus Megistoleon Navás (Neuroptera, Myrmeleontidae), Zootaxa 3635 (2), pp. 194-200 : 195-198

Megistoleon ritsemae (van der Weele, 1907)

( Figs. 1 , 3 , 5–8 )

Diagnosis. Thorax mostly dark brown with two pale lateral stripes; forewings broad, hind wings narrower, almost falcate and a little longer than the first pair; forewing membrane mostly hyaline with dark brown infuscation at the apex and well defined markings just before the white pterostigma and in the radial area ( Fig. 1 ).

Redescription. Size. Body length 41.4 mm (min-max 40.7–42.6); forewing length 47.2 mm (44.2–51.4), ratio width/length 0.028; hind wing length 49.0 mm (46.0–53.6), ratio width/length 0.13.

General coloring. Dorsally dark brown with yellowish stripes on the thorax and dark brown abdomen, ventral side very pale; brown markings of the wings restricted to the apical area.

Head. Vertex moderately raised, vertex and occiput pale brown with a central black stripe; frons and clypeus with a central black marking and with lateral light brown margins; labrum light brown; genae light brown; maxillary palpi light brown; labial palpi light brown with darker last palpomeres; antennae totally black, flagellomeres covered by short black setae.

Thorax. Pronotum dark brown with two lateral yellowish stripes and covered by sparse long and dark setae ( Fig. 3 ); mesonotum and metanotum dark brown, the paler stripes of the pronotum continue along the sides of prescutum, mesoscutum, mesoscutellum, metascutum and metascutellum; yellowish brown areas are also present at wing insertion; pleural area marked by a longitudinal black stripe; ventral side very pale, almost whitish.

Legs. Coxae almost whitish; all pairs of legs with light brown femora and dorsally darker tibiae, tarsi brown; legs covered by long dark setae.

Wings. Wings of different shape: forewings broad with rounded apex, hind wings noticeably narrower, slightly falcate and a little longer than the first pair, venation mostly dark brown, longitudinal veins with alternating pale dashes; forewing with costal area divided in two rows of cells from Rs insertion and in three rows from middle length; pterostigma large, white and disposed after a contiguous dark marking; a small dark distinct spot is evident on the white coloured hypostigmatic cell; forewing membrane hyaline proximally with a stained apex; crossveins between M and CuA highlighted in brown; radial area with a dark brown elongate and curved marking; hind wing membrane basally hyaline and distally with a very large irregular brown marking; pterostigma very large, white, linked to a second white marking more apical in position; a small white spot is present near the posterior margin and bordered by the main brown area; apical wing margin of both wings infuscated ( Fig. 1 ).

Abdomen. Abdominal tergites brown with paler, yellowish, posterior margins; sternites pale brown with darker lateral-posterior margins; pleural membrane light brown; abdomen with a thick covering of short black setae. Male terminalia as in Figs. 5–6 . Ectoproct with the posterior portion darker than the anterior one; IX sternite completely pale. Male genitalia as in Figs. 7–8 . Gonarcus arch-like; mediuncus flattened, only slightly prominent; parameres strongly connected to each other with an extended, flattened and sclerified apical part.

Specimens examined. 23 in alcohol: “Africa – Gabon: Makokou, Ipassa 520 m / 16.II-1.III.2012, C. Deiaco leg.”, D. Badano coll.; 13 pinned: “ 26.XII.1991 / Mt. Cameroon, Cameroon / leg. Rautenstrauch”, D. Badano coll.

Distribution. This rare antlion has been reported from Guinea, Congo, Gabon, Cameroon and Uganda (Prost 2010).

Ecology. The bio-ecology of this myrmeleontid is unknown, it appears to be a forest species. In Gabon (Makokou, Ipassa) it was collected at light during the first part of the night, from about 19:00 to 22:00, in a secondary growth forest (Deiaco pers. comm.).

Figures

FIGURES 1 – 2. Habitus of Megistoleon species. 1. M. ritsemae, male (Cameroon, Mt. Cameroon). 2. M. thaumatopteryx sp. nov., holotypus, female (Mozambique, Sofala prov.), abdomen in situ.

FIGURES 3 – 4. Pronotum of Megistoleon species. 3. M. ritsemae (Gabon, Ipassa), alcohol preserved specimen. 4. M. thaumatopteryx sp. nov., holotypus, female (Mozambique, Sofala prov.).

FIGURES 5 – 8. Megistoleon ritsemae. 5. Male terminalia, lateral view. 6. Male terminalia, ventral view. 7. Male genitalia, gonarcus-paramere complex, ventral view. 8. Male genitalia, gonarcus-paramere complex, lateral view.