Rhoizema mahalevonum, Johanson, Kjell Arne & Oláh, János, 2006

Johanson, Kjell Arne & Oláh, János, 2006, Eleven new species of Sericostomatoidea from Madagascar (Trichoptera: Helicopsychidae, Petrothrincidae, Sericostomatidae), Zootaxa 1205, pp. 1-30 : 22-27

Rhoizema mahalevonum , new species

Figs 51–57 , 60

This new species is close to the South African R. saxiferum , but is characteristic in having simple maxillary palps without additional processes, wings are more slender and have hyperboloid apices, the forewing discoidal cell is located more centrally, in both wings fork 1 originating more distally on the discoidal cell, in the forewing fork 5 is absent; the IXth sternum is simple (cf bi­lobed in saxiferum ); the gonocoxite has a median hook oriented anteriorly, and the corners of gonocoxite are more strongly angled. The species is separated from other Rhiozema species by the broader gonocoxite.

Body pale brown. Male head and thorax ( Figs 51–53 ). Head dark. Antennal scape about 2x longer than wide ( Fig. 51 ). Maxillary palp ( Fig. 52 ) 1­segmented, about as long as the second segment of the labial palp ( Fig. 53 ). Head ( Fig. 51 ) without interantennal setal warts; cephalic setal warts oval, located near posterior margin of head; postocular warts rounded. Pronotum ( Fig. 51 ) with 1 pair of large, rounded setal warts nearly tangential medially; mesoscutellum with 1 pair of long longitudinal warts.

Male wings ( Fig. 54 ). Forewing length 6.0 mm, hind wing length 4.7 mm. Denuded wing membrane pale with pale flavous veins. Forewing slender, apex hyperboloid, forks 1 and 2 present; discoidal cell situated near middle of wing; thyridial cell absent; Cu1 and Cu2 run parallel forming a longitudinal fold between wing basis and posterior wing margin.

Male abdomen. VIIth sternal process short, broad, with rounded apex.

Male genitalia ( Figs 55–57 ). Segment IX strongly produced anteriorly into a triangular lobe with slightly concave dorsal and ventral margins ( Fig. 55 ), posterior margin forms lateral plate starting immediately ventral to superior appendage; IXth sternum strongly produced posteriorly and in lateral view ( Fig. 55 ) forms a conical lobe angled about 90° to anterodorsal and posterior margins of segment IX; in ventral view tongue­shaped with slightly bilobed apex ( Fig. 57 ). Xth tergum about horizontal with nearly parallel dorsal and ventral margins, nearly as long as segment IX ( Fig. 55 ); in dorsal view ( Fig. 56 ) sharply triangular. Superior appendage up­turned, tuboid ( Fig. 55 ); in dorsal view slightly clubshaped ( Fig. 56 ). Gonocoxite simple, large, spatulate in lateral aspects ( Fig. 55 ) and with a median, large subapical hook,, directed anteriorly ( Figs 56, 57 ). Phallus forming a very long tube, basally oriented posterodorsad, bending posteriorly at basal 1/3 of length, basal part more strongly sclerotized than distal part. Endophallus decorated with a row of oblique lines.

Etymology. The species is named after the type locality of the species.

Holotype male: MADAGASCAR: Maroantsetra, Mahalevona, ii. 1958 [R. Paulian] (MNHN, in alcohol). Paratypes: MADAGASCAR: Maroantsetra, Sahasoa, iii. 1958 [R. Paulian] — 1 male (NRM); ditto, except — 1 male (JOS).

Figures

FIGURE 60. Map of Madagascar showing distributions of Sericostomatidae spp.: Rhoizema mahalevonum (rectangle); and Cheimacheramus rossi (circle).

FIGURES 51 – 57. Rhoizema mahalevonum, new species, holotype. Male genitalia: 51 — head and thorax, dorsal; 52 — maxillary palp; 53 — labial palp; 54 — right wings; 55 — genitalia, lateral; 56 — genitalia, dorsal; 57 — genitalia, ventral.