Orphnus (Phornus) Paulian 1948

Subgenus Phornus Paulian, 1948

Phornus Paulian, 1948: 15.

Type species

Orphnus strangulatus Paulian, 1948 (original designation).

Diagnosis

Medium sized beetles (body length 10.0– 14.5 mm). Colour uniformly brown to black. Dorsal surface of body more or less densely punctate, punctation of head and pronotum denser than of elytra. Elytra with flat to slightly convex intervals, first five to seven elytral striae more or less marked as slightly depressed lines. Head armature of males as short tubercle or transverse frontoclypeal carina. Pronotal disc of males slightly flattened anteromedially in some species. Stridulatory field in males with sparse coarse carinae, separated by 1/40 to 1⁄30 length of stridulatory field in central ¼ rd (Figs 1K, 2I). Sides of abdominal sternite 2 with more or less developed accessory plate (Figs 1G, 2H). Parameres with rounded apices in dorsal view, without lateral teeth. Endophallus without sclerotized armature.

Composition

In the present work we treat the subgenus as comprising six species: two originally described by Paulian (1948) and four new species. Petrovitz (1971) described two further species in the subgenus Phornus, O. planicollis and O. compactus, although he noted that they had no similarity to O. giganteus and O. strangulatus. These species have genital and stridulatory structures more similar to those of O. bicolor (Fabricius, 1801), the type species of Orphnus (sensu stricto), and therefore we transfer them to the nominotypical subgenus.

Orphnus giganteus differs from other members of the subgenus in a number of characters (see description below) and its taxonomic position needs further clarification. Until additional comparative data are available, we follow Paulian (1948) and treat this species as a member of subgenus Phornus.

Distribution

Members of the subgenus Phornus are distributed in Equatorial Africa and the majority of species apparently have allopatric ranges. Most of the known localities are south of the Congo Depression, notably on the Lunda and Katanga plateaus and the Eastern Arc Mountains (Fig. 6).

Key to the subgenus Phornus (males):

1. Macropterous, humeral humps well developed (Fig. 1A) …………………………………………2 – Brachypterous, humeral humps feebly marked to indistinct (Fig. 3A) ………………………………3

2. Pronotum as wide as elytra (Fig. 1M), densely punctate; head wide, frons convex and densely punctate (Fig. 1 C–D); eyes small, feebly visible in dorsal view ………… O. giganteus Paulian, 1948

– Pronotum narrower than elytra (Fig. 1N), sparsely punctate on disc; head narrower, frons concave and sparsely punctate (Fig. 2 C–D); eyes large ……………………………… O. renaudi sp. nov.

3. Frontoclypeal process tubercle-shaped or horn-shaped, not sinuate medially (Figs 3 B–C, 4H–I). Disc of pronotum somewhat flattened anteriorly; parameres more or less tapering apically (in lateral view) …………………………………………………………………………………………4

– Frontoclypeus with a low transverse keel, from ½ to almost whole head width (Fig. 5 B–C, J–K); keel may be feebly sinuate medially; disc of pronotum more or less convex, not flattened anteriorly; parameres rounded apically (in lateral view)……………………………………………5

4. Pronotum larger (Fig. 1P), more densely punctate, punctures on disc somewhat elongated (Fig. 3A); pronotum without longitudinal medial stria basally; frontoclypeal process horn-shaped; parameres more strongly sclerotized, with acute apices (in lateral view, Fig. 3D) ……… O. valeriae sp. nov.

– Pronotum smaller (Fig. 1O), more sparsely punctate with rounded punctures (Fig. 4A); pronotum with distinct medial longitudinal stria basally; frontoclypeal process tubercle-shaped; parameres less sclerotized, with angulate apices (in lateral view, Fig. 4F) ……………… O. ferrierei sp. nov.

5. Frontoclypeus with a low transverse keel, almost as wide as frontoclypeus (Fig. 5 B–C); anterior margin of clypeus somewhat rounded, keel-shaped; abdomen shorter and somewhat convex ventrally (in lateral view contour of abdominal sternites is somewhat rounded) … O. parastrangulatus sp. nov.

– Frontoclypeus with a higher transverse keel, slightly sinuate medially, about half the length of frontoclypeus (Fig. 5 J–K); anterior margin of clypeus somewhat rectangular, sharp; abdomen longer and almost flat (in lateral view contour of abdominal sternites is almost straight) …………… ……………………………………………………………………… O. strangulatus Paulian, 1948