Cyrtonion ghanense Hansen, 1989

Fikáček, Martin, 2008, A new species of the genus Cyrtonion (Coleoptera: Hydrophilidae: Megasternini) from the Democratic Republic of the Congo, Acta Entomologica Musei Nationalis Pragae (suppl.) 48 (1), pp. 27-35 : 31

Cyrtonion ghanense Hansen, 1989

( Figs. 3 , 5-6 )

Cyrtonion ghanense Hansen, 1989: 262 .

Cyrtonion ghanense: HANSEN (1999) : catalogue; HEBAUER (2006): catalogue; FIKÁČEK (2006): taxonomy.

Type material examined. PARATYPE: ♁, ‘ Ghana E. R. / Mt.Atewa / rainforest / R. W. Taylor, 17-20 Oct 68 // ANIC / Berlese No. 126 // PARATYPE / Cyrtonion / ghanense / M. Hansen.’ ( ANIC).

Additional material examined. CAMEROON: SUD- OUEST, Bakingili , 20 m a.s.l., 13.vi.1984, J.A. Di Giulio lgt., 1 ♁ ( FHPC) . GHANA: ASHANTI PROV., Kumasi, Bobiri Forest Reserve [= ca. 30 km E of Kumasi, 2.5 km of Kubeasi], 2.-3.i.1966, S. Endrödy-Younga lgt., 3 ♁♁ 2 ♀♀, 15 spec. ( ZSMC, NMPC) . REPUBLIC OF THE CONGO: LEKOUMOU, Sibiti , IRHO [= Institut de recherches pour les huiles et les oléagineux], rain forest, sifted fallen oilpalm fruits, 25.xi.1963, Endrödy-Younga lgt., 2 ♁♁ 3 ♀♀ ( HNHM, NMPC) ; BOUENZA, without more detailed geographic data, catarract, sifted in float, 30.xi.1963, Endrödy-Younga lgt., 1 ♁ ( HNHM) .

Differential diagnosis. The species is externally identical with C. sculpticolle and C. moto sp. nov. From the latter species, it differs by pointed apex of the median lobe ( Fig. 3 ). In contrast to C. sculpticolle , the median lobe is slightly wider in C. ghanense , lateral sides of the apical part of the median lobe are more or less straight and the apex is more sharply pointed.

Variation. Rather wide variation concerning the size, coloration and development of the pronotal and elytral bulges was found in the series from Bobiri Forest Reserve ( Ghana). The size of the beetles (body length × width) can vary from 2.0× 1.3 mm to 2.5× 1.6 mm irrespective to the sex. Pronotal and elytral bulges are usually higher and more conspicuous in larger specimens. Coloration of the dorsal side varies from black (paratype specimen examined) to brown. Male genitalia including the apical part of the median lobe show no variation in all specimens examined.

Distribution. So far known from Ghana, Cameroon and the Republic of the Congo ( Fig.6 ).

Figures

Figs. 1-4. Aedeagophores of Cyrtonion Hansen, 1989 species. 1-2 – C. moto sp. nov., holotype; 3 – C. ghanense Hansen, 1989, paratype; 4 – C. sculpticolle (Régimbart, 1907), paratype. 1 – aedeagus; 2-4 – apical portion of the median lobe.

Fig. 5. Cyrtonion ghanense Hansen, 1989, Ghana (Bobiri Forest Reserve), dorsal habitus (2.0 mm).

Fig. 6. Known distribution of the species of the genus Cyrtonion Hansen, 1989. Green area covers distribution of evergreen rain forest.