Discheramocephalus bisulcatus Darby, 2013

Jałoszyński, Paweł, 2020, Notes on Malagasy Discheramocephalus Johnson (Coleoptera: Ptiliidae), Zootaxa 4885 (4), pp. 591-595 : 594-595

Discheramocephalus bisulcatus Darby

( Fig. 1–3 , 7 , 10–12 )

Discheramocephalus bisulcatus Darby, 2013: 241 , Fig. 1 , 19, 21, 27.

Material studied: 1 ♁, 2 ♀♀, Madagascar, Ranomafana National Park , 21.26S, 47.43E, 900–1000 m, 12.04.2019, sifted from leaf litter in secondary forest, leg. P. Jałoszyński ( MNHW) .

Emended diagnosis. Head with biarcuate (broadly M-shaped) frontal groove, lacking well-defined paired impressions; frons in front of groove strongly microsculptured; pronotum with two pairs of longitudinal sulci reaching anterior pronotal margin, inner pair gradually broadening posterad, pronotum also with two pairs of oval antebasal impressions between sulci; proximal flagellomeres more than 3 times as long as broad; ‘cavities’ of abdominal segment VIII in male and female narrower than 1/4 width of segment; posterior margin of sternite IX in male and female similar, with broad median area devoid of denticles; aedeagus stout, in dorsal view with rounded sides, in lateral view abruptly bent ventrad at obtuse angle.

Supplementary description. Male ( Fig. 4–5 ) not differing externally from female; antennae ( Fig. 6 ) with conspicuously elongate antennomeres 3–9, each 3 times or more longer than broad; abdominal segment VIII in both sexes with pair of small lateral internal ‘cavities’, each narrower than 1/4 of width of segment, in male ( Fig. 8 ) ‘cavities’ appear slightly smaller than in female ( Fig. 9 ); posterior margin of sternite IX in both sexes ( Fig. 13–14 ) of similar shape, with lateral groups of 2–3 large denticles and arcuate median region lacking denticles.

Aedeagus ( Fig. 15–17 ) relatively stout and short, less than 0.2 times as long as body, in dorsal view ( Fig. 15 ) with evenly rounded sides, apex ( Fig. 16 ) subtrapezoidal, in lateral view distinctly bent ventrad by an obtuse angle ( Fig. 17 ). Endophallus poorly visible (also with phase contrast).

Spermatheca ( Fig. 18 ) simple, lacking loops and coils, with elongate funnel.

Remarks. Males of this species were not known so far; they are externally indistinguishable from females. The latter were adequately described by Darby (2013), except for the details of abdominal structures, which are added in the present study.

Discheramocephalus bisulcatus clearly differs from its sympatric Malagasy relative D. vasilii in cephalic, pronotal and genital characters while both species have a similar shape of the posterior margin of the sternite IX. This latter structure, i.e. the median portion of the posterior margin lacking denticles and flanked by groups of large teeth, differentiates the Malagasy species from those known from other regions.

Figures

FIGURES 1–6. Discheramocephalus vasilii Darby, male (1–3), and D. bisulcatus Darby, male (4–6). Dorsal habitus (1, 4); head, pronotum and elytral base in dorsal view (2, 5); antenna in dorsal view (3, 6).

FIGURES 7–9. Abdominal internal ‘cavities’ of segment VIII. Discheramocephalus vasilii Darby, male (7); D. bisulcatus Darby, male (8) and female (9).

FIGURES 10–18. Discheramocephalus vasilii Darby, male (10–12), and D. bisulcatus Darby, male (13, 15–17) and female (14, 18). Posterior margin of abdominal sternite IX (10, 13–14); aedeagus in dorsal (11, 15) and lateral (12, 17) views; apex of aedeagus in dorsal view (16); spermatheca (18).