Hypocaccus (Nessus), Reichardt, 1932

Lackner, Tomáš & Seres, Gábor, 2018, Revision of the subgenus Nessus of the genus Hypocaccus from Central Europe, with description of a new species (Coleoptera: Histeridae), Acta Entomologica Musei Nationalis Pragae (Acta. Ent. Mus. Natl. Pragae) 58 (2), pp. 419-439 : 420-421

Genus Hypocaccus C. Thomson, 1867 Subgenus Nessus Reichardt, 1932

Type species. Saprinus rubripes Erichson, 1834: 193 , by original designation.

Diagnosis (applies to Central European taxa). Members of the subgenus Nessus differ from members of the nominotypical subgenus as well as from the subgenus Baeckmanniolus Reichardt, 1926 in generally smaller size, and in the absence of several deep elongate rugae on the frons (the pronotum is furthermore glabrous in Baeckmanniolus , while it is punctate in the other two subgenera). The frontal disc of Nessus species is adorned with dense punctation or numerous short elongate rugae (see e.g. LACKNER 2010: fig. 420). On the other hand, members of the nominotypical subgenus, as well as the subgenus Baeckmanniolus possess usually only several, often single or double deep longitudinal rugae on their frontal disc (see e.g. LACKNER 2010: fig. 436). Members of the three respective subgenera differ also in their behavior: species of Nessus are found mostly on carrion or in dung, or, in case of the newly described species, in burrows of small mammals. Members of the nominotypical subgenus, and the subgenus Baeckmanniolus on the other hand, usually occur on beaches, riverbanks or sandy shoals of streams, only occasionally are found on sandy soils further away from water (for details see also LACKNER 2010: 134, 140). Species of the genus Hypocaccus from Central Europe can be identified using the works of MAZUR (1973), MAZUR & KASZAB (1980) or KRYZHANOVSKIJ & REICHARDT (1976).

Key to the species of the subgenus Nessus of the genus Hypocaccus from Central Europe

1(2) Protibia on outer margin with 5–7 denticles, of which the distalmost three (or four) are triangular and conspicuously larger than the proximal rest ( Fig. 31 ). ...................... Hypocaccus rubripes ( Erichson, 1834)

2(1) Protibia on outer margin with 8–11 shorter denticles, of which the distalmost three (or four) are not triangular and not conspicuously larger than the proximal rest ( Fig. 32 ).

3(6) Dorsal elytral striae reaching approximately 3/4 of the length of elytra; the first dorsal elytral stria shorter than striae 2–4 ( Fig. 1 ).

4(5) Pronotum broader, lateral sides not conspicuously convergent apically ( Fig. 14 ); males with two faint tubercles on basal third of metaventrite, best visible in lateral view ( Fig. 15 ); sternite VIII of male genitalia narrowing apically ( Fig. 16 ); aedeagus shorter and stouter ( Fig. 23 ). ... Hypocaccus hungaricus sp. nov.

5(4) Pronotum narrowing apically ( Fig. 1 ); metaventrite in males without tubercles; sternite VIII of male genitalia sub-rectangular, apex with a brush of tiny setae ( Fig. 3 ); aedeagus overall thinner and longer ( Fig. 10 ). ................ Hypocaccus rufipes ( Kugelann, 1792)

6(3) Dorsal elytral striae reaching approximately 1/2 of the length of elytra, first dorsal elytral stria slightly to conspicuously longer than striae 2–4 ( Fig. 40 ).

7(8) Dorsum with faint bluish to greenish metallic tinge ( Fig. 40 ); frons with very dense punctation oflen intermingled with tiny rugae; aedeagus sub-parallel, overall thinner, bluntly pointed apically ( Fig. 53 ). .... ..................... Hypocaccus curtus ( Rosenhauer, 1847)

8(7) Dorsum light to dark brown, without metallic tinge ( Fig. 45 ); frons without tiny rugae, punctation of frons less dense; aedeagus shorter and stouter, acutely pointed apically ( Fig. 62 ). ......................................... ................. Hypocaccus controversus G. Müller, 1937

Figures

Figs 31–32. Protibiae, dorsal view. 31 – Hypocaccus (Nessus) rubripes (Erichson, 1834); 32 – H. (N.) curtus (Rosenhauer, 1847) (both re-drawn from VIENNA 1980).

Figs 1–2. Hypocaccus (Nessus) rufipes (Kugelann, 1792), habitus. 1 – dorsal view; 2 – ventral view.

Figs 14–15. Hypocaccus (Nessus) hungaricus sp. nov. 14 – habitus, dorsal view. 15 – ventrolateral view, arrow points the metaventrite with tubercles.

Figs 16–24. Male genitalia of Hypocaccus (Nessus) hungaricus sp. nov. 16 – VIII sternite and tergite, ventral view; 17 – ditto, dorsal view; 18 – ditto, lateral view; 19 – IX and X tergites, dorsal view; 20 – ditto, lateral view; 21 – IX sternite (spiculum gastrale), ventral view; 22 – ditto, lateral view; 23 – aedeagus, dorsal view; 24 – ditto, lateral view.

Figs 3–11. Male genitalia of Hypocaccus (Nessus) rufipes (Kugelann, 1792). 3 – VIII sternite and tergite, ventral view; 4 – ditto, dorsal view; 5 – ditto, lateral view; 6 – IX and X tergites, dorsal view; 7 – ditto, lateral view; 8 – IX sternite (spiculum gastrale), ventral view; 9 – ditto, lateral view; 10 – aedeagus, dorsal view; 11 – ditto, lateral view.

Figs 40–43. Hypocaccus (Nessus) curtus (Rosenhauer, 1847), dorsal habitus.40 – Saprinus curtus Rosenhauer, 1847, lectotype.41 – Saprinus puncticollis Küster, 1849, lectotype. 42 – Saprinus cribellaticollis Jacquelin Du Val, 1858, lectotype. 43 – Saprinus sicanus Marseul, 1862, lectotype.

Figs 46–54. Male genitalia of Hypocaccus (Nessus) curtus (Rosenhauer, 1847). 45 – VIII sternite and tergite, ventral view; 46 – ditto, dorsal view; 47 – ditto, lateral view; 48 – IX and X tergites, dorsal view; 49 – ditto, lateral view; 50 – IX sternite (spiculum gastrale), ventral view; 51 – ditto, lateral view; 52 – aedeagus, dorsal view; 53 – ditto, lateral view.

Figs 44–45.Hypocaccus (Nessus) curtus (Rosenhauer, 1847), dorsal habitus. 44 – Saprinus revisus Marseul, 1876, lectotype. 45 – Hypocacculus (Nessus) controversus G. Müller, 1937, lectotype.

Figs 55–63. Male genitalia of Hypocaccus (Nessus) controversus (Müller, 1937). 55 – VIII sternite and tergite, ventral view; 56 – ditto, dorsal view; 57 – ditto, lateral view; 58 – IX and X tergites, dorsal view; 59 – ditto, lateral view; 60 – IX sternite (spiculum gastrale), ventral view; 61 – ditto, lateral view; 62 – aedeagus, dorsal view; 63 – ditto, lateral view.