Otiorhynchus (Nihus), REITTER, 1912

Germann, Christoph, 2014, On the identity of Otiorhynchus (Nihus) subcostatus STIERLIN, 1866, description of Otiorhynchus muffi sp. nov., and an illustrated key to the species of Nihus REITTER, 1912 with taxonomic comments on both the subgenera Nihus and Eunihus REITTER, 1912 (Coleoptera, Curculionidae), Contributions to Natural History 25, pp. 45-69 : 52-56

Key to the species of Nihus REITTER, 1912

Species of the subgenus Nihus are recognisable by the following traits (modified after Reitter 1913): i) sloped and glossy apex of rostrum, ii) tuberculate pronotum, iii) frons between the eyes not or hardly wider than the rostral dorsum between the insertions of the antennae, iv) comparably dense vestiture of body. Eunihus shares the traits mentioned for Nihus , except for the frons which is considerably wider than the rostral dorsum.

Sizes vary, also due to polyploidy in the case of O. carinatopunctatus and supposedly also in O. subcostatus . A sexual dimorphism is present where males are narrower with stronger legs ( O. azaleae , O. spaethi , O. hypocrita ) or males are stouter and more globular ( O. gredleri ). Also genital structures vary to a certain extent, see as an example the form of the plate of the spiculum in the case of O. spaethi ( Figs 20–21) or O. azaleae ( Figs 22–23). On the other hand the shape of the spermatheca was found to be rather constant in all species examined and hence not useful for species discrimination.

All examined specimens (except for the widespread and unambiguously recognisable species O. uncinatus and O. carinatopunctatus ) are listed and their records are shown on the maps ( Figs 29–30).

1 All elytral striae and intervals homogeneously shaped .............................. 2

– uneven intervals elevated ........................................................................... 7

2 Smaller, less massive, all intervals with raised long and towards their tips strongly clubbed setulae ( Fig. 2)........................... uncinatus GERMAR, 1824

– different ...................................................................................................... 3

3 Pronotum and elytra elongate, egg-shaped, parallel sided in the middle and broadly rounded at apex, pronotum with large, flattened and glossy tubercles, setulae on elytra long, slender and raised (more than 5 times longer than wide), vestiture with less dense standing scales, the glossy surface of the elytra clearly visible in between. Rostral dorsum weakly conical from frons to middle of rostral dorsum ....................................................... 4

– pronotum about as long as wide, elytra oval to broad oval, pronotum finely tuberculate, setulae shorter and broader (up to 4 times longer than wide), vestiture with dense standing scales almost completely covering the elytral surface. Rostral dorsum parallel sided or subconical from frons to insertion of antennae ................................................................................................. 5

4 Pronotum with large flattened tubercles, bigger, habitus strong, setulae raised (angle> 45°) ( Figs 7, 28) ...................... hypocrita RoSENHAUER, 1847

– pronotum tuberculate, tubercles merged to a longitudinal wrinkle at disc, smaller, habitus more gracile, setulae less raised (angle <30°) ( Fig. 6) .......................................................................... venustus STIERLIN, 1880

5 More massive (or globular in males, females of parthenogenetic populations long broad oval), body colour dark brown to blackish, eyes small, strongly bulged (button-like), laterally protruding from head outline. Medianlobus of penis parallel, apex rounded, blunt ( Figs 8–10, 28) ............................................................... gredleri DANIEL & DANIEL, 1898

– more gracile (except parthenogenetic form of O. azaleae Figs 11–13), elytra oval, eyes larger, less bulged ...................................................................... 6

6 Rostral dorsum parallel sided. Medianlobus of penis parallel, apex broadly rounded, with pointed tip ( Figs 11–13, 22–23, 26)... azaleae PENECKE, 1894

– Rostral dorsum subconical, laterally constricted before frons and weakly broadened towards antennal insertion. Medianlobus of penis rounded, apex continuously pointed ( Figs 14–15, 20–21, 27) ........... spaethi REITTER, 1913

7 Habitus massive, shoulders sloped, uneven elytral intervals strongly elevated, only these with long raised setulae, eyes protruding ( Fig. 3)............. .......................................................... carinatopunctatus (RETZIUS, 1783) (= scaber (LINNAEUS, 1758) sensu auctorum)

– habitus less massive, shoulders rounded, uneven intervals moderately to faintly elevated, setulae on both stria and intervals, eyes flat.................... 8

8 Elytra and pronotum more rounded, raised setulae shorter and less curved (best visible in lateral view at the elytral decline), adherent scales more uniformly coloured, bright scales pale-grey with a pearly shimmer, brown scales lighter dark, therefore vestiture less contrasting. Plate of spiculum small with rounded and converging branches forming an oval gap in-between ( Figs 5, 19) ........................................................ subcostatus STIERLIN, 1866

– Elytra more elongate oval, raised setulae longer and more strongly curved (best visible in lateral view at elytral decline), adherent scales with coppery shimmer, more contrasting (more darker brown scales), conspicuously spotty. Plate of spiculum robust, with rectangular branches parallel to diverging, forming a trapezoid gap in-between ( Figs 1, 4, 16)................... muffi sp. nov.