Astylogethes Kirejtshuk, 1992

Audisio, Paolo, Cline, Andrew Richard, Biase, Alessio De, Antonini, Gloria, Mancini, Emiliano, Trizzino, Marco, Costantini, Lorenzo, Strika, Sirio, Lamanna, Francesco & Cerretti, Pierfilippo, 2009, Preliminary re-examination of genus-level taxonomy of the pollen beetle subfamily Meligethinae (Coleoptera: Nitidulidae), Acta Entomologica Musei Nationalis Pragae 49 (2), pp. 341-504 : 409-412

19. Astylogethes Kirejtshuk, 1992 stat. nov.

( Figs. 19 a–h )

Astylogethes Kirejtshuk, 1992: 168 (described as a subgenus of Meligethes Stephens, 1830 ).

Type species. Nitidula subrugosa Gyllenhal, 1808: 236 (by original designation) [= Astylogethes subrugosus ( Gyllenhal, 1808) comb. nov.].

Generic redescription and diagnosis. Inclusive species vary greatly in size (1.4–3.0 mm length), and share the following combination of characters.

Body color and pubescence: pubescence silvery-whitish, short and fine, recumbent, never obscuring the blackish and usually shining dorsal body surface; pronotal and elytral sides narrowly flattened, typically the same color as disc; lateral margin of pronutum and elytra with a series of faintly distinct, small and short setae, each seta usually 0.3–0.5× as long as those on elytral disc; posterior margin of pronotum comprising moderately long, usually distally bifid or trifid microsetae, microsetae uniformly distributed on middle region anterior to scutellum ( Fig. 19g ).

Dorsal habitus: body more or less convex, variably shaped, usually moderately slender and oval ( Fig. 19a ); dorsal punctures on discal portion of pronotum as large as or larger than eye facet, usually deeply impressed and densely distributed; anterior margin of clypeus truncate, and distinctly narrowly bordered ( Fig. 19b ), without small, faintly distinct, medial bulge; circum-ocular furrows (occipital sulci) on dorsal side of head almost complete, narrow, moderately to deeply impressed ( Fig. 19b ); eyes large and usually moderately projecting laterally ( Figs. 19a, b, c ); pronotum with distinct obtuse posterior angles, never directed posteriorly ( Fig. 19a ); scutellum regularly punctured in most of exposed portion ( Fig. 19g ); elytra completely transversely strigose ( Fig. 19g ), or with simple punctation, faint traces of orange peel-like rugosity present; elytral humeral angle moderately distinct, not protruding laterally ( Fig. 19a ); elytral humeral striae variable, faintly distinct to indistinct; elytral presutural striae distinct, originating at scutellar vertex, terminating close to elytral apex, and delimiting on each elytron a scarcely raised and narrow sutural border, border narrower than proximal portion of 3 rd antennomere; elytral apices truncately rounded in both sexes ( Fig. 19a ); pygidium partially exposed, moderately convex, usually apically rounded in both sexes ( Fig. 19a ), A. caudatus with lobed median protrusion directed posteriorly (Fig. 118 l in AUDISIO 1993b), more developed in females than in males.

Ventral habitus: antennal furrows markedly delimited, nearly parallel-sided, slightly sinuate; mentum subpentagonal ( Fig. 19c ); prosternal antennal furrows of anterior margin of prosternum strongly raised but short ( Fig. 19c ); prosternal process usually relatively narrow, subapical dilated portion 2.0–2.1× as wide as maximum width of 1 st antennomere, usually bluntly acuminate distally ( Fig. 19d ); lateral borders of prosternal process delimiting shallowly impressed but distinct furrows, distally terminating over predistal lateral expansions, approaching posterior margin ( Fig. 19d ); posterior margin of mesoventrite simple, never medially incised; male impressions on metaventrite scarcely developed; first two visible abdominal ventrites simple in both sexes, without tufts of setae; caudal marginal lines of metacoxal cavities simple, parallel and contiguous to posterior margin of metacoxal cavities, with moderately deep arched impression of outer ‘axillary’ line ( Fig. 19h ); ‘axillary’ space on first abdominal ventrite reduced, ‘axillary’ angle subacute ( Fig. 19h ); relatively large, long, and deeply impressed arched impressions on basal portion of last visible abdominal ventrite, frequently partially covered by distal portion of penultimate visible abdominal ventrite ( Fig. 19f ).

Appendages: male 1 st antennomere 0.8–0.9× as long as width of protibiae excluding distal teeth ( Figs. 19a, c ); 3 rd antennomere in both sexes usually 2.0–2.1× as long as wide, 0.9–1.0× as long but distinctly thinner than 2 nd antennomere ( Fig. 19c ); 4 th and 5 th antennomeres in both sexes subequal, short, nearly as long as wide; antennal club compact, small, simple, comprising last 3 antennomeres in both sexes (8 th antennomere scarcely widened, 0.4–0.5× as wide as 9 th antennomere) ( Figs. 19a, c ), slightly narrower than width of protibiae, sexual dimorphism absent; labial palpi relatively short in both sexes ( Fig. 19c ), terminal segment nearly1.8× as long as wide; maxillary palpi moderately long and slender in both sexes ( Fig. 19c ), terminal segment 2.1–2.2× as long as wide; mandible mid-sized ( Fig. 19c ), apex moderately acuminate, no sexual dimorphism; tarsal claws simple, never toothed at base; tarsi of normal size and shape, 0.6–0.7× as long as corresponding tibiae ( Fig. 19a ); protibiae with a series of small, even, short and rounded teeth on lateral margin ( Figs. 19a, e ; Figs. 126 i–l in AUDISIO 1993b); lateral margin of meso- and metatibiae bearing a single and usually even row of large and robust pegs ( Fig. 19h ), without U-shaped sinuosity at distal third; meso- and metatibiae of variable width, usually moderately slender and narrow ( Figs. 19a, h ), never subtrapezoidal or axe-shaped; sexual dimorphism scarcely expressed in metatibiae; tarsal plates of prolegs only moderately wider in males; posterior margin of metafemora simple in both sexes, without tubercles or projections.

Male genitalia: processes along inner side of parameres absent (Figs. 137 m –p in AUDISIO 1993b), distal margin subtruncate, without deep median longitudinal desclerotization from proximal portion of tegmen extending to medial distal V-shaped excision; median lobe of aedeagus variable, without lateral emargination, narrowed and subtruncate distally, without distal marked excision or emargination.

Female genitalia (ovipositor): long and narrow, relatively large; styli absent, replaced by two small sensorial setae close to apex of contiguous or very narrowly divergent gonostyloids (Figs. 157 g –h in AUDISIO 1993b); gonostyloids moderately sclerotized and lightly pigmented distally, with a simple, never indentate outer portion of basicoxites, and a single, narrow, lightly pigmented and sclerotized arcuate area along the outer subdistal portion of gonostyloids. ‘Central point’ of ovipositor usually located more distad than middle, without proximad directed spicule.

Etymology. The generic name is derived from a combination of the Greek ‘ α ’, having a privative meaning, combined with Latin ‘ stilus ’, to emphasize the peculiar absence of distal styli on ovipositors in inclusive species, and from ‘- gethes ’, to emphasize its phylogenetic relationship with Meligethes . Gender masculine.

Biology. All species are strictly associated for larval development with flowers of Campanulaceae ( EASTON 1951a; KIREJTSHUK 1992b; AUDISIO 1993b, and unpublished data), in particular Campanula L. and Jasione L.

Phylogenetic position. Available molecular and morphological datasets provide combined evidence of a possible clade that includes Astylogethes , Lamiogethes gen. nov., Rubiogethes gen. nov., and potentially Stachygethes gen. nov. and Paleogethes gen. nov. Lamiogethes gen. nov. and Stachygethes gen. nov. develop on Lamiaceae , whereas Rubiogethes gen. nov. is known from Rubiaceae , and Paleogethes gen. nov. from Boraginaceae . Clearly defined phylogenetic relationships between these taxa remain elusive, and are only weakly supported with molecular data.

Taxonomy and geographic distribution. Astylogethes includes three described species distributed in the Palaearctic Region, and which were formerly attributed to the ‘ Meligethes subrugosus ’ species-group.

Astylogethes caudatus (Guillebeau, 1897) comb. nov. Europe, N Turkey (Boreal or mountain areas) Astylogethes corvinus ( Erichson, 1845) comb. nov. Palaearctic Region, excluding N Africa Astylogethes subrugosus ( Gyllenhal, 1808) comb. nov. Palaearctic Region

Figures

Fig. 19. Astylogethes Kirejtshuk, 1992: a–h – A. subrugosus (Gyllenhal, 1808). a – male habitus (length 2.4 mm); b – dorsal view of head; c – ventral view of head and anterior portion of prosternum; d – prosternal process and mesoventrite; e – outer margin of protibia; f – exposed portion of last visible abdominal ventrite; g – scutellum and microsetae on middle of posterior margin of pronotum; h – caudal marginal line of metacoxal cavity. Scale bars: Figs. c, d, f = 100 μm; Fig. e = 20 μm.