Meligethes Stephens, 1830

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 : 456-460

32. Meligethes Stephens, 1830

( Figs. 32 a–g )

Meligethes Stephens, 1830: 30 . Odonthogethes Reitter, 1871: 154 .

Type species. Meligethes – Nitidula rufipes Marsham, 1802: 130 , nec Nitidula rufipes (Linnaeus, 1767) (subsequent designation by THOMSON 1859) [= Nitidula atrata A. G. Olivier, 1790: 18 ; = Meligethes atratus (A. G. Olivier, 1790) ]. Odonthogethes – Meligethes hebes Erichson, 1845: 172 (by monotypy) [= Nitidula denticulata Heer, 1841: 402 ; = Meligethes denticulatus ( Heer, 1841) ].

Generic redescription and diagnosis. Inclusive species vary greatly in size (2.2–4.5 mm length), and share the following combination of characters.

Body color and pubescence: pubescence variable, usually short and fine, a few species with long and prostrate setae, golden to silvery-whitish and dense, rarely partially obscuring the usually dark brown (rarely reddish, metallic green, or metallic violet) dorsal body surface; pronotal and elytral sides relatively widely flattened, typically same color as disc, a few species paler, reddish; lateral margin of pronotum and elytra with a series of faintly distinct, small and short setae, each seta 0.3–0.5× as long as those on elytral disc; posterior margin of pronotum with long, usually distally bifid microsetae, microsetae also uniformly distributed on middle region anterior to scutellum ( Fig. 32d ).

Dorsal habitus: body moderately convex, usually wide and oval ( Figs. 32a, f ); dorsal punctures on discal portion of pronotum as large as or larger than eye facet, dense, usually moderately to deeply impressed; anterior margin of clypeus always truncate, simple, i.e. without small distinct medial bulge, distinctly bordered ( Fig. 32b ); circum-ocular furrows (occipital sulci) on dorsal side of head absent ( Fig. 32b ); eyes large and usually moderately projecting laterally ( Fig. 32b ); pronotum with markedly distinct posterior angles, faintly acute to almost at right angle ( Fig. 32f ), frequently distinctly directed posteriorly ( Fig. 32a ); scutellum uniformly punctured on most of exposed portion ( Fig. 32c ); elytra usually with simple punctation, a few species with transversely strigose sculpturing ( Fig. 32d ); elytral humeral angle distinct, obtuse, frequently slightly protruding laterally and posteriorly ( Figs. 32a, f ); elytral humeral stria usually partially distinct, long, and shallowly impressed ( Fig. 32a ), rarely indistinct; elytral pre-sutural striae visible, usually originating posterior to scutellar vertex, terminating prior to elytral apex, and delimiting on each elytron a more or less distinct, flat sutural area, widest at posterior third, nearly as wide as proximal width of 3 rd antennomere; elytral apices truncately rounded in both sexes ( Figs. 32a, f ); pygidium partially exposed, moderately convex, apically rounded in both sexes ( Figs. 32a, f ).

Ventral habitus: antennal furrows markedly delimited, and moderately convergent posteriorly; mentum subpentagonal ( Fig. 32e ); prosternal antennal furrows on anterior margin of prosternum almost completely obliterated ( Fig. 32e ); prosternal process variably shaped, moderately wide, subapical portion 1.6–2.0× as wide as maximum width of 1 st antennomere, apex usually bluntly rounded ( Fig. 32g ); lateral borders of prosternal process delimiting shallowly impressed but distinct furrows, distally terminating at predistal lateral expansions ( Fig. 32g ); posterior margin of mesoventrite simple, never medially incised, longitudinal ridge on mesoventrite usually strongly raised, long, and well-marked (Figs. 167–168 in KIRK- SPRIGGS 1996); male impressions on metaventrite and/or tubercles variably 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, without deep arched impression of outer ‘axillary’ line; ‘axillary’ space on first abdominal ventrite well developed, ‘axillary’ angle widely obtuse; large and deeply impressed arched impressions on basal portion of last visible abdominal ventrite, partially covered by distal portion of penultimate visible abdominal ventrite ( Fig. 32c ).

Appendages: male 1 st antennomere 0.8–1.0× as long as width of protibiae excluding distal teeth ( Figs. 32a, f ); 3 rd antennomere usually 2.7–2.8× as long as wide in both sexes, 1.4–1.5× longer and distinctly thinner than 2 nd antennomere ( Fig. 32b ); 4 th and 5 th antennomeres subequal in both sexes, relatively short, moderately longer than wide ( Fig. 32b ), distinctly longer in some Oriental species; antennal club compact, usually moderately large, simple, comprising last 3 antennomeres in both sexes ( Fig. 32b ), usually as wide as width of protibiae, sexual dimorphism absent; labial palpi long and slender in both sexes ( Fig. 32e ), terminal segment 1.9–2.1× as long as wide; maxillary palpi long and slender in both sexes ( Fig. 32e ), terminal segment 2.7–2.9× as long as wide; mandible mid-sized, length variable, apex bifid, moderately acuminate, sexual dimorphism absent; tarsal claws variable, strongly toothed at base (as in Fig. 17m ), bluntly toothed at base, or simple and not toothed; tarsi usually moderately short, 0.5–0.6× as long as corresponding tibiae ( Figs. 32a, f ); protibiae usually with reduced teeth on outer margins ( Figs. 32a, f ); lateral margin of meso- and metatibiae bearing a single and regular row of long and thin pegs ( Figs. 32a, f ), without U-shaped sinuosity at distal third; meso- and metatibiae of variable width, usually long and slender ( Figs. 32a, f ), rarely wider and shorter, never subtrapezoidal or axe-shaped; scarce sexual dimorphism in meso- and metatibiae shape and armature; tarsal plates of prolegs wider in males; posterior margin of metafemora simple in both sexes, without tubercles or projections.

Male genitalia: variable, processes along inner side of parameres usually absent (Figs. 133 g –h, m–n in AUDISIO 1993b) or minute, usually with deep and narrow excision along distal margin, 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, rounded, distally subtruncate to acuminate, frequently with distal minute excision or emargination; main sclerites of internal sac (flagellum) small, arcuate, and moderately sclerotized, typically 3–5× shorter than aedeagus.

Female genitalia (ovipositor): large and usually strongly sclerotized; styli usually short but distinct, simple and pigmented, inserted close to apex of typically contiguous or rarely apically narrowly diverging gonostyloids; each gonostyloid distally unpigmented, with a simple never indentate outer portion of basicoxites (Figs. 153 g –h in AUDISIO 1993b), and a single, narrow, slightly 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 Greek ‘γηθέω’ (= enjoying), combined with the suffix ‘μέλι’ (= honey, nectar), to emphasize association of these beetles to flowers and nectaria.

Biology. All species are apparently strictly associated for larval development with flowers of Rosaceae , in particular bushes of Rosa L., Rubus L., and allied genera ( AUDISIO 1993b).

Phylogenetic position. Available molecular and morphological datasets provide strong and concordant evidence of the robustness of a relatively large clade that includes Meligethes , Brassicogethes gen. nov., and Meligethinus ( STRIKA 2004; TRIZZINO et al. 2009; LAMANNA 2009, and unpublished data). With regards to Meligethes , this genus exhibits a series of mainly plesiomorphic characters, provided in the above generic diagnosis, which suggests a relatively basal phylogenetic position in the Meligethinae clade, with probably closer affinities to members of the [ Pria + Microporum ] complexes of genera ( Fig. 43 ), rather than to other genera formerly prescribed to Meligethes s. l.

Taxonomy and geographic distribution. Meligethes includes 31 described Palaearctic and Oriental species, which are distributed from Western Europe and North Africa to Japan and southeastern China and Taiwan. Most of the known species are distributed in Middle Asia, the Eastern Palaearctic, and transitional areas in the Oriental Region (e.g. the northern Indian Subcontinent, northern Indochina, and China). Several new species still awaiting description are also known from these areas. All new species will be published in an upcoming revision of the genus (JELÍNEK & AUDISIO in prep.).

Two probably artifical species groups were formerly recognized in the genus, i.e. the ‘ atratus ’ and ‘ denticulatus ’ species-groups. The latter group corresponded to the previously recognized Meligethes subgenus Odonthogethes , which was characterized by strongly toothed tarsal claws, and usually right angled posterior pronotal angles.

Meligethes atratus ( Olivier, 1790) Europe

Meligethes auricomus Rebmann, 1956 S China

Meligethes auripilis Reitter, 1889 S China

Meligethes binotatus Grouvelle, 1908 N India, China

Meligethes bourdilloni Easton, 1968 Nepal, China

Meligethes brevipilus Kirejtshuk, 1980 S China

Meligethes castanescens Grouvelle, 1903 NE India, S China

Meligethes chinensis Kirejtshuk, 1979 S China

Meligethes cinereus Jelínek, 1978 Bhutan

Meligethes cyaneus Easton, 1957 E China, Japan

Meligethes denticulatus ( Heer, 1841) Palaearctic Region, excluding N Africa

Meligethes ferrugineus Reitter, 1873 NE India

Meligethes flavicollis Reitter, 1873 E Siberia , Japan, E China

Meligethes flavimanus Stephens, 1830 Palaearctic Region, excluding N Africa

Meligethes griseus Jelínek, 1978 Bhutan

Meligethes hammondi Kirejtshuk, 1980 E China

Meligethes lloydi Easton, 1968 Nepal, S and E China, Taiwan

Meligethes lutra Solsky, 1876 Middle Asia

Meligethes melleus Grouvelle, 1908 Myanmar

Meligethes nepalensis Easton, 1968 Nepal

Meligethes pectoralis Rebmann, 1956 SE China, Taiwan

Meligethes semenovi Kirejtshuk, 1979 SE Siberia : Ussuri; E China

Meligethes shirakii Sadan. Hisamatsu, 1956 S Japan: Amami Islands; China: Sichuan; Taiwan Meligethes shirozui Sadan. Hisamatsu, 1965 Taiwan

Meligethes torquatus Jelínek, 1997 Taiwan

Meligethes transmissus Kirejtshuk, 1988 S China

Meligethes violaceus Reitter, 1873 E China, Japan, Russian Far East

Meligethes vulpes Solsky, 1876 Middle Asia

Meligethes wagneri Rebmann, 1956 SE China

Meligethes xanthopus Solsky, 1876 Uzbekistan

Meligethes zakharenkoi Kirejtshuk, 2005 Taiwan, SE China 4)

Figures

Fig. 32. Meligethes Stephens, 1830: a–e, g – M. atratus (A. G. Olivier, 1790); f – M. denticulatus (Heer, 1841). a, f – male habitus (a – length 3.6 mm; f – length 3.4 mm); b – dorsal view of head; c – exposed portion of last visible abdominal ventrite;d – scutellum and microsetae on middle of posterior margin of pronotum;e – ventral view of head and anterior portion of prosternum; g – prosternal process. Scale bars: Fig. b, e = 200 μm; Figs. c, d, g = 100 μm.

Fig. 17. Aristogethes Audisio & Cline, gen. nov.: a – A. translatus (Grouvelle, 1913); b – A. pecten (Audisio, Kirk-Spriggs & Kirejtshuk, 1998); c, e–k – A. pubescens (Reitter, 1872); d, m – A. marshalli (Grouvelle, 1914). a, b – male habitus (a – length 2.6 mm; b – length 2.4 mm); c, d – dorsal view of head; e – ventral view of head and anterior portion of prosternum; f – prosternal process and mesoventrite; g – anterior portion of scutellum and microsetae on middle of posterior margin of pronotum; h – exposed portion of last visible abdominal ventrite; k – caudal marginal line of metacoxal cavity; m – last tarsomere of middle leg. Scale bars: Figs. d, f, h, k, m = 100 μm; Fig. g = 20 μm.

Fig. 43. Cladogram of hypothetical phylogenetic relationships between the 43 recognized genera of Meligethinae, as inferred from an exploratory and preliminary cladistic analysis based on 72 morphological characters. Asterisks indicate genera for which molecular data is available for some species.