Thymogethes Audisio & Cline, 2009

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 : 394-398

15. Thymogethes Audisio & Cline , gen. nov.

( Figs. 15 a–k )

Type species. Meligethes lugubris Sturm, 1845: 49 (by present designation) [= Thymogethes lugubris ( Sturm, 1845) comb. nov.].

Generic description and diagnosis. Inclusive species vary greatly in size (1.5–2.9 mm length), and share the following combination of characters.

Body color and pubescence: pubescence silvery-whitish, usually short and fine, recumbent, in some species setae much longer and denser and obscuring the blackish dorsal body surface; pronotal and elytral sides narrowly flattened, typically the same color as disc. Lateral margin of pronotum 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 with long, usually distally trifid or multifid microsetae, microsetae uniformly distributed on middle region anterior to scutellum ( Fig. 15d ).

Dorsal habitus: body moderately convex, usually long and slender ( Figs. 15a, b ); 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 faintly to strongly arcuately emarginate, distinctly narrowly bordered ( Fig. 15e ), usually with small, faintly distinct, medial bulge slightly protruding anteriorly; narrow circum-ocular furrows (occipital sulci) present on dorsal side of head, moderately to deeply impressed, complete ( Fig. 15e ); eyes large and moderately projecting laterally ( Figs. 15a, b ); pronotum with right angled to obtusely rounded posterior angles, never directed posteriorly ( Figs. 15a, b ); scutellum regularly punctured on posterior part of exposed portion ( Fig. 15d ); elytra with variable punctation, punctures simple or frequently distinctly transversely strigose; elytral humeral angle moderately distinct, not protruding laterally ( Figs. 15a, b ); elytral humeral striae scarcely distinct; elytral pre-sutural striae distinct, originating at scutellar vertex, terminating close to elytral apex, and delimiting on each elytron a slightly raised and narrow sutural border, usually narrower than proximal portion of 3 rd antennomere; elytral apices truncately rounded in both sexes ( Fig. 15a ); pygidium partially exposed, moderately convex, apically rounded in both sexes ( Figs. 15a, b ).

Ventral habitus: antennal furrows markedly delimited, parallel-sided, slightly divergent posteriorly; mentum subpentagonal, submental impression normal shaped ( Fig. 15c ); antennal furrows of anterior margin of prosternum strongly raised and moderately long ( Figs. 15c, f ); prosternal process relatively wide, subapical dilated portion nearly 2.3−2.5× as wide as maximum width of 1 st antennomere, usually bluntly convex distally ( Fig. 15f ); lateral borders of prosternal process delimiting moderately to shallowly impressed distinct furrows, distally terminating over predistal widely developed lateral expansions, close to faintly microscopic denticulate posterior margin ( Fig. 15f ); posterior margin of mesoventrite simple, never medially incised ( Fig. 15f ); male impressions on metaventrite and tubercles variably developed; first two visible abdominal ventrites simple in both sexes, without tufts of setae; caudal marginal lines of metacoxal cavities medially slightly and regularly deviating posteriorly, only partially subparallel and contiguous to posterior margin of metacoxal cavities ( Fig. 15g ), arched impression of outer ‘axillary’ line exceptionally deep; ‘axillary’ space on first abdominal ventrite markedly reduced, ‘axillary’ angle bluntly acute ( Fig. 15g ); relatively small, short, but deeply impressed arched impressions on basal portion of last visible abdominal ventrite, usually partially covered by distal portion of penultimate visible abdominal ventrite ( Fig. 15h ); last visible abdominal ventrite in males frequently with tubercles or raised median ridges posteriorly.

Appendages: male 1 st antennomere 0.7–0.8× as long as width of protibiae excluding distal teeth ( Figs. 15a, b ); 3 rd antennomere long and slender in both sexes, usually 2.5–2.7× longer than wide, and nearly 0.8–0.9× as long and distinctly thinner than 2 nd antennomere ( Figs. 15a, c ); 4 th and 5 th antennomeres subequal in both sexes, short, slightly longer than wide; antennal club compact, mid-sized, simple, comprising last 3 antennomeres in both sexes (8 th antennomere scarcely widened, nearly 0.5× as wide as 9 th antennomere) ( Fig. 15c ), distinctly narrower than width of protibiae, sexual dimorphism absent; labial palpi short in both sexes ( Fig. 15c ), terminal segment nearly1.6–1.7× as long as wide; maxillary palpi moderately long in both sexes ( Fig. 15c ), terminal segment 2.1–2.3× as long as wide; mandible mid-sized ( Figs. 15a, b ), apex acuminate, no sexual dimorphism; tarsal claws simple, never toothed at base; tarsi of normal size and shape, 0.5–0.7× as long as corresponding tibiae ( Figs. 15a, b ); protibiae with a series of variably shaped, usually moderately large, and frequently uneven (more or less sharply acuminate) teeth on lateral margin ( Figs. 15a, b ; Figs. 128 h–i and n–q in AUDISIO 1993b), with subdistal group of longer teeth perpendicular to tibial margin with the first and penultimate teeth usually larger than others; lateral margin of meso- and metatibiae bearing a single and usually moderately even row of relatively small robust spurs, without sinuosity at distal third ( Figs. 15a, b ); meso- and metatibiae of variable width, usually slen- der and narrow ( Figs. 15a, b ), never subtrapezoidal or axe-shaped; faint sexual dimorphism in metatibial shape ( Figs. 15a, b ); tarsal plates of prolegs distinctly wider in males; anterior margin of profemora and posterior margin of metafemora in both sexes without gibbosities, tubercles, or spines.

Male genitalia: processes along inner side of parameres absent (Fig. 144 in AUDISIO 1993b), tegmen with shallowly to deeply incised distal margin, without deep median longitudinal desclerotization from proximal portion of tegmen extending to medial distal V-shaped excision; median lobe of aedeagus long and slender, without lateral emargination, narrow, bluntly acuminate and variably shaped distally, usually with minute distal excision.

Female genitalia (ovipositor): variably shaped, usually small; styli short, simple, cylindrical, frequently more darkly pigmented, inserted close to apex of contiguous gonostyloids; each gonostyloid lightly sclerotized and frequently more darkly pigmented distally, with a simple, never indentate outer portion of basicoxites (Figs. 160 e–n in AUDISIO 1993b), and a single, narrow, lightly pigmented and sclerotized arcuate area along outer subdistal portion of gonostyloids. ‘Central point’ of ovipositor usually nearly centrally located, or placed slightly more distad than middle, without proximad directed spicule.

Etymology. The generic name is derived from the Latin Thymus (= thyme), to emphasize the characteristic larval association of several species with members of this Lamiaceae genus and related genera, and ‘- gethes ’, to emphasize its phylogenetic relationship with Meligethes . Gender masculine.

Biology. All species are strictly associated for larval development with flowers of Lamiaceae , in particular members of the Thymogethes lugubris species-group are associated with Thymus L., Mentha L., or Dracocephalum L., whereas members of the T. exilis species-group are associated with Thymus L., Rosmarinus L., Lavandula L., or Satureja L. ( AUDISIO 1993b).

Phylogenetic position. Available molecular and morphological datasets provide evidence for a monophyletic clade including Thymogethes gen. nov. as sister to Sagittogethes gen. nov., both being moderately related to Afrogethes gen. nov. and allied genera. However, phylogenetic relationships of these taxa remain unclear, and only partially supported with molecular data.

Taxonomy and geographic distribution. Thymogethes gen. nov. includes 20 described species and one currently under description, mostly distributed in the southwestern Palaearctic

( EASTON 1954a; KIREJTSHUK 1992b; AUDISIO 1993b; JELÍNEK & AUDISIO 2007; AUDISIO et al. in press). Thymogethes species are attributed to two formerly recognized species-groups, i.e. the ‘ Meligethes lugubris ’ and ‘ M. exilis ’ species-groups.

Thymogethes abiens (Kirejtshuk, 1979) comb. nov. E European Russia

Thymogethes acicularis (C. N. F. Brisout S Europe, Turkey de Barneville, 1863) comb. nov.

Thymogethes egenus ( Erichson, 1845) comb. nov. S Europe, Near East

Thymogethes exilis ( Sturm, 1845) comb. nov. Europe, N Turkey, N Morocco

Thymogethes fumatus ( Erichson, 1845) comb. nov. S Europe

Thymogethes funereus ( Jelínek, 1967) comb. nov. S Europe, Near East

Thymogethes gagathinus ( Erichson, 1845) comb. nov. Palaearctic Region, excluding N Africa Thymogethes grenieri (C. N. F. Brisout SW Mediterranean de Barneville, 1872) comb. nov.

Thymogethes intermixtus (Kirejtshuk, 1979) comb. nov. Kyrgyzstan

Thymogethes klapperichi (Easton, 1957) comb. nov. Middle Asia, Iran

Thymogethes lugubris ( Sturm, 1845) comb. nov. Europe, Caucasus, Turkey, N Middle Asia,

E Siberia

Thymogethes nigritus (Lucas, 1849) comb. nov. W Mediterranean

Thymogethes nitidicollis (Reitter, 1873) comb. nov. Japan, E Siberia, N Korea

Thymogethes normandi (Easton, 1954) comb. nov. SW Europe, N Africa

Thymogethes norvegicus (Easton, 1959) comb. nov. S Scandinavian and Baltic areas

Thymogethes oreophilus ( Audisio, 1984) comb. nov. N and Central Italy, SW Switzerland

Thymogethes otini (Easton, 1954) comb. nov. N Africa, S Iberian Peninsula

Thymogethes rebmanni (Easton, 1957) comb. nov. Middle Asia

Thymogethes subfumatus (Ganglbauer, 1899) comb. nov. SE France and NW Italy: Maritime Alps Thymogethes submetallicus (Sainte-Claire Deville, 1908) S Europe, N Middle Asia, S Siberia comb. nov.

Figures

Fig. 15. Thymogethes Audisio & Cline, gen. nov.: a, h – T. egenus (Erichson, 1845); b – T. subfumatus (Ganglbauer, 1899); c–g, k – T. nigritus (Lucas, 1849). a, b – male habitus (a – length 2.5 mm; b – length 2.7 mm); c – ventral view of head and anterior portion of prosternum; d – anterior portion of scutellum and microsetae on middle of posterior margin of pronotum; e – dorsal view of head; f – prosternal process and mesoventrite; g – caudal marginal line of metacoxal cavity; h – exposed portion of last visible abdominal ventrite; k – middle leg with outer margin of mesotibia. Scale bars: Figs. c, e, f, g, h = 100 μm; Fig. d = 20 μm.