Xerogethes 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 : 366-368

7. Xerogethes Audisio & Cline , gen. nov.

( Figs. 6 f–h , 7 a–g )

Type species. Meligethes rotundicollis C. N. F. Brisout de Barneville, 1863: 56 , 97 (by present designation) [= Xerogethes rotundicollis (C. N. F. Brisout de Barneville, 1863) comb. nov.].

Generic description and diagnosis. Inclusive species vary greatly in size (1.4–2.7 mm length), and share the following combination of characters.

Body color and pubescence: pubescence usually moderately long and fine, recumbent, golden to silvery-whitish, never obscuring the variably colored dorsal body surface (brown, blackish, reddish, or blackish with orange spots on elytra), X. osellai Audisio & Jelínek, 2000 possesses elongate, suberect, dense silvery pubescence; pronotal and elytral sides narrowly flattened, typically the same color as disk, rarely pale reddish. 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 with long, usually distally bifid or trifid microsetae, microsetae uniformly distributed on middle region anterior to scutellum ( Fig. 7g ).

Dorsal habitus: body markedly convex, short or slender, more or less oval ( Fig. 7a ); dorsal punctures on discal portion of pronotum as large as or larger than eye facets, usually moderately deeply impressed and densely distributed; anterior margin of clypeus distinctly sinuately emarginate, simple, i.e. without small distinct bulge medially, and distinctly bordered ( Figs. 7a, b ); circum-ocular furrows (occipital sulci) on dorsal side of head complete and distinct ( Fig. 7b ); eyes large and usually moderately projected laterally ( Figs. 7a, b ); pronotum with faintly distinct posterior angles, rounded to obtuse and never posteriorly directed ( Fig. 7a ); scutellum regularly punctured in most of exposed portion; elytra with simple punctation, never transversely strigose; elytral humeral angles narrowly rounded, scarcely distinct, not protruding laterally ( Fig. 7a ); elytral humeral striae faintly distinct; elytral pre-sutural striae visible, originating at scutellar vertex or slightly posteriorly, terminating at elytral apex, and delimiting on each elytron a faintly distinct, flat, not distinctly raised sutural border; border widest at posterior third, usually distinctly narrower than proximal width of 3 rd antennomere; elytral apices truncately rounded in both sexes ( Fig. 7a ); pygidium partially exposed, moderately convex, apically rounded in both sexes ( Fig. 7a ).

Ventral habitus: antennal furrows markedly delimited, nearly parallel-sided, or slightly divergent posteriorly; mentum subpentagonal ( Fig. 7c ); prosternal antennal furrows on anterior margin of prosternum moderately raised and short ( Fig. 7c ); prosternal process variably shaped, usually relatively narrow, subapical dilated portion 2.0–2.1× as wide as maximum width of 1 st antennomere, apex usually bluntly acuminate ( Fig. 7d ); lateral borders of prosternal process delimiting shallowly impressed but distinct furrows, distally terminating over predistal lateral expansions ( Fig. 7d ); posterior margin of mesoventrite simple, never incised medially ( Fig. 7d ); male impressions on metaventrite moderately developed; first two visible abdominal ventrites simple in both sexes, without tufts of setae; caudal marginal lines of metacoxal cavities always simple, parallel and contiguous to posterior margin of metacoxal cavities, without deep arched impression of outer ‘axillary’ line ( Fig. 7f ); ‘axillary’ space on first abdominal ventrite moderately developed, ‘axillary’ angle obtuse ( Fig. 7f ); large and deeply impressed arched impressions on basal portion of last visible abdominal ventrite, usually not covered by distal portion of penultimate visible abdominal ventrite ( Fig. 7e ).

Appendages: male 1 st antennomere 0.8–1.0× as long as width of protibiae excluding distal teeth ( Figs. 7a, b, c ); 3 rd antennomere in both sexes 1.9–2.1× as long as wide, only 0.8–0.9× as long as but distinctly thinner than 2 nd antennomere ( Figs. 7a, b, c ); 4 th and 5 th antennomeres in both sexes subequal, short, slightly longer than wide; antennal club compact, small, simple, comprising last 3 antennomeres in both sexes ( Figs. 7a, c ), much narrower than width of protibiae, sexual dimorphism absent; labial palpi moderately long in both sexes ( Fig. 7c ), terminal segment 1.8–1.9× as long as wide; maxillary palpi moderately long and slender in both sexes ( Fig. 7c ), terminal segment 2.1–2.2× as long as wide; mandible mid-sized ( Fig. 7b ), apex scarcely acuminate and simple, no sexual dimorphism present; tarsal claws simple, never toothed at base (as in Fig. 5e ); tarsi of normal size and shape, 0.6–0.7× as long as corresponding tibiae ( Fig. 7a ); protibiae with a series of usually small, fine, rarely large and wide, moderately sharp teeth on lateral margin ( Fig. 7a ; Figs. 127 a–c in AUDISIO 1993b); meso- and metatibiae on lateral margin bearing a moderately even row of fine pegs ( Fig. 7a ), without U-shaped sinuosity at distal third; meso- and metatibiae of variable width, usually moderately flat, but slender ( Fig. 7a ), never distinctly subtrapezoidal or axe-shaped; no sexual dimorphism in tibial shape; tarsal plates of prolegs sligthly 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. 6f, g ; Figs. 137 a–l in AUDISIO 1993b), distal margin arcuately shaped or minutely incised, without deep median longitudinal desclerotization from proximal portion of tegmen extending to medial distal Vshaped excision; median lobe of aedeagus variable, without emargination laterally, rounded, distally subtruncate to acuminate, without distal minute excision or emargination.

Female genitalia (ovipositor): uniformly shaped, usually small; styli moderately long, simple, cylindrical, not distinctly pigmented, inserted close to apex of peculiarly bifid and distally diverging gonostyloids, their combined divergence more or less widely V- or Ushaped ( Fig. 6h ; Figs. 155 h–m in AUDISIO 1993b); each gonostyloid scarcely sclerotized and pigmented distally, with a simple, never indentate outer portion of basicoxites, and a single, narrow, scarcely pigmented and sclerotized arcuate area along outer subdistal portion of gonostyloids. ‘Central point’ of ovipositor centrally located or located more proximad than middle, with or without proximad directed short spicule.

Etymology. The generic name is derived from the Greek ‘ξηρoς’ (= dry, arid), to emphasize the association of most inclusive species with dry, xeric environments, and from ‘- gethes ’, to emphasize its phylogenetic relationship with Meligethes . Gender masculine.

Biology. All species are strictly associated for larval development with flowers of Brassicaceae , especially Sisymbrium L., Erysimum L., and allied genera ( EASTON 1957a; AUDISIO 1993b, and unpublished data).

Phylogenetic position. Available molecular and morphological datasets suggest a clearly monophyletic clade including Xerogethes gen. nov. and Clypeogethes (both genera developing on Brassicaceae ). See above comments on Acanthogethes for discussion on possible relationships of Xerogethes gen. nov. and Clypeogethes with members of the Lariopsis generic complex and Acanthogethes .

Taxonomy and geographic distribution. Xerogethes gen. nov. includes five described species distributed from western Europe and North Africa to the Near East ( AUDISIO 1993b; AUDISIO et al. 2000).

Xerogethes brisouti ( Reitter, 1871) comb. nov. NW Africa, Iberian Peninsula, S France

Xerogethes discoideus ( Erichson, 1845) comb. nov. SE Europe, Near East

Xerogethes kraatzii ( Reitter, 1871) comb. nov. SE Europe, Near East

Xerogethes osellai ( Audisio & Jelínek, 2000) comb. nov. Central Turkey

Xerogethes rotundicollis (C. N. F. Brisout de Barneville, 1863) W Europe, N Africa, Near East, Middle East comb. nov.

Figures

Fig. 6. Clypeogethes Scholz, 1932 and Xerogethes Audisio & Cline, gen. nov.: a, c – C. chlorocyaneus (Jelínek & Audisio, 1977); b, d–e – C. elongatus (Rosenhauer, 1856); k–n – C. lepidii (Miller, 1851); f–g – X. osellai (Audisio & Jelínek, 2000); h – X. rotundicollis (C. N. F. Brisout de Barneville, 1863). a – male habitus (length 2.5 mm); b, c, h – ovipositors; d–e, f–g – male genitalia; k – exposed portion of last visible abdominal ventrite; m – dorsal view of head; n – ventral view of head and anterior portion of prosternum. Figs. b–h: refer to AUDISIO (1993b) and AUDISIO et al. (2000) for scale. Scale bars: Figs. k, m, n = 100 μm.

Fig. 7. Xerogethes Audisio & Cline, gen. nov.: a – X. osellai (Audisio & Jelínek, 2000); b–g – X. rotundicollis (C. N. F. Brisout de Barneville, 1863). a – male habitus (length 2.0 mm); b – dorso-lateral view of head; c – ventral view of head and anterior portion of prosternum; d – prosternal process and mesoventrite; e – exposed portion of last visible abdominal ventrite; f – caudal marginal lines of metacoxal cavities; g – microsetae on middle of posterior margin of pronotum. Scale bars: Figs. b, c, d, e, f = 100 μm; g = 30 μm.

Fig. 5. Neolariopsis Audisio & Cline, gen. nov.: a, c–h – N. cercoides (Reitter, 1872); b – N. thalycroides (Kirejtshuk & Audisio, 1995). a, b – male habitus (a – length 2.1 mm, b – length 2.1 mm); c – dorsal view of head; d – ventral view of head and anterior portion of prosternum; e – middle leg with outer margin of mesotibia; f – prosternal process and mesoventrite; g – exposed portion of last visible abdominal ventrite; h – antenna. Scale bars: Figs. c, d, f = 100 μm; Figs. e, h = 20 μm; Fig. g = 30 μm.