Sebastiangethes Audisio, Kirk-Spriggs & Cline, 2008

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 : 442-445

28. Sebastiangethes Audisio, Kirk-Spriggs & Cline, 2008

( Figs. 28 a–i )

Sebastiangethes Audisio, Kirk-Spriggs & Cline, 2008: 421 .

Type species. Sebastiangethes anthystrixoides Audisio, Kirk-Spriggs & Cline, 2008: 425 (by original designation).

Generic redescription and diagnosis. The single known species (1.8–2.7 mm length; 0.8–1.3 mm width) exhibits the following combination of characters.

Body color and pubescence: pubescence long, golden to silvery-whitish and dense, recumbent, partially obscuring the predominantly dark brown dorsal body surface, usually not obscuring the narrowly flattened, paler pronotal and elytral sides ( Fig. 28a ); lateral margins of elytra with a series of distinct long setae, 0.9–1.0× as long as those on elytral disc; posterior margin of pronotum with relatively short, distally multifid microsetae, microsetae also present on middle portion anterior to scutellum (as in Fig. 27f ).

Dorsal habitus: body moderately convex, oval ( Fig. 28a ); dorsal punctures on discal portion of pronotum as large as or larger than eye facets, moderately to deeply impressed ( Fig. 28a ); anterior margin of clypeus strongly sinuate in middle and distinctly bordered ( Fig. 28a ), simple, i.e. without small distinct medial bulge; circum-ocular furrows (occipital sulci) on dorsal head surface almost obliterated and indistinct; eyes large and markedly projecting laterally ( Fig. 28a ); posterior angles of pronotum distinct, blunt, obtuse ( Fig. 28a ), not directed posteriorly; scutellum uniformly punctured on most of exposed portion (as in Fig. 27f ); elytra with normal punctures, never transversely strigose; elytral humeral angle distinct, widely obtuse, not protruding laterally ( Fig. 28a ); elytral humeral striae indistinct; elytral pre-sutural striae faintly visible, almost indistinct anteriorly, originating posterior to scutellar vertex, terminating at elytral apex, and delimiting on each elytron a faintly distinct, flat, unraised sutural border, more distinct at distal fourth, narrower than proximal width of 3 rd antennomere; elytral apices truncately rounded in both sexes ( Fig. 28a ); pygidium partially exposed, moderately convex, apically rounded in both sexes ( Fig. 28a ).

Ventral habitus: antennal furrows distinct and moderately to strongly convergent, inner margins well-delimited, mentum subtrapezoidal ( Figs. 28d, i ); prosternal antennal furrows on anterior margin of prosternum indistinct, reduced to flattened traces, almost completely obliterated in females, prosternal process narrow and parallel-sided ( Fig. 28i ), subapical portion 1.5–1.7× as wide as maximum width of 1 st antennomere, bluntly convex distally; lateral borders of prosternal process delimiting shallowly impressed distinct furrows, distally terminating at predistal lateral expansions; posterior margin of mesoventrite simple, not medially incised; male impressions on metaventrite faint; first two visible abdominal ventrites simple in both sexes, without tufts of setae, caudal marginal lines of metacoxal cavities simple, subparallel and contiguous to posterior margin of metacoxal cavities, with shallow arched impression of outer ‘axillary’ line; ‘axillary’ space on first abdominal ventrite moderately developed, ‘axillary’ angle bluntly obtuse; moderately distinct and scarcely impressed arched impressions on last abdominal ventrite, partially covered by distal portion of penultimate visible abdominal ventrite.

Appendages: male 1 st antennomere 1.0–1.2× as long as width of protibiae excluding distal teeth ( Fig. 28a ); 3 rd antennomere in males ~3× as long as wide, 1.1–1.3× as long as and markedly thinner than 2 nd; 4 th and 5 th antennomeres subequal in males, usually long, 2.0–2.3× as long as wide ( Fig. 28a ); male antennal club variable, with usually allometric development; large, loose, markedly asymmetrical and comprising last 5–6 antennomeres in large males ( Fig. 28a ), but smaller, short, nearly symmetrical, and composed of the last 3 antennomeres in some small-sized males; but several observed small males (1.9–2.1 mm) exhibit ‘normal’ antennae, with strongly enlarged and six-jointed antennal club; antennal club simple and 3- jointed in females; labial palpi long and thin, especially in males, terminal segment 2.3–2.8× as long as wide; maxillary palpi long and thin, especially in males ( Fig. 28b ), terminal segment 2.8–3.2× as long as wide; mandible large, moderately long, ~1.6–1.8× longer than wide in large males, shorter in small males and females, apex bifid and acuminate ( Fig. 28c ); tarsi of normal size and shape, 0.6–0.7× as long as corresponding tibiae ( Fig. 28a ); tarsal claws simple, not toothed at base (as in Fig. 24f ); protibiae with reduced teeth on outer margins ( Fig. 28a ); meso- and metatibiae on lateral margin bearing a single and regular row of long and thin, yellowish pegs, without U-shaped sinuosity at distal third; meso- and metatibiae subtrapezoidal, especially in males, abruptly dilated inwards at basal portion, subparallelsided ( Fig. 28a ); moderate sexual dimorphism in tibial shape; tarsal plates of prolegs faintly wider in males; posterior margin of metafemora simple in both sexes, without tubercles or projections.

Male genitalia: peculiarly shaped, processes along inner side of parameres absent ( Fig. 28e ), without deep median longitudinal desclerotization from proximal portion of tegmen extending to medial distal V-shaped excision, tegmen with weak, distal arcuate emargination; median lobe of aedeagus without lateral emarginations and distally subtruncate ( Fig. 28f ); main sclerites of internal sac (flagellum) peculiarly large, forceps-shaped, sclerotized, typically 0.6–0.7× shorter than aedeagus ( Fig. 28g ).

Female genitalia (ovipositor): large; styli moderately long and distinct, simple, unpigmented, inserted near apex of contiguous gonostyloids, each gonostyloid lightly sclerotized and moderately pigmented distally, with peculiarly indentate outer portion of basicoxites ( Fig. 28h ), and a single, large, scarcely pigmented but slightly more sclerotized arcuate area along outer subdistal portion of gonostyloids. ‘Central point’ of ovipositor located more distad than middle, without proximad directed spicule.

Etymology. The genus was named for our late friend and colleague Sebastian Endrödy-Younga (1934–1999) who, during the years 1973–1998, collected a very large and only partially studied assemblage of southern African Nitidulidae , and from ‘- gethes ’, to emphasize its phylogenetic relationship with Meligethes . Gender masculine.

Biology. Larval development is strictly associated with male inflorescences of Asteraceae within the isolated tribe Tarchonantheae , specifically Tarchonanthus camphoratus L. ( AUDISIO et al. 2008).

Phylogenetic position. This genus is strongly isolated in the Anthystrix complex of genera, exhibiting several peculiar traits such as a ‘ Pria -like’ slender and loose male antennal club, markedly sinuate anterior margin of clypeus, elongate segments of male maxillary and labial palpi, long and slender male mandibles, long and narrow prosternal process, nearly indistinct prosternal antennal furrows, strongly convergent antennal furrows on ventral side of head (with inner margin only evident), indistinct postocular furrows on dorsal side of head, and very large and strongly sclerotized internal sac bacula in the male genitalia.

Taxonomy and geographic distribution. This taxon includes a single African species ( AUDISIO et al. 2008) distributed from Northern Cape (Kuruman area) in NW South Africa to E Namibia (two recently examined specimens, include the following data: Namibia , 46 KM E Otavi, 29.iii.1992, C. V. O’Brien, L. B. O’Brien & G. B. Marshall leg.: CAS, CAR). Very likely also present in southern and western Botswana.

Sebastiangethes anthystrixoides Audisio, Kirk-Spriggs South Africa: Northern Cape; E Namibia & Cline, 2008

Figures

Fig. 28. Sebastiangethes Audisio, Kirk-Spriggs & Cline, 2008: a–i – S. anthystrixoides Audisio, Kirk-Spriggs & Cline, 2008. a – male habitus (length 2.7 mm); b – right maxilla and palpus; c – left mandible; d – labrum; e–f – male genitalia; g – major sclerites of male endophallus; h – distal portion of ovipositor; i – ventral view of head and anterior portion of prosternum. Drawings b–i: refer to AUDISIO et al. (2008) for scale.

Fig. 27. Tarchonanthogethes Audisio & Cline, gen. nov.: a, c–i – T. rotundiclava (Kirejtshuk & Easton, 1988); b – T.sp.; k – T. martini (Grouvelle, 1899). a, b – male habitus (a – length 2.6 mm; b – length 2.0 mm); c–d – male genitalia (c – length 0. 43 mm; d – length 0.38 mm); e – major sclerites of male endophallus (length 0.20 mm); f – scutellum and microsetae on middle of posterior margin of pronotum; g – ventral view of body; h – male antenna (length 0.65 mm); i – dorsal view of head; k – distal portion of ovipositor (length 0.4 mm). Scale bars: Figs. f, i = 100 μm; Fig. g = 300 μm.

Fig. 24. Chromogethes Kirejtshuk, 1989: a – C. formosus (Kirejtshuk, 1989); b–h – C. mastax (Audisio & De Biase, 2004); k – C. splendidulus (Reitter, 1873). a – male habitus (length 2.0 mm); b, k – dorsal view of head; c – scutellum and microsetae on middle of posterior margin of pronotum; d – ventral view of head and anterior portion of prosternum; e – exposed portion of last visible abdominal ventrite; f – tarsal claws of middle leg; g – outer margin of mesotibia; h – prosternal process and mesoventrite. Scale bars: Figs. b, d, e, g, k = 100 μm; Fig. c, f = 30 μm; Fig. h = 200 μm.