Chileanthicus latibasis ( Lea, 1922 ) Kejval, 2009

Kejval, Zbyněk, 2009, Taxonomic revision of the genus Chileanthicus Werner (Coleoptera: Anthicidae) 2180, Zootaxa 2180 (1), pp. 1-82 : 58-59

Chileanthicus latibasis ( Lea, 1922) comb. nov.

( Figs 155–159 )

Formicomus latibasis Lea, 1922: 504 .

Type locality. Australia, South Australia, Kilkerran , 34°19'S 137°35'E .

Redescription (male, Brookfield Con. Park, ANIC). Head and pronotum pale rufous brown; elytra brown, with paler suture, base, and two yellowish brown, transverse bands ( Fig. 155 ), interrupted on suture; legs pale brown, femora darkened distally; antennae and palpi pale rufous brown.

Head 1.1 times as long as wide, widely rounded to angulate posteriorly; tempora moderately divergent in dorsal view, posterior temporal angles rather distinct. Eyes small, somewhat convex. Dorsal surface nearly matte, rather densely punctured ( Fig. 155 ); punctation distinctly double, rather evenly developed, somewhat sparser basally. Setation pale to whitish, short, mostly decumbent, with few, inconspicuous erect setae. Antennae at most moderately enlarged in terminal third; antennomere III twice as long as wide, about as long as IV; antennomere X 1.5 times, antennomere XI about 2.2 times as long as wide.

Pronotum robust, about as long as wide, slightly wider than head, widely rounded anteriorly; pronotal disc moderately convex, somewhat flattened postero-medially, its lateral margin forming rounded but distinct edge, lateral outlines moderately arcuately narrowing towards base in dorsal view. Surface nearly matte; dorsal punctation as on head. Setation as on head.

Elytra 1.7 times as long as wide, conjointly rounded apically. Surface moderately glossy, distinctly punctured ( Fig. 155 ); basal punctation distinctly double, coarse punctures smaller and much sparser than those on head. Setation similar, only somewhat longer and more distinct than on head, mostly pale to brownish, silvery and distinctly swirled on paler bands ( Fig. 155 ); erect setae somewhat more numerous, short, inconspicuous.

Metafemora unidentate ( Fig. 156 ), subapical process strong, narrowed and pointed apically, facing inner side of tibia; metatibiae somewhat enlarged at about mid-length, with two longitudinal grooves on inner side at the widest place, and simple apically. Setation rather uniformly short and fine, mostly subdecumbent.

Abdominal sternum VII and tergum VII simple. Sternite VIII ( Fig. 157 ); paired prongs strongly divergent and angulately produced laterally in basal half, then abruptly curved mediad and dilated into large, somewhat less sclerotized apical lobe, surface/margins of lobed apical portion at places rather densely, finely setose. Tergite VIII nearly evenly rounded posteriorly. Segment IX (spiculum) as in Fig. 158 .

Aedeagus ( Fig. 159 ); apical portion of tegmen 1.8 times as long as basal-piece, rather wide, narrowed subapically and with rounded apex in dorsal view, with paired triangular lobe on ventral side subapically; median lobe of aedeagus laterally flattened, wide, densely spinulose in apical half.

Female. Externally differing from male by simple metatibiae, lacking longitudinal grooves.

Body length (♂ ♀). 3.5–4.8 mm.

Variation. Numerous specimens have a more or less darker coloured body, in extreme cases nearly brown black (especially the head and elytra), dark portions of the elytra with a slight bronze to violet reflection. The head in most specimens have the tempora rather subparallel in dorsal view and distinctly narrower than the pronotum.

Type material. Holotype: ♀, Latibasis Lea TYPE Kilkerran [h+p] // Formicomus latibasis Lea S. Australia. TYPE I.15266 [h; “TYPE” red] // S. Aust. Museum specimen [p; orange label] ( SAMA).

Additional material. 2 ♂♂, Sas , Brookfield Conservation Park, 34°21'S 139°31'E, mallee, 2.xii.1991 - 2.i.1992, J. Stelman & S. Williams leg. ( ANIC) ; 1 ♂, 1 ♀, same locality, litter under mallee, 30.iii.-3.iv.1992, A. Calder & W. Dressler leg. ( ANIC) ; 3 ♂♂, same locality, 18.i.-24.ii.1993, mallee, J. Stelman & S. Williams leg. ( ANIC) ; 5 ♂♂, 1 ♀, same locality, malle, 24.ii.-20.iii.1993, E. S. Nielsen leg. ( ANIC) ; 1 ♀, same locality, mallee with Triodia , 24.xi.1992 - 18.i.1993, J. Stelman & S. Williams leg. ( ANIC) ; 1 ♀, Sas , 11 km S of Paruna, 9.ii.1970 ( ANIC) .

Differential diagnosis. C. latibasis differs from most species by the following combination of characters: metafemora unidentate, lateral margins of pronotal disc rather rounded (not sharp), body setation short (erect setae inconspicuous), and punctation of elytra distinctly double ( Fig. 155 ). Within the group of species showing these characters (or similar conditions), C. latibasis can be recognized by its rather robust appearance (wide, posteriorly widely rounded to angulate head, wide pronotum), narrow and simply shaped transverse bands of the elytra, with silvery setae moderately swirled medially, simple male sternum III (lacking median protuberance), and male metatibiae simple apically with two longitudinal grooves on inner side. Morphology of male sternite VIII and the aedeeagus ( Figs 157, 159 ) is quite distinctive and cannot be confused with those of the other species.

Distribution. Australia (South Australia).

Figures

FIGURES 155–159: Chileanthicus latibasis (Lea), male, Brookfield Con. Park (ANIC): 155, body form and punctation of head (top) and elytra (bottom); 156, metafemur; 157, sternite VIII; 158, segment IX (spiculum); 159, apical portion of aedeagus in ventral (right) and lateral (left) view. Scale (1.0 mm): A, 155; B, 156; (0.5 mm): B, 157; C, 158; D, 159.