Stereus arenarius Peck & Cook, 2009

Peck, Stewart B. & Cook, Joyce, 2009, Review of the Sogdini of North and Central America (Coleoptera: Leiodidae: Leiodinae) with descriptions of fourteen new species and three new genera, Zootaxa 2102 (1), pp. 1-74 : 26

Stereus arenarius Peck & Cook , new species

( Figs. 3 , 62–67 , 68 )

Type material. Holotype: ♂ ( CNCI) . UNITED STATES: Colorado: Alamosa County: Great Sand Dunes National Monument , 1.VIII.1969, 7600’, E. C. Becker . Paratypes (2): same data as holotype , ♀ ( CNCI) ; CANADA: Alberta: 11 mi S Empress , 4.VIII.1981, R. S. Anderson, light traps in sand dunes , ♀ ( SBPC) .

Diagnostic description. Body reddish brown, shining. Length of pronotum + elytra = 3.2 mm (male), 3.5–3.6 mm (females). Head finely, sparsely punctate. Pronotum widest at basal two-fifths; sides strongly, roundly angulate at basal two-fifths; basal angles obsolete; with fringe of elongate setae laterally; ratio length:width = 1:1.4; finely, sparsely punctate with no visible microsculpture. Elytra wider than pronotum, with fringe of elongate setae laterally; ratio length:width = 1:0.7; with 9 regular, closely punctate striae; stria 1 clearly impressed, remaining striae weakly or not impressed; intervals minutely punctate; uneven intervals with scattered larger punctures. Antennal club ( Fig. 62 ) broad, ratio club width:length = 1:2.0; antennomeres 7 and 8 equal in width, width ratio of antennomeres 6:7:8:9 = 1:1.5:1.5:2.8; antennomere 9 strongly asymmetrical. Terminal antennomere with a narrow, glabrous apical ridge. Mandibles ( Fig. 63 ) elongate, with elongate, narrow apices; left mandible with a tooth on apical one-half of inner margin. Profemur and mesofemur unarmed in both sexes; metafemur robust in both sexes, in male ( Fig. 64 ), posterior margin serrulate. Protibia of both sexes widened at apex, with rounded lobe at outer margin; dorsal surface with shallow tarsal depression. Mesotibia of both sexes widened at apex. Metatibia of male ( Fig. 64 ) and female widened at apex, spurs enlarged, spatulate. All tibiae of both sexes spinose on outer margin. Protarsi slender.

Male. Aedeagus ( Fig. 65 ) with median lobe broad, evenly tapering to rounded apex. Parameres extend beyond apex of median lobe, slender, apices concave medially, with two short setae. Female. Coxites ( Fig. 67 ) moderately elongate, cylindrical; styli elongate, inserted at apices of coxites. Sternite 8 ( Fig. 66 ) weakly, broadly triangular at apex; anterior apophysis broadly triangular.

Distribution. The species is known only from Alberta and Colorado ( Fig. 68 ), but may be assumed to occur in intervening areas.

Field notes and habitats. The preferred habitats seem to be sand dunes or sandy areas, based on label data, and the modifications of the tibiae, which seem to be adapted to digging.

Seasonality. Adults of the species are known only from the month of August.

Etymology. The name is Latin, arena, for sand, referring to the assumed preferred habitat for the species.

Figures

FIGURE 68. Known North American localities of Stereus arenarius (asterisks), Sogda obtusa (black dots), Sogda enigma (open squares).

FIGURES 1–4. Sogdini, habitus photos. 1. Triarthron lecontei, total length 3.4 mm. 2. Hydnobius autumnalis, total length 3.0 mm. 3. Stereus arenarius, total length 3.4 mm. 4. Sogda obtusa, total length 3.4 mm.

FIGURES 62–67. Stereus arenarius. 62. Male right antenna, dorsal view. 63. Mandibles, dorsal view. 64. Male right metafemur and metatibia. 65. Aedeagus, dorsal view. 66. Female sternite 8, ventral view. 67. Female coxites and styli, ventral view. Scale bar = 0.3 mm (Figs. 63, 67), 0.4 mm (Figs. 62, 65), 0.5 mm (Fig. 66), 0.75 mm (Fig. 64).