Neoathyreus antennatus, Howden, Henry F., 2006

Howden, Henry F., 2006, New species and a new subgenus of South American Neoathyreus Howden and Martínez (Coleoptera: Geotrupidae: Athyreini), Zootaxa 1137, pp. 37-52 : 41-43

Neoathyreus antennatus , new species ( Figs. 7–11 )

Holotype. Male, length 12.8 mm, greatest width 8.3 mm. Dorsally reddish brown. Clypeus with both oblique anterior and posterior carinae well developed; median tubercle almost twice height of lateral tubercle on each side, anterior surface slightly slanted posteriorly; posterior carina on each side not depressed below level of lateral tubercles. Vertex between eyes almost flat, coarsely, closely granulate. Gena sparsely granulate near base, glabrous laterally, margin reflexed. Antenna with unusually thickened club ( Fig. 9 ), appearing oval in both lateral and ventral views, club not unlike those of many bolboceratines. Pronotum ( Figs. 7, 8 ) with small fossa on each side contiguous with marginal bead posterior to eye; fossa approximately equal in diameter to width of adjacent bead. Anterior pronotal margin between fossae elevated to distinct tubercle on bead at midline. Pronotum with inner carina on each side arising approximately 1.0 mm posterior to fossa, carina anteriorly abruptly elevated to rounded, abruptly obtuse angle, angle not slanted inwardly, carina posterior to angle not broken, gradually bowed inwardly to termination about 0.6 mm from posterior margin; pronotal concavity deepest between obtuse angles, becoming shallow posteriorly, midline in median half of pronotum narrowly glabrous, remainder of concavity punctate­rugose, many punctures each with erect, inconspicuous, tan seta. Outer carinae obsolete. Lateral pronotal fovea on each side small, circular; margin below fovea not indented, bead uninterrupted; surface laterad to inner carinae granulate, setose. Elytron lacking distinct striae or elevated intervals, four striae indicated at base by vague indentations, two intervals indistinctly elevated; surface of elytral disc granulate­punctate, most punctures each with semi­erect seta. Metasternum between middle coxae very slightly convex, midline slightly impressed, anterior edge medially forming wide, obtuse angle; metasternal surface setose­granulate. Foretibia with six teeth on outer margin. Genitalia as in Figs. 10, 11 .

Allotype. Female, length 11.2 mm, greatest width 7.5 mm. Differing from male as follows: clypeus with anterior carina on each side bowed upward to midline, forming sharp, obtuse angle; from obtuse angle carina then extending posteriorly along midline to median tubercle; this tubercle only slightly anterior to lateral tubercle on each side, tubercles of equal size; posterior carina on each side only slightly bowed and elevated to median tubercle, length of median and posterior carinae approximately equal; vertex slightly more granulate; pronotum with tubercle on anterior median marginal bead less elevated; inner pronotal carina with obtuse angle lower, less rounded, separated by 0.8 mm less than in holotype (function of size); concavity reduced in width and depth; elytron with no indication of elevated intervals; foretibia with basal sixth tooth minute.

Type Series. Holotype, male, Bolivia, Do. Sta Cruz, Pica Ichilo, Buena Vista, Oct. 1949, coll. Martínez. H. & A. Howden coll. ex A. Martínez coll. ( CMNC). Allotype, female, same data as holotype ( HAHC). Paratypes, 4 males, 2 females. Bolivia: 4 males, 1 female, Prov. Ichilo, Depto Santa Cruz, 3–5 km SSE of Buena Vista, ± 440 m, Febr. 5–12, 2000, 17 29' 96" S 63 39' 13" W. W. B. Warner; 1 female, Santa Cruz, Lomas de Arena Bol. Pk. 10.II.1999, L. A. Stange. Paratypes are in: FSCA, HAHC, NKMC, WBWC.

Excluded from type series (see remarks): 1 female, Argentina, Corrientes, Alto Parana, Ituzaingo, Oct. 1975, coll Martínez ( HAHC).

Remarks. The four male paratypes range from 10.5 to 11.3 mm in length and from 6.8 to 7.5 mm in greatest width. The single female paratype is 11.1 mm in length and 7.5 mm in greatest width. In two males the outer pronotal carina on each side between the inner carina and the posterior angle is vaguely indicated by an indistinct elevation or small glabrous area. In the smallest specimen the pronotal cavity is shallower than the others and the anterior angle of the inner carina on each side is abruptly obtuse. One small male has only five teeth evident on the foretibia. The apical lobes of the male genitalia vary slightly in size and shape, but all have the outer angle sharply acute. Other variation is minimal.

The single female from Corrientes, Argentina, is almost certainly N. antennatus , but because of the distance between Corrientes and the type locality, a male is needed to verify its identity. Also, there is the possibility that the specimen is mislabeled.

Neoathyreus antennatus and the related species, N. goyasensis (Boucomont) , are, as far as I know, the only two described species in the genus that have the antennal club greatly thickened and oval in both sexes. In N. goyasensis the inner pronotal carina posterior to the anterior angle of the carina is interrupted for a short distance; it is complete in N. antennatus . Although the male genitalia of the two species differ mainly in the shape of the inner part of the apical lobes, the known range of the two species will separate them. The species, N. acutus Howden , which is partly sympatric with N. antennatus and superficially resembles it, lacks the thickened antennal club and has the outer pronotal carinae distinct. No other described species is likely to be confused with N. antennatus .

Etymology. The name “ antennatus ” refers to the unusual antennal club.

Figures

FIGURES 7 – 11. Neoathyreus antennatus, n. sp.: 7, Head and pronotum, dorsal view; 8, Head and pronotum, lateral view: 9, Antenna; 10, Male genitalia, dorsal view; 11, Male genitalia, lateral view. Scale lines for genitalia = 0.2 mm.