Neoathyreus (Mesoathyreus) guyanensis, 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 : 50-51

Neoathyreus (Mesoathyreus) guyanensis , new species ( Figs. 16–21 )

Holotype. Male, length 14.5 mm, greatest width 9.0 mm. Dorsally shiny reddish brown. Clypeus ( Fig. 17 ) with pronounced, erect horn, 2.1 mm long from anterior edge of clypeus to apex; anterior clypeal carina on each side extending medially up anterior face of horn, joining 1 mm from apex of horn; posterior carina on each side extending up posterior side of horn to apex. Lateral clypeal tubercle on each side above antennal insertion small; clypeal surface between carinae with scattered small punctures. Vertex slightly convex medially anterior to shallow, transverse depression between eyes; surface with widely scattered, small punctures. Pronotum ( Fig. 16 ) at anterior margin behind each eye with small fovea, diameter slightly more than width of adjacent marginal bead; anterior half of pronotum transversely concave for distance equal to width of head; surface of concavity anterior to ends of inner carinae with scattered punctures, surface of anterior half of concavity between carinae alutaceous, impunctate, posterior to that surface with scattered small punctures; most pronotal punctures each with short, fine, erect seta. Outer pronotal carina on each side indicated by irregular, impunctate, very slightly elevated area; lateral pronotal margin not indented below lateral fovea. Scutellum, elytra, and ventral characters as described in subgeneric description. Genitalia as in Figs. 20, 21 .

Allotype. Female, length 14.6 mm, greatest width 9.0 mm. Differing from male as follows: clypeus ( Figs. 18, 19 ) lacking horn, median tubercle about twice height of lateral tubercle on each side, anterior carina on each side joining medially just anterior to apex of median tubercle; surface of clypeus and vertex more closely punctate than in male, punctures small, usually separated by two or more diameters, most punctures each with small anterior tubercle and short, fine central seta; pronotum ( Fig. 18 ) with low, rounded inner and outer carinae, inner carinae slightly more elevated in anterior half of length; pronotal concavity shallow; except for carinae, entire pronotum punctate­tuberculate as on vertex, spacing closer, particularly on pronotal sides; pronotal margin below lateral fovea slightly sinuous; pygidium apically more widely rounded than in male; foretibia with seven teeth on outer margin, minute eighth basal tooth indicated on right tibia.

Type Series. Holotype, male, [ Guyane = French Guiana], Dd. Saramaca Pk. Rte des Compagnons, Guyane Fse, 11.IX.1984, M. Duranton Recolt. ( CMNC). Allotype, female, Dd. Saramaca, Mgne des Singes, Guyane Fse, 8.IX.1984, M. Duranton Recol. ( HAHC). Paratypes, 1 male, 2 females: 1 female, same data as allotype except VIII.1985; 1 male, Guyane Francaise, Kourou RN 1 Pk84, cryldé, 30.X.2001, M. Duranton coll.; 1 female, same data as male paratype except Pk 71, X.2001. Paratypes are in: HAHC.

Remarks. Variation between the two female paratypes and the allotype is slight, the two paratypes measure 13.5 and 14.3 mm in length and 8.0 and 9.0 in greatest width. The smaller female has six teeth on the foretibia, the larger one seven. The larger female has a slightly deeper pronotal concavity, but other variation is not obvious. The one male paratype measures 12.5 mm in length and 7.1 mm in greatest width. Its small size, making it a minor male, causes it to resemble a female rather than the major male holotype. It is similar to the females except that the median clypeal tubercle is distinctly higher, three or more times the height of the lateral tubercles. The pronotal concavity resembles those of the larger females, and there is a small, almost impunctate, alutaceous area near the middle of the concavity. Other dorsal characters resemble those of a female. The outer margin of the foretibia has seven teeth. The male genital characters resemble those of the holotype.

The minor male and the females will key to couplet 26 in my 1985 revision of Neoathyreus . The male major, lacking a distinct outer carina, will not key past couplet 10, partly because it does not fit the generic description of either Neoathyreus or Athyreus . The sexual differences, a character of Athyreus , and the unique blunt apical lobe of each mandible ( Fig. 19 ) distinguish this species from any other Neoathyreus and it is therefore placed in the separate subgenus, Mesoathyreus .

Etymology. The species name “ guyanensis ” refers to French Guiana, the area in which the species occurs.

Figures

FIGURES 16 – 21. Neoathyreus (Mesoathyreus) guyanensis, n. sp.: 16, Dorsum of male major; 17, Male major, head and pronotum, lateral view; 18, Dorsum of female; 19, Head of female, note right mandible; 20, Male genitalia, dorsal view; 21, Male genitalia, lateral view. Scale lines for genitalia = 0.2 mm.