Deltorhinum armatum sp. nov.

(Figs. 1–2, 18–20)

Diagnosis. Differ from all other species in the genus by the bilobate pronotal anterior edge combined with the strong oblique bulges on each side of midline anteriorly.

Description. Holotype male: Body and legs black. Clypeus moderately upturned medially; median projection feebly emarginate medially; marginal bead unmodified, weakly defined laterally. Gena bluntly angular laterally. Frontal carina distinctly arcuate in dorsal view, median portion higher than lateral portions. Vertex minutely punctate. Pronotal surface minutely punctate, punctures large in depressions; pronotal median longitudinal sulcus wide and deeply impressed throughout. Pronotal anterior edge bilobate medially; lobate portion preceded by a large, transverse, v-shaped depression and a blunt, oblique, transverse bulge on each side of midline, with a small depressed area on each side of midline. Pronotal basal surface smooth on most of width along posterior edge, a few weakly defined larger punctures on median fifth. Elytral surface minutely punctate; striae fine and sharply defined, more deeply impressed on apical declivity, punctures transverse and encroaching on interstriae. Elytral epipleuron unmodified, hidden in dorsal view. Protibia with punctures more or less set on a single oblique row on dorsal surface. Profemur sharply carinate anteriorly. Mesofemora and metafemora simply convex ventrally. Mesotarsi and metatarsi with first tarsomere slightly longer than width at apex. Pygidial surface finely punctate throughout, basal sulcus narrowly rugose, apical marginal bead sharply defined internally.

Measurements (4 specimens): body length: 8.0– 9.5 mm.

Holotype 3 (CMNC): Chapada [dos Guimarães], Brazil, Acc. No. 2966 / Nov. / H. & A. HOWDEN COLLECTION, ex. A Martinez coll. / WOLRD SCARAB. DATABASE, WSD00008015 / Holotype 3, Deltorhinum armatum sp. nov. F. Génier, 2010. Aedeagus and internal sac extracted.

Material examined (3 3, 1Ƥ). BRAZIL: MATO GROSSO, Chapada dos Guimarães, (15°26'54''S, 55°45'49''W), xi.1963, coll. Alvarenga & Werner - 1Ƥ (paratype) (CMNC); same locality, xi, coll. [anonymous] - 23 (holotype, 1 paratype) (CMNC, GHC); same locality, 25.i.1961, coll. J. & B. Bechyné - 13 (paratype) (BDGC).

Etymology. Armatum, a Latin adjective in apposition referring to the convoluted anterior pronotal development in this species.

Natural history. Unknown.

PLATE 1. Figs. 1–2, Deltorhinum armatum sp. nov. (holotype, male); Figs. 3–7, D. batesi Harold (holotype, male); Figs. 8–9, D. bilobatum sp. nov. (holotype, male). Figs. 1, 3, 8, habitus; Figs. 2, 4, 9, head and pronotum, dorsal view; Fig. 5. head and pronotum, lateral view; Fig. 6. protibia, dorsal view; Fig. 7. pygidium.

Variation. Little variation except for size and the more coarsely punctate pronotum in the only known female specimen.