Neomida diminuta sp. n. differs from all other Neomida by its minute size (TL 1.74 mm), while other species in the genus are at least 1.85 mm long. It differs from N. suilla and N. picea in the possession of two clypeal tubercles instead of one, from N. cioides in the subcylindrical and straight frontal horns, and from N. inermis by its subtle clypeal sinuosity instead of conspicuous and cylindrical tubercles. Neomida diminuta sp. n. males have eyes, body shape and cephalic horns similar to those of N. occidentalis, but the latter are twice as long. In N. diminuta sp. n., the epipleura extends from base to apex of elytra, a feature observed only in other six species of Neomida: N. cioides (Champion), N. deltocera Triplehorn, N. occidentalis, N. pentaphyllodes (Champion), N. picea (Laporte and Brullé) and N. suilla.

The name “diminuta” means small, referring to its minute size.

Male. Body moderately convex, opaque, glabrous; length 1.74 mm; elytra, pronotum and head reddish-brown; antennae and legs golden-yellow. Head with vertex deeply concave; frons armed with a pair of long, subcylindrical, subparallel narrow horns, each rising close to an eye; clypeus with two small sinuosities contiguous to antennal insertions. Eyes with anterior portion emarginated by antennal insertion, forming a lower lobe approx. four times as large as upper lobe. Antennae with antennomeres 5–11 expanded forming a club. Pronotum strongly transverse, approx. twice as wide as long, widest and longest at middle, sides subparallel and narrowed anteriorly; lateral edges explanate, visible for their entire lengths from above; anterior edge truncate. Elytra approx. twice as long as pronotum, widest at middle and narrowing to apex, epipleura extending to apex. Hind wings developed, apparently functional. Ventral surface slightly darker than dorsum, punctation sparser; prosternal process subparallel. Protibiae with outer edge serrate; apex bearing a row of spines; inner apical angle with two long spines. Hind tarsi with basal tarsomere approx. as long as the following three together. Aedeagus with basale approx. three and a half times as long as apicale, curved at base, sides subparallel, a bit wider in the second third; apicale with sides subparallel, narrowing near middle to apex; penis about as long as basale, cylindrical, expanded at apex, with struts converging and fusing at basal one-fifth; internal sac not observed (possibly lost during dissection). Female unknown.

Male holotype (in mm): TL 1.74, PL 0.49, PW 0.89, EL 1.17, EW 0.98, GD 0.69; ratios: PL/PW 0.55, EL/EW 1.19, EL/PL 2.39, GD/EW 1.70, TL/EW 2.46.

Male holotype (MNHN) labeled: “Dup Colomb 41 [sic] {circular green label}\ ♂ {small green label}\ Neomida diminuta, HOLOTYPUS, Aloquio & Lopes-Andrade {handwritten in red label}”.

Neomida diminuta sp. n. was collected in 1841 and remained unrecognized as a tenebrionid beetle in the Muséum national d’Histoire naturelle of Paris, France, until recently. It was found among specimens identified as Cis Latreille (Ciidae), possibly confounded due to its small size and head bearing horns. The great age certainly affected important morphological features, such as body vestiture, pronotal and elytral punctation and integrity of membranous structures as the internal sac of aedeagus. Information on host fungus was not available. The extension of exposed epipleura and other conspicuous characters need to be more carefully observed, because they can be important for proposing species-groups or even subgenera for Neomida, in order to facilitate the work with such a speciose genus.

Males of N. suilla differ from males of all other described New World Neomida, except N. picea (Laporte and Brullé), in having a single prominent median clypeal tubercle (Triplehorn 2006). Neomida suilla differs from N. picea by its shorter length, and males in having triangular-shaped cephalic horns with a tuft of bristles at their tips (Fig. 5, arrow).

Male. Body moderately convex, opaque, with vestiture of small seta; length 1.85–2.25 mm; elytra, pronotum and head reddish-brown; antennae, legs and mouthparts golden-yellow. Head with clypeus bearing a single prominent tubercle near the middle of anterior edge; frons armed with a pair of long, flattened, subtriangular, broad horns, each rising close to an eye and directed upward; horns with a row of bristles extending from about the middle of anterior edge to apex (Fig. 5, arrow); vertex deeply concave; Eyes with anterior portion emarginate by antennal insertion, forming a lower lobe about three times larger than upper lobe. Antennae with antennomeres 5–11 expanded forming a club; antennomeres 6–11 bearing multi-pronged sensilla (sensillifers) at the upper portion. Pronotum strongly transverse, twice as wide as long, widest posteriorly and longest at middle; lateral edges explanate, visible for their entire lengths from above; anterior edge slightly curved outward. Elytra approx. two and a half times as long as pronotum; sides subparallel at basal half, then narrowing to apex, epipleura extending to apex. Hind wings developed, apparently functional. Ventral surface slightly darker than dorsum, punctation sparser; prosternal process subparallel, narrowest at apex. Protibiae with outer edge serrate; apex bearing a row of spines; inner apical angle with two long spines. Aedeagus with basale about three times as long as apicale; basale most expanded near its base; apicale strongly narrowed at apex and with two lateral projections (ala) directed anteriorly and fitting the basale (Fig. 7, arrow); penis about as long as basale, cylindrical, expanded at apex, with struts converging and fusing at basal one-seventh of the length; internal sac narrow, elongated, about twice as long as penis. Females similar to males except for the following features: head without clypeal tubercle and frontal horns, and vertex devoid of concavity; eyes with lower lobe twice as long as upper one. Female abdominal terminalia with bursa copulatrix approx. one and a half time as long as gonocoxites together; common oviduct approx. as long as window of bursa; window of bursa about four times as long as spermatheca; spermatheca (Fig. 11) with check valve small, oval, bearing an invagination from upper portion to about middle; paraprocts about as long as gonocoxites together; baculi of basal gonocoxites perpendicular in relation to baculi of paraprocts; gonocoxites transversely divided into three parts; gonostyli inserted at top of apical gonocoxites.

Males (n = 30), measurements (in mm): TL 1.90–2.20 (2.10 ± 0.09), PL 0.45–0.60 (0.56 + 0.04), PW 0.90–1.05 (1.00 + 0.04), EL 1.00–1.40 (1.28 + 0.08), EW 0.95–1.10 (1.05 + 0.04), GD 0.70–0.80 (0.74 + 0.03); ratios: PL/PW 0.50–0.60, EL/EW 1.00–1.35, EL/PL 2.00–2.67, GD/EW 0.64–0.75, TL/EW 1.82–2.15. Females (n = 10), measurements (in mm): TL 1.85–2.20 (2.08 + 0.10), PL 0.45–0.60 (0.56 + 0.05), PW 0.90–1.05 (1.00 + 0.04), EL 1.25–1.40 (1.32 + 0.05), EW 0.95–1.10 (1.06 + 0.05), GD 0.70–0.75 (0.74 + 0.02); ratios: PL/PW 0.50–0.60, EL/EW 1.18–1.35, EL/PL 2.17–2.78, GD/EW 0.68–0.74, TL/EW 1.91–2.10.

15 males and five females (1♂ and 1♀ ANIC, 13♂ and 3♀ CELC, 1♂ and 1♀ OSUC) labeled: “BRASIL: MG, Rio Doce, Lago da Candonga; área de mata, 16.ix.2009, leg. E.F. Barbosa”. 15 males and five females (1♂ and 1♀ ANIC, 13♂ and 3♀ CELC, 1♂ and 1♀ OSUC) labeled: “BRASIL: ES, Linhares, Mata do Lago, 16.vii.2010, leg. S.Z. Aloquio Jr.”.

All specimens of N. suilla were found in basidiomes of Ganoderma sp., which is the primary host fungus record for the species. Neomida suilla was collected in two localities of the Brazilian Atlantic Forest (Fig. 13) separated by approx. 500 linear km, each at an extreme of the Doce River. These two localities are the most southern records for the species, which was known from only two localities in the Lesser Antilles (St. Vincent and Guadeloupe) and one in Recife (in the state of Pernambuco, Brazil). Its occurrence in the Lesser Antilles and in distant localities of the Brazilian Atlantic Forest suggests a wide distribution throughout the east coast of tropical South America.