Stenhelmoides onorei, Monte, Cinzia & Mascagni, Alessandro, 2012

Monte, Cinzia & Mascagni, Alessandro, 2012, Review of the Elmidae of Ecuador with the description of ten new species (Coleoptera: Elmidae), Zootaxa 3342, pp. 1-38 : 23-25

Stenhelmoides onorei sp. nov.

( Figs. 34–38 )

Diagnosis. Stenhelmoides onorei sp. nov. is included in the guyanensis group, because it presents the following combination of characters: body elongated and rather flattened on dorsal discal areas; front emerging with clypeus on the same plane between bases of antennae; prosternal process not foveate,, coarsely granulate; metasternal disc and abdominal intercoxal process flat; profemur and metafemur without plastron setae on surface; mesofemur with a row of dense, long, golden hair-like setae at midlength of posterior face; protibial cleaning fringe short, occupying middle third of tibial length; mesotibia and metatibia with only a short row of smoothing setae at distal end of cleaning fringe; elytrae with granules grouped into bands. From all other members of the guyanensis group, the new taxon can be distinguished by the shape of elongated, sinuate, pronotal reddish macula and by its distinct aedeagus.

Description. Holotype: Male ( Figs. 34, 36, 37, 38 ). Total length 3.6 mm, greatest width 1.3 mm. Body elongate, with sub-parallel sides, moderately convex.

Color: Cuticle dark reddish brown overlaid with gray plastron except an elongate, sinuate area reddish on midline of pronotum and a elongate, narrow sutural band on each elytra; mouthparts, antennae, scutellum and tarsi reddish.

Head: Partly retractable, frons gray. Surface with round, sparse, coarse granules. Antennae 11-segmented, filiform; first two basal articles thicker than the remaining ones; first antennal segments subequal to combined length of antennal segments 2–4. Clypeus sub-triangular, with the front-clypeal suture slightly deep; surface finely granulated with long golden setae along anterior margin. Labrum glossy with a transverse row of hair-like setae near midlenght.

Thorax: Pronotum as long as wide (1.1 mm and 1.1 mm, respectively); anterior width less than posterior width; base broader than apex. Surface microreticulate, with gray plastron except median reddish area, which presents a elongate, sinuate reddish macula. Surface in front of scutellum, within the reddish macula, with a weak concavity. Pronotal granules flat, coarse, round scattered at random, each with a short seta arising from its base. Elytra more than twice as long as pronotum; nearly parallel-sided; anterior margin convex; humeral angles broadly rounded; apices conjointly rounded. Each elytra with six longitudinal bands of granules, four discal bands more evident than two lateral bands. First, third and fourth bands formed by four irregular rows of granules extending from base to apex; second band formed on the basal third by four irregular rows of granules for a short distance then from only one row that reaches the apex. Elytral surface with granules similar to those on the pronotum; each granule with a short basal seta; reddish sutural margin finely, intermittently microreticulate, with irregular transverse depressions. Scutellum sub-triangular, without plastron. Prosternum moderately long in front of anterior coxae; its apicomedial area reddish and granulated, while the remaining ones with gray plastron and with coarse round granules; disc slightly angulate at border of reddish area. Prosternal process very slightly longer than wide; apex largely rounded; surface as prosternum. Hypomera granulated with gray plastron particularly on posterior part, where it has obscured granules. Mesoventrite with a deep medial groove for reception of prosternal process. Metaventrite with a deep medial groove. Pro- and metafemur without hair-like setae at midlength on inner surface. Mesofemur ( Fig. 36 ) with a longitudinal, narrow and short row of dense, long, golden hair-like setae at midlength of the superior surface. All tibiae with a prominent row of dense, sub-sinuate, stout, scraping setae on inner margin. Tibial cleaning fringes as follows: protibia with short, very narrow band occupying middle third of anterior surface; mesotibia and metatibia distal 4/5 of posterior surface. Protibial cleaning fringe bordered apicolaterally by 7 stout, smoothing setae; mesotibial leaning fringe bordered apicolaterally by 6 stout, smoothing setae; metatibial cleaning fringe bordered apicolaterally by 8 stout smoothing setae. Pro-, meso- and metatarsal segments with short sparse setae ventrally.

Abdomen: Surface of ventrites with plastron gray; flat abdominal intercoxal process; granules of first ventrite coarse and dense in the middle, becoming sparser and smaller laterally. Ventrites 2–4 with granules smaller than first ventrite. Ventrite 5 with granules as ones of first ventrite. Apical margin of ventrite 5 broadly rounded with apicomedially margin slightly but distinctly crenulated.

Genitalia: Parameres as long as median lobe. Parameres in dorsal view ( Fig. 37 ) with lateral margins largely rounded, internal margin slightly concave in the basal and apical part; apex rounded, base largely rounded. Parameres in lateral view ( Fig. 38 ) wide, gradually narrower towards sub-acute apex, which is slightly curved downwards. Median lobe in dorsal view ( Fig. 37 ) wider at base then gradually narrower towards apex; apex slightly rounded; basolateral apophyses strongly curved downwards and very slender. Median lobe in lateral view ( Fig. 38 ) slender nearly for almost the entire length, with acute apex moderately bent downwards. Phallobase ( Figs. 37, 38 ) about one and a half times the length of the parameres.

Female ( Fig. 35 ). All morphological characters as in male except ventrite 5 with apicomedially margin not crenulated, and by second elytral band of granules, which is formed by four irregular row of granules extending from the base to the apex.

Intraspecific variation. The specimens examined do not show significant morphological variability.

Type locality. Ecuador: Napo, Yasuní National Park, PUCE (Pontificia Universidad Católica del Ecuador) Scientific Station.

Type series. Holotype: Male, Ecuador, Napo, Yasuní National Park, PUCE Scientific Station, 300 m, G. Onore leg., 1.IV.1997 ( MZUF Collection number 15633). Paratype: 1 female, same data as holotype ( MZUF).

Etymology. We take great pleasure in naming this species in honour of its collector and our friend, Prof. Giovanni Onore, President of the Otonga Fundation.

Figures

FIGURES 34 – 38. Stenhelmoides onorei sp. nov. 34) Holotype, dorsal habitus (total length: 3.6 mm). 35) Paratype, female, dorsal habitus (total length: 3.6 mm). 36) Mesofemur of the left leg. 37) Male genitalia, dorsal view. 38) Male genitalia, lateral view (total length of the male genitalia: 0.9 mm)