Diomus panamensis Gonzalez & Vetrovec 2021, new species

(Figs. 6 m-6x)

Holotype ♂ “ Panamá, Chiriqui prov., / Boquete – El Pianista Trail. / 08°49.228’N 82°25.220’W, 1400- / 1700m, 28.v.2015, indiv. collecting, / L. Sekerka & K. Štajerová lgt”, “ ♂ 2046” (NMP).

Paratypes: 1 ♂ same data as holotype (NMP).

Diagnosis. The head and thorax are yellow, the pronotum has five diffuse brown spots and the elytra are brown with a broad black lateral border, along with a narrow black basal border and a very narrow black sutural border (Fig. 6m); this combination of colors seems enough to identify the species, except that there are specimens that have entirely brown elytra. The male genitalia present the only sure characters to identify this species, which is characterized by the presence of two sclerosed areas (teeth) near the apex of the penis guide and apex not strongly inclined to one side (Figs. 6 u-6v), penis with a short apical filament no more than 1/10 of the length of the penis tube and penis capsule with well differentiated arms (Figs. 6 w-6x), characters that assign it to group “C” of Gordon (1999). (Fig. 6j), They are complemented by the absence of a dorsal keel (Fig. 6t) (this feature immediately differentiates it from D. chiriqui n. sp.), absence of hairiness in the penis guide and presence of inner hairiness in the paramere (Figs. 6 s- 6t), features that are only shared with two species, D. caius Gordon, 1999, from BahÍa, Brazil, only 1.8 mm long and elytra background color yellow (against 2.6 mm and elytra background color brown in the present species), and D. castilloi González & Honour, 2011 from Perú, of 1.6 to 1.7 mm and elytra background color black with yellow spots.

Description. Color pattern (Figs. 6 m-6p). Head entirely yellow, including antennae and mouthparts. Pronotum yellow with five small light brown spots, little noticeable, one in the center of the base and the others in a semicircle around the first. Scutellar shield black. Elytra brown with black borders, lateral border 1/3 as wide as the elytron, somewhat separated from the lateral margin in the posterior 1/3, widened at the humeral angle to cover the humerus, tapering towards the scutellar shield, from where it projects very narrowly as a vitta by the suture up to the apex (Figs. 6 m-6n). Epipleuron black. Ventral side black, except head and prothorax yellow, prosternum and abdomen brown, with ventrite 1 and anterior middle area of ventrite 2 black. Legs yellow except brown coxa. Pubescence yellow. Morphology. Body oval, elytra with regularly curved sides, widest anterior to middle of elytra (Fig. 6m). Frons shorter than twice the width of an eye. Eyes oval, slightly longer than wide. Eye canthus one quarter the width of an eye. Clypeus apex weakly convex (Fig. 6o). Antennae with eleven antennomeres, club weakly defined. Apical maxillary palpomere securiform.Prosternum Y-shaped, short. Abdominal postcoxal lines incomplete, extended to hind margin of ventrite, evenly rounded (Fig. 6q). Tarsus trimerous. Head punctures small, not very apparent, separated by a diameter; pronotum punctures slightly larger and dense than those on head, separated by less than a diameter; elytra punctures somewhat larger than on the pronotum, separated by 1 ½ diameters on average; ventral side punctures sparse, more abundant on the prosternum, separated by four times their diameter on the metaventrite; abdominal punctures fine, fairly regular, scant near ventrite 5 apex and on postcoxal plates. Pubescence decumbent, dense, associated with punctures; pronotum and elytra hairs approximately 1/2 longer than scutellar shield, abundant but not very visible due to its translucent color; abdominal pubescence short and sparse, long and quite dense on the lateral borders of ventrites 3 to 5. Male terminalia. Apex of ventrite 5 slightly notched in the center, apex of ventrite 6 truncate medially, notched in the center (Fig. 6q). Tegmen more than twice as long as wide, phallobase as long as wide, apically rounded. Tegminal strut shorter than the rest of the tegmen. Penis guide asymmetric, more than three times longer than wide, sides parallel in the basal two-thirds then converging, ending in a rounded apex turned to one side, shortly before the apex two very large teeth united at the base and loose, separated from the rest of the penis guide; in lateral view in a very regular triangle, without dorsal keel and ending in a rather sharp point, inner side membranous without pubescence. Parameres exceeding the penis guide by 1/4 of the length, with a lateral widening at the base, then thinned to continue in the shape of a paddle, broad and rounded apex. Pubescence around the outer border in the apical 1/6, as long as the paramere, additionally an oblique row of long bristles arising in the middle of the paramere shortly after middle, angled toward the border in the anterior lateral angle (Figs. 6 s-6v). Penis curved in a semicircle in the basal half, tube thinning smoothly in all its extension, slightly curved in the distal half, in the apical 1/6 it forms a sinuous curve ending in a thin filament, the inner part very membranous with some isolated spines; penis capsule with the inner arm 1 ½ times as long as wide, perpendicular to the penis tube, almost sub-square outer arm of the same length as the inner but wider, slightly inclined outwards with respect to the penis tube, very concave basal margin, accessory piece present (Figs. 6 w-6x). Female. Unknown. Variation. A second male specimen of this species has entirely brown elytra, including epipleuron, without traces of black spots, which makes the habitus indicated in the holotype useless for the identification of the species in specimens with this color design.

Measurements (mm): TL 2.4-2.6; PL 0.55-0.6; PW 1.25-1.35; EL 1.8-2.0; EW 1.6-1.8; GD 1.2-1.3.

Geographic distribution. Panama, ChiriquÍ province.

Remarks. For an analysis of the taxonomic status of the genus Diomus, see discussion under D. chiriqui sp. n. Diomus panamensis n. sp. presents the characters of the genus, including the descending incomplete postcoxal lines, the trimerous tarsi, the short antenna of eleven antennomeres and the apical maxillary palpomere securiform, as well as the asymmetric male penis guide.

Etymology. The species is named after Panama, the country where the known specimens of the species were collected.