Arthrobrachus armandoi n. sp.

(Figure 4)

Holotype: Male from Rep. Argentina, Prov. Río Negro, H. Richter // Bariloche //3642// circular (orange) // Arthrobrachus armandoi Estrada, 2015 // Holotype. Deposited in MLPA.

Paratype: Two males labelled as follows: Rep. Argentina, Prov. Río Negro H. Richter // Bariloche //3645// L.P. // Arthrobrachus armandoi Estrada, 2015 // Paratype. Deposited in MLPA (1♂). Argentina, Río Negro // Bariloche //3645// circular (orange) // Arthrobrachus armandoi Estrada, 2015 // Paratype. Deposited in MLPA (1♂).

Etymology. in honour to my father, Armando Estrada H., who taught me about the value and courage of ethics and perseverance in life, and in recognition of his unforgettable sympathy to the coleoptera.

Diagnosis. Antennae with four mesally dilated preapical antennomeres (Fig. 4 i); pronotum without circular impression on basal angles; ventrite 6 with two lateral, flat, transverse and separated plates (Fig. 4 h); parameres scarcely sclerotized in the base; tegmen without dorsal flange at base of parameres, tegminal plate reduced and scarcely sclerotized, lateral arms thick, subparallel in the distal part, convergent and strongly curved almost in right angle at the base, apodeme long, laminate, with a dorsal apophysis, well sclerotized (Fig. 4 a,b,c); median lobe sclerotized, sides subparallel, apex acuminate, slighty curved from a lateral view, forming an obtuse angle with the apodeme, flection area moderately wide (Fig. 4 d,e,f).

Description. Average body length 3.29 mm (range: 2.75–3.55 mm), length: width ratio 1.98:1, sides subparallel; coarse and dense punctures in head, pronotum and elytra; dorsal vestiture with dense, thick, erect hairs, evenly distributed; body dark testaceous, elytra slightly less coloured than the rest of the body.

Head: Included the eyes slightly narrower than the apex of the pronotum (0.9:1); antenna as long as the pronotum (1.04:1), generally with four mesally dilated preapical antennomeres (Fig. 4 i).

Thorax: Pronotum wider than long (1.61:1), with moderate transverse convexity and slight longitudinal convexity, base wider than the apex (1.27:1) and slightly narrower than the humeral base (0.74:1), anterior margin slightly convex, anterior and posterior margins moderately marked, lateral margins slightly convex, anterior and posterior angles marked, disc without circular impression on basal angles; elytra longer than wide (1.5:1), sides parallel, rounded at distal third, disc slightly convex, subvertical at lateral edges and slightly descending in apical third; epipleura wide, narrowed and slightly dentate toward the apex; legs: all the tibiae with thin, right, fine spines.

Abdomen: Vestiture of fine, thin hairs; punctuation scattered, fine; ventrite 5 with distal margin slightly emarginated at center and slightly bent ventrally; ventrite 6 with two transverse, flat plates, broadly separated, mesal margins of each plate rounded, distal margin substraight and with thin, short hairs; last tergite with distal margin widely rounded (Fig. 4 h); segment 9 with tergum like a narrow strip, sternal arms narrow, apodeme fine and long (Fig. 4 g). Genitalia: Parameres short, wide, more or less flattened, sides subparallel, apex wide and rounded, lateral edges bent ventrally, scarcely sclerotized in the base, from a lateral view their ventral margin forming an obtuse angle with the tegmen; tegmen without dorsal flange at the base of the parameres, lateral arms thick, subparallel, and strongly curved almost in right angle at the base, tegminal plate reduced and scarcely sclerotized, with V-shaped distal margin, projected on the base of the apodeme, apodeme well sclerotized, long, laminate, with a dorsal apophysis (Fig. 4 a–c); median lobe subcylindric, dorsal surface sclerotized, sides subparallel, apex acuminate, slighty curved from a lateral view, forming an obtuse angle with the apodeme, flection area moderately wide, apodeme long (Fig. 4 d–f, f1).

Distribution. ARGENTINA (Fig. 10): Provinces of Río Negro (MLPA) and Neuquén (MLPA).