Dichotomius (Dichotomius) buqueti ( Lucas, 1859 )

4. Dichotomius (Dichotomius) buqueti ( Lucas, 1859) View in CoL species group

Diagnosis: This species group was revised by Arias-Buriticá and Vaz-de-Mello (2019). The species of the D. buqueti species group are recognized by the following combination of characters: (1) Medium to large-sized individuals (18–37.4 mm). (2) Both sexes with triangular head ( Fig. 10a, b View Figure 10 ). (3) Clypeus in most widely emarginated and flat, with strong transverse wrinkles. (4) Ventral clypeal process conical with obtuse tip ( Fig.10c View Figure 10 ). (5) Males with lamelliform cephalic process, subquadrangular at the base and ending at the apical conical process directed forward; with a smaller process on each side at the base of the leading edge at the eye ( Fig. 10a View Figure 10 ). (6) Females with a four-pointed process between the eyes ( Fig.10b View Figure 10 ) (except in D. haroldi which has two small separate processes).(7) Protibial spur without angle near the apex ( Fig. 10d View Figure 10 ). (8) Both sexes with excavated pronotum in anterior third, with two central tubercles, being stronger in males than in females ( Fig. 10a, b View Figure 10 ). (9) Pygidium with incomplete apical margin ( Fig. 10e View Figure 10 ). (10) Basal area of parameres ending in a strong constriction giving the appearance of spina in lateral and ventral views ( Fig. 10f, h View Figure 10 ). (11) Subgenital plate present ( Fig. 10h View Figure 10 ). (12) Parameres subtriangular in lateral view ( Fig.10f View Figure 10 ), with long setae at apical area ( Fig. 10 View Figure 10 f-h). (13) ME subquadrangular with two extensions on the right and setae present throughout the surface ( Fig. 10l View Figure 10 ).

Composition: Three valid species: Dichotomius buqueti ( Lucas, 1859) , D. haroldi ( Waterhouse, 1891) and D. nutans ( Harold, 1867) .

Geographic distribution: Chacoan dominion (Chaco and Pampean provinces), and Paraná dominion (Atlantic, Esteros del Iberá and Paraná Forest provinces) ( Fig. 9b View Figure 9 ) .