Dichotomius haroldi ( Waterhouse, 1891 )

Arias-Buriticá, Jorge Armando & Vaz-de-Mello, Fernando Z., 2019, Redefinition and taxonomic revision of the “ buqueti ” species-group, Dichotomius Hope, 1838 (Coleoptera: Scarabaeidae: Scarabaeinae), Revista Brasileira de Entomologia 63 (1), pp. 43-52 : 48-50

Dichotomius haroldi ( Waterhouse, 1891)

( Figs. 6 A–J, 8 B)

Pinotus haroldi Waterhouse, 1891 : page 359 (original description). Pinotus verticalis Felsche, 1901 : page 136 (original description).

Dichotomius verticalis ( Felsche, 1901) : page 389. Pereira, F.S. 1953 (synonym).

Type Material: Pinotus haroldi Waterhouse. Holotype. (♂.) [1,circle label with red border] Type [2,square label with green line, handwritten] Cordova 18./3 [3,square label, handwritten] Pinotus haroldi (Type) Waterh [4,quadrangular and red label with black borders] HOLOTYPE 1♂. [ BMNH]. Pinotus verticalis Felsche. Holotype. (♂.) [1,quadrangular label, second word handwritten] Bahia Blanca [2,quadrangular orange label] Typus. [3,quadrangular green label] Coll. C. Felsche Kauf 20, 1918 [4,square label with doble purple line, handwritten] verticalis Felsche [5,quadrangular red label with black borders] HOLOTYPE 1♂. [ SMTD].

Additional specimens. (27♂♂. 25♀♀.): ARGENTINA: Cerro Corta Pie, II/ 1942, 2♀. [ MZSP] . Buenos Aires: II/ 1942, 4♂. 4♀. [ MZSP]; XI/ 1942, 1♂. 2♀. [ MZSP]; III/ 1950, 3♂. [ CEMT]. Partido Puán, Felipe Solá, I/ 1948, Martínez, A. 2♀. [ CEMT] Dto. Puán, Felipe Solá, XI/ 1959, Martínez, A. 1♂. [ MZSP]. Felipe Solá, II/ 1942, 8♂. 2♀. [ MZSP] ; Martínez, A., II/ 1942, 2♂. 5♀. [ MZSP]; Martínez, A. X/ 1942, 1♂. 1♀. [ MZSP]; X/ 1942, Pohl, B. 1♀. [ MZSP]. XII/ 1961, Martínez, A. 1♀. [ MZSP] . [Buenos Aires]: Saavedra, Goyena I, 1960, Martínez, A. 1♂. 2♀. [ MZSP]. Córdoba: 1♀. [ MZSP]. San Francisco, X/ 1961. 1♀. [ CEMT] . Santiago del Estero: Pinto, I/ 2006, Abadie, E. 1♂. [ CEMT]. Río Salado Wagner Col. 1♂. [ MZSP] decembre Collection Wagner 1♂. [ MZSP]. Ojo de Agua, Coll. Martínez, Feb[rero]. [1]974 1♂. 1♀. [ CMNC]. Ojo de Agua, 17.II. 1982, H. & A. Howden. 1♂. [ CMNC] .

Males: Length 18–28 mm; width 11–14.5 mm. Black color with brown setae at both sides of head and pronotum ( Fig. 6A ).

Head: As long as it is wide with prolonged anterior margin giving the appearance of a blunt triangle. Clypeus with a brilliant flange, without clypeal teeth. Surface of clypeus with strong and parallel wrinkles. Genae with curved and pronounced anterior edge, lateral edge straight and then curved, surface with strong wrinkles. Clypeus-genal suture evident, reaching the cephalic process. Frons with threehorns, the centralis long, sub-quadrangularand directed backwards, dorsoventrally flattened at the basal area, surface with softer wrinkles than the clypeus andcompressed on the apical zone at which it ends with a cylindrical, blunt and brilliant tip that continues to the anterior region. The two lateral horns are triangular, small (less than 1 mm), directed upwards and diagonal to the base of the central horn. In small males the three cephalic processes are less developed.

Thorax: Pronotum twice as wide as it is long. Surface with elongated punctures separated by once their length or diameter across the whole surface. Anterior region with a wide and smooth edge; there is an acute angle behind the cephalic horn, then this edge gets compressed toward the anterior angles. The anterior angle is curved. In the side view, the anterior region of the pronotum is vertical to the dorsal region, excavated in the central region and curved toward the lateral zones, giving the appearance that the central horn of the head fits into this excavation. In the anterior–dorsal view the thorax has a deep excavation, formed around to the two long humps that reach the anterior angle of the pronotum, in the central zone there is a small continuous invagination with an elongated fovea to the back region of the pronotum. Both lateral foveae are big, deep and elongated. Hypomere with shagreened surface and ocelated punctures rounded on anterior edges and elongated on the posterior edges on which being separated by one time their diameter. All punctures with erect, long brown setae, which can be seen on dorsal view and less dense at the central region. The central region under the femur surface is brilliant with the same puncture pattern. Shagreened prosternum, prolonged from its middle region until covering the antero-medial zone of the mesosternum. From the posterior edge of the prosternum many yellow setae emerge directed toward the mesosternum.

Elytra with soft and bicarinate striae, with medium and ocellated punctures spaced by about three times their diameter. Interstriae with shagreened surface with small and bright puncturesseparated byfive times theirdiameter.Mesosternum strongly narrowed medially, on which there is a brilliant and smooth processthat avoids the meso-metasternalsuture, there is a shagreened surface toward the sides with soft and ocellated punctures and dense yellow setae. Mesepisternum with big and ocellated punctures, separated by about one time its diameter, with a seta out of each one. Metasternum with shagreened, shiny central area withoutsetae; strongcarinafrom 1/3 of metasternumtothe backending in a deep fovea. Side edges of the anterior area shagreened with dense setigerous punctures, posterior area shagreened with large setigerous punctures. Metepisternum equal to mesepisternum.

Abdomen: Sternites shagreened with small punctures separated by seven times their diameter, denser in the 5th and 6th sternites. Lateral margins of sternites 1–5 with dense ocelated punctures. 6th sternite very narrowed medially. Pygidium shagreened with elongated punctures separated by one time their diameter, incomplete margin in the middle inferior region. Male genital organ: Side view of aedeagus with sub-quadrangular phallobase, basal region with a medium bulge on both sides, apex with a constriction of approximately 115 ◦. Sub-triangular parameres with a thin at the inferior base, which continues with an invagination toward the middle zone; thin and blunt apex, with a flat surface from which emerge shortsetae ( Fig. 6B ). Dorsallysymmetric with enlarged base and becoming thinner toward the apical zone in which ending with a blunt tip; setae can be seen in lateral view. Internal region with a convex and soft invagination in the first third of the apical area of parameres ( Fig. 6C ). In ventral view, parameres are thin at basal zone with an acute prolongation described in the lateral view: blunt and flat apex where setae can be seen. Between parameres, and inserted from the apical to basal zone, there are two lamellated and overlapped processes: the left paramere process over the right one. These processes go from the apical zone for two-thirds of parameres ( Fig. 6D ). Internal sac is tubular with raspules on the basal two-thirds; there is a big, sub-quadrangular and brown copulatrix lamellae, with two darker lateral prolongations, the entire surface of the lamellae covered by bristles which become longer toward the lateral margins ( Fig. 6E ). Apical zone with three accessory lamellae; the central one is long with undefined form, more sclerotized in the central area surrounded by a semi-quitinized membrane ( Fig. 6F ). Left lateral lamellae has “C” form, with enlarged and sclerotized superior margin with defined edges ( Fig. 6G ). Right lateral lamella has “N” form, enlarged, sclerotized in the middle with surrounding semiquitinized membrane that makes it look wider than the apical region of the sclerite ( Fig. 6H ).

Female: length 19–20 mm; width 12–13.1 mm. It differs from males due to having a softer anterior edge of the gena and frons with two lateral horns ( Fig. 6I ). The excavation of the pronotum is softer, so that the back central fovea is stronger and longer ( Fig. 6J ). 6th abdominal sclerite not shortened medially.

Commentaries: The species is distinguished from the others of the group “buqueti” because the males present a process of three horns in thefrontwherethe twolateral hornshave less than 1 mmand the females only have the lateral horns in the front. Thorax with a deep excavation in the central area, which continues as an elongated fovea in the posterior area of the pronotum. Black elytra with soft and bicarenate striae. This species is preferentially associated to areas adjacent tothe Chaco dry forestsand grasslandsof the Pampa.

Distribution: This species is distributed in Argentina in the Buenos Aires, Córdoba and Santiago de Estero provinces ( Fig. 8 ).

Figures

Fig. 6. Dichotomius haroldi. (A) Dorsal habitus of the male. (B) Lateral view of aedeagus. (C) Dorsal view of parameres. (D) Ventral view of the parameres. (E) Copulatrix lamellae. (F) Central accessory lamella. (G) Left lateral accessory lamella. (H) Right lateral accessory lamella. (I) Head of female. (J) Thorax of female. Line scale 1 mm.

Fig. 8. Distribution maps of the “buqueti” species group.