Dichotomius (Luederwaldtinia) vidaurrei, Nunes & Vaz-De-Mello, 2013

Nunes, Rafael V. & Vaz-De-Mello, Fernando Z., 2013, New brachypterous species of Dichotomius Hope, with taxonomic notes in the subgenus Luederwaldtinia Martínez (Coleoptera: Scarabaeidae: Scarabaeinae), Zootaxa 3609 (4), pp. 411-420 : 412-413

Description of Dichotomius (Luederwaldtinia) vidaurrei new species

Material studied: Holotype: 3 BOLIVIA: Santa Cruz: Prov.: Cordillera. Loc: Palmar de las Islas. 29/I/2007 / Leg. T. Vidaurre / Dichotomius vidaurrei sp. nov., Holotype. R.V. Nunes and F.Z. Vaz-de-Mello, 2011 [MNKM]. Paratypes: 7 3, 2 Ƥ same data as holotype [CEMT, MNKM]; 1 3 same data but 1-6/II/2007 [CEMT].

Diagnosis: since this species has the pronotal disc covered with ocellate punctures ( Fig. 1 E), it belongs to the D. batesi species group of Luederwaldtinia . Within this group, D. vidaurrei can be distinguished by the presence of three smooth knobs on the head, pronotum wider than elytra, absence of humeral callus, and atrophied hind wing that reaches, at most, one third the length of elytra ( Fig. 1 E).

Holotype: male: length: 12.8 mm. Maximum width (pronotum): 8 mm. Black, weakly shiny. Head: triangular, surface transversally ridged, except on three smooth knobs at clypeofrontal region. Ventral clypeal process bifurcated. Clypeal teeth separated by a strong, U-shaped emargination. Clypeogenal suture indistinct. Dorsal clypeal and genal margins with a single row of short setae, the length of these setae doubles on clypeal teeth margin. Head surface lacking horns, acute tubercles, and carinae, with three smooth knobs on clypeofrontal region. Antennal club with light red tumescence. Pronotum: wider than long and wider than elytra. Disc with ocellate punctures, separated by approximately their diameter. Ocellate punctures present also along posterior margin, lateral margin. and on anterior angle. Weakly-defined posterior longitudinal sulcus. Pronotal disc with feeble anterior declivity. Anterior angles rounded. Hypomeron: with a lateral band of ocellate punctures, wider anteriorly and posteriorly and reduced to a single row medially. Prosternum: with elliptical ocellate, setose punctures (setae are half the length of hypomeral setae). Mesosternum: narrowed and shiny with foveolate microsculpture medially. Ocellate punctures present laterally. Mesepisternum: ocellate, setose punctures separated by approximately twice their diameter. Metasternum: portion between mesocoxae one half wider than the rest of the lobe. Anterior lobe completely glabrous with few ocellate punctures on lateral margins. Elytra: weakly shiny. Discal striae distinctly punctate. Punctures with the same width of striae and separated by 3/4 their diameter.

Lateral (ninth) stria reaching the base. Interstriae convex, barely shiny. Legs: bearing sparse, black pilosity, denser on mesotibiae and metatibiae. Apical fourth of protibial spur strongly curved inward. Protibiae with four lateral teeth. Metatibial spur truncate. Hind wing: Not articulated and non-foldable. Basal sclerites glabrous. Membrane extending up to the point equivalent to the lacking folding articulation. Subcostal vein joining costal axis at its basal quarter. Medial vein extending until the one third of coastal axis. Distinct pilosity present on the apical third of costal axis. Cubital and anal veins absent. Subvenations absent ( Fig. 1 G). Abdomen: sixth sternite strongly narrowed medially. Posterior margin of sixth sternite with complete margin. Pygidium: as long as wide, shiny with sparse, ocellate punctures on the basal half. Phallobase: dorsally with apical border strongly curved, angulation present. Parameres: almost symmetrical, apically flattened (on lateral view). Dorsoventrally apex with medially directed hooks ( Fig. 1 F).

Morphological variation. Length varies from 9–14 mm. In some individuals, clypeogenal suture as well the posterior longitudinal sulcus on pronotum sometimes more or less distinct. Female differ from males as follows: Legs: protibial spur feeble, curved at apical fourth of length. Abdomen: sixth abdominal sternite medially with twice the width of other sternites.

Distribution. Known only from Palmar de las Islas, Cordillera province, Santa Cruz, Bolivia.

Etymology. Named after Tito Vidaurre Sánchez, scarabaeoidologist who collected the type series. Tito’s enthusiastic interest and knowledge of scarabs has lead to a large amount of new data on Bolivian scarabs.

Systematics. The D. batesi species group, in which D. vidaurrei is placed, has many taxonomic problems; despite the taxonomic synopsis by Pereira (1947). Without further taxonomic research, it is difficult to make conclusions on what species are close relatives of D. vidaurrei .

Ecological information. The type series was collected for an ecological project under the name “ Dichotomius sp.2” ( Vidaurre et al. 2008). Dichotomius vidaurrei was collected with pitfall traps baited with human feces. Specimens were collected at “Bosque Chaqueño” and “Bosque de Palmas”, both ecosystems are considered disturbed. Within the study site D. vidaurrei is rare; with only 22 of the 3382 collected individuals belonging to this species. This species is sympatric with an unidentified species of the D. carbonarius group and with Dichotomius nisus (Olivier) . Three paratypes were hand collected during the day.

Figures

FIGURE 1. Dichotomius mysticus (A) dorsal habitus; (B) dorsal view of genitalia; (C) hind wing; and (D) tarsi and tarsal claw (indicated by black arrow). Dichotomius vidaurrei (E) dorsal habitus; (F) dorsal view of genitalia; and (G) hind wing. Scale bar = 1.5 mm.