Discodon obscurior Pic, 1906

Biffi, Gabriel & Geiser, Michael, 2022, A revision of Discodon tricolor (Guérin-Méneville) and its mimics from the Atlantic forests of Brazil (Coleoptera: Cantharidae), European Journal of Taxonomy 834 (1), pp. 148-189 : 159-161

Discodon obscurior Pic, 1906 stat. nov.

Figs 5A–C, 6D, O, 7D, 8D, 9D, 10D, 11J–L, 15D

Discodon albonotatum var. obscurior Pic, 1906: 90 .

Discodon albonotatum var. obscurior – Delkeskamp 1939: 155 (catalogue); 1977: 259 (catalogue). — Blackwelder 1945: 364 (checklist).

Diagnosis

Similar to D. nigrocephalum by general coloration ( Fig. 5A–B). It differs especially by the elytra being smoother ( Fig. 5A), the pronotum ( Figs 7D, 8D) with anterior and lateral margins broadly arched, the shape of the lobe of the tarsal claws ( Fig. 9D), the ventrite VII of males ( Fig. 10D) and females ( Fig. 15D) and the aedeagus ( Fig. 11J–L). The colour of the antennae ( Fig. 5A–B) of D. obscurior is usually light brown to orangish.

Type material

Lectotype (here designated)

BRAZIL • ♀; Rio de Janeiro, Nova Friburgo ; Feb.–Mar. 1903; E. Gounelle leg.; “Muséum Paris, Coll. M. Pic ”; MNHN, Paris EC13554 ( Fig. 5A–C).

Paralectotype

BRAZIL • 1 ♀; same collection data as for lectotype; MNHN, Paris EC 13555 .

Other material examined (38 specimens)

BRAZIL • 28 ♂♂, 10 ♀♀; Rio de Janeiro, Petrópolis ; 5–7 Mar. 1962; J. Bechyné leg.; MZSP 46398 to 46435 .

Re-description

Body length: 11.0–13.0 mm. Coloration ( Fig. 5A–B): head pitch black, lustrous, except in lateral corners of clypeus, dark brown; mandibles dark brown, darker at base and tip; maxillary and labial palpi dark brown, light brown in last palpomeres; antennomere I black, the latter light brown, sometimes orangish. Pronotum ( Figs 7D, 8D) lustrous, partly translucent, with broad irregular black band from anterior to posterior margin, black band usually with lateral projections in posterior third; background pale yellow with diffuse orange regions. Scutellum and elytra entirely pitch black, slightly lustrous. Thorax, legs and abdomen black, tarsal claws brown.

Male ( Fig. 5A–B)

Head short, slightly wider than long, excluding eyes; integument smooth, densely covered with short and fine yellow setae; frons short, vertex flat, occipital region convex, broadly rounded behind eyes. Clypeus flat, anterior margin emarginate, slightly projected anteriorly with median incision. Eyes large, rounded, slightly prominent. Mandibles falciform, acute, without accessory teeth. Last maxillary and labial palpomeres securiform. Antennae ( Fig. 6D) long, slightly flattened dorsoventrally; antennomeres III–X narrowing proximally, sub-serrate; antennomeres without longitudinal lines. Pronotum ( Fig. 7D) wide, 1.5 times as wide as long; anterior margin, anterior angles and lateral margins broadly arched; lateral margins with shallow notch at posterior third; integument smooth, densely covered with very fine yellow setae. Elytra long, each elytron 4.2 times as long as wide, wider medially; integument coriaceous, densely covered with short and fine decumbent setae, and much longer thick erect setae. Legs slender, densely pubescent, covered with long and thick setae; tarsi flattened dorsoventrally, fourth tarsomere with transversal slit at base; anterior prothoracic tarsal claws ( Fig. 9D) broadly lobed basally, lobe with sinuous to truncate margin; posterior claws on meso- and metathoracic tarsal claws apparently split at apex, with fine protruding tooth slightly shorter than claws. Abdomen weakly sclerotised, coriaceous, densely covered with long setae; ventrite VI notched at posterior margin; ventrite VII ( Fig. 10D) with concave lobes, inner margins divergent, directed ventrally, with sharp borders; outer margins straight, apical margins truncate, meeting medially. Aedeagus ( Fig. 11J–L): ventral wall of tegmen short, lateral margins convergent from apical half; apex forming a pair of rounded lobes and salient border projecting ventrally; fringe of long setae along lateral margins of tegmen dorsally; parameres very long, robust, falciform, projecting dorsally, apex rounded with small acute tip; median lobe membranous, with very long and broad flattened central sclerite dorsally.

Female

Similar to male; antenna ( Fig. 6O) longer; pronotum ( Fig. 8D) more transverse, wider, 1.6 times as wide as long, sub-rectangular, anterior margin nearly straight, lateral margins without notch; tarsal claws without basal lobe or apical slit; ventrite VI not notched, distal margin slightly arched, concave; ventrite VII ( Fig. 15D) broad, lateral and distal margins sinuous, apex without strong projections, with shallow lobes not strongly projecting posteriorly.

Distribution

Brazil (Rio de Janeiro state) ( Fig. 16).