Discodon tricolor
Creators: name: Biffi, Gabriel
name: Geiser, Michael
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Insecta
Coleoptera
Cantharidae
Discodon
Discodon tricolor

description: Discodon tricolor (Guérin-Méneville, 1832)
Figs 2, 6A, L, 7A, 8A, 9A, 10A, 11A–C, 15A
Silis tricolor Guérin-Méneville in Griffith, 1832, pl. 36 fig. 10; 1844: 47, pl. 14 fig. 10.
Discodon albonotatum Pic, 1906: 90 (excluding “var. obscurior ”). Silis tricolor – Pic 1909: 8. — Delkeskamp 1939: 188 (catalogue). — Blackwelder 1945: 368 (checklist).
Discodon albonotatum (partim) – Delkeskamp 1939: 155 (catalogue); 1977: 259 (catalogue) (syn.). — Blackwelder 1945: 364 (checklist).
Discodon tricolor – Delkeskamp 1977: 259 (catalogue). — Wittmer 1977: 4 (type specimen). — Vanin 2014: 50 (mimicry).
Diagnosis
Discodon tricolor differs from the other species for having most of the antennomeres yellow. Discodon tricolor is similar to D. vanini sp. nov. and D. neoteutonum sp. nov., differing from these species by the ventral wall of the tegmen (Fig. 11A–C) longer, about as long as wide, and the median lobe with a narrow central sclerite; the last ventrite of the females (Fig. 15A) with a distal margin almost straight, with a slight median projection.
Type material
Holotype of Discodon tricolor BRAZIL • ♂; Minas Gerais, “du midi de la capitale des mines”; “ Silis tricolor Guér. icon. R.A.”; MNHN, Paris EC14297 (Fig. 2A–C).
Lectotype of Discodon albonotatum (here designated) BRAZIL • ♂; Rio de Janeiro, Itatiaya [Itatiaia]; 2400 m a.s.l.; Feb. 1899; E. Gounelle leg.; “Museum Paris, Coll. M. Pic ”; MNHN, Paris EC13550 (Fig. 2D–F).
Paralectotypes of Discodon albonotatum (3 specimens) BRAZIL • 1 ♀; São Paulo, Vale do Rio Pardo; Dec. 1898; E. Gounelle leg.; “Museum Paris, Coll. M. Pic ”; MNHN, Paris EC13549 • 1 ♂; Rio de Janeiro, Itatiaya [Itatiaia]; 2400 m a.s.l.; Feb. 1899; E. Gounelle leg.; “Museum Paris, Coll. M. Pic ”; MNHN, Paris EC13551 • 1 ♀; Rio de Janeiro, Itatiaya [Itatiaia]; 850 m a.s.l.; Feb. 1899; E. Gounelle leg.; “Museum Paris, Coll. M. Pic ”; MNHN, Paris EC13552.
Other material examined (29 specimens)
BRAZIL • 2 ♂♂, 1 ♀; Rio de Janeiro, Itatiaia; Feb. 1955; Dirings leg.; MZSP 46319 to 46321 • 5 ♂♂, 2 ♀♀; same collection data as for preceding; Mar. 1959; MZSP 46322 to 46328 • 1 ♂; same collection data as for preceding; Apr. 1959; MZSP 46329 • 1 ♂; same collection data as for preceding; Jan. 1963; MZSP 46330 • 2 ♂♂, 3 ♀♀; same collection data as for preceding; Jan. 1967; MZSP 46331 to 46335 • 1 ♀; same collection data as for preceding; 5 Feb. 1963; J. Halik leg.; MZSP 46336 • 2 ♂♂, 1 ♀; Rio de Janeiro, Parque Nacional do Itatiaia; above 1200 m a.s.l.; 5 Apr. 1964; C.E. and E.S. Ross legs.; NHMB [labelled as “ D. tricolor (Guér.) mit Typus verglichen”] • 1 ♂; same collection data as for preceding; 4 Feb. 1927; Dr Seitz leg.; NHMB [labelled as “ D. albonotatum Pic ” by Wittmer] • 1 ♂; same collection data as for preceding, Maromba; 7 Apr. 1989; B. Harky leg.; MZSP 46337 • 1 ♂; “Mar” [Rio de Janeiro, Parque Nacional do Itatiaia, Maromba]; 1100 m a.s.l.; 11 Feb. 1926; Zikán leg.; NHMB • 1 ♂, 2 ♀♀; São Paulo, São José dos Barreiros, Parque Nacional Serra da Bocaina; 1400 m a.s.l.; 21–24 Mar. 1997; Pinto-da-Rocha, Campaner and Vanin leg.; MZSP 46338 to 46340 • 1 ♀; Minas Gerais [Passa Quatro]; 18 Mar. 22; [Zikán leg.]; NHMB • 1 ♂; “ America, Brasilia, coll. Rich Hicker ”; NHMB.
Re-description
Body length: 10.4–14.0 mm. Coloration (Fig. 2): head pitch black, lustrous, except in front of antennae sockets and anterior margin of clypeus, dark brown; mandibles dark brown, darker at base and the tip; maxillary and labial palpi black, except apex of last palpomeres, dark brown; antennomeres I and sometimes II black, the latter testaceous to light brown. Pronotum (Figs 7A, 8A) lustrous, translucent, with broad irregular black band from anterior to posterior margin, wider posteriorly and narrower near anterior margin; background bright yellow to light orange with barely defined orange and brown lateral patches. Scutellum and elytra pitch black, slightly lustrous; at mid-length of each elytron, large whitish to pale yellow round spot nearly reaching lateral borders but not meeting at suture. Thorax, legs and abdomen pitch black, tarsal claws brown.
Male (Fig. 2)
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 small, rounded, prominent. Mandibles falciform, acute, without accessory teeth. Last maxillary and labial palpomeres securiform. Antennae (Figs 2A, 6A) slightly flattened dorsoventrally; antennomeres wider distally; antennomeres IX–XI distinctly narrower than preceding ones. Pronotum (Fig. 3A) about 1.5 times as wide as long; anterior margin broadly arched, anterior angles indistinct; lateral margins with a shallow notch at posterior third, pronotum wider behind notch; integument smooth, densely covered with very fine yellow setae. Elytra long, each elytron 3.4 times as long as wide, wider at apical third; 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 a transversal slit at base; anterior prothoracic tarsal claws (Fig. 9A) broadly lobed basally, lobe with sinuous 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 deeply notched at posterior margin, V-shaped, lateral apices arched; lobes of ventrite VII (Fig. 10A) elongate, oblong, concave, internal margins directed ventrally, distal margins rounded. Aedeagus (Fig. 11A–C): ventral wall of tegmen short and broad, lateral margins slightly convergent, distal margin forming a pair of broadly rounded lobes; between lobes, small acute tip directed ventrally; fringe of long setae along lateral margins of tegmen dorsally; parameres broadly separated, robust, long and broad, parallel, curved ventrally, apex acute; median lobe short, membranous, partially retracted behind parameres; very long and narrow sclerite curved ventrally, apex acute.
Female
Similar to male; antennae (Fig. 6L) shorter, antennomeres less broad; pronotum (Fig. 8A) trapezoidal, much broader, 1.7 times as wide as long, lateral margins sinuate, without notches; tarsal claws without basal lobe or apical slit; ventrite VI not notched, distal margin slightly arched, concave; ventrite VII (Fig. 15A) broad, lateral margins arched, distal margin sinuous, with a short and broad medial lobe.
Note on nomenclature
Delkeskamp (1977) and Wittmer (1977) both indicated Guérin-Méneville’s 1844 work as the original reference for Silis tricolor, since it contains the first published description of that species. Delkeskamp (1977) also cites “Blanch. in Griffith, Anim. Kingdom 1, 1832, l. 36, fig. 10”, a plate published 12 years prior to Guérin-Méneville’s description.According to ICZN Art. 8.7, an illustration of a species published before 1930 that is accompanied by a new name does however already count as a valid description “by indication” and makes this name available, even without being accompanied by a description in words or an explicit statement that the name is new. We therefore regard the illustration in Griffith’s “Animal Kingdom” as the first available evidence of this species. As the species name Silis tricolor is explicitly attributed to “Guérin” on Griffith’s plate, F.E. Guérin-Méneville remains the author of the species (not Blanchard), but the year of description must be corrected to 1832.
Distribution
Brazil (Minas Gerais, Rio de Janeiro and São Paulo states) (Fig. 16).
description: Published as part of Biffi, Gabriel & Geiser, Michael, 2022, A revision of Discodon tricolor (Guérin-Méneville) and its mimics from the Atlantic forests of Brazil (Coleoptera: Cantharidae), pp. 148-189 in European Journal of Taxonomy 834 (1) on pages 151-154, DOI: 10.5852/ejt.2022.834.1907, http://zenodo.org/record/7017677