Discodon marginicolle, Biffi & Geiser, 2022

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 : 165-166

Discodon marginicolle sp. nov.

urn:lsid:zoobank.org:act:CECFCC8E-713B-4A5F-B6B0-9995F9A776B3

Figs 3E , 6G, R , 7G , 8G , 9G , 10G , 12G–I , 15G

Diagnosis

Similar to D. neoteutonum sp. nov. by the shape and coloration of the elytral spots. It differs from this species by the antennae being entirely black ( Fig. 3E ), with the antennal lines in males ( Fig. 3G ), the pronotum almost entirely black ( Figs 7G , 8G ), and the aedeagus with distal margin of the tegmen with three projecting lobes ( Fig. 12G–I ); females with ventrite VII broad, with a sinuous distal margin and a less pronounced median projection ( Fig. 15G ). The aedeagus of D. marginicolle sp. nov. is similar to that of D. aurimaculatum sp. nov., differing in the shape of the distal projections of the ventral wall of the tegmen; besides, the antennae of D. aurimaculatum do not have antennal lines and the elytral spots are rounder.

Etymology

The specific epithet refers to the barely defined dark-orangish spot in the margin of the pronotum.

Type material

Holotype BRAZIL • ♂; Rio de Janeiro, Nova Friburgo, Macaé de Cima ; Jan. 2000; P. Grossi leg.; CEMT CUIABA 00118359 ( Fig. 3 E ).

Paratypes (4 specimens) BRAZIL • 1 ♂; same collection data as for holotype; MZSP 46458 • 2 ♀♀; Nova Friburgo, Mury ; 1050 m a.s.l.; Mar. 1941; NHMB • 1 ♀; Terezópolis ; Jan. 1980; A. Bello leg.; CEMT CUIABA 00118360 .

Description

Body length: 11.0–13.0 mm. Coloration ( Fig. 3E ): head pitch black, lustrous, except in corners of clypeus, dark brown; mandibles dark brown, darker at tip; maxillary and labial palpi black and antennae entirely black. Pronotum ( Figs 7G , 8G ) lustrous, mostly black, except for orangish to dark brown irregular patches near anterior and posterior angles. Scutellum and elytra pitch black; at mid-length of each elytron, large sulphur to greyish hemispheric to triangular spot nearly reaching lateral borders but not meeting at suture. Thorax, legs and abdomen pitch black, tarsal claws dark brown.

Male ( Fig. 3E )

Head short, nearly as long as wide, 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, with a pair of lobes slightly projected anteriorly. Eyes small, rounded, prominent. Mandibles falciform, acute, without accessory teeth. Last maxillary and labial palpomeres securiform. Antennae ( Fig. 6G ) sub-serrate, slightly flattened dorsoventrally; antennomeres III–VI wider distally, the latter nearly parallel, antennomere XI narrowing apically; antennomeres IX– XI with short longitudinal lines dorsally. Pronotum ( Fig. 7G ) about 1.1 times as wide as long; anterior margin slightly arched, anterior angles rounded; lateral margins with shallow notch at posterior third, pronotum wider near notch; integument smooth, densely covered with very fine clear setae. Elytra long, each elytron about 5.5 times as long as wide, almost parallel; 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. 9G ) with pointing tip, broadly lobed basally, lobe with rounded margin; posterior claws on meso- and metathoracic tarsal claws apparently split at apex, with fine protruding tooth shorter than claws. Abdomen weakly sclerotised, coriaceous, densely covered with long setae; ventrite VI broadly concave at posterior margin; ventrite VII ( Fig. 10G ) elongate, halves triangular, internal margins straight, lateral margins arched, apices rounded. Aedeagus ( Fig. 12G–I ): ventral wall of tegmen elongate, apical margins convergent, forming a pair of parallel lateral projections with acute apices and central projection, strongly curved ventrally and with acute hook-like apex; fringe of long setae along lateral margins of tegmen dorsally; parameres very short, hidden between tegmen and median lobe; median lobe long, conical, membranous, with a pair of strong sclerites, each with double acute apices; sides of median lobe with a tuft of thick spine-like setae.

Female

Similar to male; antennae ( Fig. 6 ) shorter, antennomeres broader, without antennal lines; pronotum ( Fig. 8 ) trapezoidal, broader, 1.6 times as wide as long, lateral margins sinuate, without notches; tarsal claws without basal lobe or apical slit; ventrite VI with distal margin slightly arched, concave; ventrite VII ( Fig. 15G ) broad and short, distal margin sinuous, with a broad medial lobe projecting posteriorly.

Distribution

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

Figures

Fig. 3. Primary types, habitus, males. A. Discodon neoteutonum sp. nov. (holotype, MZSP 46341). B. Discodon vanini sp. nov. (holotype, MZSP 46355). C. Discodon lineaticorne sp. nov. (holotype, MZSP 46436). D. Discodon aurimaculatum sp. nov. (holotype, MZSP 46447). E. Discodon marginicolle sp. nov. (holotype, CEMT CUIABA 00118359). F. Discodon tamoio sp. nov. (holotype, MZSP 46470). Scale bars = 5.0 mm.

Fig. 6. Right antennae, dorsal view. A–K. Males. L–U. Females. A, L. Discodon tricolor (Guérin- Méneville, 1832). B, M. Discodon neoteutonum sp. nov. C, N. Discodon vanini sp. nov. D, O. Discodon obscurior Pic, 1906 stat. nov. E, P. Discodon lineaticorne sp. nov. F, Q. Discodon aurimaculatum sp. nov. G, R. Discodon marginicolle sp. nov. H, S. Discodon tenuecostatum sp. nov. I, T. Discodon tamoio sp. nov. J, U. Discodon viridimontanum sp. nov. K. Discodon crassipes Wittmer, 1952. Scale bars = 1.0 mm.

Fig. 7. Pronotum of males, dorsal view. A. Discodon tricolor (Guérin-Méneville, 1832). B. Discodon neoteutonum sp. nov.C. Discodon vaninisp. nov. D. Discodon obscurior Pic, 1906 stat. nov. E. Discodon lineaticorne sp. nov.F. Discodon aurimaculatumsp. nov. G. Discodon marginicolle sp. nov.H. Discodon tenuecostatum sp. nov. I. Discodon tamoio sp. nov. J. Discodon viridimontanum sp. nov. K. Discodon crassipes Wittmer, 1952. Scale bar = 1.0 mm.

Fig. 8. Pronotum of females, dorsal view. A. Discodon tricolor (Guérin-Méneville, 1832). B. Discodon neoteutonum sp. nov.C. Discodon vaninisp. nov. D. Discodon obscurior Pic, 1906 stat. nov. E. Discodon lineaticorne sp. nov.F. Discodon aurimaculatumsp. nov. G. Discodon marginicolle sp. nov.H. Discodon tenuecostatum sp. nov. I. Discodon tamoio sp. nov. J. Discodon viridimontanum sp. nov. K. Discodon testaceipes Pic, 1930 stat. nov. Scale bar = 1.0 mm.

Fig. 9. Tarsal claws and leg of males. A–K. Anterior claw of fore tarsus, lateral view. A. Discodon tricolor (Guérin-Méneville, 1832). B. Discodon neoteutonum sp. nov. C. Discodon vanini sp. nov. D. Discodon obscurior Pic, 1906 stat. nov. E. Discodon lineaticornesp. nov. F. Discodon aurimaculatum sp. nov. G. Discodon marginicolle sp. nov. H. Discodon tenuecostatum sp. nov. I. Discodon tamoio sp. nov. J. Discodon viridimontanum sp. nov. K. Discodon crassipes Wittmer, 1952. L. Hind leg of male Discodon crassipes Wittmer, 1952, ventral view. Black arrows show the lobe of the anterior tarsal claw of the protarsi. Scale bars: A–K = 0.5 mm; L = 1.0 mm.

Fig. 10. Ventrite VII of males. A. Discodon tricolor (Guérin-Méneville, 1832). B. Discodon neoteutonum sp. nov. C. Discodon vanini sp. nov. D. Discodon obscurior Pic, 1906 stat. nov. E. Discodon lineaticorne sp. nov. F. Discodon aurimaculatum sp. nov. G. Discodon marginicolle sp. nov. H. Discodon tenuecostatum sp. nov. I. Discodon tamoio sp. nov. J. Discodon viridimontanum sp. nov. K. Discodon crassipes Wittmer, 1952. Scale bar = 1 mm.

Fig. 12. Aedeagus, dorsal, ventral and lateral views.A–C. Discodon lineaticornesp. nov. D–F. Discodon aurimaculatum sp. nov. G–I. Discodon marginicolle sp. nov. J–M. Discodon tenuecostatum sp. nov. Scale bars = 1 mm.

Fig. 15. Ventrite VII of females. A. Discodon tricolor (Guérin-Méneville, 1832). B. Discodon neoteutonum sp. nov.C. Discodon vaninisp. nov. D. Discodon obscurior Pic, 1906 stat. nov. E. Discodon lineaticorne sp. nov.F. Discodon aurimaculatumsp. nov. G. Discodon marginicolle sp. nov.H. Discodon tenuecostatum sp. nov. I. Discodon tamoio sp. nov. J. Discodon viridimontanum sp. nov. K. Discodon testaceipes Pic, 1930 stat. nov. Scale bar = 1 mm.

Fig. 16. Distribution map of the Discodon tricolor species complex.