Bacis nigropictus Crotch, 1876

Lopes, Peterson Lásaro, Gasca-Álvarez, Héctor Jaime & Skelley, Paul E., 2020, Redescriptions, new synonymy, new combination and new records of Bacis Dejean, 1836 and Oligocorynus Dejean, 1876 (Coleoptera: Erotylidae: Erotylinae) for Colombia, Zootaxa 4809 (2), pp. 349-362 : 350-353

Bacis nigropictus Crotch, 1876

( Figs. 1–29 , 57–60 )

Bacis nigropictus Crotch 1876: 557 ; Fleutiaux 1886: 224; Kuhnt 1909: 48, 1911: 34; Blackwelder 1945: 463, list; Alvarenga 1994: 118, catalog. Type series: Venezuela (UMZC, not examined).

Zonarius limbatus Kuhnt 1910: 249 , 253, fig. 14; Kuhnt 1911: 30; Blackwelder 1945: 462, list. New synonym. Lectotype, here designated: Venezuela, Mérida: Mérida (8°35’53’’N, 71°8’41’’W), 104093, †999 (ZMHB, examined). Paralectotypes: Colombia—Starke col., ♂, 21678, †971 (ZMHB, examined); †995 (ZMHB, examined); Kuhnt det., 4678, †997 (ZMHB, examined).

Oligocorynus limbatus (Kuhnt) ; Alvarenga 1994: 109, catalog.

Redescription. Length: 9 mm, thorax/abdomen R=1.6. Body moderately oval, subcordiform, sides slightly curved, moderately convex. Head orange with irregular vertical black band, antennae black, clypeus black apically, orange at base, pronotum black with two orange lateral maculae, mesoventrite, mesanepisterna, mesepimera and metaventrite orange, coxae and femora dark yellow, elytra dark orange with eight black maculae, abdominal ventrites dark orange ( Figs. 1–4 ).

Head (R=0.8): ocular striae restricted to eye margin, eyes faceted, interocular distance ~2/3 of head width ( Fig. 5 ). Stridulatory organs absent at base of head in both sexes. Antennae (R=11.6): antennomeres VIII and XI elongate ( Fig. 6 ). Clypeus (R=0.4) sub-rectangular, apex truncate ( Fig. 5 ). Labrum (R=0.7): sub-rectangular, without apical elevation, absence of membranous cover at proximal half ( Fig. 7 ). Epipharynx with setae in median region and at anterior margin, median region covered with microtrichiae, tormae with anterior projection reaching the basal third of labrum, posterior projection of tormae almost as long as the anterior projection ( Fig. 8 , arrow). Mandibles slightly asymmetrical, with three incisors, membranous lobe covered with microtrichiae on molar region, with two carinae on dorsal region, ventral cavity with internal incisor margin sinuate, left mandible with proximal incisor smaller and attached to middle incisor as a lobe ( Figs. 9–12 ). Maxillae (R=2.7): lacinia with an apical curved hook, with long setae denser distally, palpomere I elongate, palpomeres II–III as wide as long, palpomere IV wide, galea (R=1.9) subfalciform, with moderately long setae denser distally ( Figs. 13–14 ). Hypopharynx with two basal arms extending to posterior region of mentum ( Fig. 15 , arrow). Labium (R=1.5): ligula long (~3/4 width of the mentum), fused at middle, with a basal sclerite extending through almost the entire ligula, outer angles rounded, basal palpomere with moderately curved base, inner angle of distal margin slightly narrow, mentum with medial region without definite shape ( Fig. 16 ).

Thorax: pronotum (R=0.4) glossy, lateral region of posterior margin with a depression, surface of depression punctate, prosternum with few short setae, procoxal lines absent. Scutellar shield (R=0.7) semiovoid. Metaventrite (R=0.4): mesocoxal lines conspicuous. Legs: metathoracic legs with femora as wide as the prothoracic legs. Elytra (R=2.4): surface with fine punctures (φ~ 0.05 mm), with elytral striae moderately conspicuous, geminate; interstriae with punctures moderately conspicuous. Metathoracic wings (R=2.3): with two axillary veins, veins AA 3+4 reaching CuA 3+4, veins MP 3+4 reaching MP 1+2, vein cua1-mp4 complete, vein r4 complete ( Fig. 17 ).

Abdomen: surface with few short setae. Male genital segments and genitalia: tergite VIII (R=0.6) subtriangular, uniformly sclerotized, base curved, setae denser distally ( Fig. 18 ); sternite VIII (R=0.3) transverse, distal margin emarginate, setae denser distally ( Fig. 19 ); tergite X (R=0.8) U-shaped; lateral shafts slightly curved, apex truncate, setae denser distally ( Fig. 20 ); laterotergite IX (R=1.4) elongate, asymmetrical, lateral lobes sub-triangular; sternite IX setae denser distally ( Fig. 21 ). Aedeagus: tegmen elongate at middle, dorsal longitudinal line sclerotized, tegmen arm long, with two sclerotized lines, lateral lobes width ~1/8 of tegmen length, setae denser distally, lateral region of median lobe narrow, internal sac short ( Figs. 22–24 ); head of flagellum subtriangular ( Fig. 25 , MAAEIS). Female genital segments and genitalia: tergite VIII (R=0.5) transverse, setae denser distally ( Fig. 26 ); sternite VIII (R=0.6) transverse, setae denser distally, median strut approximately three times longer than base ( Fig. 27 ); tergite IX and sternite IX indistinct, membranous, surface with microtrichiae uniformly distributed. Ovipositor: proctiger lobe long ( Figs. 28–29 , arrow), covering the vulval lobe, subvulval lobe as wide as the basal segments of the gonocoxites, gonocoxites ~1/2 of ovipositor length with narrowed and rounded apex, gonostyli setae moderately long ( Figs. 28–29 ). Spermatheca ellipsoidal.

Intraspecific variation. Integument color from light-orange to light-brown, with bands, legs and sternites dark brown; inner spots of elytra can be fused in pairs.

Diagnosis. Bacis nigropictus can be recognized among other species of Bacis by its dorsal coloration, with eight black elytral spots and pronotum orange with black longitudinal medial band, and clypeus truncate.

Etymology. The genus name is derived from the Greek bacis, “soothsayer”; the specific epithet is derived from the Latin nigro, “black” and pictus, “painted, colored”, referring to the elytral and pronotal coloration.

Material examined. Venezuela—ex-Coll. C. Felsche, donation 1907, 2 ex.: †846, 845 ( SMTD) ; †843 ( SMTD); Brazil— ♂, Mus antiqu., †844 ( SMTD) .

Geographical distribution. Colombia, Venezuela (Mérida), Brazil.

Remarks. Although the type series of B. nigropictus has not been examined, Crotch’s original description indicates that B. nigropictus and Oligocorynus limbatus are the same species. By comparing specimens of Oligocorynus to specimens of B. nigropictus , it is evident that the latter have an increased and more gradual curvature of the elytral sides (“ breviter ovatus ”, as described by Crotch [1876]), a trait typical of the genus Bacis , not of Oligocorynus . In any case, the diagnosis presented above places this species among those currently included in Bacis . The Venezuelan syntype of Zonarius limbatus is here chosen as the lectotype, because it came from the same type locality as Bacis nigropictus (see Crotch 1876). The Colombian syntypes of Z. limbatus are designated as paralectotypes ( Figs. 57–60 ).

Figures

FIGURES 1–8. Bacis nigropictus Crotch, 1876, specimen from Brazil. Habitus: (1–2) dorsal, (3) lateral, and (4) ventral view (scale bars for 1–4 = 3 mm); (5) head (scale bar = 0.3 mm); (6) left antenna (scale bar = 1 mm); (7) labrum (scale bar = 0.3 mm); (8) epipharynx (scale bar = 0.3 mm; arrow: torma).

FIGURES 9–16. Bacis nigropictus Crotch, 1876. (9–10) Mandibles, dorsal view (arrow: proximal incisor); (11–12) mandibles, ventral view (arrow: proximal incisor); (13) maxilla, dorsal view, (14) maxilla, ventral view, (15) hypopharynx, dorsal view (arrow: hypopharynx arm); (16) labium, dorsal view. Scale bars = 0.3 mm.

FIGURES 17–25. Bacis nigropictus Crotch, 1876. (17) Right metathoracic wing (scale bar = 3 mm); (18) eighth abdominal tergite; (19) eighth abdominal sternite; (20) tenth abdominal tergite; (21) ninth abdominal sternite (scale bars for 18–21 = 0.3 mm); (22–24) aedeagus, dorsal, ventral, and lateral view, respectively (scale bar = 0.5 mm); (25) head of flagellum (scale bar = 0.1 mm).

FIGURES 26–29. Bacis nigropictus Crotch, 1876. (26) Eighth abdominal tergite; (27) eighth abdominal sternite; (28) ovipositor, dorsal view (arrow: proctiger lobe); (29) ovipositor, ventral view. Scale bars = 0.3 mm.

FIGURES 57–60. Type material of Zonarius limbatus Kuhnt, 1911. (57) Lectotype; (58–60), paralectotypes. Photographs provided by Bernd Jaeger.