Sternacutus similis, Santos-Silva & Bezark, 2024

Santos-Silva, Antonio & Bezark, Larry G., 2024, New species, notes and record of New World Acanthocinini (Coleoptera: Cerambycidae, Lamiinae), Zootaxa 5551 (1), pp. 167-185 : 181-184

Sternacutus similis sp. nov.

( Figs 27–31 )

Description. Holotype male. Head capsule dark brown, except gulamentum brown anteriorly, gradually lighter toward prothorax; ventral mouthparts orangish; anteclypeus and labrum mostly testaceous; scape dark brown, slightly lighter on apical quarter; pedicel orangish brown basally, brown on remaining surface; antennomere III light brown on basal 2/3, blackish on apical third; antennomeres IV–V yellowish brown on basal half, blackish on apical half; antennomeres VI–X orange on basal third, dark brown on apical 2/3; antennomere XI orange on basal half, dark brown on apical half. Pronotum and sides of prothorax blackish; prosternum brown laterally, light reddish brown centrally; prosternal process light reddish brown except dark brown apex. Ventral surface of meso- and metathorax dark brown laterally, dark reddish brown centrally. Scutellum brown centrally, dark brown laterally. Elytra dark brown, except brown base and blackish remaining basal quarter. Pro- and mesocoxae reddish brown, gradually orange toward trochanter; metacoxae dark brown on outer surface, orange on inner surface; trochanters and femoral clubs orange; pro- and mesofemoral clubs mostly dark brown; metafemoral club mostly brown; protibia reddish brown on basal half, blackish on apical half; meso- and metatibiae brown basally, reddish brown on remaining basal half, dark brown on apical half; pro- and mesotarsomeres I reddish brown on basal half, dark brown on apical half; metatarsomere I orange on basal half, blackish on apical half; tarsomeres III–V dark brown; tarsomeres V reddish brown on basal 2/3, more orangish on metatarsomere V, dark brown on apical third. Abdominal ventrites reddish brown, gradually orangish toward ventrite 5, with irregular dark brown areas.

Head. Frons abundantly, minutely punctate; with abundant yellowish pubescence not obscuring integument, except glabrous median groove, pubescence yellower close to eyes; with one long, erect brown seta near eyes. Area between antennal tubercles with dense pale-yellow pubescence centrally, except glabrous median groove; remaining surface of vertex with moderately abundant pubescence not obscuring integument, pubescence pale-yellow centrally between eyes, gradually yellowish-brown toward prothorax, except dense yellow pubescence close to eyes, and glabrous median groove and narrow V-shaped transverse band between antennal tubercles and eyes. Area behind upper eye lobes with moderately abundant pale-yellow pubescence not obscuring integument. Area behind lower eye lobes with dense yellow pubescence close to eye, glabrous close to prothorax. Genae 0.57 times length of lower eye lobe; with sparse yellowish-white pubescence, except dense yellow pubescence closet to frons and clypeus and glabrous apex; with a few long, erect brown setae interspersed. Wide central area of postclypeus with pubescence as on frons, except glabrous central area; with one long, erect brown seta on each side. Sides of postclypeus glabrous. Labrum with moderately abundant yellowish-white pubescence not obscuring integument, except glabrous anterocentral third and anterior margin with short fringe of yellowish-brown setae; with a few long, erect dark-brown setae interspersed on posterior half. Gulamentum smooth, glabrous, except sparse whitish pubescence on intermaxillary process. Antennal tubercles with abundant pale-yellow pubescence partially obscuring integument, except brown pubescence partially obscuring integument dorsally, this pubescence not reaching dorsal apex. Distance between upper eye lobes 0.19 times distance between outer margins of eyes; in frontal view, distance between lower eye lobes 0.54 times distance between outer margins of eyes. Antennae 3.4 times elytral length, reaching elytral apex just before middle of antennomere V. Scape with abundant yellowish pubescence not obscuring integument dorsally and laterally, except sparser yellowish-brown pubescence on apical quarter, and abundant whitish pubescence not obscuring integument ventrally; with sparse, long, erect, thick black setae on apical quarter of ventral surface. Pedicel with abundant pale-yellow pubescence on dorsal base, white on base lateral and ventral surfaces, brownish on remaining surface; with a few long, erect, thick blackish setae ventrally. Antennomeres III–XI with abundant whitish pubescence not obscuring integument on light integumental area, and dark with short whitish setae interspersed on dark integumental area, whitish setae more bristly from VIII; ventral surface of III–V with sparse, moderately long, erect, thick blackish setae ventrally, gradually sparser toward V; ventral apex of VI–VII with two moderately long, erect, thick blackish setae. Antennal formula based on length of antennomere III: scape = 0.97; pedicel = 0.12; IV = 0.95; V = 0.86; VI = 0.88; VII = 0.85; VIII = 0.91; IX = 0.94; X = 0.97; XI = 1.03.

Thorax. Prothorax wider than long; anterior constriction narrow, well marked; sides slightly divergent from anterior constriction to middle, then slightly rounded widened toward lateral tubercles and subparallel-sided between them and posterolateral angles; Lateral tubercles small, conical, slightly inclined backward, located on posterior fifth. Pronotum slightly gibbose on each side of anterior half and slightly longitudinally tumid on center of posterior half; moderately abundantly, coarsely punctate near anterior and posterior margins and centrally, sparsely, coarsely punctate on remaining surface; with large, subreniform dark-brown pubescent macula on each side of middle, from anterior quarter to middle; with irregular dark-brown pubescent macula on each side of middle; with subglabrous area on each side near posterior margin; with large, rectangular area centrally on anterior third with sparse yellowish pubescence close to anterior margin, transverse, moderately pale-yellow pubescent band on middle, longitudinal yellowish pubescent band on center of anterior half, subglabrous on remaining anterior half, and sparse yellowish-brown pubescence on posterior half; remaining surface with pale-yellow pubescence, dense on some areas, abundant and not obscuring integument on others, except V-shaped whitish pubescent macula on center of posterior quarter. Sides of prothorax with abundant pale-yellow pubescence partially obscuring integument, except large dark-brown pubescent macula centrally, not reaching anterior margin, and glabrous anterior sulcus. Prosternum with abundant pale-yellow pubescence partially obscuring integument laterally and moderately abundant white pubescence on remaining surface, except glabrous anterior sulcus. Prosternal process with moderately abundant white pubescence not obscuring integument; narrowest area 0.24 times procoxal width. Mesoventrite with sparse whitish pubescence centrally and white pubescence laterally, lateral pubescence more yellowish-white toward apex. Mesanepisterna with abundant whitish pubescence close to mesoventrite, dense yellowish-brown pubescence centrally, and distinctly sparse yellowish-brown pubescence on outer side. Mesepimera with dense yellowish-brown pubescence. Metanepisterna with dense yellowish pubescence. Metaventrite with dense yellowish pubescence laterally, pubescence gradually sparser, whitish toward central region, except dense whitish pubescence close to metacoxal cavities. Mesoventral process with moderately abundant white pubescence not obscuring integument; narrowest area 0.37 times mesocoxal width. Scutellum sparse yellowish pubescence, except abundant, both yellowish and pale-yellow pubescence on close to margins, denser close to posterior margin. Elytra. Sides slightly convergent from humeri to middle, more distinctly convergent toward apex on posterior half; apex oblique, slightly concave between outer and sutural angles; centrobasal crest elevated, with dense, bristly blackish pubescence; humeral carinae absent; moderately abundantly, coarsely punctate on anterior half, punctures gradually sparser toward apex on posterior half; with abundant pubescence not obscuring integument, pubescence mostly yellowish on anterior third and laterally, mostly whitish on remaining dorsal surface, with abundant, irregular dark-brown pubescent maculae and spots interspersed, larger dark pubescent maculae oblique, located dorsally just after middle. Legs. Femoral peduncles with abundant white pubescence not obscuring integument; femoral clubs with abundant light yellowish-brown pubescence not obscuring integument dorsally and on superior region of sides, and abundant white pubescence not obscuring integument on remaining surface. Protibiae with abundant whitish pubescence on basal half, more yellowish depending on light intensity and source, sparse yellowish-brown pubescence dorsally and laterally on anterior half, except both whitish and yellowish pubescence apically, and dense, bristly yellowish-brown pubescence on ventral apical half; meso- and metatibiae with sparse yellowish-brown pubescence basally, dense whitish pubescence on remaining basal half, and sparse, bristly, both yellowish-brown and brown setae on apical half of dorsal and lateral surfaces, and dense, bristly yellowish-brown pubescence on apical half of ventral surface; dorsal surface of mesotibiae with abundant, short, thick, erect dark-brown setae, setae gradually shorter toward apex. Dorsal surface of tarsomeres with abundant white pubescence not obscuring integument; metatarsomere I distinctly longer than II–III together.

Abdomen. Ventrites with abundant whitish pubescence not obscuring integument, denser apically on ventrites 1–4; apex of ventrite 5 strongly concave.

Dimensions (mm). Total length, 5.50; prothoracic length, 1.00; anterior prothoracic width, 1.25; posterior prothoracic width, 1.40; maximum prothoracic width, 1.65; humeral width, 2.15; elytral length, 4.00.

Type material. Holotype male from BOLIVIA, Santa Cruz: 4–6 km SSE Buena Vista, F & F [ Flora & Fauna Hotel ], 1–6.IV.2003, R. Clarke leg. ( MNKM).

Etymology. The species name “ similis ” (Latin, meaning “similar”) refers to the fact that this species is similar to several already described species of the genus.

Remarks. Sternacutus similis sp. nov. is similar to S. angulistigma (Bates, 1885) , S. cinerascens (Bates, 1863) , S. compactus Roguet, 2023 , S. cribripennis (Bates, 1885) , S. dimidiatus (Aurivillius, 1922) , and S. griseostigma (Monné & Monné, 2012) . It differs from S. angulistigma (see photographs on Bezark 2024 and drawing in the original description) by the body stouter, width about 0.4 times the total length (slender, with width almost 0.3 times the total length in S. angulistigma , the difference much more conspicuous when comparing the two species); from S. cinerascens (see photographs on Bezark 2024) especially by the upper eye lobes distinctly wider and the distance between them slightly wider than the width of one upper lobe (distinctly narrower and the distance between then larger than twice the width of one upper lobe); from S. compactus (see photographs on Bezark 2024 and original description) by the lateral tubercles of the prothorax smaller (moderately large in S. compactus ), the elytral length about 1.9 times the humeral width (about 1.6 times in S. compactus ), outer apex of elytra projected (not projected in S. compactus ), and prosternal and mesoventral processes wider (slender in S. compactus ); from S. cribripennis (see photographs on Bezark 2024 and Santos-Silva & Devesa 2021) by the stouter body, width about 0.4 times the total length (slender, about 0.5 in S. cribripennis ), elytra with a short and longitudinal yellowish pubescent band between base and centrobasal crest slightly contrasting with the pubescence on its sides (distinctly contrasting with the pubescence on its sides in S. cribripennis ), with large dark macula on the posterior half of elytra oblique (not oblique in S. cribripennis ), and by the metafemoral clubs distinctly stouter in males (slender in S. cribripennis ); from S. dimidiatus (see photographs on Bezark 2024) by the stouter body (slender in S. dimidiatus , about as in S. angulistigma ), distance between upper eye lobes slightly larger than the width of one upper lobe (wider than twice the width of one upper lobe in S. dimidiatus ), and elytra without transverse dark macula on middle of the dorsal surface (present in S. dimidiatus ); and from S. griseostigma (see photographs on Bezark 2024 and original description), by the pronotum with large subreniform dark macula on each side of middle (absent in S. griseostigma ), pronotum without narrow longitudinal light pubescent band on each side of the posterior half (present in S. griseostigma ), and elytra without wide and large dark zig-zag macula on posterior half (present in S. griseostigma ).

Figures

FIGURES 27–31. Sternacutus similis sp. nov., holotype male: 27) Dorsal habitus; 28) Ventral habitus; 29) Lateral habitus; 30) Head, frontal view; 31) Centrobasal crests of elytra.