Leptostylus arcuatus, 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 : 169-173

Leptostylus arcuatus sp. nov.

( Figs 2 , 12–16 )

Description. Holotype male. Integument mostly dark brown; ventral mouthparts light brown except palpomeres partially darker; anteclypeus brown with irregular dull yellowish-brown areas; labrum dark brown posteriorly, gradually lighter toward anterior margin, except yellowish-brown anterocentral area and narrow lateral area from base to apex; antennomere III partially reddish brown basally; antennomere IV orange on basal eight; antennomere V orange, except dark brown apex. Trochanters reddish brown; base of femoral clubs dark reddish brown; tarsomeres V light reddish brown; apex of abdominal ventrite 1 dull yellowish brown; apex of abdominal ventrites 2–4 reddish brown.

Head. Frons densely, minutely striate, with abundant, shallow, fine punctures interspersed; with short, scale-shaped pubescence, dense on some areas, sparser or absent on others, pubescence brown, yellowish white, yellowish-brown, or yellowish. Area between antennal tubercles with abundant, scale-shaped yellow pubescence, except glabrous median groove; area between antennal tubercles and upper eye lobes sparsely, coarsely punctate, with sparse brown pubescence, with a few short, decumbent yellowish-brown scale-shaped setae interspersed, except glabrous median groove; remaining surface of vertex sparsely, coarsely punctate, with abundant, scale-shaped yellow pubescence not obscuring integument, except glabrous median groove. Area behind upper eye lobes with dense yellow pubescence. Area behind lower eye lobes with dense yellow pubescence with two large, irregular glabrous areas interspersed. Genae 1.35 times longer than lower eye lobe; microsculptured, with abundant, scale-shaped yellow pubescence with irregular glabrous areas interspersed, except smooth and glabrous apex. Wide central area of postclypeus with sparse yellowish-white pubescence; with one long, erect dark yellowish-brown seta on each side. Sides of postclypeus glabrous. Labrum abundantly punctate on posterior half, punctures both coarse and moderately fine, smooth on anterior half; with sparse brown pubescence on posterior half, glabrous on anterior half, except anterior margin with sparse, short yellow setae; punctate area with one long, erect dark-brown seta on each side and long, erect setae centrally, central setae dark brown basally, pale yellow on remaining surface. Antennal tubercles with sparse, both brown and yellowish-brown pubescence, pubescence partially lost. Distance between upper eye lobes 0.36 times distance between outer margins of eyes; in frontal view, distance between lower eye lobes 0.64 times distance between outer margins of eyes. Antennae 1.65 times elytral length, reaching elytral apex at basal third of antennomere VIII. Scape with moderately abundant, scale-shaped brown pubescence not obscuring integument, with irregular areas with scale-shaped, both pale-yellow and whitish pubescence interspersed. Pedicel subglabrous on basal half, with thick, both brownish and yellowish pubescence on apical half. Antennomere III with moderately abundant, thick brown pubescence not obscuring integument and three irregular rings with thick, both yellowish and whitish pubescence, one basally, two about middle.Antennomere IV with white pubescent ring basally and moderately abundant brown pubescence not obscuring integument on remaining surface. Antennomere V with abundant white pubescence partially obscuring integument.Antennomeres VI–VII, IX, and XI with abundant brownish pubescence partially obscuring integument and moderately abundant, short, bristly whitish setae interspersed. Antennomeres VIII and X with abundant brownish pubescence partially obscuring integument and moderately abundant, short, bristly whitish setae interspersed on basal half, and abundant whitish pubescence partially obscuring integument on apical half. Antennal formula based on length of antennomere III: scape = 0.87; pedicel = 0.95; IV = 0.89; V = 0.40; VI = 0.32; VII = 0.29; VIII = 0.22; IX = 0.22; X = 0.21; XI = 0.22.

Thorax. Prothorax wider than long; sides with large, rounded protuberance about middle; anterior constriction narrow, well marked. Pronotum with three rounded tubercles, one on each side of anterior half, another somewhat elongated, located centrally from middle to about posterior quarter; sparsely, coarsely punctate, except smooth tubercles; with moderately sparse, scale-shaped, both light brown and yellow pubescence, except scale-shaped white pubescence on parts of posterocentral region and irregular glabrous areas (probably, part of pubescence was lost), and glabrous tubercles. Sides of prothorax moderately sparsely, coarsely punctate, punctures almost absent anteriorly; with scale-shaped yellow pubescence not obscuring integument, pubescence denser posteriorly toward coxa, except brown scale-shaped pubescence posteriorly toward pronotum and glabrous anterior sulcus. Prosternum with moderately abundant, thick yellow pubescence laterally and sparse whitish pubescence centrally. Prosternal process with sparse whitish pubescence; narrowest area 0.1 times procoxal width. Mesoventrite with sparse whitish pubescence, except dense yellow pubescence on sides. Mesanepisterna and mesepimera with abundant yellowish-white pubescence not obscuring integument, pubescence denser on mesepimera. Mesoventral process with sparse whitish pubescence; sides convergent from base to apical fifth, then slightly widened; apex truncate; narrowest area 0.2 times mesocoxal width; apex 0.3 times mesocoxal width. Metanepisterna with abundant yellowish pubescence not obscuring integument. Metaventrite with abundant, both yellowish and brownish pubescence laterally, abundant yellowish pubescence not obscuring close to metacoxae, sparse yellowish-white pubescence anterocentrally, glabrous on remaining surface (pubescence probably lost). Scutellum with abundant, scale-shaped pale-yellow pubescence on center of anterior half and sparse brownish pubescence on remaining surface. Elytra. Surface entirely irregular; centrobasal crest elevated, moderately long, with abundant, thick, bristly, both brown and yellowish-brown pubescence (pubescence partially lost on anterior third); with four longitudinal carinae, irregularly tuberculate dorsally, innermost less distinct, starting on apex of centrobasal crest, disappearing from posterior third, one dorsally, starting on anterior fifth, arched from posterior quarter, disappearing from posterior fifth, one humeral, disappearing near apex, another laterally, located near humeral carina, from anterior fifth to posterior quarter; with sparse small tubercles throughout, not considering those on carinae; moderately abundantly, coarsely punctate on basal half, punctures gradually finer toward apex on posterior half; apex moderately narrowly rounded; most tubercles with short tuft of brown setae; with very sparse yellow pubescence on center of dorsal surface of anterior fifth, probably lost, moderately abundant brown pubescence on dorsal surface of anterior fifth close to humerus; moderately sparse, thick, both yellow and whitish pubescence on anterior fifth close to suture; sparse yellowish-brown pubescence between epipleural margin and humeral carina on anterior half; moderately abundant, both yellowishbrow and white pubescence between epipleural margin and humeral carina on posterior half; considering both elytra, with large arc with dense yellowish-white pubescence dorsally, posterior margin of arc located on beginning of posterior quarter and anterior areas located about apex of anterior quarter, arc distinctly narrowed anteriorly; area between apex of centrobasal crests and yellowish-white arc with abundant yellowish-brown pubescence not obscuring integument, except wide, transverse whitish pubescent band close to centrobasal crests; area between yellowish-white arc and humeral carinae with moderately abundant yellowish-brown pubescence not obscuring integument; posterior quarter of dorsal surface with moderately abundant, both yellow and brown pubescence not obscuring integument, except irregular areas with yellowish-white pubescence and irregular glabrous areas. Legs. Femora with abundant, scale-shaped brown, pale-yellow, and white pubescence irregularly distributed dorsally and laterally not obscuring integument, pubescence sparser on femoral peduncle; ventral surface with abundant whitish pubescence not obscuring integument, pubescence denser on femoral club. Tibiae with moderately sparse, scale-shaped brown pubescence, with irregular rings and arcs with both pale-yellow and white pubescence, except basal third of protibiae almost glabrous and apical 2/3 with dense, bristly brownish pubescence, base of meso- and metatibiae almost glabrous ventrally and apical third with dense, bristly dark yellowish-brown pubescence, and dorsal sulcus of mesotibiae with abundant, short, erect dark yellowish-brown setae. Dorsal surface of tarsomeres I– III with abundant white pubescence partially obscuring integument about basal half, and abundant yellowish-brown pubescence not obscuring integument on apical half; tarsomeres IV–V with moderately abundant yellowish-white pubescence not obscuring integument; metatarsomere V slightly shorter than II–III together.

Abdomen. Ventrites 1–4 with abundant pale-yellow pubescence laterally, pale-yellow pubescence irregularly denser on some areas, with irregular white pubescent maculae interspersed, and abundant yellowish-white pubescence not obscuring integument centrally, except glabrous apical area and denser yellowish-white pubescence close to glabrous apex on ventrite 4; ventrite 5 with abundant yellowish pubescence not obscuring integument laterally, irregularly denser on some areas, and moderately sparse yellowish-white pubescence centrally. Apical margin of ventrite 5 concave.

Dimensions (mm). Total length, 5.35; prothoracic length, 1.10; anterior prothoracic width, 1.20; posterior prothoracic width, 1.50; maximum prothoracic width, 1.65; humeral width, 2.35; elytral length, 3.80.

Type material. Holotype male from COSTA RICA, Alajuela: Cariblanco area , 1.VI.1980, J.E. Wappes leg. ( FSCA).

Etymology. The species name arcuatus (Latin, meaning “arched”) refers to the distinctive elytral markings

Remarks. Leptostylus arcuatus sp. nov. is similar to L. albicinctus Bates, 1885 but differs as follows: prothorax without dense whitish pubescence; light elytral pubescent band on posterior region of elytra forming a distinct arc; and prosternal and mesoventral distinctly narrower ( Fig. 2 ). In L. albicinctus , the pronotum has dense whitish pubescence, light elytral pubescent band on the posterior region of elytra is transverse and usually triangularly projected forward close to suture, and the prosternal and mesoventral processes are much wider. It is somewhat similar to L. xanthopygus Bates, 1880 (see photographs on Bezark 2024 and in Santos-Silva & Botero 2023), but differs by the prosternal and mesoventral processes notably narrower (much wider in L. xanthopygus ). Leptostylus arcuatus differs from L. transversus (Gyllenhal, 1817) by the narrowest area of the prosternal and mesoventral processes much narrower (respectively, about half procoxal width and distinctly wider than half of mesocoxal width in L. transversus ).

Figures

FIGURES 2–11. Leptostylus, prosternal and mesoventral processes: 2) L. arcuatus sp. nov., holotype male; 3) L. skillmani Santos-Silva, 2022, holotype female; 4) L. quintalbus Bates, 1885, male; 5) L. panamensis Heffern & Santos-Silva, 2022, holotype female; 6) L. densepunctatus Botero, Pérez-Flores & Santos-Silva, 2024, holotype male; 7) L. xanthopygus Bates, 1880, female; 8) L. bicolor Heffern & Santos-Silva, 2023, holotype female; 9) L. carinatus Santos-Silva & Botero, 2023, holotype female; 10) L. perniciosus Monné & Hoffman, 1981, paratype male; 11) L. obrienorum Nascimento & Heffern, 2018, holotype male.

FIGURES 12–16. Leptostylus arcuatus sp. nov., holotype male: 12) Dorsal habitus; 13) Ventral habitus; 14) Lateral habitus; 15) Head, frontal view; 16) Centrobasal crests of elytra.