Leptostylus indistinctus, Vlasak & Santos-Silva, 2021

Vlasak, Josef & Santos-Silva, Antonio, 2021, Description of five new species of American Acanthocinini (Coleoptera, Cerambycidae, Lamiinae), Zootaxa 5061 (3), pp. 476-492 : 482-485

Leptostylus indistinctus sp. nov.

( Figs 15–21 )

Description. Holotype male ( Figs 15–19 ). Head capsule dark brown, except brown vertex; ventral mouthparts mostly dark reddish brown, except labial palpomeres II–III and maxillary palpomeres II–IV dark brown (apex of maxillary palpomere IV yellowish); anteclypeus brownish; labrum brownish with dark brown areas; scape greenish, except brownish dorsal apex; pedicel dark brown; antennomeres III–IV yellowish-brown with irregular brown maculae interspersed, except dark brown apex; antennomeres V–VII pale yellow with a few brownish maculae interspersed, except dark brown apex; antennomeres VIII–X brown on basal quarter and apical third, pale yellow on remaining surface; antennomere XI brown. Prothorax and ventral surface of meso- and metathorax dark brown. Scutellum dark brown with yellowish-brown areas interspersed. Elytra mostly greenish, with small dark brown areas interspersed, V-shaped brown band on base of posterior third of dorsal surface, and arched brown band on posterior quarter. Femora greenish, except dark brown peduncle and basal area of club on profemora, and dark reddish-brown inner side of peduncle of meso- and metafemora. Tibiae with brown basal and central rings (slightly lighter on meso- and metatibiae), dark brown on remaining surface. Tarsi dark brown, except dark reddish-brown base of meso- and metatarsomeres V. Ventrite 1–2 dark brown; 3–4 with anterocentral area orangish and remaining surface dark brown; 5 orangish except dark brown sides of basal half.

Head. Frons minutely, shallowly, abundantly punctate; with dense straw colored pubescence and brownish pubescence interspersed on superior area; with one long, erect black seta on each side close to eyes. Antennal tubercles with whitish pubescence basally, light yellowish-brown apically. Vertex and superior area behind upper eye lobes with light yellowish-brown pubescence not obscuring integument, except glabrous median groove, and narrow whitish band close to it; remaining surface of area behind upper eye lobes with dense yellowish-brown pubescence. Area behind lower eye lobes with dense yellowish-brown pubescence superiorly and inferiorly close to eye, glabrous centrally and close to prothorax. Genae with abundant pale yellowish-brown pubescence, and a few long, erect dark setae interspersed. Wide central area of postclypeus with abundant pale yellowish pubescence partially obscuring integument, and one long, erect dark seta on each side. Labrum with abundant straw colored pubescence posteriorly, and long, erect dark setae interspersed, and golden pubescence anteriorly. Gulamentum with somewhat abundant yellowish-brown pubescence anteriorly. Distance between upper eye lobes 0.28 times distance between outer margins of eyes; in frontal view, distance between lower eye lobes 0.62 times distance between outer margins of eyes. Antennae 2.8 times elytral length, reaching elytral apex at apex of antennomere V. Scape with dense white pubescence and irregular glabrous areas interspersed, except brownish pubescence on apex of dorsal surface. Pedicel with brownish pubescence and yellowish-white setae interspersed. Antennomeres III–IV with somewhat dense whitish pubescence, except brownish pubescence on dark areas; antennomeres V–VI with dense white pubescence, except dark anterior areas with yellowish pubescence, and dark apical area with sparser white pubescence; remaining antennomeres with dense white pubescence, except dark areas with brownish pubescence and short whitish setae interspersed. Antennal formula based on length of antennomere III: scape = 0.83; pedicel = 0.14; IV = 0.94; V = 0.79; VI = 0.71; VII = 0.69; VIII = 0.69; IX = 0.67; X = 0.55; XI = 0.65.

Thorax. Prothorax wider than long; sides with large rounded tubercle about middle. Pronotum with five tubercles, one on each side of anterior third, the most elevated, one of each side of posterior third, another centrally on posterior half; coarsely, abundantly punctate, except smooth area close to posterior margin; mostly with whitish pubescence, slightly yellower laterally on anterior 2/3, except: L-shaped yellow pubescent band on each side of central area; three brownish pubescent maculae close to anterior and posterior margins; brownish pubescence on part of central tubercle; and brownish pubescence close to inner side of each L-shaped yellow pubescent band. Sides of prothorax with abundant whitish pubescence, gradually yellowish toward prosternum, except brownish pubescent macula close to center of anterior margin and under lateral tubercle (pubescence on these areas short and sparse); posterior area with long, erect dark setae interspersed. Prosternum with abundant pale yellowish-brown pubescence laterally, sparser yellowish-white on wide central area. Narrowest area of prosternal process 0.27 times procoxal width. Wide central area of mesoventrite with somewhat abundant grayish-white pubescence on middle, sparser, shorter laterally. Sides of mesoventrite, mesanepisternum, and mesepimeron with pale yellowish-brown pubescence and irregular maculae with brownish, slightly conspicuous pubescence interspersed. Mesoventral process with abundant grayish-white pubescence. Metanepisternum and sides of metaventrite with abundant yellowish-white pubescence (slightly yellowish on base of metanepisternum) and irregular glabrous areas interspersed; remaining surface of metaventrite with abundant grayish-white pubescence, except glabrous narrow area close to metathoracic discrimen. Scutellum with dense dark brown pubescence, except somewhat sparse yellowish-brown pubescence on anterocentral area, and dense yellowish-brown pubescence close to margins on basal half. Elytra. Subparallel-sided on anterior 2/3, convergent on posterior third; apex subrounded; centrobasal crest well-elevated, without erect setae, with two short projections, one after middle, another apically; somewhat coarsely and abundantly punctate; depressed from apex of centrobasal crests to just before middle; with somewhat small tubercle on each side of anterior quarter, placed near suture after centrobasal crest; humeral carina distinct from near humerus to about posterior quarter; with two longitudinal wide carinae dorsally, from slightly before middle to about posterior fifth, and somewhat abundant acute tubercles on this area; with wide, arched white pubescent band on basal fifth, not reaching humeri, with two longitudinal yellowish pubescent bands interspersed (these bands follow, fragmented, toward posterior third), brownish pubescent band between posterior half of centrobasal crests, V-shaped white pubescent band dorsally close to suture (apex starting on middle), fragmented white pubescent band from near apex of inferior arms of V-shaped band to epipleura, brownish pubescence on brown bands on posterior third, and remaining surface with pale yellowish-brown pubescence, and white pubescence interspersed on some area. Legs. Femora with abundant white pubescence and also abundant areas with shorter and sparser pubescence interspersed on club; inner apex triangularly projected. Tibiae with abundant white pubescence not obscuring integument on light areas, brownish and whitish setae interspersed on dark areas, except dense, bristly yellowish-brown pubescence on posterior third of ventral surface; with short, thick, sparse black setae ventrally, more abundant on posterior third, and abundant similar setae on dorsal surface of posterior third of mesotibiae. Metatarsomere I slightly longer than II–III together.

Abdomen. Ventrites with abundant grayish-white pubescence partially obscuring integument. Apex of ventrite V widely concave.

Female ( Figs 20–21 ). Similar to male. Differs by the antennae slightly shorter (2.6 times elytral length, reaching elytral apex at apex of antennomere VI).

Chromatic variation. Maculae on antennomeres III–IV brownish; basal and central rings of tibiae orangishbrown; ventrites 1–2 dark brown laterally, orangish centrally; ventrites 3–4 orangish except dark brown posterocentral area; ventrite 5 orangish.

Dimensions (mm) (holotype male/ paratype male/ paratype females). Total length, 8.10/8.65/8.05–8.75; prothoracic length, 1.50/1.75/1.45–1.60; anterior prothoracic width, 1.70/1.90/1.75–1.80; posterior prothoracic width, 2.05/2.35/2.15–2.20; maximum prothoracic width, 2.40/2.75/2.40–2.60; humeral width, 3.15/3.45/3.15–3.40; elytral length, 5.80/6.05/5.75–6.25.

Type material. Holotype male/ paratype female from COSTA RICA, Puntarenas: Santa Elena, Monteverde area , 29.VI.2017, J. Vlasak leg. ( MZSP). Additional paratypes (1 male, 2 females), same data as holotype ( JVCO).

Etymology. The name “indistinctus” (Latin, meaning not easily distinguished) refers to the somewhat nondescript appearance of this species.

Remarks. By the prosternal process not noticeably wide, this species appears to be more similar to species of Amniscus Dejean, 1835 than to species of Leptostylus LeConte, 1852 and Leptostylopsis Dillon, 1956 . However, species of Amniscus have erect elytral setae, which are absent in Leptostylus and Leptostylopsis . According to Monné et al. (2020): “ Leptostylus and Leptostylopsis are very problematic and the separation between them is nearly impossible. The features pointed out to separate them are questionable, especially because Leptostylus includes species with characters extremely variable as, for example, the prothoracic shape, position and shape of the lateral tubercles of the prothorax, which may even be absent, distance between lower eye lobes frontally, etc […] The characteristics pointed out by Dillon (1956a) to separate them thus become very questionable.” According to Lingafelter & Micheli (2009): “Dillon’s separation of the genera based on the level of tuberculation of the pronotal disk, antennal length, and mesosternal process no longer functioned. These genera are still in need of revision, as are many in Acanthocinini .” As the separation between Leptostylus and Leptostylopsis is nearly impossible using the currently known features, we prefer to describe the new species, provisionally, in the former.

Leptostylus indistinctus sp. nov. is similar to L. arciferus Gahan, 1892 (see photographs on Bezark, 2021), but differs especially by the posterior dark band of the elytra inclined backward from sides to suture (inclined upward from sides to suture in L. arciferus ), and by the longer antennae in both sexes (shorter in both sexes of L. arciferus ).

Figures

FIGURES 15–21. Leptostylus indistinctus sp. nov. 15–19) Holotype male: 15) Dorsal habitus; 16) Ventral habitus; 17) Lateral habitus; 18) Head, frontal view; 19) Prosternal and mesoventral processes. 20–21) Paratype female: 20) Dorsal habitus; 21) Ventral habitus.