Nealcidion antonellum, Vlasak & Nascimento & Santos-Silva, 2025

Nealcidion antonellum sp. nov.

( Figs 11–16 View FIGURES 11–16 )

Description. Holotype male. Integument mostly dark brown; ventral mouthparts yellowish brown with irregular brown areas, except maxillary palpomeres I–III and labial palpomeres I–II dark brown with pale apex, and maxillary palpomere IV and labial palpomere III brown with reddish-brown apex; anteclypeus mostly dark yellowish brown; labrum dark yellowish brown on anterior half; pedicel reddish brown basally, dark brown on remaining surface; antennomeres III–V reddish brown except dark-brown apex; antennomeres VI–VII reddish brown, slightly darker apically; antennomeres VIII–XI brown basally, orangish brown about remaining basal half, brown on remaining surface. Mesoventral process mostly dark reddish brown. Sides of metaventrite dark reddish brown. Elytral longitudinal carina partially reddish brown; posterior sixth mostly reddish brown. Femora mostly reddish brown, slightly darker depending on light intensity. Tibiae slightly lighter toward apex. Abdominal ventrites dark reddish brown, except dull yellowish-brown apex of ventrites 1–4 (this area distinctly narrow on ventrite 1).

Head. Frons abundantly, minutely punctate; with abundant yellowish-brown pubescence partially obscuring integument, pubescence paler on wide central area; with a few long, erect dark-brown setae close to eyes.Area between and on antennal tubercles with dense, both yellow and pale-yellow pubescence except glabrous median groove and somewhat sparse, both pale-yellow and brownish pubescence on area close to base of antennal tubercles. Remaining surface of vertex with dense, both yellow and pale-yellow pubescence anteriorly, this area projecting centrally towards prothorax and becoming sparser and yellowish white, except glabrous, circular spots close to eyes, and large glabrous area on each side close to prothorax; with a few long, erect setae close to eyes, setae brownish basally, gradually yellowish toward their apices.Area behind eyes with dense, both yellow and pale-yellow pubescence close to eye, glabrous close to prothorax. Genae 0.6 times frontal length of lower eye lobe; abundantly microsculptured, except smooth apex; with abundant yellowish-white pubescence not obscuring integument, pubescence sparser toward sides, except glabrous smooth area; with a few long, erect brown setae interspersed. Wide central area of postclypeus with abundant, both yellowish-white and pale-yellow pubescence not obscuring integument close to frons, subglabrous on transverse central region, and somewhat sparse yellowish-white setae directed forward close to anteclypeus, setae longer laterally, absent centrally; with one long, erect seta on each side close to frons, setae dark brown with pale apical third. Sides of postclypeus glabrous. Labrum abundantly, finely punctate on posterior half, smooth on anterior half; with abundant yellowish-white pubescence not obscuring integument on posterior half and sides of anterior half, glabrous on remaining surface, except sparse fringe of yellowish-brown setae on anterior margin; with long, erect setae interspersed on posterior half, setae dark brown with pale apex or entirely yellowish brown. Outer sides of mandibles triangularly depressed on basal third; depression with abundant whitish pubescence not obscuring integument and a few long, erect dark-brown setae; remaining surface glabrous. Gulamentum smooth, glabrous, except intermaxillary process abundantly, finely punctate, with somewhat sparse yellowish-white pubescence. Maximum diameter of upper eye lobes larger than basal diameter of scape; distance between upper eye lobes 0.23 times distance between outer margins of eyes; in frontal view, distance between lower eye lobes 0.59 times distance between outer margins of eyes. Antennae 2.5 times elytral length, reaching elytral apex at basal quarter of antennomere VI. Scape, strongly, abruptly widened ventrally near base; distinctly flattened on basal 2/3 of dorsal surface; with dense pale-yellow pubescence on basal 3/4 of dorsal and lateral surfaces, very sparse on apical quarter of dorsal and inner surface, abundant, partially obscuring integument on apical quarter of outer surface, except dorsal apex with abundant yellowish pubescence and lateral apices with abundant whitish pubescence partially obscuring integument; ventral surface with sparse whitish pubescence basally and abundant whitish pubescence not obscuring integument on remaining surface, pubescence slightly sparser apically; with a few long, erect setae on apex of ventral surface and inferior region of lateral surfaces. Basal half of pedicel with abundant yellow pubescence dorsally and abundant white pubescence laterally and ventrally; apical half with abundant brown pubescence not obscuring integument, with sparse, short, decumbent whitish setae apically; with a few long, erect yellowish setae interspersed ventrally. Antennomeres III–V with dense whitish pubescent ring basally, yellowish-white pubescent ring on apical third, abundant dark-brown pubescence not obscuring integument, with short, decumbent whitish setae interspersed between the two light pubescent rings, and abundant dark-brown pubescence not obscuring integument between second light pubescent ring and apex, with a few short, decumbent whitish setae on apex; ventral surface with long, erect yellowish-brown setae interspersed. Antennomere VI with dense whitish pubescent ring basally and just after middle, somewhat sparse brown pubescence with sparse, short, decumbent whitish setae interspersed dorsally and laterally, and dense white pubescence connecting anterior and posterior rings ventrally; apical quarter with somewhat sparse brown pubescence with a few short, decumbent yellowish-white setae interspersed. Antennomere VII with dense whitish pubescence on basal 2/3, except sparser pubescence dorsally from basal quarter to about middle, and abundant brown pubescence not obscuring integument on apical third. Antennomeres VIII–X with dense yellowish pubescence on basal 2/3 and abundant brown pubescence not obscuring integument on apical third. Antennomere XI with dense yellowish pubescence except sparse yellowish pubescence apically. Antennal formula (ratio) based on antennomere III: scape = 0.74; pedicel = 0.11; IV = 0.83; V = 0.71; VI = 0.64; VII = 0.57; VIII = 0.57; IX = 0.58; X = 0.55; XI = 0.49.

Thorax. Prothorax wider than long; anterior constriction narrow, well marked; sides slightly divergent from anterior constriction on anterior quarter, with large, rounded projection from anterior quarter to posterior third, then parallel-sided toward posterolateral angles. Pronotum sparsely, coarsely punctate on anterior 2/3, punctures distinctly more abundant and coarser on posterior third, forming three rows, one continuous, oblique laterally, arched and almost reaching posterior margin centrally, the other transverse on each side between the former and posterior sulcus; with large U-shaped dark-brown pubescent macula, from posterior margin to anterior fifth; with dense, both yellow and pale-yellow pubescence on remaining surface, except glabrous sides of anterior and posterior sulci, except small dark-brown pubescent spots on sides of anterior 2/3, irregular area with somewhat sparse brown pubescence on each side of anterior 2/3, and dense, longitudinal yellowish-white pubescent band close to area with somewhat sparse brown pubescence; with a few long, erect dark-brown setae on sides of posterior third. Sides of prothorax with abundant pale-yellow pubescence partially obscuring integument close to pronotum, abundant yellowish-white pubescence partially obscuring integument close to prosternum, and abundant brown pubescence centrally, with short, decumbent whitish setae interspersed, except glabrous anterior and posterior sulci. Prosternum with abundant yellow pubescence partially obscuring integument, except glabrous anterior sulcus. Prosternal process inverted Y-shaped; anterior 2/3 with abundant yellow pubescence partially obscuring integument, except narrow longitudinal white pubescent band centrally and white pubescence on sides; remaining surface with a few short white setae; narrowest area 0.27 times procoxal width. Central area of mesoventrite and mesoventral process with abundant yellowish-white pubescence not obscuring integument; superior area of mesoventrite close to mesocoxal cavities with dense yellow pubescence and remaining surface with abundant pale-yellow pubescence partially obscuring integument; remaining surface of mesoventral process with sparse whitish pubescence; sides of mesoventral process convergent toward truncate apex; apex 0.44 times mesocoxal width; central area longitudinally carinate. Mesanepisterna with abundant yellowish-white pubescence anteriorly, pubescence gradually yellower toward mesepimeron, especially toward elytra, except irregular brown pubescent macula with short, decumbent, yellowish-white setae interspersed. Mesepimera with abundant yellowish pubescence close to mesanepisternum and dense yellow pubescence on remaining surface. Metanepisterna with dense yellow pubescence except somewhat abundant whitish pubescence basally and near apex. Sides of metaventrite with abundant yellow pubescence not obscuring integument, with small, irregular glabrous areas interspersed, except dense yellow pubescence laterally near metacoxal cavities and abundant pale-yellow pubescence internally near metacoxal cavities; remaining surface with abundant yellowish pubescence not obscuring integument on anterior half and abundant light yellowish-brown pubescence not obscuring integument on posterior half, except glabrous metathoracic discrimen. Scutellum with dense yellowish-brown pubescence except sides with sparse blackish pubescence. Elytra. Humeri not projected; anterior half parallel-sided; sides slightly convergent from middle to posterior third, distinctly convergent from this point to near apex, then parallel-sided; apex obliquely truncate with sutural angle slightly projected; centrobasal crest small, slightly elevated, with bristly tuft of dark-brown setae; dorsal surface with three longitudinal carinae, one well marked, from centrobasal crest to near outer apical angle, one well-marked from near humerus to posterior quarter, apically fused with the former, another laterally, moderately marked, from anterior third to slightly after middle; humeral carina almost absent; abundantly, coarsely punctate on anterior third and sides of anterior 2/3, punctures gradually finer and sparser toward apex on remaining surface; pubescence forming complex pattern of yellowish, pale-yellow, yellow, yellowish-brown, and dark-brown pubescence, highlighting three areas with yellow or pale-yellow pubescence dorsally, considering both elytra: one V-shaped, the smallest, on anterior third, another large, wider, somewhat V-shaped about middle, another almost hourglass-shaped on posterior third, one irregular, somewhat small macula with dark-brown pubescence on middle; dark spots with tuft of short, erect dark setae.

Legs. Coxae with abundant yellow pubescence externally and abundant whitish pubescence internally. Trochanters with abundant whitish pubescence not obscuring integument. Femoral peduncles with abundant yellow pubescence dorsally and on inner surface, and abundant whitish pubescence not obscuring integument on remaining surface; femoral clubs with abundant pale-yellow pubescence dorsally and on inner surface, except whitish pubescence on apex of profemora; inner and ventral surface of profemoral club with abundant whitish pubescence not obscuring integument, except abundant yellow pubescence on apical region and irregular area with sparser, both yellowish and whitish pubescence on posterior third of inner surface; basal third of inner surface of meso- and metafemora with moderately abundant yellowish-white pubescence not obscuring integument, remaining surface with abundant pale-yellow pubescence (yellower depending on light intensity), except fragmented area with sparse brownish pubescence with short, decumbent yellowish setae interspersed. Dorsal and lateral surfaces of protibiae with dense yellowish-white pubescence, except two arcs with abundant brown pubescence not obscuring integument, one on anterior half, another on posterior half; ventral surface glabrous basally, with sparse whitish pubescence on remaining basal half, abundant, bristly yellowish-brown pubescence on posterior half, and sparse, moderately long, erect yellowish-white setae interspersed on apical half; with small, slightly elevated tooth located about middle of outer side of ventral surface, and elongated carina centrally on apical quarter, carina gradually elevated toward its anterior region, then obliquely inclined toward near apex of tibia. Mesotibiae with dense yellowish-white pubescence on basal half, except arc with brown pubescence not obscuring integument dorsally and laterally, located about middle of basal half; posterior half with dense yellowish pubescence on outer surface, inner surface with slightly conspicuous brown pubescence close to basal half, and abundant, both whitish and yellowish pubescence not obscuring integument on remaining surface, abundant, short, thick, erect setae dorsally, setae slightly longer close to anterior half, dark brown close to anterior half, shorter, yellowish brown on remaining surface, and ventral surface mostly with abundant, bristly yellowish-brown pubescence. Metatibiae with pubescence similar to that on mesotibiae, but dorsal surface with sparse, short, thick, erect dark-brown setae; with long, erect, both yellowish-white and yellowish-brown setae interspersed on posterior half. Dorsal surface of protarsomeres I with dense, large yellowish-white pubescent macula centrally and abundant dark-brown pubescence not obscuring integument on remaining surface; dorsal surface of mesotarsomeres I with dense yellowish-white pubescence except base and apex with abundant dark-brown pubescence not obscuring integument; dorsal surface of metatarsomeres I with dense yellowish-white pubescence except abundant dark-brown pubescence not obscuring integument on apex; basal 3/4 of pro- and mesotarsomeres II with dense yellowish-white pubescence on wide central area and abundant dark-brown pubescence not obscuring integument on remaining surface; metatarsomeres II with dense yellowish-white pubescence except abundant dark-brown pubescence not obscuring integument on apex; dorsal surface of basal 2/3 of tarsomeres III with abundant yellowish-white pubescence not obscuring integument and remaining surface with moderately abundant dark-brown pubescence not obscuring integument; dorsal surface of tarsomeres IV mostly glabrous; dorsal surface of tarsomeres V with dense yellowish-white pubescence except apex with moderately abundant brown pubescence not obscuring integument.

Abdomen. Ventrites 1–4 with dense yellowish-brown pubescence laterally, with irregular glabrous areas interspersed; basal half of central area of ventrite 1 with dense yellowish pubescence and remaining surface with abundant yellowish-white pubescence not obscuring integument; central area of ventrite 2 with abundant yellowish-white pubescence basally, pubescence gradually sparser, whiter toward glabrous apex; central area of ventrites 3–4 with whitish pubescence not obscuring integument, pubescence slightly more abundant on basal quarter of ventrite 3, except glabrous apices; ventrite 5 with moderately sparse yellowish pubescence on basal half and centrally, pubescence denser and yellower on remaining surface; apex of ventrite 5 distinctly concave.

Dimensions (mm) (holotype male/ paratype male). Total length, 12.70/13.15; prothoracic length, 1.80/2.35; anterior prothoracic width, 2.25/2.60; posterior prothoracic width, 2.60/3.00; maximum prothoracic width, 3.10/3.55; humeral width, 4.35/4.90; elytral length, 9.70/6.65.

Type material. Holotype male from COLOMBIA, Boyacá: Provincia del Norte , NW of Soatá, 2950 m, 6°22’03”N 72°42’54”W, 5–7.III.2017, V. Sinyaev leg. ( MZSP) GoogleMaps . Paratype male from ECUADOR, Imbabura: Cabañas Intag Colibri , 1900 m, Intag, 18 Jun 2023, J. Vlasak leg. ( JVCO) .

Etymology. The species is dedicated to Anton Kozlov ( Russia), for sending and donating the holotype to the MZSP collection; “anton” plus “ellum” (Latin, suffix (neuter), added to form a diminutive—little Anton).

Remarks. Nealcidion antonellum sp. nov. is similar to N. lineatum ( Bates, 1863) (see photographs on Bezark (2025), in Santos-Silva et al. (2021), and Vlasak & Santos-Silva (2022)) by the pubescence pattern. However, it differs as follows: lateral protuberance of prothorax more projected and area behind it more abruptly narrowed; apical area of elytra abruptly narrowed and subparallel-sided; dark elytral spots with short tuft of erect dark setae; and prosternal process inverted Y-shaped. In N. lineatum , the lateral protuberance of the prothorax is slightly projected and the area behind it is not abruptly narrowed, the apical area of elytra is gradually narrowed and not subparallel-sided, the dark spots on elytra are without tuft of erect setae, and the prosternal process is not Y-shaped. It differs from N. apunctatum Vlasak & Santos-Silva, 2024 (see photographs on Bezark (2025) and in Vlasak & Santos-Silva (2024)) by the slender body (stouter in N. apunctatum ), scape abruptly widened ventrally near base (not so in N. apunctatum ), and the prosternal process inverted Y-shaped (not so in N. apunctatum ); from N. calcaratum Vlasak & Santos-Silva, 2022 (see photographs on Bezark (2025) and in Vlasak & Santos-Silva (2022)) especially by the protarsomeres I–II without ventral modifications (present in males of N. calcaratum ); from N. scutellatum (Bates, 1881) (see photographs on Bezark 2025) by the femoral clubs distinctly narrower (stouter in males of N. scutellatum ), and elytra with proportionally small dark macula on half of elytra (with large dark macula in N. scutellatum ); and from N. sublineatum Vlasak & Santos-Silva, 2022 (see photographs on Bezark (2025) and in Vlasak & Santos-Silva (2022)), by the slender body (stouter in N. sublineatum ), and the prosternal process inverted Y-shaped (not so in N. sublineatum ).