Thoracibidion mariavanessae, Noguera, 2025

Thoracibidion mariavanessae new species

( Figs. 1–4 View FIGURES 1–4 , 5–8 View FIGURES 5–8 )

Type material. Holotype male. MEXICO, Jalisco, Centro Ecoturístico Amixtlán , Municipality of San José del Carmen, 19°30’16.52”N, 103°42’49.08”W, 18-VI-2015, active at night on dead tree, Cols. N. Gutiérrez and F. A. Noguera ( CNIN) GoogleMaps . Paratypes, 1 male, 1 female, same data as holotype ( EBCC) GoogleMaps .

Diagnosis. Individuals of this species are very similar to those of Thoracibidion pleurostictum (Bates, 1885) , but they differ from them by the following characters: the pronotal disc is completely covered with dense pale-golden pubescence that obscures the integument, except for a longitudinal, glabrous fusiform band between the anterior tubercles, from the anterior depression to posterior third, and with four very short transverse carinae only on glabrous area; the elytra are about three times longer than the prothorax and have a narrow dark-brown band on the apex that slightly extends upward close to the suture. In T. pleurostictum ( Figs. 9–12 View FIGURES 9–12 and 13–15 View FIGURES 13–15 ), individuals have a glabrous, subtriangular, glabrous area on the pronotal disc that is distinctly wider, extending from the middle of the anterior depression obliquely to the anterior tubercles and then descending vertically on the posterior tubercles, and has a greater number of transverse carinae both in front of and behind the middle callus, extending along the glabrous area on the disc; the elytra is about 2.5 times longer than the prothorax, and the dark area of the elytral apex is larger.

Description. Holotype male ( Figs. 1–4 View FIGURES 1–4 ). Integument mostly shiny dark brown; elytra light yellowish brown except dark-brown triangular macula dorsally, from base to anterior quarter, reaching suture, another subtriangular dark-brown macula on middle, from epipleural margin to side of dorsal surface, one narrow dark-brown band apically, projected upward close to suture on posterior sixth, and a longitudinal dark-brown band on anterior quarter, located beneath humerus and adjacent to epipleural margin.

Head. Frons inclined anteriorly inward, areolate-rugose, with sparse, fine, translucent, whitish, and pale brightyellowish pubescence not obscuring integument. Median groove reaching postclypeus anteriorly and extending to vertex posteriorly, deeper between antennal tubercles and slightly raised between upper eye lobes. Frontoclypeal sulcus deeply curved, extending to pretentorial pits. Anteclypeus and postclypeus transversely depressed, forming a moderately raised keel between them, both glabrous and smooth, except for a widely scattered erect setae. Labrum transversely angled on basal third and with lateral and apical margins curved. Interantennal space wide, 1.7 times the width of one upper ocular lobe, strongly depressed, with a median longitudinal elevation on each side extending from base of antennal tubercle to middle of frons. Antennal tubercles prominent, with thickened upper margins and internal apex with a prominent triangular projection with subacute apex. Upper interocular space with an elongated depression on each side of median groove, extending from base of antennal tubercle to apex of eye. Vertex areolate-rugose, with pubescence similar to that on frons, which disappears close to prothorax. Lower eye lobes prominent, with coarse ommatidia. Genae triangular, with a rounded apex, 0.4 times the width of lower eye lobe. Upper ocular lobes with three rows of ommatidia, separated by 2.5 times their width. Antennae 1.9 times longer than body, extending beyond elytral apex about middle of seventh antennomere; with fine pale-gray and pale-yellowish pubescence, sparser toward apical segments, except scape and pedicel with very sparse pubescence, with dorsal portion of scape almost glabrous; from pedicel to seventh antennomere with a fringe of erect setae on ventral margin, sparser toward seventh, scape with erect setae only on basal third and antennomeres eight to ten with an erect seta on each side of apex. Scape pyriform, with a longitudinal depression dorsally on basal third, deep on base and shallower toward its apex; pedicel constricted basally; antennomeres third to sixth with a distinct, defined dark longitudinal carina dorsally; last antennomere slightly curved. Antennal formula based (proportion) on length of antennomere III: scape = 0.48; pedicel = 0.20, IV = 0.93, V = 0.96, VI = 1.03, VII = 1.00, VIII = 0.96, IX = 0.93, X = 0.86, XI = 1.20.

Thorax. Prothorax 1.6 times longer than wide; sides nearly straight, slightly constricted posteriorly. Pronotum with a broad, transverse depression on posterior third and another narrower, bisinuate anteriorly; disc with four tubercles: two on middle, subconical and slightly prominent, and two adjacent to posterior depression, slightly more lateral than the former, oblique, slightly curved, and formed by two contiguous rough areas; a very slightly prominent median callus, narrow, ovoid, with shallow, irregular rugosities, and four moderately elevated, transverse carinae behind median callus; with dense pale-golden pubescence obscuring integument except for a longitudinal, glabrous fusiform band between the anterior tubercles, from the anterior depression to posterior third. Prosternum longitudinally convex; anterior half with a semicircular glabrous area with fine, low transverse rugosities that extend to the sides of the prothorax, where it is bordered posteriorly by a carina; remainder surface covered with dense pubescence similar to that of pronotum, but somewhat shorter. Prosternal process narrow, 0.15 times width of procoxal cavity at mid-height, longitudinally depressed, with curved and elevated lateral margins, distinctly narrowed centrally, strongly widened apically, and with rounded apex; covered with dense pale-golden pubescence. Mesoventrite sloping, slightly longitudinally convex, centrally as long as width of mesocoxa, with dense pale-golden pubescence. Mesanepisterna and mesepimera with pubescence as on mesoventrite. Mesoventral process 0.6 times width of mesocoxa at its mid-section, with curved sides, strongly widened distally, apex truncate and semicircular notched centrally; with dense pale-golden pubescence. Metaventrite with discrimen not reaching anterior margin; with dense pale-golden pubescence, except glabrous area close to discrimen, which has scattered few shallow punctures, each with a long, semi-erect setae. Elytra 3.5 times longer than wide, parallel-sided on anterior 2/3, curved, gradually narrowed toward apex on posterior third; apex emarginate, with short triangular projection on sutural angle and spine-like projection on outer angle; without pubescence except for a few pubescence on epipleural margin and apex; finely punctate, each puncture with long, sub-erect seta, setae shorter and more superficial toward elytral apex, arranged serially in four clearly defined lines on disc from near anterior margin to almost apex. Legs. Profemur strongly widened on middle; with a broad and moderately deep depression from base to middle of ventral surface; with moderately dense pale-golden pubescence except glabrous ventral surface which has very sparse sub-erect setae; meso- and metafemur moderately pedunculate; with basal half laterally flattened; covered with dense pale-golden pubescence and sub-erect setae throughout, more abundant on dorsal and ventral sides. Protibia curved, with a dark carina on inner and outer sides extending from base to middle; covered with short, sub-erect setae throughout and long setae interspersed; meso- and metatibia straight, with a dark carina on inner and outer sides extending from base to near apex; with sparse pubescence on outer side and abundant, long, sub-erect setae on inner side and dorsal and ventral surfaces. Dorsal surface of tarsi with short, sub-erect pale-golden setae and some long setae interspersed; protarsi with the first segment shorter than II–III combined; meso- and metatarsi with first segment longer than II–III combined.

Abdomen. Ventrites with pale-gray, shiny, sericeous pubescence obscuring integument, except central apex of first four ventrites, which are glabrous and have numerous long, sub-erect setae; remaining surface of all ventrites sparse, long, erect setae somewhat more abundant toward sides; fifth ventrite slightly shorter than fourth, with a rounded apex.

Female ( Figs 5–8 View FIGURES 5–8 ). Similar in shape to male but differs as follows: antennae 1.2 times longer than body, extending beyond apex of elytra about middle of ninth antennomere; with antennal formula based (proportion) on length of antennomere III: scape = 0.51; pedicel = 0.18, IV = 0.75, V = 0.84, VI = 0.81, VII = 0.84, VIII = 0.66, IX = 0.63, X = 0.57, XI = 0.66; fifth abdominal ventrite longer than fourth and with a superficial, transverse oval depression on last third.

Etymology. This species is dedicated to María Vanessa, my life partner for the past twenty years. Together, we have shared both the joys and challenges of life and have raised five wonderful children. I am deeply grateful to her for all of it.

Dimensions in mm. Holotype male, total length, 15.0; prothoracic length, 3.1; basal prothoracic length, 2.0; humeral width, 3.0; elytral length, 9.5. Paratype female, total length, 15.4; prothoracic length, 3.0; basal prothoracic length, 2.1; humeral width, 3.0; elytral length, 10.2. Paratype male, total length, 15.7; prothoracic length, 3.4; basal prothoracic length, 2.3; humeral width, 3.2; elytral length, 9.9.

Remarks. This species represents the northernmost record of the genus Thoracibidion recorded to date. Thoracibidion buquetii (Thomson, 1867) is recorded from Mexico, but without any known locality so far ( Monné 2024), and T. pleurostictum is recorded only from the state of Chiapas ( Monné 2024).

Regarding T. pleurostictum , individuals of this species show variation throughout their known distribution (see Fig. 13–15 View FIGURES 13–15 ), with the integument ranging from reddish-brown to dark brown or fuscous, and the spots on the middle and apex of the elytra varying in size and shape. However, the width of the glabrous area on the pronotal disc and the length and number of transverse carinae on this area are consistent among the individuals observed.