Tybalmia diffusa, Vlasak & Santos-Silva, 2023

Vlasak, Josef & Santos-Silva, Antonio, 2023, New descriptions, synonymies and records in South American Lamiinae (Coleoptera, Cerambycidae), Zootaxa 5284 (1), pp. 153-166 : 158-161

Tybalmia diffusa sp. nov.

( Figs 11–18 , 38–42 )

Description. Holotype male ( Figs 11–15 ). Integument mostly blackish; anteclypeus partially testaceous; anterior region of labrum testaceous; pedicel blackish basally, dark brown on remaining surface; antennomeres III–V dark brown, blackish on apex; antennomeres VI–XI dark brown basally, blackish on remaining surface.

Head. Frons parallel-sided; somewhat sparsely and coarsely punctate; with dense, longitudinal yellow pubescent band close to eyes, these bands following toward frontal region of antennal tubercles; with abundant yellow pubescence not obscuring integument on remaining surface, pubescence paler than that on area close to eyes, except glabrous median groove. Antennal tubercles elevated; slightly inclined inward, projected forward, with blunt apex; frontal region with sparse yellow pubescence laterally, with short, erect dark setae interspersed; remaining surface with pubescence slightly more abundant than on sides of frontal region, except central yellow pubescent band on frontal region. Area between antennal tubercles and upper eye lobes with transverse, shallow, glabrous sulcus, straight centrally, arched laterally, reaching superior region of upper eye lobes, forming a cross with median groove; with abundant yellow pubescence not obscuring integument, except glabrous central area, glabrous area bifid anteriorly, diamond shaped on remaining surface. Remaining surface of vertex and area behind eyes with dense yellowish-brown pubescence, except longitudinal brownish pubescent band on each side of median groove, from area near transverse anterior sulcus to near prothorax, gradually widened toward its posterior region, glabrous median groove, and central area behind upper eye lobes with pubescence slightly less dense, and central area behind lower eye lobes with distinctly sparser pubescence. Genae sparsely, finely punctate, except smooth apex and part of area close to eye; with moderately abundant yellowish-brown pubescence toward ventral surface, sparse frontally, except glabrous smooth areas. Wide central area of postclypeus with abundant, bristly yellow pubescence not obscuring integument, and long, erect setae of same color interspersed close to anteclypeus, some erect setae blackish basally. Sides of postclypeus glabrous. Labrum coplanar with anteclypeus at posterior 3/4, abruptly inclined at posterior area of anterior quarter, and almost vertical close to anterior margin; moderately sparsely, finely punctate on posterior 3/4, punctures slightly denser and coarser close to inclined area, smooth on anterior quarter; posterior 3/4 with somewhat sparse pale-yellow pubescence, slightly denser laterally, except glabrous longitudinal central area, and long, erect setae interspersed close to anterior quarter, setae blackish with yellowish-brown apex; anterior quarter glabrous on its posterior region, with somewhat abundant yellowish-white pubescence not obscuring integument close to anterior margin, and with dense, long golden setae directed forward laterally. Distance between upper eye lobes 0.21 times distance between outer margins of eyes; in frontal view, distance between lower eye lobes 0.48 times distance between outer margins of eyes. Antennae 2.75 times elytral length, reaching elytral apex at middle of antennomere VI. Scape distinctly clavate; coarsely rugose on anterior quarter of sides and ventral surface; with abundant yellowish-brown pubescence not obscuring integument on anterior 2/3, slightly sparser yellowish-white pubescence on posterior third of sides and ventral surface, almost glabrous on posterior third of dorsal surface; with sparse, moderately long, erect dark-brown setae ventrally, erect setae absent on apical region. Pedicel with somewhat abundant, short, erect dark-brown setae basally, and abundant light yellowish-brown pubescence on remaining surface; ventral surface with long, erect dark-brown setae interspersed. Anterior quarter of antennomere III and anterior third of IV with yellowish-brown pubescence, pubescence denser on outer side; remaining dorsal and lateral surfaces with abundant brownish pubescence not obscuring integument, except apex with sparser yellowish-brown pubescence; remaining ventral surface with abundant yellowish-white pubescence not obscuring integument, distinctly sparser close to apex; with abundant, long, erect dark-brown setae interspersed ventrally, erect setae denser on III. Antennomere V–XI with dense whitish pubescence basally, and abundant brownish pubescence not obscuring integument on remaining surface; V and XI with sparse, long, erect dark-brown setae interspersed ventrally; VI–VII with a few long, erect dark-brown setae interspersed ventrally. Antennal formula based on length of antennomere III: scape = 0.67; pedicel = 0.12; IV = 0.71; V = 0.63; VI = 0.60; VII = 0.57; VIII = 0.57; IX = 0.56; X = 0.60; XI = 0.81.

Thorax. Prothorax wider than long; anterior and posterior constrictions well marked; sides slightly divergent from anterior sulcus to lateral tubercles, parallel-sided from lateral tubercles to posterolateral angles; lateral tubercles somewhat large, rugose basally, conical apically, starting about middle and ending on posterior fifth. Pronotum with two moderately wide and shallow transverse sulci, anterior one sinuous, located between sulcus of anterior constriction and apex of anterior quarter, posterior one starting on posterior region of lateral tubercles of prothorax; area between these two sulci with two transverse gibbosities on each side, anterior one slightly more elevated, and longitudinal gibbosity centrally; somewhat abundantly, coarsely punctate, punctures distinctly sparser and shallower on central region of anterior 3/4; center of anterior 2/3 with longitudinal, partially fragmented yellowish-brown pubescent band, distinctly widened from its basal area; sides with dense yellowish-brown pubescence, with abundant, small, glabrous or subglabrous spots interspersed, except base of lateral tubercles of prothorax with grayish-white pubescence, area close to lateral tubercles of prothorax with sparser yellowish-white pubescence, preceded by irregular glabrous area, sides of area between lateral tubercles of prothorax and sulcus of posterior constriction without glabrous or subglabrous areas interspersed; lateral yellow pubescence obliquely projected toward central region on posterior third, and following longitudinally toward sulcus of posterior constriction; remaining surface with abundant brownish pubescence partially obscuring integument, with sparse, short, decumbent yellowish-white pubescence interspersed; lateral tubercles of prothorax and area behind them with long, erect dark-brown setae interspersed. Sides of prothorax with lateral tubercles surrounded by glabrous sulcus; remaining surface somewhat rugose, sparsely, coarsely punctate; with dense yellowish-brown pubescence with abundant glabrous or subglabrous spots interspersed. Prosternum with dense yellowish-brown pubescence laterally on posterior half, then with somewhat sparse yellowish-brown pubescence laterally toward anterior sulcus; central region almost glabrous, and anterior sulcus entirely glabrous. Sides of prosternal process strongly divergent toward apex; narrowest area 0.26 times procoxal width; with abundant pale yellowish-brown pubescence not obscuring integument on anterior 3/4, sparser, yellowish white on posterior quarter, except fringe of yellowish-brown setae on apex. Mesoventrite with dense yellowish-brown pubescence laterally, abundant yellowish pubescence centrally, pubescence longer and more abundant anterocentrally. Mesanepisternum with dense yellowish-brown pubescence, except large, irregular central area with shorter, sparser dark pubescence with yellowish-brown pubescence interspersed. Mesepimeron with dense yellowish-brown pubescence, except narrow yellowish-white pubescent band close to metanepisternum. Mesoventral process slightly concave centrally on anterior half, concavity distinctly coarser on posterior half; apex emarginate centrally; sides slightly concave on anterior half, subparallel-sided on posterior half; with abundant yellowish pubescence not obscuring integument close to margins, pubescence sparser and more yellowish white centrally. Metanepisternum with dense yellowish-brown pubescence, except part of anterior third with sparser pubescence. Metaventrite with abundant yellowish-brown pubescence almost obscuring integument, except large, oblique dense band on sides, anterior third close on each side of central region partially with whitish pubescence, anterolateral areas with dark pubescence with yellowish-brown pubescence interspersed, and glabrous metathoracic discrimen. Scutellum with dense yellow pubescence, except subtriangular anterocentral region with dark pubescence partially obscuring integument. Elytra. Humerus with a single, elongate, glabrous, smooth tubercle; anterior fifth under humerus coarsely rugose-punctate; anterior quarter of dorsal surface sparsely rugose-punctate; remaining surface finely, very sparsely punctate; with dense greenish-brown pubescence, except sparser brownish pubescent band surrounding scutellum, narrowly, longitudinally projected along suture on anterior fifth, and subglabrous spots surrounding punctures, part of them fused on anterior third, and two large, subelliptical maculae with dark-brown pubescence dorsally just after middle. Legs. Procoxae ( Fig. 15 ) with large, conical tubercle. Femora with abundant yellowish-brown pubescence partially obscuring integument dorsally and laterally, except dark greenish-brown pubescent maculae on dorsal surface of posterior half, with short, decumbent yellowish-brown setae interspersed, and apex with yellower pubescence; ventral surface with sparser yellowish-brown pubescence; sides and ventral surface of profemora coarsely, transversely rugose. Protibiae with dense yellowish-brown pubescence, except posterior 2/3 of ventral surface with dense, bristly dark-brown pubescence; dorsal surface and sides with moderately sparse and long, erect dark setae interspersed. Anterior 2/3 of mesotibiae and anterior 3/4 of metatibiae with dense yellowish-brown pubescence; sides of posterior third of mesotibiae and posterior quarter of metatibiae with sparser yellowish-brown pubescence; dorsal and ventral surfaces of posterior third of mesotibiae and posterior quarter of metatibiae with dense, bristly dark-brown pubescence. Dorsal surface of tarsomeres mostly with yellowish-white pubescence partially obscuring integument.

Abdomen. Ventrites with dense yellowish-brown pubescence and irregular dark-brown pubescent areas interspersed, except glabrous central apex of ventrites 1–4, glabrous area smaller on ventrite 1 than on ventrites 2–4. Apex of ventrite 5 rounded, slightly concave centrally.

Female ( Figs 16–18 ). Similar to male, differing by the antennal tubercles not projected dorsally; shorter antennae, 1.9 times elytral length, reaching elytral apex at posterior third of antennomere VII; scape slightly widened from anterior third; humeral tubercle not elongated; and ventrite 5 with narrow sulcus on anterocentral half, and slightly depressed on center of posterior third.

Variation. Shape and size of elytral dark macula on posterior half of elytra very variable in both sexes ( Figs 38–42 ); scutellum almost entirely covered with dense yellow pubescence.

Dimensions (mm) (holotype male/ paratype males/ paratype females). Total length, 23.05/19.6–21.70/23.20– 24.15; prothoracic length, 3.40/3.35–3.60/3.20–3.75; anterior prothoracic width, 5.05/4.65–4.90/4.85–5.20; posterior prothoracic width, 5.45/4.90–5.60/5.45–5.50; maximum prothoracic width, 6.55/5.75–6.45/6.35–6.70; humeral width, 8.60/7.70–8.55/9.20–9.35; elytral length, 16.15/13.55–15.15/17.10–18.25.

Type material. Holotype male from ECUADOR, El Oro: 600 m, rt. 585, 15 km W of Piñas , 1-3.VIII.2021, J. Vlasak leg. ( MZSP) . Paratype female, same data as holotype ( MZSP), 4 paratype males and 1 paratype female , same data as holotype ( JVCO) .

Etymology. The specific epithet “diffusa” (Latin, meaning spread or disseminated) refers to the distribution of the small dark maculae on the elytra. In T. diffusa , the maculae are more evenly distributed across elytra, while in the other species of the genus they are concentrated and often fused together in the basal quarter.

Remarks. Tybalmia diffusa sp. nov. is similar to T. caeca Bates, 1872 , but differs by the antennal tubercles in males slightly inclined inward (not inclined inward in males of T. caeca ), and anterior quarter of the elytra not densely granulate-punctate in both sexes (anterior quarter of the elytra granulate-punctate in both sexes in T. caeca ). The new species differs from T. tetrops Bates, 1872 by the pronotum without three small dark spots arranged triangularly on center of the pronotum (present in T. tetrops ), basal quarter of the elytra not densely granulate-punctate (densely granulate-punctate in T. tetrops ), and dorsal surface of the elytra with a single and large dark macula about middle and not preceded by yellowish pubescence (with two smaller dark maculae preceded by yellowish pubescence in T. tetrops ). Tybalmia diffusa sp. nov. differs from T. pixe Dillon & Dillon, 1945 by the frons without dense yellowish pubescent band on center of superior region, distinctly contrasting with the pubescence close to it (present in T. pixe ), absence of yellowish pubescent macula close to the dark macula on posterior half of elytra or, at most, with slightly distinct yellowish pubescent macula in some specimens (present and distinct in T. pixe ), basal third of elytra not densely asperate (densely asperate in T. pixe ), and apex of the scutellum slightly wider than the maximum diameter of the scape (narrower in T. pixe ).

Figures

FIGURES 11–18. Tybalmia diffusa sp. nov. 11–15) Holotype male: 11) Dorsal habitus; 12) Ventral habitus; 13) Lateral habitus; 14) Head, frontal view; 15) Pro- and mesocoxae; prosternal and mesoventral processes. 16–18) Paratype female: 16) Head, frontal view; 17) Dorsal habitus; 18) Ventral habitus.

FIGURES 38–42. Tybalmia diffusa sp. nov., paratypes, dorsal habitus: 38–41) Males; 42) Female.