Hylotribus humeralis, Roza & Mermudes, 2019

Roza, André Silva & Mermudes, José Ricardo Miras, 2019, Three new species of Hylotribus Jekel, 1860 from Brazil, with new records and discussion of species relationships and wing variation within the genus (Coleoptera Anthribidae), Zootaxa 4711 (1), pp. 140-156 : 142-144

Hylotribus humeralis sp. nov.

( Figs 1–5 )

Etymology. Humeralis, from Latin humero (shoulder), refers to the prominent humeri of the elytra with dense yellow scales.

Diagnosis. Frons ( Fig. 3 ) with narrow light yellow spots on each side of inner margin of eye and middle of vertex. Pronotum ( Figs 1 and 4 ) with posteriorly oriented median tubercle and with longitudinal pale yellow stripe divided obliquely into two beyond anterobasal carinae, forming an inverted V-shaped pattern reaching posterior margin of pronotum; each side of yellow stripe with irregular black spot formed by black scales. Elytral humeri ( Figs 1–2 ) with tufted pale yellow scales.

Description, male. Measurements (n =2): TL = 2.9–3.4 mm (average = 3.1 mm); RL = 0.6–0.7 mm (average = 0.65 mm); RAW = 0.5 mm; RBW = 0.4 mm; PL = 0.9–1.0 mm (average = 0.95 mm); PW = 1.1–1.2 mm (average = 1.15 mm); EL = 1.8–2.0 mm (average = 1.9 mm); EW = 0.7 mm.

Vestiture. Integument black ( Figs 1–5 ). Dorsal vestiture ( Figs 1–5 ) with predominant semi-decumbent blackbrownish scales intermingled with decumbent yellow and whitish scales, moderately denser on pronotum and elytra. Pronotum and elytra with semi-decumbent black scales on tufted tubercles, lateral base of pronotum and middle of elytra. Frons ( Fig. 3 ) with narrow yellow stripe on each side of inner margin of eye and middle of vertex, with some sparse yellow scales along rostrum. Antennae with some sparse elongate and white setae, shorter and more concentrated on club. Pronotum with three tubercles tufted with elongate and black scales; median tubercle ( Figs 4–5 ) with longitudinal pale yellow stripe posteriorly extended, divided obliquely in two beyond anterobasal carinae, forming an inverted V-shaped pattern reaching posterior margin of pronotum; each side of yellow stripe with irregular black spot formed by black scales. Scutellar shield ( Fig. 1 ) with anteriorly oriented, elongate, suberect and sparse brownish-black scales. Elytra ( Figs 1–2 ) with sparse decumbent white to pale yellow scales; humeri with tufted pale yellow scales, on interstria 1 with alternate dark and pale yellow vestiture, darker areas longer than yellow gap; basal tubercles with sparse pale yellow scales on anterior surfaces, with pair of irregular black stripes, oblique and posteriorly extended from the basal tubercles, diverging and reaching outer margin in middle of elytra; with a second pair of stripes having same shape, on interstria 1 in middle of elytra (divided or not) diverging to outer margin but only reaching half of elytra in four-fifths of its length. Ante-apical tubercle tufted with black scales, irregularly reaching sutural margin; without any black transverse stripe. Ventral side and legs ( Figs 1–2 ) with decumbent and white scales, moderately dense; femora and tibiae with two white ring-shaped transverse stripes.

Morphology. Head 1.5 times as wide as width of rostrum at base. Head and rostrum strongly punctate-corrugate. Rostrum ( Figs 1–3 ) moderately long, 1.2 to 1.4 times longer than wide, 1.5 times longer than head length, slightly depressed near frons, with prominent longitudinal carinae. Antennae ( Fig. 1 ) with segments I and II moderately thick; III 1.5 times longer than II; IV–VIII progressively smaller, club robust.

Pronotum ( Figs 1 and 4 ) slightly wider than long, subplane and punctate-corrugate, with three tubercles at transverse midline, the central tubercle evidently more developed. Ante-basal carinae almost straight, 3-fragmented. Elytra ( Figs 1–2 ) almost three times longer than wide; with prominent humeral callus, epipleura vertical and flattened; basal gibbosities formed by elongate and narrow interstriae 1–3, slightly more developed and subrounded at top; posteriorly to the middle with one tubercle moderately developed on interstria 3; with two ante-apical tubercles less developed, moderately acute at apex of interstriae 3 and 5. Macropterous.

Ventrites I–III subequal in length at middle, each one slightly longer than IV. Ventrite V 1 /3 times longer than IV, amply impressed at disc, subtruncate at apex.

Female. Unknown.

Biology and distribution. Hylotribus humeralis sp. nov. occurs during the Southern Hemisphere summer, in December. It inhabits high altitude areas of PARNASO, in Rio de Janeiro State, around 2,120 m. It occurs in the “Campos de Altitude”.

Remarks. Hylotribus humeralis sp. nov. ( Figs 1–5 ) is easily distinguished from the rest of this group by the vestiture of the pronotum ( Fig. 4 ). The median tubercle is clothed by a longitudinal pale yellow stripe that is posteriorly oriented and obliquely divided into two, and which passes the anterobasal carinae and forms an inverted V-shaped pattern reaching the posterior margin of the pronotum (present otherwise only in Hylotribus queirozi sp. nov., which lacks the elytral humeri with lateral tufted pale yellow scales). Each side of the yellow stripe has an irregular black spot formed by black scales. Additionally, on the elytra, the humeri have tufted pale yellow scales, the basal tubercles are slightly more developed than the two ante-apical tubercles along interstria 3 (developed and robust basal and ante-apical tubercles occur in H. fluminensis , and ante-apical tubercles are more developed than the basal tubercles in H. sublimis and H. gauchus ), and there are no secondary tubercles or white tuft of pilosity on interstria 3 or 5 ( H. fluminensis , H. sublimis and H. gauchus have white tufts of pilosity on interstria 3 and 5). Furthermore, a black transverse stripe between the ante-apical tubercles of the elytra is present in H. fluminensis , H. sublimis and H. gauchus , but lacking in H. humeralis .

Type material. Holotype: BRAZIL. Rio de Janeiro. Teresópolis. Parque Nacional da Serra dos Órgãos. PVE Pt. 14A, 22° 27’ 37.3” S, 43° 01’ 39.3” W, 2127m, 1 male, XII.2014, R. Monteiro col. ( DZRJ) . Paratype: BRAZIL. Rio de Janeiro. Teresópolis. Parque Nacional da Serra dos Órgãos. PVE Pt. 14B, 22° 27’ 37” S, 43° 01’ 37.4” W, 2125m, 1 male, XII.2014, R. Monteiro col. ( DZRJ) .

Figures

FIGURES 1–5. Hylotribus humeralis sp. nov., holotype male from Brazil, Teresópolis-RJ. 1. Habitus, dorsal; 2. Habitus, lateral; 3. Head and rostrum, frontal; 4. Pronotum; 5. Prothorax, lateral.