Hylotribus nanico, 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 : 144-147

Hylotribus nanico sp. nov.

( Figs 6–10 )

Etymology. Nanico is a popular Brazilian word. From greek nános means ‘dwarf’, or Latin nanus + -ico, which refers to the one that has the smaller appearance or the low body stature, like that of a dwarf. The name is a noun in apposition.

Diagnosis. Dorsum of rostrum ( Fig. 8 ), frons and anterior middle of vertex with dense yellow and decumbent scales. Pronotum ( Figs 6 and 9 ) with moderately denser yellow scales on median third, forming longitudinal medial stripe reaching lateral tubercles of pronotum and which is larger anteriorly and with a subtriangular black spot. Femora ( Fig. 7 ) with dark integumental area at proximal two thirds, and on tibia at middle; femora and tibia with dense yellow scales, tibiae with brownish scales at middle third. Ventral vestiture ( Fig. 7 ) with each side of ventrites I–IV with subrounded dark spot with dense brownish scales. Elytra ( Figs 6–7 ) with humeral callus on interstria 8 and slight swelling on slightly costate interstria 7; basal gibbosities moderately wide and acute at top, subequal in size to ante-apical tubercles of interstria 3; interstria 5 slightly swollen in middle; apical declivity with a moderately developed tubercle on each of interstriae 4 and 6, these moderately acute at apex, and linked by an intumescence that reaches interstria 9 at apex.

Description, female. Measurements (n =2): TL = 2.9–3.3 mm (average = 3.1 mm); RL = 0.5–0.6 mm (average = 0.55 mm); RAW = 0.6–0.7 mm (average = 0.65 mm); RBW = 0.5–0.6 mm (average = 0.55 mm); PL = 1.1–1.3 mm (average = 1.2 mm); PW = 1.2–1.5 mm (average = 1.35 mm); EL = 1.8–1.9 mm (average = 1.85 mm); EW = 0.8 mm.

Vestiture. Integument black ( Figs 6–10 ), antennae, tibiae and tarsi brown; antennal club yellowish-brown. Dorsum of rostrum ( Fig. 8 ), frons and anterior middle of vertex with dense yellow and decumbent scales. Posterior edge of head subglabrous. Antennae with some elongate and sparse light yellow setae, shorter and more concentrated on club. Pronotum ( Figs 6 and 9 ) with moderately denser yellow scales on median third, forming a longitudinal middle stripe reaching lateral tubercles of pronotum and anterobasal carina, and which is larger anteriorly and with a subtriangular black spot; lateral tubercles tufted with suberect black-brownish scales, median tubercle with yellow and brownish suberect scales; posterior declivity of pronotum with large and well defined stripe, almost quadrangular, clothed by yellowish scales; each side with irregular black spots. Scutellar shield ( Fig. 6 ) with elongate, suberect sparse brownish-black scales, anteriorly oriented. Elytra ( Figs 6–7 ) with yellow to white vestiture denser on anterior two thirds; humeri whiter, with tufted and denser pale yellow scales; interstria 1 with alternate dark and pale yellow vestiture, darker areas longer than yellow gaps; basal tubercles tufted with pale yellow and black-brownish scales; ante-apical tubercles with a distinct transverse dark stripe between them; apical third of elytra and pygidium with dense black-brownish scales. Femora ( Fig. 7 ) with dark integumental area at proximal two thirds, and on tibia at middle; femora and tibia with dense yellow scales, tibiae with brownish scales at median third. Ventral vestiture ( Fig. 7 ) with moderately dense yellow scales, each side of ventrites I–IV with subrounded dark spot with dense brownish scales. Ventrite V with suberect black-brownish scales.

Morphology. Head ( Fig. 8 ) 1.3 times as wide as width of rostrum at base. Head and rostrum microsculpture obliterated by vestiture. Rostrum short, as wide as long, as long as head length, slightly depressed near frons, with prominent longitudinal carinae. Antennae ( Fig. 6 ) with segments I and II moderately thick; III as long as II; IV–VIII progressively shorter, VIII subequal to half of IX, club robust.

Pronotum ( Figs 6 and 9 ) slightly wider than long, coarsely punctate, the punctures partially obliterated by vestiture; with three tubercles at transverse midline, the central tubercle slightly more developed, others at sides almost indistinct. Ante-basal carinae 2-fragmented, clearly sinuous and elongate at middle, with lateral segment short and curved. Prosternum subplane and punctate-corrugate. Scutellar shield ( Fig. 6 ) subtriangular. Elytra ( Figs 6–7 ) with humeral callus on interstria 8, and slight swelling on slightly costate interstria 7; basal gibbosities on interstria 3 moderately wide and acute at top, subequal in size with ante-apical tubercles; interstria 5 slightly swollen in middle; apical declivity with two moderately developed tubercles on interstriae 4 and 6, these moderately acute at apex and linked by an intumescence that reaches interstria 9 at apex. Apterous (checked in one specimen with raised elytra). Ventrites I–III at middle subequal in length; IV very short. Ventrite V two times longer than IV, slightly truncate at apex.

Male. Unknown.

Biology and distribution. Hylotribus nanico sp. nov. occurs during the Southern Hemisphere spring (November) and autumn (April), possibly occurring also in summer. It inhabits high altitude areas of PARNASO, in Rio de Janeiro State, between 1,812 m and 1,935 m. It occurs in the high-montane forest.

Remarks. Hylotribus nanico sp. nov. ( Figs 6–10 ) differs from other species in the genus in the diagnostic characters cited above, but mainly by the vestiture of rostrum and frons, the apical declivity with two moderately developed tubercles on interstriae 4 and 6 that are moderately acute at the apex and linked by an intumescence that reaches interstria 9 at apex, and the subrounded dark spot clothed with dense brownish scales on each side of ventrites I–IV.

Type material. Holotype: BRAZIL. Rio de Janeiro. Teresópolis. Parque Nacional da Serra dos Órgãos. PVE Pt. 13B, 22° 27’ 14.3” S, 43° 01’ 13.2” W, 1935 m, 1 female, IV.2015, R. Monteiro col. ( DZRJ) . Paratype: BRA- ZIL. Rio de Janeiro. Teresópolis. Parque Nacional da Serra dos Órgãos. PVE Pt. 12A, 22° 27’ 18.2” S, 43° 00’ 58.9” W, 1812 m, 1 female, XI.2015, R. Monteiro col. ( DZRJ).

Figures

FIGURES 6–10. Hylotribus nanico sp. nov., holotype female from Brazil, Teresópolis-RJ. 6. Habitus, dorsal; 7. Habitus, lateral; 8. Head and rostrum, frontal; 9. Pronotum; 10. Prothorax, lateral.