Omotrachelus longirostris Borovec, 2023

Borovec, Roman, 2023, New data on Omotrachelus Kolbe, with description of five new species (Coleoptera; Curculionidae; Entiminae; Cneorhinini), Zootaxa 5357 (4), pp. 502-514 : 508-510

Omotrachelus longirostris Borovec sp. nov.

Figs (3, 8, 14, 20)

http://zoobank.org/ urn:lsid:zoobank.org:act:8625900D-BD27-4DE7-8835-9F0169C56D37

Type locality. Cameroon, Mt. Cameroon NP, “Drink Gari” research plot.

Type material. Holotype: ♁, Cameroon, Mt. Cameroon NP, “Drink Gari” research plot, N 04°05′58.4″ E 009°03′46.5″, 7.XII. 2021, 635 m, sifting forest litter, P. Baňař & P. Hlaváč lgt. ( MMB) . Paratypes: 73 specs., same data as holotype ( BMNH, CMNC, ECRI, JKWP, MMB, MNHN, NMPC, RBSC) .

Description. Body length 2.13–2.72 mm, holotype 2.49 mm. Body densely covered with moderately small, rounded, finely striate appressed scales, 4–5 across width of one interstria, hardly visible through incrustation. Elytral interstriae 1, 3, 5, 6 and 7 with one conspicuous, regular row of spatulate, apically broadly rounded semi-erect setae, slightly longer than half the interstria width, distance between two setae slightly longer than length of one seta; setae on interstriae 6 and 7 slightly shorter than the others. Pronotum and head with rostrum densely irregularly scattered with subspatulate, semi-appressed setae, directed anteriad, narrower and shorter than elytral ones. Antennae and legs with short, inconspicuous, narrow, semi-appressed setae, weakly prominent from outline of terminalia.

Rostrum ( Fig. 8 ) long and slender, 1.31–1.38× as long as at base wide, at base 1.05–1.08× as wide as at apex, subparallel-sided, at midlength slightly narrowest, in basal half indistinctly tapering anteriad, in apical half indistinctly enlarging anteriad, in both halves with straight sides; in lateral view regularly curved, only in short apical part dorsal margin declined. Epifrons wide, at base as wide as rostrum and 1.38–1.45× as wide as at apex, evenly tapering anteriad with slightly rounded sides, dorsally flat, with shallow longitudinal depression at base. Frons short, smooth, glabrous, somewhat prominent anteriorly. Epistome short, arched. Deciduous mandibular processes strongly protruding, moderately long, sabre-shaped, equally wide along entire length, apically broadly rounded, situated just near base of mandible. Antennal scrobes in dorsal view visible only in their anterior part as very narrow and short furrows; in lateral view straight, vanishing in long distance before eye, with dorsal margin directed towards ventral margin of eye. Head moderately narrow; vertex narrow, slightly wider than space between antennal insertions, flat. Eyes vaulted, slightly prominent from outline of head; in lateral view circular, dorsally placed.

Antennae ( Fig. 3 ) short; scape slightly curved at midlength, 4.9–5.2× as long as wide, in apical half evenly slightly enlarging apicad, at apex 0.8× as wide as club. Funicle segment 1 1.8–2.0× as long as wide and 2.0–2.3× as long as segment 2, this is 1.2–1.3× as long as wide; segments 3 and 4 1.2× as wide as long; segment 5 1.3× as wide as long; segment 6 1.5–1.6× as wide as long; segment 7 1.6–1.7× as wide as long; club 1.6–1.8× as long as wide.

Pronotum ( Fig. 3 ) small, 1.47–1.53× as wide as long, widest at basal third, with distinctly rounded sides, more tapering anteriad than posteriad, with base V-shaped; in lateral view distinctly vaulted at basal two thirds and flat at anterior third. The whole area of pronotum distinctly roughly punctured with 5 large punctures across length of pronotum, space between punctures shorter than radius of puncture.

Elytra ( Fig. 3 ) long oval, 1.25–1.29× as long as wide, behind base shortly constricted, widest at midlength with regularly rounded sides, apically narrowly tapering; base weakly V-shaped; interstriae 9 with small subhumeral bump, hardly visible in dorsal view. Sutural interstriae with low, large glabrous granules at base; striae roughly punctured; odd interstriae more elevated than even ones.

Protibiae short, widest at midlentgh, 4.8–5.2× as long as wide at midlength, apically subtruncated, armed with short and stout, yellow bristles, at apical half of inner margin finely denticulate. Tarsi slender; segment 2 isodiametric; segment 3 1.5–1.6× as wide as long and 1.5–1.6× as wide as segment 2; onychium slender and long, 1.7–1.8× as long as segment 3.

Penis ( Fig. 14 ) short, subparallel-sided, apical portion distinctly three-lobed, lateral lobes narrow, sharp, triangular, middle lobe wide, rounded; in lateral view penis regularly curved, tip short, elongate, slightly curved outside. Temones long, as long as body of penis. Endophallus with two short and wide sclerites.

Spermatheca ( Fig. 20 ) with short, curved cornu; ramus and collum short, wider than long, rounded; corpus with small hump between ramus and collum. Sternite VIII with short and wide apodeme, Y-shaped terminating just at base of plate; plate moderately large, umbrella-shaped, regularly rounded apically. Gonocoxites flat, subtriangular, with long and slender apical styli.

Biology. All specimens were sifted from forest litter.

Etymology. The Latin name refers to the obviously long, subparallel-sided rostrum.

Remarks. Omotrachelus longirostris shows several unique characters within the genus such as rostrum long and slender, 1.31–1.38× as long as at base wide, antennal scrobes in lateral view hidden a long distance before eye, pronotum roughly punctured with space between punctures shorter than radius of puncture, elytral interstriae 1, 3 and 5 with conspicuous row of setae and interstriae 2 and 4 lacking setae, penis apically three-lobed and spermatheca with small hump between ramus and collum.

Figures

FIGURES 6–10. Head with rostrum in dorsal and lateral view. 6. Omotrachelus geiseri. 7. O. kaniai. 8. O. longirostris. 9. O. parallelus. 10. O. thoracomimus. Scale 0.50 mm.

FIGURES 1–4. Dorsal habitus. 1. Omotrachelus geiseri. 2. O. kaniai. 3. O. longirostris. 4. O. parallelus. Not to scale.

FIGURES 11–21. 11–16: penis in dorsal and lateral view. 11. Omotrachelus geiseri. 12. O. kaniai. 13. O. angulatus. 14. O. longirostris. 15. O. parallelus. 16. O. thoracomimus. 17–21: spermatheca. 17. O. geiseri. 18. O. kaniai. 19. O. angulatus. 20. O. longirostris. 21. O. parallelus. Scale 0.125 mm for 20, 21; 0.25 mm for 17–19; 0.50 mm for 11, 12, 14–16; 1.00 mm for 13.