Bulirschius densatus Borovec, 2025

Borovec, Roman, 2025, Two new and one enigmatic genus of Oosomini from South Africa with description of seven new species (Coleoptera: Curculionidae: Entiminae), Zootaxa 5642 (2), pp. 101-126 : 110-111

Bulirschius densatus Borovec , sp. nov.

Figs (3, 15, 16, 26, 29, 35, 40) http://zoobank.org/ urn:lsid:zoobank.org:act:2FC57B58-03F7-46C4-9C5D-5B7BC456C0DC

Type locality. South Africa, Western Cape, Swartberge, Blesberg .

Type material. Holotype: ♂, S. Afr. [ South Africa, Western Cape], Swartberge Blesberg - E, 23.25 S – 22.41 E, 2000 m, 6.xii.1978, E-Y: 1532, groundtraps, 76 days, leg. Endrödy-Younga, groundtraps with fermented banana bait ( TMSA) . Paratypes: 6 specs., same data as holotype; 6 specs., same data as holotype, but 5.xi.1978, E-Y: 1505, 41 days, groundtraps with meat bait; 1 spec., same data as holotype, but 1820 m, 33.25 S – 22.40 E, 17.xii.1978, E-Y: 1536, 75 days, groundtraps with feces bait; 16 specs., same data as holotype, but 6.xi.1978, E-Y: 1510, sifted, fynbos; 1 spec., same data as holotype, but 4.xi.1978, E-Y: 1504, collected at night (all TMSA, 1 spec. RBSC) .

Note. The coordinates are likely erroneous and should be 33°25′ S, as this latitude places the locality in Groot Swartberg Nature Reserve in the Western Cape, while 23°25′ S places locality in Botswana at an elevation of 1100 m and out of fynbos habitat. Correct coordinates 33°25′ S are stated on only one specimen from the type series .

Diagnosis. Elytra with one dense regular row of semi-erect setae on each interstria, distance between two setae slightly shorter than length of one seta; rostrum and epifrons subparallel-sided with straight sides; pronotum and elytra wide and short; abdominal ventrites glabrous; metaventral process narrow.

Description. Body length 1.88–2.75 mm, holotype 2.13 mm. Body ( Fig. 3 ) dark brownish to blackish, basal part of antennal scapes and funicles paler, reddish brown. The whole dorsal part of body densely covered by rounded appressed scales, fully covered integument, 4 scales across width of one interstria. Elytra with one dense regular row of semi-erect setae, slightly longer on posterior declivity than on disc, subspatulate, on declivity slightly longer than half width of interstria, distance between two setae slightly shorter than length of one seta. Pronotum and head with rostrum with similar setae, shorter than those on elytral disc, very densely irregularly scattered. Vestiture of appressed and semi-erect setae blackish, lacking any spots.

Rostrum ( Figs. 15, 16 ) short, 1.33–1.40× as wide as long, subparallel-sided, at base as wide as at apex, with straight sides. Epifrons narrow, subparallel-sided with straight sides, at base 0.6× as wide as rostrum in relevant part, dorsally flat, posteriorly with moderately deep transverse furrow at level of anterior eyes margins. Frons very short, deepened, matt, punctured. Eyes in dorsal view well prominent from outline of head. Head under scales densely punctured.

Antennal scape ( Fig. 3 ) 5.61–5.80× as long as wide at apex, here 0.9× as wide as club. Funicle with article 1 1.8–2.0× as long as wide and 1.1× as long as slenderer article 2, this is 1.8–2.0× as long as wide; articles 3–6 1.2–1.3× as wide as long; article 7 1.3–1.4× as wide as long; clubs 1.5–1.6× as long as wide.

Pronotum ( Fig. 3 ) very wide and short, 1.67–1.78× as wide as long, widest at posterior third with distinctly rounded sides, conspicuously more tapering anteriad than posteriad; disc regularly domed; base slightly arched.

Elytra ( Fig. 3 ) oval, wide, 1.13–1.16× as long as wide, widest at midlength with regularly rounded sides, apically broadly rounded; striae narrowly punctured, hardly visible under appressed scales; interstriae flat; subhumeral calli missing.

Tibiae short, 5.2–5.6× as long as wide at midlength; protibiae apically rounded with sparse fringe of fine and short black setae; all tibiae with long brown mucro. Tarsi with tarsomere 2 1.5–1.6× as wide as long; tarsomere 3 1.4–1.5× as wide as long and 1.3× as wide as tarsomere 2; onychium of protarsi 1.2–1.3× as long as tarsomere 3, of metatarsi 1.3–1.4×.

Abdominal ventrites ( Fig. 26 ) 1.09–1.12× as wide as long, glabrous. Metaventral process narrower than transverse diameter of metacoxa.

Penis ( Fig. 29 ) moderately long and slender, slightly evenly enlarging apicad with straight sides, apical part regularly subtriangular with straight sides, tip narrowly rounded; in lateral view evenly enlarging apicad, widest at apical part, tip shortly elongated; endophallus with two sclerites, short, subequal in length. Tegmen with long parameres based at base.

Sternite VIII ( Fig.40 )with short apodeme, widest at midlength, 1.6× as long as plate; plate narrowly subtriangular, 1.6–1.7× as long as wide, pointed. Gonocoxites evenly tapering apicad, with long apical styli. Spermatheca ( Fig. 35 ) with wide, regularly curved and pointed cornu; corpus elongated; ramus small, wider than long, rounded; nodulus distinctly longer and wider than ramus, about twice as long as wide at base, at middle curved outside.

Derivation of name. Dense regular rows of erect setae on all elytral interstriae suggested the Latin name of this new species.

Biology. Type material was collected by sifting or use of pitfall traps in fynbos.

Distribution. South Africa (Western Cape).

Differential diagnosis. Bulirschius densatus is similar to B. ruiterbos and B. inconspicuus in the elytra lacking subhumeral bumps, rostrum in apical portion at most as wide as the base, dense, regularly rounded appressed scales, erect setae short, subspatulate, not prominent from the outline of body in dorsal view. It differs from both of these species by having a wide body, wide and short pronotum and elytra with dense semi-erect elytral setae. It differs from B. ruiterbos also by short and wide rostrum with straight sides, eyes prominent from outline of head and narrow metaventral process; from B. inconspicuus also by transverse furrow between head and rostrum at level of anterior eye margins, abdominal ventrites glabrous, long onychium and plate of female sternite VIII lacking sclerites.

Figures

FIGURES 1–4. Dorsal habitus. 1. Andringitrabius polymitus. 2. Holotype labels of Andringitrabius. 3. Bulirschius densatus. 4. B. dysommatiformis. Not to scale.

FIGURES 13–24. 13–24: Head including rostrum in dorsal and lateral view. 13, 14. Andringitrabius polymitus. 15, 16. Bulirschius densatus. 17, 18. B. dysommatiformis. 19, 20. B. inconspicuus. 21, 22. B. ruiterbos. 23, 24. B. tesinskyi. Scale 0.50 mm.

FIGURES 25–43. 25: Right protibia. Bulirschius tesinskyi. 26–28: Abdominal ventrites. 26. B. densatus. 27. B. ruiterbos. 28. B. tesinskyi. 29–33: Penis in dorsal view. 29. B. densatus. 30. B. dysommatiformis. 31. B. inconspicuus. 32. B. ruiterbos. 33. B. tesinskyi. 34: Tegmen. B. tesinskyi. 35–39: Spermatheca. 35. B. densatus. 36. B. dysommatiformis. 37. B. inconspicuus. 38. B. ruiterbos. 39. B. tesinskyi. 40–42: Female sternite VIII. 40. B. densatus. 41. B. inconspicuus. 42. B. tesinskyi. 43: Ovipositor. B. tesinskyi. Scale 0.50 mm for 25–28, 34, 40–43; 0.25 mm for 29–33, 35–39.