Ochthebius (Aulacochthebius) tenuipunctus, Regimbart

Perkins, Philip D., 2023, Taxonomic revision of African water beetles in the genus Ochthebius Leach (1815) subgenus Aulacochthebius Kuwert (1887) (Coleoptera: Hydraenidae), Zootaxa 5228 (5), pp. 501-546 : 529-530

O. (Aulacochthebius) tenuipunctus Régimbart

Figs. 2 , 4 , 15 , 27, 28 , 29

Ochthebius tenuipunctus Régimbart 1906: 275

Type locality: Kenya: Lake Victoria , Winam Gulf [“Baie de Kavirondo ”] .

Material examined (54): Benin: Dep. Atlantique, Ouidah , at sea level, (6°19′50.6′′N, 2°5′12.6′′E), 8.ii.2006, leg. Goergen, Komarek & Houngua (22) (6 NMW) ; Dep. Mono, Come, Dohi (village), (6°23′7.4′′N, 1°56′14.5′′E), 2.ii.2006, leg. Goergen, Komarek & Houngua (7) (42 NMW) ; Dep. Oueme, Porto Novo, Lopodji (village), (6°26′50.5′′N, 2°39′30.1′′E), 8.ii.2006, leg. Goergen, Komarek & Houngua (24) (2 NMW) . Kenya: 10 mi. S. Nanyuki , (0°7′S, 37°5′E), 5.ii.1968, leg. P. J. Spangler (1 male NMNH) . South Africa: Mpumalanga Province, Stn. VD 1, VAL 743BB, headwaters of Vaal River between Breyten & Lake Chrissie , headwater stream, marginalvegetation, 22.VII.1959, (26°17′S, 30°3′15′′E) (1 male AMG) ; Vaal R., Stn. V.D. 21, (26°49′10′′S, 30°08′00′′E), marginal vegetation, NIWR-VAL 884J (1 male AMG) ; Vaal River System, VAL Stn. 0894H (26°51′5′′S, 29°41′50′′E) (1 male AMG) .

Differential diagnosis. Differentiated from other members of the O. (A.) tenuipunctus Group by thecombination of the comparatively large size (ca. 1.40 mm), and by the aedeagus. Similar in size to O. (A.) plicicollis ;distinguished therefrom by the shorter and shallower midlongitudinal impression of the pronotum, and by the aedeagus.

Redescription. Size: specimen from Kenya (length/width, mm): body 1.40/0.63 (length to elytral apices); head width 0.37; pronotum length 0.30, width at base 0.24, width at hyaline border 0.57, width of lateral sclerotized lobes 0.44 at anterior, 0.42 at posterior; elytra 0.87/0.63. Habitus as illustrated ( Fig. 15 ). Dorsum black, legs brown, hyaline borders of prothorax translucent to light yellowish. Eyes with moderately coarse, convex facets. Frons with deep impressions, borders of impressions rounded, smooth. Clypeus with very few, very shallow setigerouspunctures. Labrum anterior margin arcuate.

Pronotal reliefs very smooth, with very sparse and very short setae; anterior and posterior transverseimpressions deep, anterior contiguous with shallow transverse impression immediately behind anterior margin of lateral lobe; median longitudinal impression very shallow, extending from anterior transverse impression to ca. midlength. Pronotum anterior margin bisinuate. Pronotum lateral hyaline borders very wide, extended from posterior to anterior angles, outer margin markedly arcuate; sides of non-hyaline part with long conspicuous setae immediately above and resting on hyaline border; anterior and posterior hyaline borders very narrow.

Elytra transversely convex, wider than hyaline part of pronotum, posteriorly acuminate, sides markedly arcuate; very smooth, with serial rows of very shallow, widely spaced punctures, each with very short seta; lateral margin with very long yellow setae, dense at and slightly behind humeral angle, sparse on remainder of margin; most of margin also with very dense, very short setae that extend outward from margin. Elytral apices truncate.

Venter ( Fig. 15 ): Tabella oval, slightly wider than long (as ca. 80:70), slightly convex; first four ventrites bearing rather long hydrofuge pubescence; remaining ventrites glabrous, shining, with sparse setae.

Distribution. Currently known from Kenya and South Africa ( Figs. 25 , 29 ).

Remarks. All three specimens from South Africa are dissected males. The aedeagi of these specimens do not differ significantly from that of the specimen of O. (Aulacochthebius) tenuipunctus from Kenya.

Figures

FIGURE 2. Dorsal habitus of species in O. (A.) tenuipunctus Group.

FIGURE 4. Venter and aedeagi (ventral view, flagellum deleted) of species in O. (A.) continentalis Group and O. (A.) tenuipunctus Group. Not to same scale.

FIGURE 15. O. (A.) tenuipunctus Régimbart, habitus and aedeagus of specimen from Kenya.

FIGURES 27–28. Geographical distributions. 27. O. (A.) species in Kenya and Uganda. 28. O. (A.) strangulatus Régimbart, O. (A.) tenuipunctus Régimbart and O. (A.) nigeriensis n. sp.

FIGURES 29–30. Geographical distributions. 29. O. (A.) mpumalangicus n. sp., O. (A.) tenuipunctus Régimbart and O. (A.) solitarius n. sp. 30. O. (A.) libertarius Aguilera et al. and O. (A.) continentalis Orchymont.

FIGURES 24–26. Geographical distributions. 24. O. (A.) continentalis Orchymont. 25. O. (A.) scutatus n. sp. 26. O. (A.) persetosus n. sp. and O. (A.) flagellissimus n. sp.