Ochthebius (Aulacochthebius) persetosus, Perkins, 2023

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 : 521-522

O. (Aulacochthebius) persetosus , new species

Figs. 1 , 4 , 12 , 26

Type Material. Holotype (male): “ SOUTH AFRICA: Transvaal Prov. , Nelshoogte galery for. below St., (25°51’S, 30°53′E), 2 xii 1986, coll. Endrödy-Younga #2343, shore washing” ( TMSA) . Paratypes (50): Same data as holotype (13 TMSA) . South Africa: KwaZulu-Natal Province, Umlaas River , marginal vegetation, NAT 173M, (29°44′S, 30°31′E), 6.vii.1973, leg. Unknown (1 AMG) ; Mpumalanga Province, Kruger National Park, Skukuza, Sabie River , (24°57′S, 30°42′E), 22.ii.1995, leg. Endrödy-Younga (#3110) (36 TMSA) .

Differential diagnosis. Differentiated from other members of the O. (A.) continentalis Group by the combination of the dorsum of head and the pronotum with very dense, very prominent setae, the hydrofuge pubescence pattern of the abdominal ventrites (described below), and by the aedeagus.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.15/0.56; head width 0.35; pronotum 0.28/0.49; elytra 0.70/0.56. Habitus as illustrated ( Fig. 12 ). Dorsum dark brown to black except hyaline borders of prothorax transparent. Eyes with moderately coarse, convex facets. Frons with deep impressions, borders of impressions rounded. Frons and clypeus densely setose, densely punctate. Labrum anterior margin arcuate in both sexes.

Pronotum densely setose, moderately coarsely punctate; anterior and posterior transverse impressions deep, anterior narrowly separated from shallow transverse impression immediately behind anterior margin of lateral lobe; median longitudinal impression moderately deep, narrow, connecting anterior and posterior transverse impressions. Pronotum lateral hyaline borders moderately wide, extended from posterior to anterior angles; sides of non-hyaline part with long conspicuous setae immediately above and resting on hyaline border; anterior and posterior hyaline borders narrow.

Elytra wider than non-hyaline part of pronotum, posteriorly rounded, sides arcuate; ten seriate-punctate, punctures moderately large, deep, intervals narrow; each puncture with minute granule at anterior margin, and conspicuous decumbent seta that arches over puncture, attaining base of following seta; lateral margin with row of short, arcuate setae that extend outward from margin in dry specimens.

Venter ( Fig. 12 ): Mentum with sparse, moderately large setigerous punctures. Prosternum with very low midlongitudinal carina. Metaventrite tabella large, crown shaped, width ca. 0.6 width of metaventrite, slightly wider than long (ratio ca. 25:20), lateral angles slightly rounded, anterior angle prolonged as distinct carina that attains mesoventral intercoxal process; surface with few very sparse very fine punctures; row of setae along posterior margins very short, other margins without row of setae. Abdominal venter: ventrites 1–2 entirely hydrofuge pubescent; ventrite 3 with hydrofuge pubescence absent in ca. median 1/5; ventrite 4 with hydrofuge pubescence absent in ca. median 1/3; ventrite 5 with hydrofuge pubescence present only narrowly laterally; remaining ventrites glabrous, shining, with sparse setae.

Etymology. Named in reference to the densely setose dorsum.

Distribution. Currently known from northeastern South Africa ( Fig. 26 ).

Figures

FIGURE 1. Dorsal habitus of species in the O. (A.) exaratus Group (upper row), and the O. (A.) continentalis Group (remainder).

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 12. O. (A.) persetosus n. sp., holotype habitus and aedeagus.

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.