Ochthebius (Aulacochthebius) scutatus, 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 : 520

O. (Aulacochthebius) scutatus , new species

Figs. 1 , 4 , 10 , 25

Type Material. Holotype (male): South Africa ; “ S. Afr., Zululand, Mtubatuba—Dukuduku, 28°22′ S, 32°19′ E, 4.4.1974; E-Y: 319; shorewashing, pan; leg. Endrödy-Younga ” ( TMSA) . Paratypes (42): South Africa: KwaZuluNatal Province, Hluhluwe Game Res. , (28°5′S, 32°4′E), 27.xi.1992, leg. Endrödy-Younga (#2861) (3 TMSA) ; As above, shorewashing, slow water, leg. Endrödy-Younga (#2862) (11 TMSA) ; Hluhluwe Game Reserve , (28°5′S, 32°4′E), 17.xi.1992, leg. Endrödy-Younga #2824 (#2824) (17 TMSA) ; Ndumu Game Reserve , (26°53′S, 32°16′E), 12.vi.1989, leg. Endrödy-Younga & Klimaszewski (#2612) (4 TMSA) ; Western Cape Province, Elandsdrift , (34°39′S, 19°53′E), 24.ii.1981, leg. Endrödy-Younga (#1747) (7 TMSA) .

Differential diagnosis. Differentiated from other members of the O. (A.) continentalis Group by the combination of the dorsum of head and pronotum microreticulate, setae sparse, and by the aedeagus.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.26/0.57; head width 0.36; pronotum length 0.29, width at base 0.25, width at hyaline border 0.50; elytra 0.75/0.57. Habitus as illustrated ( Fig. 10 ). Dorsum dark brown except hyaline borders of prothorax transparent. Eyes with moderately coarse, convex facets. Frons with deep impressions, borders of impressions rounded. Frons and clypeus microreticulate, dull, setae sparse, indistinct except longer and more numerous laterally. Labrum anterior margin arcuate in both sexes.

Pronotum sparsely, finely setose, microreticulate, more distinctly so in impressions than on disc; 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, connecting anterior and posterior transverse impressions. Pronotum lateral hyaline borders wide, extended from posterior to anterior angles; sides of non-hyaline part with short, sparse, inconspicuous 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 large, deep, intervals narrow, very finely microreticulate, dull; each puncture with granule at anterior margin, and conspicuous decumbent seta that arches over puncture, and attains base of following seta; lateral margin with row of very short, arcuate decumbent setae.

Venter ( Fig. 10 ): Mentum with sparse, moderately large setigerous punctures. Prosternum with midlongitudinal carina. Metaventrite tabella large, kite shaped, with anterior angle extended as carina; width ca. 0.56 width of metaventrite; slightly wider than long, lateral angles slightly rounded (ca. 71 degrees), anterior angle (not including carina) ca. 120 degrees), midline lengths above and below horizontal imaginary line through widest part as 3:5; surface with few random setigerious punctures, and each side with extremely shallow, non-punctate longitudinal impression, barely visible (not showing on figure), setae along posterior margins much longer than setae along anterior margins. Abdominal venter: first four ventrites bearing rather long hydrofuge pubescence; remaining ventrites glabrous, shining, with sparse setae.

All tibiae with long, dense, spine-like setae, especially on mesotibiae.

Etymology. Named in reference to the shield-shaped metaventral tabella.

Distribution. Currently known from southern and northeastern South Africa ( Fig. 25 ).

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 10. O. (A.) scutatus 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.