Ochthebius (Aulacochthebius) exaratus, Mulsant

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 : 507-516

O. (Aulacochthebius) exaratus Mulsant

Figs. 1 , 3 , 6

Ochthebius exaratus Mulsant 1844: 67

Discussion. Refer to the discussion of O. (A.) copiosus n. sp.

Differential Diagnosis. Refer to the differential diagnosis of O. (A.) copiosus n. sp.

Redescription. Size: specimen from Portugal (length/width, mm): body (length to elytral apices) 1.28/0.57; head width 0.34; pronotum 0.27/0.43; elytra 0.78/0.57. Habitus as illustrated ( Fig. 6 ). Dorsum dark brown except hyaline borders of prothorax transparent. Eyes with moderately coarse, convex facets. Frons with deep impressions, borders of impressions rounded, smooth. Clypeus with very few, very shallow finely setigerous punctures. Labrum apicomedially produced in male, rounded in female.

Pronotal reliefs very smooth, with very sparse and very short indistinct setae; anterior and posterior transverse impressions deep, anterior narrowly separated from transverse impression immediately behind anterior margin of lateral lobe; median longitudinal impression moderately deep, extended from anterior to posterior impression.Pronotum lateral hyaline borders wide, present only in angulation behind lateral lobes; sides of lateral lobes with short setae that extend outward from cuticle in dry specimens; anterior hyaline border moderately wide; posterior hyaline border narrow.

Elytra smooth, ten seriate-punctate, punctures small; each puncture with very fine very short seta, which lies flat on cuticle; minute granule at anterior margin of each puncture, more obvious on disc; setae on lateral margins only moderately dense and only moderately long, recumbent in dry specimens.

Venter ( Fig. 6 ): Mentum with sparse, small setigerous punctures. Prosternum with very low midlongitudinal subcarina. Metaventrite tabella large, angulate anteriorly and laterally, length slightly less than width (ratio ca. 5:6); ratio of length above and below horizontal imaginary line through greatest width ca. 3:4; lateral angles slightly rounded; surface with very few, very fine punctures; tabella bordered by moderately long setae. Abdominal venter: first two ventrites and antero-lateral margin of third with hydrofuge pubescence, remainder of ventrites shining, with very sparse setae.

Distribution. Palearctic.

Figures

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

FIGURE 3. Aedeagi (ventral view, flagellum deleted) and venter of species in the O. (A.) exaratus Group.

FIGURE 6. O. (A.) exaratus Mulsant, habitus and aedeagus of specimen from Portugal.