Ochthebius involatus, Perkins, Philip D., 2011

Perkins, Philip D., 2011, New species and new collection records of aquatic beetles in the genus Ochthebius Leach from southern Africa (Coleoptera: Hydraenidae), Zootaxa 3093, pp. 1-34 : 20-22

Ochthebius (s.s.) involatus , new species

( Figs. 13 , 14, 20 )

Type Material. Holotype (male): South Africa: Western Cape Province: Kommetje (near), in running stream with Glyceria sp., elev. 60 m, 34° 9' S, 18° 20' E, 30 vii 1954, J. Balfour-Browne (NHM). Paratype: Same data as holotype (1 NHM).

Differential Diagnosis. This unusual species ( Fig. 13 ), by virtue of its depressed body form, very shallow pronotal foveae, completely random elytral punctures, and fused elytra, cannot be confused with any other southern African Ochthebius . Some external characters suggest a relationship to the intertidal species O. capicola , including the depressed body form, the random elytral punctation, the shallow labroclypeal suture, and the shallow pronotal foveae. The aedeagus ( Fig. 14) is similar to that of O. capicola in having the distal piece rather long and narrow, and in having the basal part of the parameres broadly joined to the main piece. O. involatus , however, lacks the very derived modifications of the venter present in O. capicola (see Perkins & Balfour-Browne, 1994: 150), and the dorsal habitus of the two species differ distinctively.

Description. Size: holotype (length/width, mm): body (length to elytral apices) 1.47/0.60; head 0.28/0.37; pronotum 0.39/0.49, PA 0.40, PB 0.36; elytra 0.88/0.60. Color: Dorsum dark brown; venter piceous; legs testaceous to brunneo-testaceous, maxillary palpi testaceous. Head: Eyes small compared to width of head, in dorsal aspect ca. 6 convex facets in longest series. Frons interocular foveae deep, width of each ca. 1/2 distance separating them. Ocelli not apparent. Dorsum shining, except effacedly microreticulate on clypeus at labroclypeal suture, finely sparsely punctate, punctures slightly smaller than eye facet, each puncture with fine recumbent seta. Labrum width 2x, anterior margin arcuate. Mandible without distinct spiniform setae. Pronotum: Anterior margin arcuate, lacking postocular emarginations and processes, widest just behind anterior angles, then gradually attenuate to right angled basal angles. Disc with anterior impression very shallow, margins very gradual, with three slightly deeper areas, median of which slightly larger and slightly deeper, hence impression somewhat T-shaped, very weakly effacedly microreticulate; posterior impression deeper, but also with very gradual margins and very weak microreticulate. Area between foveae weakly convex. Disc and lateral depressions very finely very sparsely punctate, each puncture with fine short recumbent seta. Lateral fossulae moderately deep, narrow, microreticulate. Small fovea anterior to each posterior angle. Elytra: Form depressed, sides weakly arcuate, explanate margin very narrow, ended slightly past midlength, apices conjointly rounded. Punctures subserial near base, otherwise random, each with fine recumbent seta. Interstices irregular, effacedly alutaceous. Venter: Mentum shining, finely sparsely punctate. Metaventrite microreticulate and densely pubescent except small oval area on posterior 1/2 of disc. Abdominal ventrites 1–5 and anterior of 6 clothed with dense hydrofuge pubescence.

Etymology. Named in reference to the inability to fly.

Distribution. Currently known only from the type locality ( Fig. 20 ).

Figures

FIGURE 13. Ochthebius involatus, dorsal and lateral habitus of holotype.

FIGURES 19 – 20. Geographical distributions of Ochthebius. 19. O. endroedyi. 20. O. anchorus, O. bicomicus, O. granulinus, O. involatus, and O. zulu.