Ochthebius (Ochthebius) alhajarensis, Ribera & Hernando & Cieslak, 2019

Ribera, Ignacio, Hernando, Carles & Cieslak, Alexandra, 2019, Aquatic Coleoptera of North Oman, with description of new species of Hydraenidae and Hydrophilidae, Acta Entomologica Musei Nationalis Pragae 59 (1), pp. 253-272 : 260

Ochthebius (Ochthebius) alhajarensis sp. nov.

( Figs 15 , 19 )

Type locality. Source of wadi Bani Awf in Jebel Al-Hajar, Oman (Loc. 4; Figs 1 , 5, 6 ).

Type material. HOLOTYPE: ♁ ( NHMW), “4 Oman 6.4.2010 J.Al-Akhdar // source of wadi Bani Awf , on rock // N23 10 36.2 E57 24 34.1 1300m // Ribera, Cieslak & Hernando leg.”, used for DNA extraction, voucher number IBE-RA104 (sequences published in VILLASTRIGO et al. 2019), aedeagus dissected and mounted in DMHF on a transparent card, with holotype label . PARATYPES (4 spec.): ( CCHB, IBEB): 3 ♀♀, same data as holotype, with paratype labels; 1 ♁, “6 Oman 6.4.2010 J. Al-Akhdar // wadi Bani Awf residual pools // N23 13 42.9 E57 25 25.8 660m // Ribera, Cieslak & Hernando leg.”.

Description. Habitus as in Fig. 15 . Body length: 2.15–2.25 mm; width: 0.90–0.95 mm. Dorsal surface black (dark brown in immature specimens); palpi, antennae and legs brown.

Upper surface of head with very long, adpressed fine whitish setae. Labrum only slightly incised, surface between punctures smooth. Frontoclypeal suture distinct, strongly arched. Surface of head largely smooth, with microreticulated areas around eyes and on neck area. With two large foveae on vertex; ocelli not visible.

Pronotum trapezoidal, almost as wide as long; surface covered with same type of setae as on head but more sparse; anterior margin straight in middle; anterior angles roughly arcuated; lateral margin irregularly defined. Hyaline membrane narrow at anterior and posterior margins, very wide at posterior corners. Surface of disk smooth, with sparse punctures and some microreticulation on margins; with shallow longitudinal and lateral furrows; sides of pronotum strongly microreticulated, with granulose appearance.

Elytra oval; with very irregular rows of shallow punctures, with long and thin whitish seta on anterior part of each puncture. Lateral rim smooth, not explanate. Membranous wings well developed.

Legs relatively long, with rows of strong setae, without natatorial setae.

Ventral surface black, surface shagreened, covered with long, thin, whitish pubescence. Margins of metaventrite and abdominal ventrites with shorter, more dense setae.

Aedeagus ( Fig. 19 ) with main piece strongly bend in almost straight angle; medial part narrow, apex dilated and sinuated. Distal lobe regularly expanded, with lower part hyaline. Parameres inserted near base of main piece, not reaching its apex.

Differential diagnosis. Ochthebius alhajarensis sp. nov. belongs to the O. punctatus group. Among the species for which we have molecular data, it is most closely related to O. klapperichi Jäch, 1989 from central Asia (studied specimen voucher No. MNCN-AI1269; VILLASTRIGO et al. 2019) at a genetic distance of 7% in the COI-3 gene, and both to another unnamed species from Tajikistan (unpublished data). They are in turn related to O. quadrifoveolatus Wollaston, 1854 and O. ragusae Kuwert, 1877 , both widely distributed in the Mediterranean region ( JÄCH & SKALE 2015). From its known closest relative, O. klapperichi , and from O. quadrifoveolatus the new species differs clearly in the shape of the pronotum, with a much narrower base and stronger fossae. The external morphology is most similar to O. ragusae , from which based on the available material apparently only differs in the stronger punctuation of the elytra. The shape of the aedeagus is, however, clearly different to that of all these species (see JÄCH 1989).

Etymology. Named after the mountain range of Al Hajar, in north Oman, were the new species was found; adjective.

Notes on the habitat. The species was found in two localities, the source of the wadi Bani Awf ( Figs 5, 6 ; see habitat notes for Hydraena naja sp. nov.) and residual pools downstream of the same wadi.

Distribution. Only known from two localities in the same stream in the Al-Hajar mountains ( Fig. 1 ).

Figures

Figs 14–17. Habitus of new species: 14 – Hydraena naja sp. nov.; 15 – Ochthebius alhajarensis sp. nov.; 16 – Ochthebius bernard sp. nov.; 17 – Agraphydrus elongatus sp. nov. Scale bars: 1 mm.

Figs 18–21. Aedeagus of new species: 18 – Hydraena naja sp. nov.; 19 – Ochthebius alhajarensis sp. nov.; 20 – Ochthebius bernard sp. nov.; 21 – Agraphydrus elongatus sp. nov. Scale bars: 0.2 mm.

Fig. 1. Sampled localities (see Table 1 for details).

Figs 2–7. Some of the sampled localities in north Oman. 2 – Loc. No. 1: Ghul spring with pools; 3 – No. 2: residual pools in wadi in Bahla city; 4 – Loc. No. 3: residual pools in wadi; 5 – Loc. No. 4: source of wadi Bani Awf; 6 – Loc. No. 4: source of wadi Bani Awf; 7 – Loc. No. 5: wadi Bani Awf. See Table 1 for details on the localities, and Fig. 1 for their geographical location.