Agraphydrus elongatus, 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 : 264

Agraphydrus elongatus sp. nov.

( Figs 17 , 21 )

Type locality. Wadi Bani Ghafir, Murri, Oman (Loc. 8; Figs 1 , 8 ).

Type material. HOLOTYPE: ♁ ( NHMW), “8 Oman 7.4.2010 Murri env. // wadi Bani Ghafir, stream with pools // N23 29 46.2 E56 53 34.8 759m // Ribera, Cieslak & Hernando leg.”, aedeagus dissected and mounted in DMHF on a transparent card, with holotype label . PARATYPES (88 spec.) ( CCHB, IBEB, MNCN, NHMW, NMPC): 15 spec., same data as holotype, with paratype labels; 8 spec. “2 Oman 5.4.2010 J. Al-Akhdar // Bahla, wadi in city residual pools // N22 57 42.1 E57 17 47.5 559m // Ribera, Cieslak & Hernando leg.”, with paratype labels (1 ♁ used for DNA extraction,voucher number IBE-RA105); 6 spec. “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.”, with paratype labels; 1 spec. “7 Oman 7.4.2010 J. Al-Akhdar // wadi Bani Awf residual pools // N23 17 23.8 E57 28 03.9 487m // Ribera, Cieslak & Hernando leg.”, with paratype label; 18 spec., “9 Oman 8.4.2010 Said Bin Sahran env. // wadi Indam, Rd. 33 residual pools // N22 45 15.2 E58 00 56.9 463m // Ribera, Cieslak & Hernando leg.”, with paratype labels; 1♁ “12 Oman 9.4.2010 1 km W Qalhat // residual pools in wadi // N22 41 25.4 E59 22 03.0 88m // Ribera, Cieslak & Hernando leg.”, with paratype labels; 3 spec. “ UAE: Ras al-Khaimah // (south), Wadi Shawkah // Hajar Mountains ( UAE 3) // ca. 80 km ESE Dubai // 23.I.2010, leg. M.A. Jäch”, “upper course // residual pools // ca. 318 m a.s.l. // 25°06′06.1″N // 56°03′26.4″E ”; 1 ♁ “ UAE: Ras al-Khaimah // (south) ( UAE 10) // Hajar Mountains // ca. 80 km SE Dubai // 26.I.2010, leg. M.A. Jäch”, “small stream // ca. 385 m a.s.l. // 25°03′25″N // 56°03′40.7″E ”; 19 spec. “ UAE: Fujairah ( UAE 12) // Wadi Maidaq // Hajar Mountains // 26.I.2010, leg. M.A. Jäch”, “ca. 8 km NW Masafi // ca. 75 km E Dubai // springfed streamlet in // canyon”, “residual pools // ca. 386 m a.s.l. // 25°20′48.7″N // 56°05′28″E ”; 16 spec. same label data, but “leg. K. Mahmoud”.

Description. Habitus as in Fig. 17 ; total length: 2.00– 3.10 mm, elytral width: 0.95–1.30 mm. Habitus slender, elytra very weakly widening posterior to midlength, almost parallel-shaped, weakly convex. Labrum, clypeus and frons black, clypeus with narrow, undefined, yellow lateral margins; maxillary palpi yellow, palpomere 4 infuscated in apical third, pronotum dark brown with narrow yellowish margins, elytra dark brown in anterior two thirds, indistinctly brighter brown in posterior third, with very narrow, undefined, yellow lateral margins, ventrites dark brown, legs slightly lighter brown.

Clypeus with weakly concave anterior margin, microsculpture absent, punctures fine, interspaces about 2–3 × as wide as punctures. Eyes large, slightly protruding, oval-shaped. Maxillary palpi very slender, palpomere 4 asymmetrical. Mentum with few scattered fine punctures in lateral thirds, microsculpture absent.

Pronotal punctation as on head. Elytral punctation as on head and pronotum, four rows of punctures moderately distinct, mesal rows 1–3 strongly reduced in number of punctures, not reaching anterior margin.

Mesoventrite with a distinct mesal bulge. Abdominal ventrite 5 with uneven, roughly shaped apical margin, excision absent, or excision present, less than 8 μ deep.

Pubescence present on less than proximal half of pro- and mesofemur, on proximal third of metafemur.

Aedeagus as in Fig. 21 . Phallobase slightly shorter than parameres, evenly converging to weakly defined manubrium. Lateral margins of parameres not constricted subapically, weakly pointed, apex weakly sclerotized. Median lobe slightly shorter than parameres, apex rounded.

Differential diagnosis. Agraphydrus elongatus sp. nov. can be easily separated from A. minutissimus (Kuwert, 1890) , the only other species of Agraphydrus known from the Arabian Peninsula ( Table 2 ; both species coexisted in locality No. 8, Fig. 8 ; see Table 3 ), by the general colouration (pale brown in A. minutissimus , uniformly dark in A. elongatus sp. nov.) and the body shape (almost cylindrical, parallel-sided in A. elongatus , not widened posteriorly). The maxillary palpi are also longer than in A. minutissimus , and the species can also be recognised by the male genitalia. The two species belong to a species group including other small and slender species, although none with a similar body shape as A. elongatus sp. nov. (A. Komarek, pers. comm. 2018).

Etymology. Named in reference to the elongated body shape. The specific name is an adjective in nominative singular.

Notes on the habitat. The species was commonly found in wadis, both in residual pools with gravelly or sandy margins and in the areas with water flow, among stones and gravel ( Figs 3, 7–9, 11 ).

Distribution. Oman and UAE ( 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 8–13. Some of the sampled localities in north Oman. 8 – Loc. No. 8: wadi Bani Ghafir; 9 – Loc. No. 9: residual pools in wadi Indam; 10 – Loc. No. 11: residual pools in wadi; 11 – Loc. No. 12: Qalhat, residual pools in wadi; 12 – Loc. No. 13: marsh next to Bamah; 13 – Loc. No. 14: residual pools in wadi Al-Mayb. See Table 1 for details on the localities, and Fig. 1 for their geographical location.

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.