Hyphydrus dioscoridis, Hájek & Reiter, 2014

Hájek, Jiří & Reiter, Antonín, 2014, Adephagous water beetles (Coleoptera: Gyrinidae, Haliplidae, Noteridae, Dytiscidae) of Yemen and Dhofar region (Oman) with description of a new Hyphydrus from Socotra Island, Acta Entomologica Musei Nationalis Pragae 54, pp. 63-99 : 74-77

Hyphydrus dioscoridis sp. nov.

( Figs 15–26 )

Hyphydrus sp. ♀: WEWALKA (2004: 470).

Type locality. Yemen, Socotra Island, wadi Dineghen, 12°36ʹ42ʺN, 54°03ʹ41ʺE, 140 m a.s.l.

Type material. HOLOTYPE: J ( NMPC), ‘ YEMEN, SOCOTRA island / wadi DENEGEN, 6 km SE / Hadibo ; 140 m a.s.l. / 12°36ʹ42ʺN; 54°03ʹ41ʺE / 4. V. 2004 lgt.A.REITER [printed] ’. PARATYPES: 1 J 5 ♀♀, same label data as holotype ( NMPC) ; 3 ♀♀, ‘Yemen, Soqotra Is. , 1.-2.xii.2003 / Dixam plateau, SIRHIN area / N 12°31ʹ08″ E 53°59ʹ09″ [GPS] / Jan Farkač lgt., 812 m // YEMEN – SOCOTRA 2003 / Expedition ; Jan Farkač / Petr Kabátek & David Král [printed]’ ( NMPC) ; 1♀, ‘ YEMEN, SOCOTRA island / wadi FAR / 45 m a.s.l. / 12°25ʹ59″N ; 54°11ʹ42″E / 14.V.2004 lgt. A.REITER [printed]’ ( NMPC) ; 1 ♀, ‘ YEMEN, Socotra Island / wadi Ayhaft , 200 m / 12º36.5ʹN, 53º58.9ʹE / Jiří Hájek leg. 7-8.xi.2010 // used for DNA extraction / voucher number IBE-RA625 [printed]’ ( IBEB) ; 3 JJ 2 ♀♀, ‘ YEMEN, Socotra Island / wadi Madar , 1180–1230 m / 12°33.2ʹN, 54°00.4ʹE, / Jiří Hájek leg. 12–14.xi.2010 ’ ( IBEB, NMPC) [one male with additional label:‘used for DNA extraction / voucher number IBE-RA612 [printed]’ ( IBEB)] .

Description of male holotype. Habitus. Body shape globose, rounded. Pronotum trapezoidal, broadest basally; sides of pronotum regularly rounded. Maximum width of pronotum distinctly smaller than maximum width of body, angle between pronotum and elytra fairly distinct. Body surface shiny ( Fig. 15 ).

Colouration. Body colouring testaceous to ochraceous with dark (brownish-black) colour pattern. Head somewhat darkened posterior to eyes; pronotum largely darkened with broad longitudinal testaceous band along sides except posterior angles; elytra with separate rounded dark lateral subhumeral spot, and irregular longitudinal markings on disc (cf. Figs 15–16 ); legs testaceous with pro- and mesotarsomeres III, and metatarsomeres III–V darkened; ventral surface darkened except head and prosternum.

Surface structure and sculpture. Head with indistinct microreticulation, chiefly anterior to eyes. Punctation fine, rather sparse, smaller on vertex, lacking posteriorly to eyes; punctures irregularly distributed, distance between punctures usually bigger than their diameter; punctures in frontolateral depressions somewhat coarser, and sometimes confluent. Clypeus broadly bordered, its anterior margin rounded ( Fig. 17 ); frontolateral depressions shallow.

Pronotum smooth, with shallow medial longitudinal scratch, and fine punctation; punctures sparser on disc and denser along lateral margins, punctation double, but differences in size of punctures rather small. Distance between punctures on disc much larger than their diameter; along margins distance between punctures approximately equal to diameter of coarse punctures. Sides of pronotum rounded, bordered except for anterior angles.

Elytra smooth, without reticulation; punctation double: size differences small, coarser punctures much sparser than finer punctures, distance between punctures larger than their diameter. Discal puncture line well marked in basal half, other puncture lines almost imperceptible. Epipleura finely punctate.

Ventral surface with reticulation only present laterally on head posterior to eyes; pro- and mesocoxae with areolate reticulation. Prosternal apophysis lanceolate, with longitudinal line of long golden setae medially. Metanepisternum (= metasternal wing) narrow, laciniate. Punctation of metaventrite consisting of fine punctures; punctation of metacoxal plates coarser and denser. Abdominal ventrites uniformly finely punctate; medially and along posterior margins with long golden setae. Apical ventrite with subapical carina raised medially to form distinct transverse swelling ( Fig. 19 ); posterior margin with line of setigerous punctures, each with golden seta.

Pro- and mesotarsi slightly broadened, with adhesive setae. Protrochanters incised.

Median lobe of aedeagus in ventral view subparallel, only slightly narrowing to apex; apex deeply incised, with several short setae ( Figs 21–22 ). Parameres (lateral lobes) triangularly shaped with apical tuft of setae ( Fig. 23 ).

Female. Similar to males ( Fig. 16 ); pro- and mesotarsi not broadened; protrochanters not incised. Microreticulation of head more distinct and punctation of elytra finer than in male; disc of elytra very finely microreticulate, thus surface rather matt. Tubercle on apical ventrite absent. Female genitalia as in Figs 24–26 .

Variability. The specimens of the type series vary in the shape and extent of dark body colouration.

Measurements: TL 3.9–4.6 mm (holotype 4.3 mm), TL-h 3.4–4.1 mm (holotype 3.7 mm); TW 2.5–3.0 mm (holotype 2.7 mm).

Differential diagnosis. Based on the combination of the following characters, Hyphydrus dioscoridis sp. nov. belongs undoubtedly to the Hyphydrus signatus species group sensu BIS- TRÖM (1982): 1) longer spine of metatibia not serrate; 2) border of head foremargin without a furrow; 3) elytral punctation double; 4) metatibia externally with a distinct row of punctures; 5) median lobe symmetric in ventral view. The new species is similar to Hyphydrus pictus Klug, 1834 from the Arabian Peninsula and north-eastern Africa, but differs from this species in the significantly coarser, deeper and denser body punctation (distance between punctures equal to diameter of punctures or even less); clypeus more broadly bordered (cf. Figs 17–18 ); head between punctures microreticulated; tubercle on apex of apical ventrite without notch (with shallow notch in H. pictus ( Fig. 20 )), and elytral disc of female microreticulate.

Molecular data. The two barcode sequences of the specimens from wadi Madar and wadi Ayhaft were identical, but with a 5% difference from the specimen from continental Yemen (33 out of 568 positions). This genetic difference is larger than that of many closely related species pairs of Dytiscidae (e.g. RIBERA & VOGLER 2004), and at a standard evolutionary rate of Adephagan Coleoptera would correspond to a separation of more than 1 million years (e.g. ANDÚJAR et al. 2012).

Etymology. The new species is named after ‘Dioscoridus’, an ancient Latin name of Socotra Island. The specific epithet is a noun in the genitive case, standing in apposition.

Collection circumstances. The new species was collected in residual pools of drying-up streams and springs in wadis (e.g. Fig. 13 ).

Distribution. So far known only from several localities in Socotra Island, Yemen.

Figures

Figs 15–26. 15–17, 19, 21–26 – Hyphydrus dioscoridis sp. nov. 15 – male habitus; 16 – female habitus; 17 – head in dorsal view; 19 – apical abdominal ventrite of male; 21 – median lobe in ventral view; 22 – median lobe in lateral view; 23 – paramere; 24 – gonocoxosternum; 25 – gonocoxae; 26 – spermatheca. 18, 20 – H. pictus Klug, 1834. 18 – head in dorsal view; 20 – apical abdominal ventrite of male.

Figs 12–14. Aquatic habitats in Socotra. 12 – temporary stream in wadi Ayhaft; 13 – spring pool with filamentous algae in wadi Madar; 14 – pools surrounded with Juncus sp. marsh in wadi Zerig.