Hydraena gracilidelphis Trizzino, Valladares, Garrido and Audisio, 2012

Trizzino, Marco, Valladares, Luis F., Garrido, Josefina & Audisio, Paolo, 2012, Morphological reply to a DNA call: a new cryptic species of Hydraena from western Europe, with a complete overview of the Hydraena gracilis complex (Coleoptera: Hydraenidae: “ Haenydra ” lineage), Journal of Natural History 46 (17 - 18), pp. 1065-1078 : 1067-1072

Hydraena gracilidelphis Trizzino, Valladares, Garrido and Audisio sp. nov.

( Figure 1A, C )

Type locality

Valverdín stream tributary to Torío river , 1120 m above sea level (42 ◦ 56 ′ 58" N, 5 ◦ 32 ′ 32" W), Valverdín, León province, Spain .

Type material

Holotype. Male ( NMW): “E [ España]: Valverdín, León, 22 September 1983, leg. L.F. Valladares ”. Specimen dry mounted, aedeagus extracted and mounted on the same card.

Paratypes (22 specimens). Two males and two females ( MNCN; types catalogue No. 2174), same date and locality data as holotype ; two males and one female ( NMW) Spain: Álava, Valderejo, Lahoz , Purón stream, 42 ◦ 53 ′ 15" N, 3 ◦ 14 ′ 12" W, 880 m, 12 July 2000, leg. L.F. Valladares ; two males and one female ( CVL) Spain: Asturias, Sotres, Invernal del Texu , 43 ◦ 13 ′ 38" N, 4 ◦ 45 ′ 14" W, 900 m, 14 July 2005, leg. L.F. Valladares and J. Garrido ; two males and two females ( CVL) Spain: Cantabria, Begés , 43 ◦ 14 ′ 21" N, 4 ◦ 38 ′ 36" “W 600 m, 14 June 2005 leg. L.F. Valladares and J. Garrido ; one female ( MNCN; types catalogue no. 2174) Spain: León, Canseco , 42 ◦ 59 ′ 2" N, 5 ◦ 31 ′ 54" W, 1185 m, 5 August 1983, leg. L.F. Valladares ; two males and two females (CAR) Spain: León, Pallide , 42 ◦ 57 ′ 11" N, 5 ◦ 13 ′ 50" W, 1160 m, 5 August 1983, leg. L.F. Valladares ; one male and two females ( CVL) Spain: León, Villalfeide , 42 ◦ 52 ′ 38" N, 5 ◦ 31 ′ 4" W, 960 m, 22 September 1983 leg. L.F. Valladares.

Additional material

Thirty-five males and 44 females (CVL) Spain: Álava, Valderejo, Lahoz , Purón stream, 1 June 2000, 12 July 2000, 27 October 2000 leg. L.F. Valladares. Two males and two females (CAR; NMW) Spain, Cádiz, Algeciras. Five males and nine females ( CVL) Spain: Cantabria, Begés , 14 June 2005 leg. L.F. Valladares. One male (CAR) Spain: Cataluña, Tordera. One male and three females ( NMW) Spain: Cataluña, Santa Coloma. One female ( NMW) Spain: Cataluña, Girona , Arbucies. Four males and three females ( CVL) Spain: León, Embalse del Porma 19 July 1983 leg. L.F. Valladares, 1 m ( CVL) Spain: León , La Mata de la Riba 19 July 1983 leg. L.F. Valladares. Four males and four females ( CVL) Spain: León , La Uña, 12 July 1983 leg. L.F. Valladares. Fourteen males and 10 females ( CVL) Spain: León, Pallide , 5 August 1983 leg. L.F. Valladares. One female ( CVL) Spain: León, Piedrafita , 22 September 1983 leg. L.F. Valladares. One male and one female ( CVL) Spain: León, Puerto de Tarna , 12 September 1983 leg. L.F. Valladares. One male ( CVL) Spain: León, Tolibia de Arriba , 21 July 1983 leg. L.F. Valladares. Twelve males and 20 females ( CVL) Spain: León, Valverdín , 12 July 1983 leg. L.F. Valladares. One male and one female ( CVL) Spain: León, Vegacervera , 22 September 1983 leg. L.F. Valladares. One male ( CVL) Spain: León, Oville , 1 August 1983 leg. L.F. Valladares. Three males and three females ( CVL) Spain: León, Villalfeide , 22 September 1983 leg. L.F. Valladares. Two males and two females (CAR) Spain: León , Valdeteja. One male (CAR) Spain: León, Puerto de Panderrueda. Three males and two females (CAR; NMW) Spain, León , Prioro. One female (CAR) Spain: León, Vegacerneja. Three males and four females (CAR; NMW) Spain: Navarra, 10 km north of Ochagavia, Irati River , 100 m.

Description

Length 2.1–2.4 mm. Head, pronotum and elytra dark brown to black. Palpi paler reddish brown. Legs dark brown, in some specimens black, tarsal segments paler reddish brown.

Head. Labrum with V-shaped notch anteriorly. Fronto-clypeal suture slightly arcuate, not strongly impressed. Middle of frons densely punctate, lateral portion of frons very densely and deeply punctate, as in related species. Occipital ridge well developed. Eyes moderately large, maxillary palpi very long, about twice as long as distance between eyes.

Pronotum. Wider than long, moderately cordiform, anterior margin concave, anterior angles rounded, not angled. Lateral margin slightly denticulate. Disc convex, as in most species of the “ Haenydra ” lineage, rather densely punctate with large punctures near anterior and posterior margins, along midline and around posterior fovae. Foveae hardly impressed.

Thorax and abdomen. Elytra peculiarly narrow and elongate, as in H. gracilis , parallelsided, rather strongly declivous laterally. Nine rows of punctures between suture and shoulder. Strial punctures moderately large, quite deeply impressed. Explanate margin of elytra moderately narrow, as in H. gracilis , H. anatolica and H. nike , distinctly narrower than in H. elisabethae , H. graciloides and H. crepidoptera .

Mentum and submentum microreticulate. Posterior genal ridge not particularly prominent, mostly glabrous. Prosternum with indistinct median keel. Angles between mesosternal disc and mesosternal process small as in e.g. H. gracilis and H. nike . Metaventral plaques well developed, posteriorly divergent. Glabrous areas behind metacoxal sockets not very pronounced; abdominal ventrites III–VI more or less entirely covered with hydrofuge pubescence, abdominal ventrites VII and VIII largely glabrous, as in related species.

Aedeagus ( Figure 1A ). Main piece ca.520 µm long with three setae on left side in lateral view. Distal half of main piece in right side view markedly wider than in H. gracilis ( Figure 1A,B ), and bearing a slightly, but clearly perceptible, U-shaped emargination along the dorsal surface ( Figure 1A ). Apex of main piece characterized by a distinct hump along the dorsal surface of the pre-apical portion, resembling the head of a dolphin ( Figure 1A ). Pre-basal tooth not very prominent, phallobase symmetrical in ventral view. Distal lobe ending in a vertical plate as in other members of the H. gracilis complex, seemingly without variability in size ( Figure 1A ).

Gonocoxite and female tergite X as in H. gracilis .

Secondary sexual characters. Male elytral apices conjointly rounded, with very small sutural notch. Female elytral apices slightly conjointly rounded ( Figure 1C ), with a more or less large V-shaped sutural notch, typical of members of H. gracilis complex ( Figure 1C,D ). Female ventrites V and VI with fringe of long setae. Male ventrite VI enlarged. Male tergite X as in H. gracilis and related species. Male mesotibiae with a row of about eight minute denticles along mesial face of posterior half. Male metatibiae with a fringe of long setae along mesial face of posterior half.

Differential diagnosis

Hydraena gracilidelphis is clearly related to other members of the H. gracilis complex ( Figure 1A–D ). The new species could be distinguished from H. gracilis , H. nike , H. elisabethae and H. anatolica only by means of the male genitalia, in particular by the wider and slightly emarginated distal half of main piece in lateral view, and by the distinct hump on its pre-apical portion ( Figure 1A ).

In H. gracilis , the dorsal surface of distal half of aedeagal main piece, in lateral view, is narrower, straight without emarginations, and without the pre-apical hump.

Both H. crepidoptera and H. graciloides can be easily distinguished from H. gracilidelphis by means of male genitalia (the main piece in lateral view is obliquely truncate apically in H. crepidoptera , slender but with a wider apex in H. graciloides ) and by the markedly differently shaped elytra of the former two species (much more widely explanate at sides, and in H. crepidoptera also more parallel-sided distad).

Distribution

Hydraena gracilidelphis is endemic to Iberian Peninsula and French Pyrenees ( Figure 2 ). The new species is distributed in the north of Catalonia, the French and Spanish Pyrenees, the Cantabrian Mountains and the Iberian and Central Spanish Systems. The records from Cádiz ( Pretner 1931; Jäch 1995) and from Portugal, Algarve ( Sharp 1878), extend its distribution to the southwest of the Iberian Peninsula.

Despite several exhaustive field researches performed by different entomologists (e.g. Sáinz-Cantero 1989; Millán et al. forthcoming), H. gracilidelphis has never been collected in Sierra Morena and Sierra Nevada, where mainly rivers with granitic substrates are found, whereas this species seems to be associated with calcareous substrates.

A single record of H. gracilis from Sierra Nevada was reported by Rosenhauer (1856) but, as underlined by d’Orchymont (1936), this citation is surely wrong and refers to a different species (probably H. tatii Sáinz-Cantero and Alba-Tercedor 1989 ).

The Portuguese record of H. gracilis reported in Valladares and Montes (1991) [Villa Real in Trás-os-Montes ( Pretner 1931)] is definitely erroneous: the correct locality is in fact Villa Real in the Guipuzkoa province (now called Urretxu) in northern Spain, and not Villa Real in Portugal. Therefore, the locality of Algarve (Monchique: Sharp 1878) is currently the only Portuguese record for this species.

All other Iberian and Pyrenean specimens previously attributed to H. gracilis almost certainly belong to H. gracilidelphis .

Ecology

The new species lives in running water, usually in mountain streams with calcareous substrate ( Berthélemy 1966). According to Berthélemy and Whytton da Terra (1977)

it is a tolerant and eurythermal species, with a wide altitudinal range along the basins, at least between 135 and 1890 m above sea level ( Garrido González et al. 1994).

Etymology

The specific epithet of the new species refers to the close relationship between this species and H. gracilis , and to the shape of the apical portion of the aedeagal main piece, resembling (in lateral view) the head of a dolphin (delphis in Latin).

Figures

Figure 1. Aedeagi in right side view of (A) Hydraena gracilidelphis sp. nov. (Spain, León, Puerto de Panderrueda) and (B) Hydraena gracilis (Austria, Niederösterreich). (C) Female elytral terminations of: H. gracilidelphis sp. nov. (Spain, León, Puerto de Panderrueda); (D) H. gracilis (Italy, Friuli, Stregna). Scale bar 0.25 mm; female elytral terminations not scaled.

Figure 2. Map of the geographic distribution of Hydraena gracilidelphis sp. nov. The green spot represents type locality.