Stictonectes abellani Millán, Picazo & Fery, 2013

Millán, Andrés, Picazo, Félix, Fery, Hans, Moreno, José Luis & Sánchez-Fernández, David, 2013, Stictonectes abellani sp. n. (Coleoptera: Dytiscidae: Hydroporinae) from the Iberian Peninsula, with notes on the phylogeny, ecology and distribution of the Iberian species of the genus, Zootaxa 3745 (5), pp. 533-550 : 534-541

Stictonectes abellani Millán, Picazo & Fery sp. n.

Stictonectes optatus (Seidlitz, 1887) ; Guignot 1959: 420 (partim); Ribera et al. 1999: 60 (partim); Fery & Fresneda 2007: 140, 147 (partim).

Type locality: Spain, Cáceres province, ca. 15 km S Coria, ca. 39.9N 6.5W.

Type material: Holotype: ♂, " 27.5.1990 (E) Cáceres, ca. 15 km S Coria, ca. 320 m, ca. 39.9N 6.5W, pond in brook, Fery leg.", " Holotype, Stictonectes abellani sp. n., Millán, Picazo & Fery det. 2013" [red, printed] (NMW). Paratypes: Spain: 48 ♂♂, 100 ♀♀, same data as the holotype (EAM, CHF). 3 ♂♂, 4 ♀♀ " 3.7.1988 (E) Cáceres, S Coria, ca. 5 km SW Cañaveral, ca. 220 m, ca. 39.76N 6.43W, brook, Fery leg." (CHF). 2 ♂♂, "9.08.1984 (E) Cáceres, ca. 10 km N Moraleja, ca. 2 km N Perales del Puerto, ca. 390 m ", " Sra de St. Olalla, affl. riv. de Acebo, small brook, Fery leg., 40.167412N 6.679499W " (CHF). 5 ♀♀, " 6.9.2010, Spain, Cáceres, Serradilla, Arroyo Trasierra (Garganta Fraile). PN Monfragüe, 330 m, 39.83538N 6.10076W, Sánchez-Fernández & Abellán leg. " (EAM). 2 ♂♂, " 7.9.2010, Spain, Cáceres, Embalse de Torrejón, Toril, Arroyo Gargantilla. PN Monfragüe, 250 m, 39.82727N 5.91855W, Sánchez-Fernández & Abellán leg." (EAM). 1 ♂, " 7.9.2010, Spain, Cáceres, Villarreal de San Carlos, Serradilla, Arroyo de Malvecino. PN Monfragüe, 307 m, 39.8520097N 6.03968W, Sánchez-Fernández & Abellán leg." (EAM). 1 ♂, 1 ♀, " 7.9.2010, Spain, Cáceres, Salto de Torrejón, Toril, Charca, arroyo de las Cansinas. PN Monfragüe, 256 m, 39.83866N 5.93890W, Sánchez-Fernández & Abellán leg." (CIE). 1 ♀, " 7.9.2010, Spain, Cáceres, Villarreal de San Carlos, Serradilla, Charca, Villarreal de San Carlos, PN Monfragüe, 292 m, 39.84529N 6.02824W, Sánchez-Fernández & Abellán leg." (EAM). 3 ♂♂, " 23.7.2011, Spain, Cáceres, Alía, Arroyo de la Jarigüela en Alía, 650 m, 39.48993N 5.24888W, Millán & col leg." (EAM). 2 ♀♀, " 27.5.1990 (E) Ciudad Real, Montes de Toledo, W Retuerta del Bullaque, brook, ca. 750 m, ca. 39.46N 4.48W, Fery leg." (CHF). 1 ♂, " 1.7.1992 (E) Ciudad Real, NW Malagón, brook, ca. 39.21N 3.89W, ca. 650 m, Fery leg." (CHF). 1 ♀, " 28.10.2002, Spain, Ciudad Real, Abenójar, Río Tirteafuera, 560 m, 38.88837N 4.40569W, Moreno & col leg." (EAM). 1 ♂, " 12.6.2008, Spain, Ciudad Real, Salto de Torrejón, Toril, Arroyo de las Cansinas. PN Monfragüe, 228 m, 39.84039N 5.95241W, Ribera & Abellán leg." (CDTB). 2 ♀♀, " 7.7.2008, Spain, Ciudad Real, Alcoba, Arroyo de los Pescados, PN Cabañeros, 657 m, 39.32006N 4.51300W, Millán & col leg." (IBE, DNA of one female extracted, voucher number IBE-PA312). 5 ♀♀, " 11.6.2009, Spain, Ciudad Real, San Lorenzo de Calatrava, Río Rigüelo, 532 m, 38.45744N 3.87100W, Moreno & Picazo leg." (IBE). 7 ♂♂, 9 ♀♀, " 27.7.2012, Spain, Ciudad Real, San Lorenzo de Calatrava, Río Rigüelo, 532 m, 38.45744N 3.87100W, Picazo & Millán leg." (EAM). 1 ♂, 7 ♀♀, " 8.6.2009, Spain, Ciudad Real, Villamanrrique, Río Dañador, 772 m, 38.44770N 2.99503W, Moreno & col leg." (EAM). 1 ♂, 2 ♀♀, " 9.6.2009, Spain, Ciudad Real, Huertezuelas, Arroyo de la Nava del Rey, 578 m, 38.52618N 3.80816W, Moreno & Picazo leg." (2 ♀♀ EAM; 1 ♂ IBE, DNA extracted, voucher number IBE- PA313). 1 ♀, " 10.6.2009, Spain, Ciudad Real, Puerto de Niefla, Brazatortas, Arroyo de los Caballeros del Escorial, 742 m, 38.51053N 4.39842W, Moreno & Picazo leg." (EAM). 2 ♀♀, " 11.6.2009, Spain, Ciudad Real, Ventillas, Fuencaliente, Arroyo de la Aliseda, 705 m, 38.48957N 4.28841W, Moreno & Picazo leg." (EAM). 3 ♂♂, 1 ♀, " 27.7.2012, Spain, Ciudad Real, Ventillas, Fuencaliente, Caño de Ventillas, 685 m, 38.49660N 4.29358W, Picazo & Millán leg." (EAM). 3 ♂♂, 5 ♀♀, " 4.8.2009, Spain, Ciudad Real, Ventillas, Fuencaliente, Caño de Ventillas, 685 m, 38.49660N 4.29358W, Millán & col leg." (EAM). 1 ♀, " 26.5.1990 (E) Córdoba, N Villa del Río, pond in brook, ca. 38.05N 4.29W, ca. 400 m, Fery leg." (CHF). 16 ♂♂, 14 ♀♀, " 16.3.1997 (E) Jaén, ca. 60 km N Andújar, ca. 38.32N 4.083W, ca. 630 m, brook, Fery leg." (CHF). Portugal: 1 ♀, " 20.7.1987 (P), N Odemira, S São Luíz/ Cercal, pond, 37.682N 8.656W, Fery leg." (CHF). 2 ♂♂, 2 ♀♀, " 29.7.1989 (P) NE Vilanova de Milfontes, Brunheiras-Cercal, brooklet/reservoir, ca. 190 m, 37.784N 8.712W, Fery leg." (CHF). 1 ♂, 3 ♀♀, " 25.5.2010, Portugal, Baixo Alentejo, Vale de Vargo, Serpa, Río Enxoé (1.2), 223 m, 37.96288N 7.38505W, A. Mellado leg." (CHF). 1 ♀, " 26.5.2010, Portugal, Baixo Alentejo, Vale de Vargo, Serpa, Río Enxoé (7.3), 201 m, 37.96268N 7.39905W, A. Mellado leg." (EAM). 2 ♀♀, " 26.5.2010, Portugal, Baixo Alentejo, Vale de Vargo, Serpa, Río Enxoé (6.3), 195 m, 37.99003N 7.4200973W, A. Mellado leg." (EAM). 2 ♂♂, 5 ♀♀, " 26.5.2010, Portugal, Baixo Alentejo, Vale de Vargo, Serpa, Río Enxoé (2.1), 238 m, 36.16817N 7.41633W, A. Mellado leg." (CAM). 1 ♂, " 27.5.2010, Portugal, Baixo Alentejo, Vale de Vargo, Serpa, Río Enxoé (7.2), 198 m, 37.98270N 7.42572W, A. Mellado leg." (MNCN). 2 ♀♀, " 27.5.2010, Portugal, Baixo Alentejo, Vale de Vargo, Serpa, Río Enxoé 3, 219 m, 37.97423N 7.3920095W, A. Mellado leg." (EAM). Notes: All paratypes are provided with the respective red printed labels.

Description. The following description relates chiefly to the male holotype. Variations of characters in the paratypes are given in a separate section at the end of the description.

Habitus oval in dorsal view ( Fig. 1 ), broadest near middle of elytra, apex pointed; rather vaulted in lateral view. Upper surface black with brownish pronotal margin and yellowish elytral pattern; surface appearing silky matt although reticulation almost totally absent; this being due to rather dense punctation, in particular with stellate punctures (see figs 2A and 2B in Bilton 2011 for a detailed view of stellate punctures).

Head mainly black; clypeus anteriorly dark brownish; anterior part of clypeus with dark brownish distinct rim, medially rim shallower ( Figs 2 a, b). Clypeal grooves shallow; alongside inner margin of eyes with strongly impressed groove. Vertex reticulated, rest smooth. Head provided with (normal) punctures, these becoming larger and denser posteriad, particularly coarse and dense in mid of frons and in shallow clypeal grooves. On vertex punctures again smaller. Except rim and vertex entire surface between normal punctures with numerous stellate punctures. Setae absent, except very few in grooves on clypeus and alongside eyes.

Pronotum black with sides between sublateral stria and pronotal margin brownish, lighter yellowish brown in anterior half ( Fig. 1 ). Sides almost straight in posterior two thirds, before slightly curved inwards. Sides with narrow rim, anteriorly somewhat broader. Short sublateral striae present ( Figs 2 a, b), but scarcely recognisable if inappropriately illuminated. Disk weakly impressed. Surface without reticulation, densely covered with normal punctures, these smaller on disk, coarser anteriad and laterally intern of striae, especially coarse before posterior margin. Between stria and margin punctation very dense and appearing rugose. Entire surface between normal punctures with numerous stellate punctures. Setation rather dense and prominent because most normal punctures provided with one seta.

Elytra mostly black with rather small yellowish brown spots ( Fig. 1 ). Sides in dorsal view almost evenly curved; elytra at apex not conjointly rounded, but pointed. Elytron and epipleuron separated by fine rim of equal width. Rim in lateral view moderately ascending to humeral angle and epipleuron not visible up to humeral angle. Discal and sutural puncture lines absent. Surface mostly covered with larger normal punctures (diameter similar to that of punctures on pronotal disc); most punctures "horseshoe-like" with anterior border rather sharp and posterior border weak or absent. Near elytral apex punctation denser, rather rugose. As on head and pronotum, entire surface between normal punctures with numerous stellate punctures. Setation rather dense, similar to that of pronotum.

Ventral side black to large extent; general appearance matt due to mostly rugose sculpture; simple reticulation largely absent. Underside of head—including mouthparts—reddish brown, genae and gula of same colour. Without crease behind eye; wrinkles beside inner margin of eye at most very indistinctly indicated anteriorly. Surface of genae with small and flat, but distinctly vaulted cells of meshes; gula similarly structured, but cells smaller; provided with a few coarse punctures.

More lateral parts of underside of prothorax somewhat lighter reddish brown than head; prosternum strongly raised in middle, here blackish brown; between procoxae dark brown, same as prosternal process (behind procoxae). Large parts of surface covered with small protuberances; raised part of prosternum very rugosely structured; between procoxae with very distinct peak-like elevation (no transverse ridge), behind longitudinally carinate; prosternal process lanceolate, strongly carinate, sides only in anterior half flattened, without coarse punctures laterally; tip of process pointed, slightly curved upwards (if specimen studied with underside turned upwards); reaching far backwards between mesocoxae and onto anteromedial metaventral process; latter provided with shallow furrow for reception of prosternal process.

Mesepisternum and mesepimeron provided with relatively flat, but distinct protuberances. Metepisternum, metaventrite in large part, and metacoxal plates with distinct, almost conical protuberances. Metaventrite medially more shiny because protuberances reduced to almost simple reticulation. Metaventrite medially very dark brownish; metacoxal interlinear space, metacoxal processes and second to fifth abdominal ventrites medially diffusely limited brownish; hind margin of third to fifth ventrites brownish translucent. Epipleura yellowish brown. Metaventrite right and left of midline with line of some punctures, lines diverging weakly posteriad. A very few additional punctures in posterior part of metaventrite. Metacoxal plates with sparse and rather shallow, but well perceptible larger punctures. Metacoxal interlinear space smooth and shiny, provided with several punctures. Epipleuron with very small protuberances and without oblique humeral carina. Protuberances on first four abdominal ventrites somewhat unequally raised, thus, surface appearing as if provided with impressions or larger punctures. Only fifth and sixth ventrites with more distinct punctures.

Anteromedial metaventral process reaching far forward and distinctly in contact with mesoventral fork. Metepisternum behind anterior margin distinctly excavated; behind with a few rather large but shallow impressions. Metaventrite in mid vaulted, especially in anterior half; in central part with distinctly impressed narrow longitudinal groove. Lateral lobe of metaventrite ("wing") relatively narrow; ratio of width of wing and width of metacoxal plate (WS:WC) ca. 1:3 (cf. fig. 1 in Larson et al. 2000:35). Metacoxal lines weakly diverging anteriad (almost parallel), reaching hind margin of metaventrite. Metacoxal processes deeply incised, interlaminary bridge totally concealed; lobes of metacoxal processes evenly rounded, outline more or less elliptical in part. Last ventrite short before hind margin strongly raised, then abruptly descending before hind margin and here provided with short but very distinct and sharp keel, running until somewhat pointed apex.

Setation on underside—except on legs and epipleuron—not very prominent and sparse, much finer than on upper surface; more or less only perceptible if adequately illuminated; present mainly on prosternum, interlinear space of metacoxa and mid of second to fourth abdominal ventrites; very few setae on sides of prosternal process; epipleuron with distinct setae; last abdominal ventrite with a few setae at apical margin and short setae on end of raised part.

Appendages: Antennomeres 1–4 pale reddish brown, fifth darkened in distal half, 6–11 more or less uniformly dark brown. Fourth antennomere shorter than third and fifth, latter both almost equal in length, second antennomere almost as long as third and fourth together. Palpomeres reddish brown, last ones somewhat darkened distally. Pro- and mesoleg as well as entire metafemur and knee of metatibia reddish brown; else metatibia black; metatarsomeres black. First three protarsomeres somewhat broadened, mesotarsomeres less so. First pro- and mesotarsomeres provided with sucker cups (difficult to observe). Claws of pro-and mesotarsi equal in size and shape, evenly curved and not particularly prolonged.

Aedeagus with median lobe in ventral and lateral view as in Figs 3 c, d; parameres with characteristic long finger-like projection ( Figs 3 a, b in oblique lateral and frontal views). For comparison median lobe and parameres of S. optatus given in Figs 3 e–h (specimen from near Mogón, Sierra de Cazorla, Jaén, Spain).

Measurements: Holotype TL 3.6 mm, MW 2.0 mm; paratypes TL 3.4–3.9 mm, MW 1.8–2.1 mm. Females generally slightly larger than males.

Females cannot be separated externally from males, except by less broadened pro- and mesotarsomeres and lack of sucker cups on first tarsomeres (both difficult to observe and to assess without males for comparison). Gonocoxosternum and gonocoxa are not illustrated because they are similar to those of other species of the genus and, consequently, they are not helpful for diagnostic purposes (cf. figs 6–7 in Fresneda & Fery 1990 and fig. 7 in Bilton 2011).

Variability: Generally the variation of most features is weak. However, specimens vary both within and between localities in the extent of the yellowish elytral spots (cf. spectrum of elytral pattern in Fig. 4 a–d, upper row of specimens), and the brownish parts of the abdominal ventrites can be more or less extended; in some specimens the ventrites are entirely black except for the translucent hind margins.

Distribution: So far only known from central-southwest Iberia, mainly in the Guadiana basin, from the Sierra Morena range ( Spain) to the Baixo Alentejo region (Beja district, Portugal).

Etymology: Named after our friend and colleague Pedro Abellán. The specific epithet is a noun in the genitive case.

Ecology: The new species seems to prefer depositional microhabitats in temporary siliceous streams with a substrate mainly composed of gravel and large boulders, and coarse organic matter. Fig. 5 shows the Río Rigüelo near San Lorenzo de Calatrava (Ciudad Real). In some cases the species was collected in very eutrophic waters remaining in residual stream pools. The pH values in the more recently studied sites range from 7 to 8, conductivity from 30 to 900 µS/cm, nitrates from 0.01 to 0.6 mg /l and phosphates from 0 to 0.5 mg /l. The new species has been found three times together with S. occidentalis , and several times with S. epipleuricus , S. optatus and especially S. lepidus . It is remarkable that at "Vilanova de Milfontes" the new species could be found together with three other Stictonectes : S. lepidus , S. occidentalis and S. optatus .

In the type locality the new species was found together with Agabus didymus (Olivier, 1795) , Bidessus coxalis Sharp, 1882 , B. minutissimus (Germar, 1824) , Colymbetes schildknechti Dettner, 1983 , Deronectes opatrinus (Germar, 1824) , Graptodytes flavipes (Olivier, 1795) , G. ignotus (Mulsant & Rey, 1861) , Hydroglyphus geminus (Fabricius, 1792) , Hydroporus decipiens Sharp, 1878 , Laccophilus hyalinus ( De Geer, 1774) , Scarodytes halensis (Fabricius, 1787) , Stictonectes lepidus (Olivier, 1795) , Stictotarsus duodecimpustulatus (Fabricius, 1792) and Yola bicarinata (Latreille, 1804) .

Figures

FIGURE 1. Habitus of Stictonectes abellani sp. n.

FIGURE 2. Details of clypeus: Stictonectes abellani sp. n. (a) male, (b) female; S. optatus: (c) male, (d) female.

FIGURE 3. Genitalia of: (a – d) Stictonectes abellani sp. n.: parameres (a) in oblique lateral and (b) in frontal view (the arrows indicate the indistinct margin of the very transparent medio-lateral part of the parameres); median lobe (c) in ventral and (d) in lateral view; (e – h) S. optatus: parameres (e) in oblique lateral and (f) in frontal view; median lobe (g) in ventral and (h) in lateral view.

FIGURE 4. Colour pattern variability in (a – d) Stictonectes abellani sp. n. and (e – h) in S. optatus.

FIGURE 5. Río Rigüelo at San Lorenzo de Calatrava, collecting site of Stictonectes abellani sp. n. (Spain, Ciudad Real, Sierra Morena, ca. 532 m. Photo F. Picazo).