Hydroporus rifensis, Manuel, Michael, 2014

Manuel, Michael, 2014, A new species of the genus Hydroporus Clairville, 1806 from the Central Rif mountains of northern Morocco (Coleoptera: Dytiscidae), Zootaxa 3841 (1), pp. 90-106 : 93-99

Hydroporus rifensis sp. n.

Figures 1 , 2, 4, 6 , 8–10 , 14, 15 , 18, 19 , 22–26 .

Type locality. Northern Morocco, Central Rif, Anasar, ca. 10 km WNW Bab Berred and 30 km ESE Chefchaouen, GPS coordinates 35°01'09.4''N 5°00'01.2''W, altitude 1,395 m.

Type material. Holotype (♂): “ 18.05.2013, Morocco, Central Rif, Anasar ca. 10 km WNW Bab Berred, ca. 30 km ESE Chefchaouen, 35°01'09.4''N 5°00'01.2''W, alt. 1395 m, among decaying vegetal material under trees on the margin of a large pond with Ranunculus and Callitriche plants, Manuel leg.” [printed], “ Holotype, Hydroporus rifensis sp. n., Manuel det. 2014” [red, printed] ( MNHN). Paratypes: 38 exs (18 ♂♂, 20 ♀♀), same data as the holotype ( MNHN, MNCN, CMM, CHF), including three DNA-extracted vouchers kept in CMM and two goldcoated paratypes mounted upside down (one male and one female) available at the MNHN for further SEM investigations. All paratypes with the respective red label.

Description. The following description relates exclusively to the male holotype until paragraph “Aedeagus” inclusively (note however that some of the pictures cited to illustrate holotype characters have been elaborated using paratypes). Variations of characters in the type series are given in a separate section at the end of the description.

Habitus ( Fig. 1 , left) oblong-elongate, with lateral outline slightly discontinuous at pronotal base. Head of moderate size; ratio between interocular distance and maximum pronotal width about 0.45. Body dorsally regularly and rather strongly convex. Elytron sides regularly curved; rather strongly attenuated towards posterior extremity.

Maximum width of body slightly before middle of total length, at about first third of elytral length. Ratio between maximum pronotal width and maximum body width about 0.85; at posterior angles pronotal width equalling width of elytra at shoulders. Pronotum dark ferrugineous with broadly testaceous margins; elytra brown with lateral borders and apex paler; head paler than pronotum and elytron. Entire dorsal surface microreticulated and rather strongly shining, with well-developed pubescence.

Head rufo-testaceous with two wide brownish markings between eyes and posterior part of vertex brown. Clypeus anteriorly rather strongly expanded; its anterior outline regularly rounded. Antero-lateral head outline discontinuous between clypeus and eye. Clypeus with two wide subcircular and densely punctated depressions. Entire head surface microreticulated with well-impressed polygonal meshes, these smaller and strongly transverse on vertex behind eyes. Punctures on head moderately coarse and dense, heterogeneous in size (their diameter equalling 1 to 2 meshes of microreticulation); behind eyes punctures very small and sparse; beside inner eye margin with a discrete irregular row of small punctures and meshes of microreticulation smaller. Small setae present only in clypeal depressions and along inner eye margin.

Pronotum dark ferrugineous with lateral margins broadly testaceous; transition to lateral paler colour rather sharp ( Fig. 1 , left). Posterior angles sharp and very slightly obtuse (almost right). Sides of pronotum converging from posterior angles; in posterior third straight then curving inwards. Posterior margin of pronotum medially strongly expanded backwards. Lateral margin with well-defined testaceous bead of moderate thickness (visible on Fig. 1 , left), distinct from anterior to posterior angle; in anterior half bead becoming gradually narrower in dorsal view (not in lateral view). Whole surface microreticulated with polygonal meshes except before continuous anterior line of small punctures (here meshes transverse); meshes more weakly impressed than on head except medially along posterior margin and laterally. On anterior part of disc meshes of about same size as on head; posteriorly becoming progressively smaller. On disc with moderately dense punctation ( Fig. 2 ); punctures of two size categories: small punctures of diameter about 1 mesh of microreticulation and larger coarse punctures with diameter equalling 1.5–2.5 meshes of microreticulation, latter more numerous; average distance between punctures about 3–4 meshes. Laterally punctation slightly denser with all punctures resembling larger punctures of disc. Posterior third of pronotum with small punctures and with rather dense and very coarse large punctures of diameter reaching about 3 meshes of microreticulation. Laterally before posterior margin punctation denser in shallow transverse depression. Punctures all bearing a conspicuous seta.

Elytra brown, distinctly paler than pronotum, with diffusely delimited paler areas on lateral margins and apex but without any defined drawing ( Fig. 1 , left). In lateral view elytral margin distinctly ascending towards humeral angle; epipleuron not visible until humeral angle. Elytral bead much thinner than pronotal bead in lateral view. Dorsal surface of elytra in anterior half rather regularly convex in profile as well as in frontal view. Microreticulation well-defined but rather finely impressed (meshes contiguous), with meshes distinctly larger than on pronotum ( Fig. 4 ); towards apex meshes more strongly impressed. Elytral punctation ( Fig. 4 ) rather fine and moderately dense; punctures homogeneous in size, their average diameter about 25 µm (2 meshes), with rare interspersed micropunctures; on elytral disc mean distance between punctures about twice diameter of punctures. Inner puncture line weakly discernible in anterior quarter; puncture lines otherwise indistinct. Pubescence welldeveloped ( Fig. 1 , left), each puncture bearing a rather long yellow seta; average length of elytral setae about 70 µm.

Ventral side. Head including genae and gula rufo-testaceous; contact line between gena and gula darker. Elytral epipleura testaceous. Ventral surface of prothorax rufo-testaceous except dark ferrugineous median region of prosternum. Rest of ventral surface black, except ferrugineous posterior part of metacoxal processes, light brown broad lateral markings and narrow posterior band on abdominal ventrites 3–4, and light brown abdominal ventrites 5–6, these darker medially along anterior margin. Genae with weakly impressed microreticulation; gula surface smooth with dense very small micropunctures, anterior half with large coarse punctures. Prosternal process (i.e. blade) ferrugineous, oblong-rhomboidal, gradually tapering backwards; in cross section rather wide, broadly and regularly convex (not roof like and not carinate) ( Fig. 8 ); its surface anteriorly microgranulose, posteriorly smooth and shining with a few small punctures; margin distinctly beaded; apex rounded ( Fig. 8 ). Entire surface of prosternal process provided with long golden setae. Between procoxae with well-defined transverse prominence, in ventral view slightly curved ( Figs 8, 9 ). File between prosternal base and blade narrow, its sides parallel; surface smooth and shining with several weakly impressed (almost indistinct) transverse grooves ( Fig. 9 ); file flanked by deeply excavated cavities in front of procoxa. Between anterior extremity of file and anterior prosternal margin surface microgranulose with small coarse punctures and short golden setae.

Whole surface of metacoxal plates microreticulated with finely impressed meshes; punctures coarse, moderately large and dense ( Fig. 6 ). Elytral epipleura with obsolete microreticulation; median region of metaventrite and most of interlinear space of metacoxal processes smooth, latter with a few small punctures; rest of ventral metathorax surface with finely impressed microreticulation; on sides of metaventrite punctures coarser and denser than on metacoxal plates. Midline of metacoxal processes deeply impressed over its entire length. Lateral lines of metacoxal processes distinct, weakly divergent anteriad ( Fig. 10 ), ending shortly behind posterior margin of metaventrite; metacoxal lines internally bordered by narrow grooves. Posterior margin of metacoxal processes medially slightly prolonged backwards, very slightly concavely sinuate along sides ( Fig. 10 ). Whole surface of abdominal ventrites 1–5 finely microreticulated; on abdominal ventrite 6 microreticulation much more strongly impressed. On abdominal ventrites 3–5 and anterior part of abdominal ventrite 6, meshes with transverse orientation. Punctures coarse and dense on abdominal ventrites 1–2; punctures much smaller and sparser on abdominal ventrites 3–4; on abdominal ventrite 5 punctation denser; on abdominal ventrite 6 punctures distinctly larger and much denser (average distance between punctures about one diameter of a puncture). Distinct and rather long setae present everywhere except on metepisterna and sides of metaventrite; midline of abdominal ventrites 4 and 5 bearing a small dense brush of long golden setae.

Appendages. Antennomeres 1–4 testaceous; antennomeres 5–10 dark brown with basal third testaceous; antennomere 11 dark brown with basal quarter testaceous ( Fig. 1 , left). Antennomeres 5–10 elongate, their length equalling 2.5–3 times their width. Palpi testaceous; last article of maxillary palpi infuscate near apex. Legs uniformly rufo-testaceous. Ventral surface of pro- and mesotarsomeres 1–3 bearing numerous densely packed small trumpet-like (distally enlarged) setae ( Fig. 14 ); central ventral surface of first pro- and mesotarsomeres provided with 6 sucker cups arranged in two longitudinal rows in an area devoid of small trumpet-like setae; 2 additional sucker cups inserted on ventral surface of second pro- and mesotarsomeres towards their proximal extremity ( Fig. 14 ). Ventral surface of fifth protarsomere provided with 4–6 thick setae ( Figs 14 , 18 ). Anterior protarsal claw in dorsal or ventral view distinctly thicker and shorter than posterior claw (this character visible on Fig. 14 ); in lateral view broader in proximal half and much more strongly curved than posterior claw ( Fig. 18 ).

Aedeagus. Median lobe in lateral and ventral views as in Figs 22–23 ; parameres as in Fig. 24 .

Measurements. Holotype: total length (TL) 4.3 mm, total length without head 3.8 mm, maximum width (MW) 2.05 mm, ratio TL/MW 2.08. Paratypes: TL 4.0– 4.35 mm (4.15 ± 0.09), TL without head 3.6–3.9 mm (3.75 ± 0.07), MW 1.9–2.1 (2.02 ± 0.05), TL/MW 2.01–2.15 (2.05 ± 0.03).

Females. Second protarsomere longer than in male (compare Fig. 15 and Fig. 14 ). Fifth protarsomere shorter than in male (compare Fig. 15 vs. 14, and Fig. 19 vs. 18); its ventral surface bearing only two (exceptionally three) thin setae inserted towards distal extremity ( Figs 15 , 19 ). Anterior and posterior protarsal claws of identical shape and size ( Fig. 19 ). Ventral central surface of pro- and mesotarsomeres 1–2 without sucker cups ( Fig. 15 ). Gonocoxosternum as in Fig. 25 ; gonocoxa as in Fig. 26 .

Variation globally weak among type series. Lateral outline in some paratypes almost continuous; in others slightly more discontinuous than in holotype. In a few specimens colour contrast between pronotum and elytra stronger than in holotype (elytra testaceous-brown). On head symmetric brown markings between eyes confluent in most paratypes; in a few specimens on contrary these markings separated medially. Posterior part of vertex pale brown to dark brown depending on specimens. Extension of paler colour on lateral and posterior part of elytron somewhat variable. In one female paratype, microreticulation on head markedly more strongly impressed and punctation finer than in other specimens of type series. Antennomeres 5–10 with testaceous colour restricted to basal quarter instead of basal third in some specimens; their shape slightly variable. Thickness of lateral bead of pronotum slightly variable. In some specimens lateral margins of pronotum less convergent in anterior half than in holotype. Punctation of pronotal disc quite variable; in some specimens denser than in holotype; sometimes decisively finer medially than laterally. In some specimens small punctures (1 mesh) not restricted to disc but also present laterally on pronotum. Mean size of elytral punctures slightly variable; in a few paratypes punctures a bit larger than in holotype, in others distinctly finer. In some specimens inner puncture line a bit more distinct than in holotype. In some specimens genae slightly darker than gula. In most mature paratypes, pale markings on abdominal ventrites 3–6 darker than in holotype (ferrugineous instead of pale brown). Some specimens with surface of gula lacking micropunctures or these restricted to posterior gula area. Shape of prosternal process in most specimens slightly narrower than in holotype (oblong-lanceolate); in some slightly more narrowly convex in cross section; sometimes apex a bit more acute than in holotype; ventral surface of prosternal process mostly smooth in many paratypes. In some specimens antero-medial region of prosternum (before file) partly smooth.

Anterior half of metacoxal lines in most specimens subparallel; sometimes a bit more divergent. Degree of impression of ventral microreticulation somewhat variable, notably on metacoxal plates. Brushes of long golden setae on middle of abdominal ventrites 4–5 lacking in most paratypes. Some specimens with pro- and mesotarsomeres and apical part of metatarsomeres slightly darkened.

Habitat. All specimens of the type series were found in May 2013 in a single large pond (dimensions about 100 m x 80 m) close to the N2 road at Anasar, Central Rif, ca. 10 km WNW Bab Berred, at an altitude of 1,395 m. Around this pond the vegetation was dominated by shrubs and sparse trees on the upper (north-western) side, while the lower (south-western) side was more impacted by human activities with a prevalence of cultivated fields. At the period of visit, the pond was densely vegetated ( Fig. 32) with Ranunculus sp. and Callitriche sp. aquatic plants, moderately abundant filamentous green algae, and scattered tufts of Juncus sp. The water was very transparent and there was no sign of pollution or other anthropogenic perturbation apart from a few scattered plastic objects. The shallow depth of this lentic water body and the aspect of the vegetation are indicative of a probable temporary nature. During wet periods the water is slowly renewed as deduced from the presence of a little brook leaving the pond towards the South (visible on Google Earth). Within the pond, specimens of H. rifensis sp. n. were extremely localised. They were found exclusively in a zone along the northern pond edge characterised by an accumulation of decaying vegetal material under trees (this zone located on the extreme right of the photo Fig. 32).

Biology. About half of the collected specimens were teneral, indicating that May is a period of intense imago emergence.

Study area. Within the Betic-Rif massif, the collecting site belongs to the external domain, separated from the more northern internal domain by the Jebha fault line which runs in a NW-SE orientation a few kilometres north from the sampling site ( Chalouan et al. 2011). The pond where H. rifensis sp. n. was discovered is more precisely located in the intra-Rif structural zone close to its northern margin, at about 30 km from the Mediterranean coast. The local geological substrate is a complex assemblage of radiolaritic argilites, calcareous marls and gresocalcareous turbidites of Upper Cretaceous (Cennomanian) age ( Chalouan et al. 2011). The pond is housed in a shallow depression along the southern versant of a mountain which culminates at an altitude of about 1,750 m, just 1.5 km north from the collecting site. The upper part of this mountain (up from the northern side of the road) corresponds to Lower Cretaceous flysh of the Tisirene nappe ( Chalouan et al. 2011), resting in abnormal contact onto the intra-Rif Cennomanian rocks. Various running water bodies originate from the northern versant of this mountain including an important coastal river, Oued Bouchia. Abundance of water in the area results from Central Rif being the most rainy place of all Morocco, with exceptionally high average annual precipitations (between 1,000 and 1,500 mm in Ketama, 40 km ESE from the type locality, at a similar distance from the sea and at a comparable altitude). Precipitations are highest from November to April and minimal in July–August (data from fr.meteovista.be). The area is also characterised by cold temperatures in winter owing to the altitude.

Derivatio nominis. The specific epithet rifensis (“from the Rif”) refers to the geographic area where the species was discovered. It is an adjective in the nominative singular.

Distribution. So far only known from the type locality, a single pond at Anasar, Central Rif (northern Morocco).

Figures

FIGURE 1. Habitus of Hydroporus rifensis sp. n. (left) (holotype, male) and Hydroporus gyllenhalii (right) (male specimen from Puente de Sanabria, Zamora province, Spain, Fery leg. 22 VII 1987).

FIGURES 2 – 7. Microsculpture of pronotal disc (2, 3), anterior juxta-sutural region of elytral disc (4, 5) and antero-lateral region of metacoxal plate (6, 7) of (2, 4, 6) Hydroporus rifensis sp. n. (2, 4: paratype, male; 6: paratype, female) and (3, 5, 7) H. gyllenhalii (3, 5: male specimen from Rigny-Ussé, Touraine, France; 7: female specimen from same locality). Figures 2 – 5 were done using a stereomicroscope with a nearly horizontal light source; pictures 6 – 7 are SEM views. All pictures shown at same scale (scale bar: 0.1 mm).

FIGURES 8 – 13. SEM views of selected structures of the ventral side of (8 – 10) Hydroporus rifensis sp. n. (8, 10: paratype, female; 9: paratype, male) and (11 – 13) H. gyllenhalii (female specimen from Rigny-Ussé, Touraine, France). (8, 11) Prosternal process; (9, 12) anterior extremity of prosternal process and file in front of prosternal process; (10, 13) metacoxal lines and metacoxal apophysis. Anterior on top in all pictures. Scale bars: 8, 10, 11, 13: 0.1 mm; 9, 12: 0.05 mm.

FIGURES 14 – 17. SEM views of ventral side of left protarsus in male (14, 16) and female (15, 17) of (14 – 15) Hydroporus rifensis sp. n. (paratypes) and (16 – 17) H. gyllenhalii (16: male specimen from Fontainebleau, Ile-de-France, France; 17: female specimen from Rigny-Ussé, Touraine, France). Anterior on the left in all pictures. Scale bars: 0.1 mm.

FIGURES 18 – 21. Drawings of fifth protarsomere and anterior claw (top) and posterior claw (bottom) in male (18, 20) and female (19, 21) of (18 – 19) Hydroporus rifensis sp. n. and (20 – 21) H. gyllenhalii. All drawings at same scale (scale bar: 0.1 mm).

FIGURES 22 – 31. Male and female genitalia of (22 – 26) Hydroporus rifensis sp. n. (paratypes) and (27 – 31) H. gyllenhalii (specimens from Plévenon, Bretagne, France). (22, 27) Median lobe of aedeagus in profile view; (23, 28) median lobe of aedeagus in ventral view; (24, 29) left paramere (external view); (25, 30) left gonocoxosternum (external view); (26, 31) gonocoxa (ventral view). Homologous structures shown at same scale for both species. Scale bars: 22 – 25, 27 – 30: 0.1 mm; 26, 31: 0.05 mm.