Hydraena lotti, Bilton, David T., 2013

Bilton, David T., 2013, Hydraena lotti sp. nov., a new member of the “ Haenydra ” lineage from the Peloponnese (Greece), with additional records of Hydraena species in the region (Coleoptera, Hydraenidae), Zootaxa 3637 (1), pp. 29-38 : 30-37

Hydraena lotti sp. nov.

( Figs 1–5)

Type locality. Greece, Pelopennese, Taygetos Mountains, Lagadha stream above Lagadha Pass on EO82 road between Kalamata and Sparti, 1,100 m, D.T. Bilton leg. ( Fig 5 ).

Type material. Holotype (male): “ 3/viii/2012 GR Peloponnese Taygetos Mts. Lagadha stream above Lagadha Pass on EO82 road 1,100 m D T Bilton leg.” (genitalia extracted and mounted on same card) and red holotype label (NMW).

Paratypes (97): Greece: 22 3, 11 Ƥ “ 3/viii/2012 GR Peloponnese Taygetos Mts. Lagadha stream above Lagadha Pass on EO82 road 1,100 m D T Bilton leg.” ( CAR, CDTB, CFA, CJF, IBE, NMPC, NMW); 2 3, 4 Ƥ “ 29/vi/2012 GR Peloponnese Taygetos Mts. Lagadha stream above Lagadha Pass on EO82 road 1,100 m D T Bilton leg. (CDTB); 20 3, 16 Ƥ “ 4/viii/2012 GR Peloponnese Taygetos Mts. headwater of Dzirorema stream ca. 2 km S of Neochori 1,150 m D.T. Bilton leg.” (CTV, MCZ, NHM, NMW, OUMNH, ZSM); 3 3, 4 Ƥ “ 4/viii/2012 GR Peloponnese Taygetos Mts. Sitsovitko stream above Machalas 1,100 m D.T. Bilton leg.” (CDTB); 7 3, 8 Ƥ “ 4/ viii/2012 GR Peloponnese Taygetos Mts. Boursos stream above Alaghonia 1,300 m D.T. Bilton leg.” (CDTB). All with red paratype labels.

Description. Size: Holotype: body length (to elytral apices) 2.2 mm; max. width (elytra) 0.77 mm. Head, pronotum and elytra black to blackish brown, somewhat lighter at all margins. Venter, lateral hypomera and pseudepipleura paler, with darker mentum. Legs reddish-brown; tarsi and maxilliary palps paler, especially towards their apices ( Fig. 1).

Head: Labrum with deep V-shaped sutural notch. Lobes each side of sutural notch shallowly concave, with reflexed margins. Concave areas of lobes with fine microsculpture and shallow punctures supplied with short reflexed setae, these setae being particularly evident close to outer margins. Central portion of labrum with a smooth, shiny triangular patch at clypeal margin. Clypeus with narrow, smooth and shiny anterior margin adjacent to this area. Remainder of clypeus with dense small, shallow punctures, and scattered deeper, slightly larger ones, some of which are supplied with short reflexed setae. Shallow punctures becoming much denser in lateral marginal fifths of the clypeus, giving these areas a rugose appearance. Frons with punctures which are both deeper and larger than those on the clypeus. Punctures on frons spaced approximately 1–2 puncture widths apart in centre, becoming confluent at lateral margins and around eyes, giving a rugose appearance to these areas. Each puncture on frons supplied with a small central reflexed seta; setae becoming longer towards lateral margins. Frons strongly shining in centre; outer regions less so.

Pronotum: Elongately hexagonal, with weakly denticulate side margins. Scattered, shallow open punctures throughout, these being 1– 2 x diameter of those on the frons. Front and hind areas of pronotum with punctures approximately 0.75–1 puncture widths apart over areas approximately ¼ of pronotal length. Puncture spacing similar in a narrow longitudinal band running down the centre of the pronotum. Lateral areas of pronotum with strong longitudinal fossae, which are deeper and broader in both front and hind thirds. Punctures on pronotum either side of fossae 1–2 puncture widths apart. Punctures in fossae shallow and sparse, giving a relatively smooth appearance to these areas. Outside fossae, pronotum smooth and shiny between punctures, with traces of reticulation developing towards front angles. Pronotal punctures supplied with fine recumbent setae, which are approximately two puncture widths long. Some setae lost, especially on disc. Wings reduced, approx. ½ length of elytra in specimens examined, and with weak venation.

Elytra: Elongate, subparallel, slightly rounded at sides and widest behind middle. Lateral margins explanate, particularly in posterior half, as in other members of the H. emarginata-saga clade. Margins apparently smooth, but weakly serrate at higher magnifications (> 60 x). Elytral apex conjointly rounded, with marked sutural notch ( Fig. 2 A). Elytral surface smooth and shining between the nine regular puncture rows. Each puncture of these rows with a fine, flat seta arising from a small tubercle at the front end of the puncture ( Fig. 2 A–B). Setae reaching backwards to front margin of next puncture in the row.

Venter: Front margin of mentum with a thin ventrally reflexed portion, furnished with fine, close, curved setae. Mentum finely reticulate, with a super-imposed network of raised ridges, giving a roughened appearance overall. Submentum densely covered in small shallow punctures; shining between punctures and around all margins of sclerite. Genae shining, with strong crenulated lines and weak reticulation between these at margins. Genal ridge obsolete; shining. Gular region heavily punctured and reticulate, except in centre and at hind margins. Lateral hypomeron of pronotum smooth, with shallow, confluent pits. Hypomeral carinae smooth and shining. Mesal hypomeron with dense hydrofuge pubescence. Pseudepipleura of elytra smooth and shining, concave due to reflexed dorsal margins of elytra. Entire meso- and metaventrites, and abdominal sterna covered in dense hydrofuge pubescence, with the exception of the metaventral plaques and abdominal ventrite VIII and a large adjacent semicircular area of ventrite VII. Areas with hydrofuge pubescence apparently also finely reticulate beneath these hairs. Metaventral plaques smooth and shining, without reticulation. Areas of sternites lacking hydrofuge pubescence with regular reticulation of large, open, meshes, these meshes becoming larger on ventrite VII and towards the apex of ventrite VIII. Glabrous area of ventrite VII with a row of punctures, each of which bears a long seta. Similar punctures with long setae concentrated towards the apex of ventrite VIII.

Legs: Mesotibia with stout setae and a row of small teeth on mesal face of posterior half ( Fig. 1, Fig. 4 E–F). Metatibia with a row of long setae on mesial face of posterior half ( Fig. 1, Fig. 4 A–B). Legs otherwise unmodified.

Aedeagus: Main piece drawn out into long, tapering finger-like projection, of characteristic shape ( Fig. 3 A). Distal lobe reflexed over the main piece, with long, thin tubular terminal appendage ( Fig. 3 A–C).

Female: Elytral apices bitruncate ( Fig. 2 B); not rounded as in males. Apices slightly raised, roof-like, in lateral view. Meso- and metatibia ( Fig. 4 C–D) without modifications seen in males. Gonocoxite and tergite X Fig. 2 C–D; spermatheca Fig. 3 D. Setae on glabrous areas of ventrites V and VI long, dense and golden.

Differential diagnosis. The new species is apparently a member of the H. emarginata complex (sensu Trizzino et al., 2013b) of the “ Haenydra ” lineage, sharing external and aedeagal characteristics with members of this group. Externally the new species most closely resembles Hydraena pelops Jäch, 1995 , known from the south and east of the Taygetos range. The two species are similar in size, colour, overall appearance, and modifications to male meso- and metatibia, and males are best distinguished on genitalia, which, whilst sharing the same basic pattern of the H. emarginata complex, differ markedly in the two species. Externally, H. pelops is more sparsely punctured on the frons than the new species, and the small punctures on the clypeus are also much shallower, both characters being present in both sexes. The elytral apices of males of the two species are almost identical, but females of H. lotti can be distinguished from those of H. pelops on this character: whereas the bitruncate apices of H. lotti are almost straight, as in Fig. 2 B, those of H. pelops slope inwards slightly towards the elytral suture. The truncate apices of the elytra of H. pelops are also typically narrower than in the new species, and more clearly serrate. Females of H. pelops have shorter hairs on the glabrous areas of ventrites V and VI than the new species, and the lateral apical margins of the gonocoxite are more concave, with longer setae.

H. lotti also resembles H. pangaei Jäch, 1992 , endemic to small springs on Mount Pangaeon in northeastern Greece, and H. samnitica Fiori, 1904 , from the central Apennines, particularly in the form of its aedeagus. The shape of the finger-like projection of the main piece differs between these species, however, as does the detailed structure of the distal lobe. Externally both H. pangaei and H. samnitica are somewhat larger at 2.5–2.7 and 2.3–2.7 mm in length respectively, and females of both species have more rounded elytral apices, those of H. samnitica much more so (see Trizzino et al., 2013b for details of these species).

Distribution. Found in four headwater streams, situated on closely adjacent sides of the watershed in the northwest of the Taygetos massif, where it is likely endemic. The type locality, the Lagadha stream, drains to the east, forming part of the Evrotas basin. The three remaining localities all drain to the west, being part of the Strogli and Nedhon drainages respectively. The short flight wings suggest poor dispersal ability, characteristic of many narrow-range endemics (see Bilton et al., 2001, Arribas et al., 2011).

Etymology. Named after the late Dr Derek Lott, in recognition of his contribution to the study of both aquatic and staphyliniform beetles.

Ecology. The new species is found in the upper reaches of swift flowing, first order streams, all four known localities being just above 1,000 m in altitude. Localities are apparently permanent, and mostly flow over a combination blue schist and metamorphosed siltstone. Most streams in the Taygetos flow over limestone, and geology may be important to the distribution of “ Haenydra ” in the region, although more data are required before firm conclusions can be drawn. H. lotti is most abundant in small shallow riffles, particularly under stones. In the type locality above Lagadha Pass ( Fig. 5 ) it shared this microhabitat with Deronectes moestus (Fairmaire) , Hydroporus tesselatus Drapiez , Agabus biguttatus (Olivier) , Hydraena armipes Rey, H. christinae Audisio, De Biase & Jäch, H. georgiadesi Orchymont, H. helena Orchymont, H. meschniggi Pretner, H. morio Kiesenwetter, H. subjuncta Orchymont , Ochthebius montenegrinus Ganglbauer, O. striatus (Castelnau), Elmis and Limnius species and Hydrocyphon novaki Nyholm. In Dzirorema and Boursos streams the species was found together with Deronectes moestus , Hydroporus tesselatus , Agabus biguttatus , Hydraena aroensis Ferro, H. christinae , H. morio , H. subjuncta , Ochthebius montanus Frivaldzsky, Hydrocyphon novaki , Elmis spp. and Limnius spp. Accompanying species in the Sitsovitiko stream were Hydraena aroensis , H. helena , H. morio , H. subjuncta , Elmis spp. and Limnius spp. In all localities H. lotti sp. nov. was the commonest Hydraena , with the exception of H. morio and H. subjuncta . The stream above Lagadha Pass flows through pine forest and is fringed with a riparian strip of Platanus orientalis L., whilst other localities are in areas burned during fires earlier this century, when the forest cover of parts of the western Taygetos was damaged or lost. These sites are mostly fringed by remnant resprouting trees and secondary scrub growth. So far the new species has not been collected together with H. pelops , which to date has been found further south and east in the Taygetos range.

Annotated checklist of Peloponnese species of the “ Haenydra ” lineage * Hydraena aroensis Ferro, 1991

Previously known only from the northern Peloponnese, (Audisio et al., 1996; Trizzino et al., 2013b). Recorded together with H. lotti sp. nov. at three localities in the northwestern Taygetos in 2012 (see above), and 28/vi/ 2012, Greece, Peloponnese, Taygetos Mts., Vrisiotiko Bk. nr. Kastorio, 500 m, D.T. Bilton leg., these extending the range of the species south considerably.

* Hydraena christinae Audisio, De Biase & Jäch, 1996

Widespread in mountain streams and rivers along the central spine of the Peloponnese, from Achaia to the southern Taygetos.

Hydraena epeirosi Ferro, 1985

Cited from the Peloponnese by Trizzino et al (2013b). I can add the following record – 24/vi/2012 Greece, Peloponnese, Selinoudas River below Kato Vlasia, 700 m, D.T. Bilton leg.

* Hydraena jaechiana (Audisio & De Biase, 1990)

The commonest “ Haenydra ” in the peninsula – widespread in streams and larger rivers.

* Hydraena lotti sp. nov.

Four streams in the northwestern section of the Taygetos, all flowing over metamorphosed mudstones and schists.

* Hydraena pelops Jäch, 1995

Known from the southern and eastern sections of the Taygetos range, in permanent sections of high altitude streams. I can add the following record – 30/vi & 3/viii/2012 Greece, Peloponnese, Loga stream above Anogia, 800 m, D.T. Bilton leg.

Hydraena vedrasi Orchymont, 1931

A widespread SE European species, which in the Peloponnese is so far only recorded from the northern mountains.

Figures

FIGURE 2. Hydraena lotti sp. nov. A) male elytral apex; B) female elytral apex; C) female tergite X; D) gonocoxite.

FIGURE 3. Hydraena lotti sp. nov. A) aedeagus, lateral view; B) aedeagus dorsal view; C) aedeagus dorsolateral view; D) spermatheca.

FIGURE 4. Hydraena lotti sp. nov. A) – B) male metatibia; C) – D) female metatibia; E) – F) male mesotibia.

FIGURE 5. Type locality of Hydraena lotti sp. nov. Greece, Peloponnese, Taygetos Mountains, Lagadha stream above Lagadha pass, 1,100 m. Photo D. T. Bilton.