Eucoryphus piscariviverus, Pusch & Stark & Pollet, 2020

Pusch, Martina H. E., Stark, Andreas & Pollet, Marc, 2020, Description of a new Eucoryphus species from the island of Corsica, France (Diptera: Dolichopodidae, Hydrophorinae), Zootaxa 4816 (4), pp. 527-540 : 530-531

Eucoryphus piscariviverus sp. nov.

( Figs 3–9 )

Material examined. HOLOTYPE ♂, inner label: | Eucoryphus piscariviverus Pusch, Stark & Pollet , | 2020 Holotype, ♂, 80 % Ethanol , France, | Corse, brook Ruisseau de Casso below Monte | Renoso, south of Ghisoni, 42°2′59.5″N, | 9°9′10.9″E, 1,880 m a. s. l., 9th August 1993, | pooter, on a large bolder near a small | waterfall, leg. M. H. E. Pusch | ( SDEI) . PARATYPES: 1 ♀, same data as holotype ( SDEI) ; 5 ♂, Zonza , Samulaghia (sampling site code: SA-BYWPT-03), 41°45′39.6″N, 9°13′37.2″E, 1244 m, 24–28.vi.2019, blue pan traps, leg. M. Pollet ; 8 ♂, 2 ♀, same location (sampling site code: SA-BYWPT-02), 41°45′70.3″N, 09°13′64.9″E, 1208 m, 24–28.vi.2019, blue pan traps, leg. M. Pollet ; 2 ♀, same location (sampling site code: SA-BYWPT-01), 41°45′42.26″N, 09°13′39.99″E, 1271 m, 28.vi.2019, collected by hand, leg. M. Pollet & A. De Braekeleer (Zonza specimens deposited in MNHN, RBINS, Pusch PC, Stark PC and MAPC) .

Etymology. The most striking feature of the male of the new species is its antenna. The shape of the appendages reminded the authors of a “fishing rod”, the modified dorsal ray (illicium) of deep sea anglerfishes. We therefore decided to fix this in the specific epithet: piscariviverus => “piscari” = “fishing” (verbum, infinitivum) and “vivere” = “living”.

Diagnosis. Medium-sized dolichopodid species with body length 3.7 mm and wing length 3.3 mm. Antenna of unique shape: scape invisible, hidden below the hypertrophied, reniform pedicel; postpedicel flattened with brown edge and barge- or bean-shaped stylus with a small cup-shaped basal part, followed by a bowed apical part, similar to the fishing rod (illicium) of deep sea anglerfishes, having a sphere-shaped base and a bottle-brush-shaped tip. Long and slender legs sparsely bristled, in male with MSSC on tarsi of leg I: basal tarsomere of leg I yellowish, only tip infuscate, and tarsomeres 2–5 infuscate and dorsally with hook-shaped bristly setae, nearly as long as diameter of segments. Currently only known from montane habitats in southern Corsica.

Description. Male ( Fig. 3 ). Body length (from base of antenna to end of abdomen): 3.7 mm; wing length: 3.3 mm, wing width: 1.3 mm (= 0.4 × as wide as long). Head ( Fig. 4A, B ). Clypeus covered with silvery pile, showing light purple metallic reflection, parallel-sided, narrowed to tongue-shaped, slightly rounded triangular apex, extended beyond lower edge of compound eye by 1/4 th of eye height. Facial margin indicated by rounded bulge. Face small, mainly covered by lower hypertrophied pedicel. Frons with dark metallic purple-green ground colour with thin silvery pruinosity. Occiput with dark metallic green ground colour, chagrined and slightly shimmering with purple. Palpus 1/4 of eye height, triangular, whitish yellow with dense whitish pile and some longer whitish setae apically. Eyes with metallic magenta-purple shimmer and short white ommatrichia. Ocellar setae thick and rather short, divergent and directed forward. Pair of outer vertical setae strong and sinuous, directed forward and inward. One pair of inner vertical setae, half as long as outer vertical setae and distinctly stronger than postocular setae; positioned mediad of outer vertical setae and dorsad of postocular setae. Most postocular setae strong and white, becoming longer and stronger towards lower part of head, upper 3‒4 setae shorter and dark. Antenna with complex shape ( Figs 3–5 ). Basic colour of antenna whitish yellow. Scape hidden by pedicel, latter bean-shaped, hypertrophied, with brownish-black appressed, hook-shaped setae. Postpedicel barge- or bean-shaped (in lateral view), flat, with brown anterior edge and long dense white setae, some hook-shaped; lower corner bent outward, with cluster of 7–8 somewhat curled, long, basally whitish and apically brownish setae; stylus with 1 st article whitish yellow and 2 nd article brownish with white base, latter distinctly curved, pubescent on apical half. Thorax ( Fig. 5 ). Mesonotum, scutellum and thoracic pleura entirely metallic green, with slight silvery pruinosity. Scutellum with 2 pairs of setae, lateral pair much smaller than median pair and rather pale, latter pair long and black. Nearly all thoracic setae black, with exception of white proepisternal and antepronotal setae. Acrostichal setae lacking. Six dorsocentral setae, remarkably different in length: first to third pair subequal, fourth pair only half as long, fifth pair longer than first three pairs, and sixth pair longest, nearly twice as long as first pair. One supra-alar seta and 1 notopleural seta of equal length, longer than prescutellar dorsocentral seta. One long dark postpronotal (“humeral”) seta, antepronotum with fringe of 6 whitish setae of equal length. Proepisternum with very long and strong white seta on basal half, directed up- and forward; with fine white hair at base of seta, and second seta half as long as anterior one in posterior part of proepisternum. Wing. Extending distinctly beyond tip of abdomen. Membrane hyaline, microtrichia equally distributed across wing surface, veins brown. Basal costal seta long, black. Costa with 2 rows of short and stiff black setae, disappearing beyond end of R 2+3. Veins R 4+5 and M 1 very slightly convergent, almost parallel; crossvein dm-m straight, nearly as long as apical section of M 4. Halter pale, calypteral fringe white. Legs long and slender. Overall appearance dark, legs I and II with contrasting whitish yellow regions on knees and basal tarsal segments ( Fig. 3 ). Darker parts of legs with light greenish metallic shimmer, more intense especially on coxae. Setation of legs generally sparse. Metatarsus of all legs roughly as long as following 4 tarsomeres combined. No modifications of pulvilli. Leg I: coxa I with irregularly arranged, whitish dorsal setae, most apical seta in av position longer and more conspicuous; trochanter I without differentiated setation; femur I slightly club-shaped with greatest diameter in basal third, with row of roughly 20 short black anterior setae; knee whitish yellow; tibia I with row of pale dorsal setae, roughly half as long as width of tibia; tarsus I with tarsomere 1 whitish yellow, tarsomeres 2–4 infuscate, dorsally with hook-shaped, bristly setae, nearly as long as diameter of segments (MSSC) (see Fig. 9B ); tarsomere 5 lighter than tarsomeres 2–4. Leg II: coxa II with 1 white av seta; femur II with 1 black ad preapical seta; knee whitish yellow; tibia II with 1 ad and 1 pd seta in basal third; second pair (ad and pd) slightly below middle of tibia with ad seta longer and more basal than pd seta; with circlet of three apical setae strictly directed apically; tarsus II with tarsomere 1 mainly pale, with apical third darkened; tarsomeres 2–5 dark, last segment only slightly lighter. Leg III: coxa III with 1 long and strong, white dorsal seta; trochanter III with long seta accompanied by several whitish setulae; femur III with 1 black ad preapical seta; knee dark; tibia III with 4 ad and 3 pd setae, more or less equally distributed over entire length of tibia; tarsus III entirely dark. Abdomen metallic green, sparsely silvery pruinose. Basal tergite with sparse whitish hairs, becoming more numerous on sides; lateral marginal setae very long, roughly ¾ as long as length of tergite. Tergites 2–4 with sparse setae only, becoming longer and darker at sides; marginal setae lacking. Five tergites visible, pubescent; tergites 4–5 prolonged ventrally, tergite 6 completely covered by tergite 5. Sternite 1 small, and sternites 1–3 only weakly sclerotised; sternite 1 with smooth protuberance at middle, pin-shaped in lateral view (best visible in moist stored material, compare Fig. 3 ). Sternite 4 distinctly modified ( Fig. 6 ), comprising dark V-shaped structure, with tongue-shaped or pillow-like base and branches, covered with short and stiff cone-shaped setae; basally with group of strong dark setae. Sternite 5 small, not visible in holotype. Hypopygium ( Fig. 7 ) (based on moist stored specimen) rather free, not enclosed by tergites 5–6 but not very prominent; epandrium dark, concolorous with tergites and covered with evenly scattered setae and setulae longer and thicker on proximal part; hypandrium stout with anvil-shaped apex, moderately shiny; epandrial lobe with prominent long dark seta; surstylus with 3 long setae; cercus 2 times as long as broad, dark, with long brownish upcurled setae.

Female ( Fig. 8A ). Body length (from base of antenna to end of abdomen): 3.5 mm; wing length: 3.5 mm, wing width: 1.4 mm (= 0.4 × as wide as long). Similar to male except as follows: Head ( Fig. 8B ). Face broader and clypeus much shorter, rounded apically without triangular tongue-shaped tip, only slightly extended beyond lower eye edge. Proboscis slightly larger. Antenna not modified, light brown, postpedicel bean-shaped, distinctly broader than long, with long whitish pubescence; stylus entirely brown, dorsal, straight. Inner vertical seta about as long as outer vertical seta. Uppermost 5–6 postocular setae dark-brown, changing to white on lower part of head. Abdomen. Sternite 1 with well-developed triangular projection in middle. Sternite 4 unmodified. Tergite 10 with three strong thorn-like dark acanthophorite spines at each side; cercus with 2 white setae, twice as long as dark setae ( Fig. 9A ).

Ecology. Eucoryphus piscariviverus sp. nov. is known from two montane locations in southern Corsica. At both locations the species was collected by hand on rocky substrates, and at Samulaghia the species was collected with blue pan traps as well. However, both collecting habitats are quite different. The Monte Renoso site is situated along the little brook Ruisseau de Casso, where it changes from a slow running one meter wide brook (after having passed through alpine meadows with low gradient) to a fast flowing brook with a very steep gradient surrounded by shrubs. The specimens were collected with a pooter at a sunny, hygropetric section on a large vertical rock (compare Fig. 1A ). In the pine woodland at Samulaghia (Zonza), on the other hand, it was collected by hand on dry flat rocks and with pan traps in only two of the four sites investigated with these traps. Ten specimens were collected on a shallow seep covering a rocky outcrop with a mild slope (compare Fig. 1B ), and five specimens in a wet marshland (compare Fig. 1C ); none were detected in traps placed in the dry woodland nor on a second larger more vertical and drier rocky outcrop. The latter 15 specimens were discovered only in blue pan traps. None of the other three locations that were investigated during the La Planète Revisitée survey in 2019 produced this species. This also holds true for the alpine pozzine site with ample dispersed rocks at Serra di Scopamène (Castellu d’Ornucciu) (compare Fig. 1D ) that resembles the type locality.

Figures

FIGURE 1. Collection localities of Eucoryphus piscariviverus sp. nov. A. The surroundings of the type locality below Monte Renoso, south of Ghisoni, Corsica (photograph by M.H.E. Pusch, 1993); B. Samulaghia (Zonza, southern Corsica), seep over slightly sloping rocks in pine forest; C. Same location, small marshland in pine forest; D. Pozzine landscape at Castellu d’Ornucciu (Serra di Scopamène, southern Corsica) (photographs B–D by M. Pollet, 2019).

FIGURE 3. Habitus of Eucoryphus piscariviverus sp. nov., holotype male, right lateral view and hand-written label of the micro-vial. Wing length 3.3 mm (photograph by A. Stark).

FIGURE 4. Eucoryphus piscariviverus sp. nov., holotype male. A. Head in lateral view; B. Head in frontolateral view (photographs by A. Stark).

FIGURE 5. Setation of head and thorax of the holotype male of Eucoryphus piscariviverus sp. nov., left lateral view (photograph by A. Stark).

FIGURE 6. Sternite 4 of holotype male of Eucoryphus piscariviverus sp. nov. A. Left lateral view; B. Angular view from behind to the upside-downed abdomen (photographs by A. Stark).

FIGURE 7. Hypopygium of holotype male of Eucoryphus piscariviverus sp. nov., left lateral view (photograph by A. Stark).

FIGURE 8. Habitus and head of Eucoryphus piscariviverus sp. nov. (paratype female). A. Female, left angular view and handwritten label of the micro-vial; B. Head, left angular view (photographs by A. Stark).

FIGURE 9. Tip of abdomen of female of Eucoryphus piscariviverus sp. nov. and male tarsus of leg I of Eucoryphus spp. (B–D). A. Tip of abdomen, paratype female, left laterocaudal view; B. Holotype male of Eucoryphus piscariviverus sp. nov., right lateral view; C. Eucoryphus coeruleus Becker; D. Eucoryphus brunneri Mik (photographs by A. Stark).