Clunio boudouresquei Moubayed-Breil, 2019

Moubayed-Breil, Joel & Dominici, Jean-Marie, 2019, CLUNIO BOUDOURESQUEI SP. N. AND THALASSOSMITTIA BALLESTAI SP. N., TWO TYRRHENIAN MARINE SPECIES OCCURRING IN SCANDOLA NATURE RESERVE, WEST CORSICA (DIPTERA: CHIRONOMIDAE) Abstract, CHIRONOMUS Journal of Chironomidae Research 32 (32), pp. 4-24 : 5-13

publication ID	https://doi.org/ 10.5324/cjcr.v0i32.3078
DOI	https://doi.org/10.5281/zenodo.7995755
persistent identifier	https://treatment.plazi.org/id/CE7A87E8-7773-6264-A061-FAC6809CFAD2
treatment provided by	Felipe
scientific name	Clunio boudouresquei Moubayed-Breil
status	sp. nov.

Treatment

Clunio boudouresquei Moubayed-Breil View in CoL , sp. n.

Clunio sp. 1 , in Moubayed-Breil & Ashe (2012), Moubayed-Breil et al. (2013).

http://zoobank.org/ 3B0274A6-5460-4D84-8028- 2BF8903468B9

Material examined

Holotype. France, West Corsica, Scandola Nature Reserve, Focolara Bay, Cala Litizia, bio-constructions of the red calcified marine alga L. byssoides of Punta Palazzu locality ( Fig. 10 View Figures 10 ), 42° 21′ 25″ N, 8° 34′ 0″ E; 1 male pharate adult, leg. J. Moubayed-Breil, 03. VI.2015. Locality No. 31 in Moubayed-Breil & Ashe (2012); locality No. 30 in Moubayed-Breil et al. (2013). Marine water temperature: 10-12°C (min.), 22-24°C (max.).

Paratypes (all leg J.M-B.): 2 male adults, 1 female adult, 6 pupal exuviae (4 males and 2 females), same locality as for holotype, 03.VI.2015 .

Holotype (mounted on 1 slide) and 2 pupal exuviae (1 male and 1 female) are deposited in the collections of the Zoologische Staatssammlung München ( ZSM), Munich , Germany. Additional paratypes are deposited in the senior author’s collection.

Diagnostic characters

Based on some characters found in the male adult (vertex with lateral projections, typical morphology of inferior volsella and both basal and caudal apodemes, presence of megaseta on gonostylus), C. boudouresquei sp. n. appears to belong to a local Tyrrhenian marine element. However, this new species can be distinguished from other European Clunio species by the blow listed characters.

Male adult: Vertex with two lateral triangular projections; antenna 10-segmented, last flagellomere longer than the 3 preceding segments; sensilla chaetica present on tibia and ta1 of PI-PIII; tergite VIII with a distinct elongate ellipse-like ridge located antero-medially, midline area with 6 short setae; apical expansion of tergite IX distinctly convex at apex; caudal apodeme with 5-6 curved claw-like tubercles; inferior volsella wider at base and narrowing distally; gonostylus unusually bearing a black fingernail-like megaseta, apex ending with a single finger-like tubercle.

Female adult: Eyes densely haired, temporals 2 including 1 inner and 1 outer vertical; clypeus semi-circular, bare; antenna 7-segmented, last flagellomere elongated, segments 6 and 7 each with 1 tubular sensilla chaetica; palpomere 2, globular, with 3 sensilla clavata distally and 1 long fine seta; tarsomere ta 1 of PI and PII is half long as ta 1 of PIII; sensilla chaetica present on tibia and tarsomere ta 1 of PI, PII and PIII; sternite VIII with 22-24 setae; dorsomesal lobe of gonapophysis VIII convex medially and projecting; apodeme lobe swollen in its postero-median part; 2 stout inwardly directed setae present on each side of gonapophysis VIII; seminal capsules sub-oval; tergite IX oval, markedly divided, with 20-22 setae; gonocoxite weekly developed; cercus sub-rectangular.

Pupal exuviae: Antero-median area of frontal apotome and thorax with wrinkles; frontal setae present on distal part of frontal apotome; dorsocentrals Dc 1 -Dc 2 and Dc 3 -Dc 4 located close together; anterior transverse rows of spines interrupted on tergite II; posterior transverse rows of hooks present on sternites V-VII.

Etymology: the new species is named ‘ boudouresquei’ in honour of our colleague Ch-Fr. Boudouresque (University of Sciences, Luminy, Marseille), who is still active in studying the biology and ecology of the Mediterranean marine flora and fauna including those of the protected area of Scandola Nature Reserve. As he always did in past, he keeps working on developing projects to preserve the marine protected area of Scandola Nature Reserve, which represents a precious and valuable inheritance area.

Male adult

(n = 5, 2 pharates; Figs 1 View Figure 1 c-h, 2a-d, 3a-b)

Total length 2.70-2.90 mm. Wing length 1.35-1.40 mm, TL/WL = 2-2.10. General colouration contrasting brown to dark brown. Head and antennae dark brown; thorax contrasting light brown to brown with dark brown mesonotal stripes; wing pale translucent; legs brown to dark brown; tergites I-VII brownish, tergite VIII and anal distinctly contrasting light brown to dark brown.

Head. Eyes sub-circular without dorso-median extension, densely hairy with long and short pinlike hairs; hairs absent on inner lateral eye margin, outer posterior margin lacking setae. Vertex ( Fig. 1c View Figure 1 , dorsal; Fig. 1d View Figure 1 , ventral) with 2 triangular lateral expansions; temporals 2 consist only of 2 outer verticals, postorbitals absent. Antenna 10-segmented, about 500 µm long, lacking plume; segment 1-2 ( Fig. 1e View Figure 1 ), segment 1 globular, segment 2 145 µm long, linearly elongated; segment 2-9 globular, nearly sub-equal (30-40 µm long); ultimate flagellomere ( Fig. 1f View Figure 1 ) 105 µm long, about 40 µm maximum width, as longer than the 3 preceding segments, thumb-like shaped; sensilla chaetica present on segments 1 to 8; antennal groove reaching segment 2; AR 0.27. Palp ( Figs 1 View Figure 1 g-h) 2-segmented, lacking sensilla clavata; left palpomeres 1-2 respectively 25 and 55 µm long, palpomere 2 ending with a long finger-like expansion; right palpomeres 1-2 ( Fig. 1h View Figure 1 ), first one indistinct, second one sub-rectangular to square-like shaped, side about 25-30 µm long. Clypeus semicircular and bare. Thorax. Antepronotum ( Fig. 1c View Figure 1 ) weakly developed with joined lobes. Antepronotals 3; acrostichals 4-5 starting close to antepronotum; dorsocentrals 5 in 1 row; prealars 2; scutellum with 8 setae. Wing. Brachiolum with 1 seta; number of setae on veins: R, 7; R 2+3, 6-7; remaining veins and squama bare. Legs. Femur of PI-PIII broad (100-110 µm maximum width); tibial spurs distinctly conspicuous and curved at apex, length (µm): PI, 40; PII, 65; PIII, 55. Tarsomeres ta 3 and ta 4 of PI and PIII (45 and 40 µm long) shorter than tarsomere ta 5 (75 and 65) as in Table 1 View Table 1 ; SV of PIII (9.48) is much higher than in PI and PII. Sensilla chaetica present on tibia and tarsomere ta 1 of PI-PIII. Length (µm) and proportions of prothoracic (PI), mesothoracic (PII) and metathoracic (PIII) legs as in Table 1 View Table 1 .

Abdomen. Hypopygium in dorsal and ventral view as in Figs 2 View Figure 2 a-b ( Fig. 2a View Figure 2 , dorsal; Fig. 2b View Figure 2 , ventral, with tergite IX removed). Laterosternite absent. Tergite VIII with a distinct elongate ellipsoidal ridge located antero-medially, midline area bearing 6 short setae (3 on each side). Tergite IX is Clunio - type, without anal point; dorsal side ( Fig. 2a View Figure 2 ) densely covered with macrotrichia-like setae in reclinate pattern (orally directed), postero-median area with about 40 short setae about 15 µm long; ventral side ( Fig. 3b View Figure 3 ) with a semi-circular posterior lamella covered with macrotrichia. Ventral side of hypopygium ( Fig. 1b View Figure 1 ) includes 4 distinct apodemes (basal, axial, lateral and caudal) which can be detailed as: basal apodeme (= sternapodeme) 140 µm maximum width, T-like shaped ( Figs 1b View Figure 1 , 3a View Figure 3 ) with anterior side concave (occasionally convex as in Fig. 3c View Figure 3 ); axial apodeme about 320 µm long, ending with a bi-lobed semi-circular apical expansion ( Figs 2a View Figure 2 , 3b View Figure 3 ); lateral apodeme (= phallapodeme) 250 µm long, inwardly bent distally; caudal apodeme ( Fig. 2b View Figure 2 ) distinctly branched on each lateral side, composed of 2 connected parts, basal one is rectangular brush-like shaped, posterior one consists of 5-6 grouped claws of typical structure. Gonocoxite about 600 µm long, 250 µm maximum width, distal inner area with dense group of long and short setae; inferior volsella 220 µm long, 15- 20 µm width medially, located distally, conical and densely covered with short and upwardly directed setae. Gonostylus ( Figs 2 View Figure 2 c-d) inversed trianglelike shaped, arched with acute posterior angle and projecting backwards posteriorly; thicker at base, much thinner in median and distal parts; length (in µm of sides): basal one about 20, concave one 25, convex one 17; apical angle ( Fig. 2d View Figure 2 ) with 1 single characteristic finger-like tubercle; crista dorsalis well-developed, consists of 2 unequal lobes occupying the entire length of gonostylus; megaseta tooth-like shaped and conspicuous, nearly as high as wide (12-15 µm), represents an unusual character in the genus Clunio .

Female adult

(n = 2, 1 pharate; Figs 1 View Figure 1 i-j, 4a-e)

Small sized species. Total length 1.65-1.70 mm. General shape is Clunio female-type. Colouration as in the male adult except for the thorax, which is less dark. Antennae light brown; legs brownish with blackish claws. Abdominal tergites and anal segment contrasting brown to dark brown. Head. Eyes densely hairy, sub-circular without dorso-median extension, hairs absent on inner lateral eye margin, outer posterior margin lacking setae. Temporals 2, including 1 inner and 1 outer vertical. Clypeus semi-circular, bare. Antenna 7-segmented, about 200 µm long; last flagellomere ( Fig. 1i View Figure 1 ) 60 µm long, elongated and lobe-like; segments 6 and 7 each with 1 tubular sensilla chaetica; antennal groove reaching segment 2; AR 0.43. Palp ( Fig. 1j View Figure 1 ) 2-segmented; segment 1, indistinct; palpomere 2, globular about 20 µm long bearing 3 sensilla clavata distally and 1 long fine seta. Thorax. Chaetotaxy indistinct. Legs. Tibia of PI, PII and PIII nearly equal (185, 180, 185 µm long); length (µm) of tibial spurs of: PI, 40; PII, 65; PIII, 5. Tarsomeres ta 1 -ta 5 of PI and PII equal in size as in Table 2 View Table 2 ; tarsomeres ta 1 and ta 5 of PI and PIII are globular and equal in size (40 µm long each); tarsomere ta 1 of PI and PII (40 µm long) is half long as ta 1 of PIII (85 µm). Femur of PI is much wider (90 µm) than in PII-PIII (70 and 60); tibia of PIII is wider (55 µm) than in PI and PII (45 µm each); tarsomere ta 1 of PII is much wider (50 µm) than in PI and PIII (27 µm each); tarsomere ta 1 of PII is wider (55µm) than in PI and PIII (30 µm each). LR value ( Table 2 View Table 2 ) of PIII (0.46) is much higher than those of PI and PII (0.22 each); SV value ( Table 2 View Table 2 ) of PI and PII (10.75 and 11) is about twice of PIII (5.35). Sensilla chaetica present in low number on tibia and tarsomere ta 1 of PI, PII and PIII. Length (in µm) and proportions of prothoracic (PI), mesothoracic (PII) and metathoracic (PIII) legs as in Table 2 View Table 2 .

Abdomen. Anal segment (dorsal, Fig. 4a View Figure 4 ; ventral, Fig. 4b View Figure 4 ) 280 µm long, 260 µm maximum width at base, 130 µm wide at caudal part. Genitalia in dorsal and ventral view as illustrated in Figs 4 View Figure 4 b-e. Notum about 140 µm long with separate rami; on each side the rami are connected to a sternal axial apodeme. Sternite VIII with 22-24 setae (11- 12 on each side of the notum). Gonapophysis VIII ( Figs 4 View Figure 4 b-d): dorsomesal lobe ( Fig. 4d View Figure 4 ) convex medially and projecting in both proximal and apical parts; ventrolateral lobe directed downwards, broader basally and narrowing posteriorly; apodeme lobe (left, Fig. 4c View Figure 4 ) distinctly swollen in its postero-median part. Presence of 2 stout inwardly directed setae on each side of gonapophysis VIII between base of sternite VIII and ventrolateral lobe. Seminal capsules 70 µm long, 40 µm maximum width, sub-oval and well-sclerotized medially. Spermathecal ducts with loops and separate openings. Tergite IX ( Fig. 4e View Figure 4 ) egg-like shaped, markedly divided, with 20-22 setae (10-11 on each side). Gonocoxite ( Figs 4 View Figure 4 a-b) weekly developed but widely extended, bearing 8-9 setae. Cercus ( Fig. 4b View Figure 4 ) sub-rectangular, normally developed and projecting upwards.

Pupal exuviae

(n = 10, 7 males and 3 females; Figs 5a, 5c, 5 View Figure 5 e-f)

Total length 2.85-3.15 mm. Colouration contrasting dark brown to yellow brown, wrinkles present on antero-median area of frontal apotome and thorax; abdomen and anal segment brownish. Cephalothorax. Frontal apotome broadly trapezoidal, frontal setae about 40 µm long, inserted posteromedially, distance between frontal setae 50 µm. Median antepronotals nearly subequal (30-35 µm long), lateral antepronotal absent; precorneals subequal, about 50 µm long, insertion arranged I, triangle. Dorsocentrals Dc 1 -Dc 2 and Dc 3 -Dc 4 located close together; Dc 4 subequal (about 10-15 µm long), Dc 3 and Dc 4 sub-equal (about 40 µm long); distance (in µm) between: Dc 1 to Dc 2 30, Dc 2 to Dc 3 80, Dc 3 to Dc 4 10.

Abdomen. Armament, chaetotaxy, distribution pattern of shagreen and details of armament on tergites and sternites II-VII as in Figs 5a, 5c, 5 View Figure 5 e-f. Tergite I and sternites I-III bare, sternite IV occasionally with 1-2 rows of small spines ( Fig. 5a View Figure 5 ). Conjunctives of tergites III-VII and sternites V-VII with one transverse row of hooks, which are smaller on sternites, conjunctive on segment VIII composed only of short posteriorly directed spines. Antero-median transverse rows of spines present on tergites II-VII, sparsely present and interrupted medially on tergite II, becoming denser and more extensive on tergites III-VI. Pedes spurii A and B absent; apophyses on tergites and sternites absent. Number and distribution pattern of lateral setae on segments I-VIII: 2 on segment I; 2/3 on II-VII; 3 on VIII. Anal segment is Clunio - type, genital sac 490-500 µm long, 70 µm maximum width, ending each with 1 pointed tubercle.

Larva

Known but not described.

Differential diagnosis

Male adult and pupal exuviae of C. boudouresquei sp. n. are compared to those of known Clunio species from seacoasts of Europe and neighbouring areas, based on material collected by the senior author in Corsica, continental France, Italy, Spain except for Bulgaria (Varna seashores, leg. P. Michailova). Some relevant specific features found in the male adult and pupal exuviae will easily separate the new species from other members of Clunio by the following combination of characters:

Male adult: Frontal area of head bearing 2 apical projections ( Figs 1 View Figure 1 c-d), is differently shaped in C. marinus ( Figs 1 View Figure 1 a-b); last flagellomere narrowed apically ( Fig. 1f View Figure 1 ), is widely clubbed in C. mediterraneus ( Fig. 1k View Figure 1 ) and linearly curved in C. sp. 1 ( Fig. 1l View Figure 1 ); typical long finger-like expansion of left palp ( Fig. 1g View Figure 1 ), is absent in both C. sp. 2 ( Fig. 1m View Figure 1 ) and C. marinus ( Fig. 1n View Figure 1 ); caudal apodeme composed of basal brush-like and 5-6 apical claws ( Fig. 2b View Figure 2 ), is lacking basal brush and less branched apically in C. mediterraneus ( Fig. 2e View Figure 2 ); megaseta present on gonostylus ( Fig. 2c View Figure 2 ), is absent in C. mediterraneus ( Fig. 2f View Figure 2 ) and C. marinus ( Fig. 2h View Figure 2 ); apex of gonostylus with only one single finger-like tubercle ( Figs 2 View Figure 2 c-d), while consists of several unequal tubercles in both C. sp. 1 ( Fig. 2g View Figure 2 ) and C. marinus ( Figs 2 View Figure 2 h-i); basal and apical parts of axial apodeme ( Figs 3 View Figure 3 a-b), are differently shaped in C. mediterraneus ( Figs 3 View Figure 3 c-d and C. sp. 1 ( Figs 3 View Figure 3 e-f).

Male pupal exuviae: Transverse row of hooks present on sternites V-VII ( Figs 5a, 5 View Figure 5 e-f), only present on sternites V-VI in C. mediterraneus ( Figs 5b, 5 View Figure 5 gh); anteromedian rows of spines on tergite II interrupted medially and sparse ( Fig. 5c View Figure 5 ), is continuous and more dense in C. mediterraneus ( Fig. 5d View Figure 5 ).

Ecology and remarks

The immature stages of Clunio spp. are typically marine dwellers of the intertidal zone along the littoral and mid-littoral zones of rocky shores, sometimes in association with populations of Mytilus spp. In some species (in particular those associated with Lithophyllum beds) the emergence of the adults is synchronized with the lunar cycle ( Neumann 1976, Neumann et al. 1997, Kaiser & Heckel 2012). The biological cycle (reproduction and emergence) of C. boudouresquei sp. n. is closely related to the typology of the intertidal zone including alternation between submerged marine habitats and terrestrial ecological conditions, which are strongly reinforced during spring tides of lunar rhythms (new and full moon).

The pavements, ‘trottoirs’ of L. byssoides represent a combination of habitats that typically characterize the intertidal zone of the protected area of Scandola Nature Reserve. They mainly consist of a pristine combination of habitats considered to be microrefugia for a dense and diversified community of marine, semi-aquatic and semi-terrestrial species, including members of several closely integrated dipteran families ( Chironomidae , Ceratopogonidae and Dolichopdidae). The newly described species is encountered in the marine mid-littoral zone of Punta Palazzu ( Fig. 6 View Figure 6 ), where larval stages occur exclusively within the large bio-constructions of the ‘long-living’ red calcified alga L. byssoides , which clearly delimit alternate cycles of both submerged and terrestrial habitats. In addition, the bio-concretions of Punta Palazzu are currently considered as the largest Lithophyllum beds in Europe, where valuable knowledge on the biology (growth rate) and ecology of the algal communities are documented by Verlaque (2010). While the biological and ecological quality of L. byssoides rims are still well-preserved at Punta Palazzu and Port-Cros Island ( Figs 6-7 View Figure 6 View Figure 7 ), other similar marine sites located along the coastal Mediterranean ecosystem of continental France are becoming extinct, or have been deeply damaged and degraded ( Figs 8-9 View Figure 8 View Figure 9 ) during the last four decades by human activities, including ecotourism and release of toxic chemical pollutants (e.g., HAP, PCB, abundance of macro- and microplastics). In addition, the L. byssoides beds delimited by the latter endangered sites, are heavily threatened by a massive proliferation of an invasive Mytilidae species ( Mytilus galloprovincialis Lamarck, 1819 ). This sea mussel significantly predominates when changes in water quality and level of pollution become increasingly high (seashores at Banyuls, SW-France, Figs 8-9 View Figure 8 View Figure 9 ), where populations are intensely enlarging and reinforcing their potential expansion in occupying up to 70-80% of the living L. byssoides original cover. Such situations are also highlighted in southern France by Blanfuné et al. (2019) for the ‘Canopy-forming Seaweeds’ of Cystoseira mediterranea Sauvageau, 1810 , where an important decline of local populations with risk of extinction are reported; Linares et al. (2010) and Garragou et al. (2017) report a similar scenario for the Mediterranean Red Coral, suggesting that constructive plans and management measures for conservation and preservation of autochthonous Tyrrhenian elements must be implemented.

Consequently, in some of the Tyrrhenian mid-littoral coastlines (Punta Palazzu, Port-Cros, Banyuls), some relevant and vulnerable Clunio species are closely confined to the Lithophyllum beds, and therefore their loss would be clearly indicative of a combination of anthropogenic impacts and global warming in this geographical region. Such relict Tyrrhenian species are considered as potentially biogeographic representatives and biological indicators of local climate change (in particular, the rise of sea level), which strongly affect both sustainability and viability of the Clunio populations.

Geographical distribution

Geographical distribution of known Clunio species from European seacoasts ( Ashe & O’Connor 2012) and the Tyrrhenian sub-region is given in in Figure 10 View Figures 10 . Clunio boudouresquei sp. n. ‘⚙’ is abundant at the type-locality of Punta Palazzu (Scandola Nature Reserve, West Corsica); weakly represented in southern France (Port-Cros and Porquerolles Islands, Cassis, Banyuls). Occurrences of C. boudouresquei sp. n. in southern France indicate that it may be more widespread in other geographical areas of the Tyrrhenian sub-region (insular and continental Provinces), and therefore can be expected from the seacoasts of some neighbouring countries like Italy and Spain. Clunio marinus ‘✻’ is found along all Atlantic seacoasts in Europe including France, Germany, England, Iceland, Ireland, Italy, Madeira, Netherland, Norway, Spain and Sweden. Clunio mediterraneus ‘✶’ is widespread in the Mediterranean Basin: Southern France (Cerbère, Banyuls, Sète, Carry, Marseille, Cassis, Port-Miou, Hyère, Porquerolles, Port-Cros, Nice), northern and western Corsica, the Balearic Islands, Italy, Spain, Turkey, Croatia (the Adriatic Sea). Clunio ponticus Michailova, 1980 ‘✪’ is only recorded from the Black Sea (Varna, Bulgaria).