The Mysidae (Crustacea: Peracarida: Mysida) in fresh and oligohaline waters of the Mediterranean. Taxonomy, biogeography, and bioinvasion Author Wittmann, Karl J. Author Ariani, Antonio P. Author Daneliya, Mikhail text Zootaxa 2016 4142 1 1 70 journal article 10.11646/zootaxa.4142.1.1 089dcc08-ba9c-4563-a6dc-d08cf2d83365 1175-5326 261102 FA423164-276C-44B0-A417-8E97AC3DF0AA Neomysis integer ( Leach, 1814 ) Fig. 20 Short selection from 22 synonymy statements with a total of 622 references: Praunus integer Leach, 1814 : Stebbing, 1893 . Mysis integer : Leach 1815 , 1817 ; White 1847 , 1850 ; Bell 1853 (with query). Mysis entier [non-Linnean assignment]: Desmarest 1823 , 1825 ; H. Milne Edwards 1837 (in remarks). Praunus flexuosus : Desmarest 1825 (in synonymy). Mysis vulgaris J. V. Thompson, 1828 : H. Milne Edwards 1837 ; Kröyer 1861 ; Czerniavsky 1882a (partim: 2, 7); Ekman 1935 ; Muus 1967 (partim: Tab. 29). Mysis scoticus J. V. Thompson, 1828 . Mysis commun [non-Linnean assignment]: H. Milne Edwards 1837 . Neomysis vulgaris : Czerniavsky 1882a (partim: 15), 1882b, 1887; Needham 1937 ; Kinne 1955 ; Ten 1991 ; Mitina & Kharina 2011 . Neomysis integer : W. M. Tattersall 1912 ; Băcescu 1941 ; Brun 1967 ; Wittmann & Ariani 2009 ; Remerie et al. 2004 ; Wittmann 2013 ; Zettler 2015 . Material examined (hand net, leg. K. J. Wittmann, if not stated otherwise): Mediterranean drainage. 3 F ad. 11.6 mm (one dissected), 1 M ad. 9.1 mm , 1 M subad., 1 F imm., Canal d'Arles à Fos within the estuary of the Grand Rhône, S = 12.3, NHMW reg. no. 22995, for additional data see Wittmann & Ariani (2009) ; 1 M ad. 7.6 mm (dissected and mounted on slides), Canal du Rhône à Sète within the estuary of the Petit Rhône, 43.6432N 004.4298E, altitude 1 m , sea distance 30 km along canals or 42 km along the river Petit Rhône, 0.2–1.8 m depth, from shore macrophytes and from boulders with filiform algae, among masses of Atyaephyra desmarestii , v = 0 m/s, S = 0.4, 1010 µS/cm, 24.5°C, pH 7.92, 6.54 mg O2/l, 53 NTU, 19 June 2009 . NE-Atlantic drainage. 1 F ad. 8.7 mm , 8 M ad. 7.6–8.7 mm , 4 F subad., 5 M subad., 15 imm., 2 juv. , France , estuary of Gironde River at Cadou , river-km K.60, 45.3097N 000.7815W , altitude 0 m, sea distance 37 km , 0.5–3 m depth, from stone walls with filiform algae, v = 0.2–0.4 m /s, S = 4.1, 7620 µS/cm, 23.6°C, pH 7.67, 6.34 mg O2/ l, 222 NTU , 22 June 2009 , NHMW 25712 ; 23 F ad. 8.7–11.6 mm , 31 M ad. 6.7–9.3 mm , 15 F subad., 15 M subad., 24 imm., 6 juv. , France , Bay of Biscay , Bassin d'Arcachon , chenal de La Hume , 44.5921N 001.1237W , S = 1.2, 2 Aug. 1983 , don. J. C. Sorbe (Arcachon), RNMH . CRUS .E.3782; 1 juv. , The Netherlands , Oude Rijn , Katwijk , at Valkenburgseweg , 52.1877N 004.4274E , altitude 0 m, sea distance 4 km , 0.2–1 m depth, among Nuphar , S = 0.4– 1.0, 23 July 1998 ; 60 F ad. 9.2–11.8 mm , 5 M ad. 9.1–10.8 mm , 2 F subad., 1 M imm., The Netherlands , Den Helder , Noordhollands kanaal, 52.9638N 004.7667E , altitude 2 m , sea distance 5 km , 1–2 m depth, among macrophytes, S = 2–3, 22 June 1989 , NHMW 25450 ; 26 F ad. 10.7–16.4 mm , 40 M ad. 9.0–12.0 mm, 2 F subad., 3 M subad., 49 imm., 23 juv. , Scotland , Argyll , Loch Creran , near Inver , 56.5137N 005.3728W , altitude 0 m, sea distance about 26 km , 0.2–0.3 m depth, among algae, low tide, tidal current v = 0.3–0.6 m /s, S = 0–25, 11 Sept. 1983 ; 1 F ad., 1 M ad., 1 imm., Scotland , Argyll , Firth of Lorn , Dunstaffnage Bay , 56.450N 005.433W , 0.1–0.2 m depth, among algae and on mud, S = 28–33 (mixoeuhaline), 12°C, 13 Sept. 1983 , NHMW 25449 . Baltic drainage. 16 F ad. 12.0– 16.7 mm , 61 M ad. 7.6–15.7 mm , 13 subad. , 5 imm., 3 juv. , Germany , Fehmarn- Belt , Puttgarden , 54.505N 011.222E , 0.3 m depth, sand, S = 14, 23 Aug. 1985 , leg. K. J. Wittmann & A. P. Ariani , RNMH .CRUS. E.3783; 172 F ad. 10.7–16.7 mm , 35 M ad. 8.5–12.9 mm , 10 F subad., 10 imm., Sweden , Askö Island , 58.8288N 017.6366E , 0.3–1 m depth, among algae, S = 7, 22 Aug. 1985 , NHMW 25713 . Supplementary description. Adult body length 6–19 mm , eyes normal. Antennal scale strongly elongate, setose all around, terminally pointed in both sexes ( Fig. 20 A, B). Its two segments separated by a transverse, not always distinct suture; apical segment is 12–18% scale length. Carapace ( Fig. 20 A) ends anteriorly in an apically acute, triangular rostrum; no subrostral plates; lateral margins of carapace produced into a pair of anteriorly directed spiniform processes; dorsal face of carapace with 5–12 cervical pores in about linear, transversal arrangement; and with 12–29 cardial pores showing a transverse arrangement in two about symmetrical, slightly curved subgroups. Thoracic endopod 8 represents the strongest leg in both sexes by being always more stout and by being 0–30% longer compared with the subequal endopods 3–7; carpopropodus of endopods 3–8 with 5–6, 5–7, 5–7, 5–7, 5–7, or 6–8 segments, respectively (adult males tend to show more segments than same-sized adult females); these endopods ending in short, weak, slightly bent claws ( Fig. 20 E). Flagellum of thoracic exopods 1 and 8 each with 8 segments, that of exopods 2–7 each with 9 (10) segments, not counting the large intersegmental joint between the 1-segmented basis and its multi-segmented flagellum. Outer distal corner of basis always ending in a small spine. First thoracic sternite produced into an anteriorly directed, distally hairy (with minute setae), terminally nearly quadrangular, medial lobe in both sexes ( Fig. 20 C, D). Adult males ( Fig. 20 C): thoracic sternites 2–5 each with small median, terminally blunt processes each bearing 2–4 minute acute scales; sternite 6 medially with transverse cuticular ridge that may represent a vestigial process; sternites 7, 8 with smooth median portions. Adult females ( Fig. 20 D): thoracic sternites 2–6 medially with vestigial processes; a total of two large, finger-like processes project from thoracic sternites 7, 8 ventrally into the marsupium; these processes show densely set knob-like structures giving their surface a moruloid appearance, no scales, large longitudinal tube inside each process. Marsupium supported by a large, backwardly produced plate ( Fig. 20 D) from last thoracic sternite. This plate present only in females and represents an apron which overlaps part of first pleon sternite. Its alignment with anterior margin of pleon suggests a function as mechanical protection of marsupium upon flipping of pleon, which occurs most violently upon sudden escape. All pleopods reduced, fused and styliform ( Fig. 20 G) in both sexes, with exception of male pleopod 4 ( Fig. 20 H). This latter pleopod biramous, strongly elongate; its 2-segmented exopod reaches beyond base of uropods. Scutellum paracaudale mostly subtriangular with convex upper and concave lower margins ( Fig. 20 K), less frequently biconvex, and even less frequently sinusoid ( Fig. 20 J); tip blunt to well rounded. Endopods of uropods with 14–55 spines arranged in dense series along proximal half of inner margin ( Fig. 20 L). Statoliths composed of fluorite (according to Lowenstam & McConnell 1968 ; confirmed by own determinations on material from Canal d'Arles à Fos, chenal de La Hume, and Askö Island ). Telson ( Fig. 20 M) entire, subtriangular, longer than ultimate pleonite; lateral margins all along with continuous series of spines, numerous fine hairs between the lateral spines ( Fig. 20 N); narrow, truncate apex with a pair of short median spines flanked by a pair of long latero-apical spines. FIGURE 20. Neomysis integer (Leach, 1814) from canals at the Mediterranean coast of France: adult male with body length 7.6 mm (A–C, E–J, L–N) from the freshwater reach of the Canal du Rhône à Sète, and incubating female 11.6 mm (D, K) caught in the mesohaline reach of the Canal d'Arles à Fos. A, anterior body region in dorsal view (pores on carapace not to scale); B, antenna, dorsal; C, thoracic sternites with median lobes in male, ventral; D, thoracic sternites in female (lobes forced into rostral plane by cover glass; in vivo projecting about ventrally), note large posterior plate from ultimate sternite; E, endopod of third thoracopod between merus and tip; F, right penis, lateral; G, third male pleopod, outer = rostral face; H, fourth male pleopod, inner = caudal face; J, posterior margin of sixth pleonite in male, lateral; K, the same for female; L, uropods, ventral; M, telson, dorsal, detail (N) shows hairs and spines on lateral margin. Distribution ( Fig. 16 ). Common in shallow coastal waters of the temperate to boreal NE-Atlantic from southern Spain to Norway , also common in the Baltic. Also found in the White Sea and the Barents Sea ( Zimmer 1933 , Holmquist 1972 , Petryashov 2004 ). A presumably disjunctive population was detected by Băcescu (1941) in the NW-Mediterranean (Rhône Delta). This species occurs from anhaline to hyperhaline conditions, yet mainly in oligo- to polyhaline waters, where it has strong osmoregulatory capabilities (at S = 3–32 according to Vilas et al. (2006 )). Freshwater records were made in waters pertaining to the drainage basins of the NE-Atlantic ( Scott 1894 , Elton 1937 , Tattersall & Tattersall 1951 , Hynes et al. 1960 , Ketelaars et al. 1999 , Lee & Bell 1999 , Braune 2004 ) and of the Baltic ( Gasiunas 1965 , 1972 ; Zettler 1998 ). NE-Atlantic populations of N. integer are commonly found from oligohaline to polyhaline conditions, with main occurrence in the mesohaline reach, rarely in fresh-water. One own sample (listed above) of a juvenile was taken in almost fresh-water ( S = 0.4–1.0) in an old Rhine branch at the coast of The Netherlands . The abundance of this species along the Westerschelde estuary at the Dutch-Belgian border is primarily correlated with salinity; here it lives at S = 0.6–27 throughout the year ( Rappé et al. 2011 ). Similarly, Roast et al. (1998) observed a minimum of S = 1 for this species in a Cornwall estuary. There is a number of additional near-freshwater records ( Castel 1993 , Bernát et al. 1994 , Köpcke & Kausch 1996 , David et al. 2005 , Vilas et al. 2009 ) as well as the above-cited true freshwater records along the Atlantic coasts of Europe. As a first freshwater record for the Mediterranean, we documented one adult male at S = 0.4 in a canal pertaining to the estuary of the Petit Rhône ( Fig. 16 ; see material list above). Brun (1967) reported this species from the chlorinity range of 0.5–5‰ (salinity 0.9–9) in the estuary of the Grand Rhône. Wittmann & Ariani (2009) found it at S = 12.3 in the Canal d'Arles à Fos at a station within this estuary. Aguesse & Bigot (1960) reported N. integer together with Mesopodopsis slabberi from the Étang Baisse Salée (Camargue, Rhône delta). The salinities of this water body ranged from S = 0.8–40.1 (mostly 3–8) in 1955–1958 . However, the exact range experienced by the mysids was not specifically indicated. For potential pathways of areal expansion to the Mediterranean, see ‘Discussion’.