Troglomysis vjetrenicensis Stammer, 1933

Wittmann, Karl J., Ariani, Antonio P. & Daneliya, Mikhail, 2016, The Mysidae (Crustacea: Peracarida: Mysida) in fresh and oligohaline waters of the Mediterranean. Taxonomy, biogeography, and bioinvasion, Zootaxa 4142 (1), pp. 1-70 : 39-41

Troglomysis vjetrenicensis Stammer, 1933

Figs 7 C, 11B, 18

Troglomysis vjetrenicensis Stammer, 1933: 1935, 1936 ; Caroli 1937; Jeannel, 1949; Thienemann 1950; Karaman 1954; Gordan 1957; Riedl 1966; Holmquist 1972; Mauchline 1972; Mauchline & Murano 1977; Ariani 1981b, 2004; Schram 1986; Ariani et al. 1993; Müller 1993; Pesce et al. 1994; Kobusch 1999; Sket 1999; Anderson 2008; Daneliya et al. 2012; ITIS 2014 ; Mees 2014; Wittmann et al. 2014; Meland et al. 2015.

Material examined. 6 F ad. 10.4–12.8 mm, mostly incubating nauplioid larvae, 1 F subad. 12.0 mm, 1 F imm. 9.7 mm, 1 M ad. 8.9 mm, plus fragments of 2 M ad. and 2 imm., subterranean freshwater lake in the karstic cave Donja Vjetrenica, 42.85N 017.98E, Herzegovina, Sept. 1960, leg. B. Sket, BUL ; 5 F ad. 9.9–11.1 mm, mostly incubating nauplioid larvae, 1 F subad. 10.6 mm, 2 M ad. 9.4–9.9 mm, sampling data as above, 26 Sept. 1964, BUL; 1 M ad. 11.9 mm in 2 parts, sampling data as above, Oct. 1986, BUL; 1 M ad. 12.5 mm, completely dissected and mounted on slides, freshwater lake in same cave, Sept. 1981, leg. A. P. Ariani; 1 M ad. 10.6 mm, fresh-water in same cave, 4 Aug. 2000, leg. B. Trontelj, BUL.

Short diagnosis. Troglomysis without eye pigment in both sexes, also body without any pigment ( Fig. 7 C). Apical segment is 6–9% total length of antennal scale ( Fig. 18 D). Total length of thoracic endopods, and of their carpopropodus, in particular, decreases strongly in series of endopod 3 to 7, and following this increases strongly to endopod 8; carpopropodus 3–8 with 5–6, 5, 4, 3–4, 3–4, and 4–5 segments, respectively ( Fig. 18 E–K). Telson with 10–13 spines all along each lateral margin, not counting the pair of apical spines; small sinusoid cleft between the apical spines, cleft lined by 5–8 laminae ( Fig. 18 S, T).

Supplements and corrections to the description by Stammer (1936). Rostrum forms a wide convex angle with broadly rounded tip ( Fig. 18 A). Eyestalks distally with external rudiments of cornea ( Fig. 18 B, C) visible in all specimens with eyes well preserved (n = 19; including the smallest one: immature female with 7.3 mm body length). Rudiments of cornea not drawn and not reported by Stammer. Antennal scale with small apical segment bearing five plumose setae ( Fig. 18 D). In contrast, Stammer drew and explicitely stated an unsegmented antennal scale. Flagellum 8-segmented in thoracic exopod 1, and 9-segmented in each of exopods 2–8 ( Fig. 18 L). Stammer figured the exopods 1, 2 correctly, but counted a surplus of one segment for each of exopods 1–8, obviously by considering the large intersegmental joint between basis and flagellum as a distinct segment. Outer distal corner of basis always well rounded ( Fig. 18 L). Thoracic endopods 3–8 ( Fig. 18 E–L): tarsus (carpopropodus plus dactylus) with 6–7, 6, 5, 4–5, 4–5, and 5–6 segments, respectively (Stammer reported only 5, 5, 4, 3, 3, and 5 "tarsal" segments, respectively, presumably by not counting the minute dactylus not mentioned by him); dactylus of endopods 3–7 with long, slender claw ( Fig. 18 E–J); dactylus 8 with very slender, seta-like claw ( Fig. 18 K) in both sexes; paradactylar setae with weak, one-sided armature of small barbs. The previously unknown paradactylar lobes ( Fig. 18 K) on endopod 8 represent an uncommon feature in Mysidae ; endopods 1–7 without such lobes ( Fig. 18 E–J). Scutellum paracaudale triangular with rounded tip, upper and lower margins inconspicuously undulate ( Fig. 18 P–R). Telson cleft is lined by laminae ( Fig. 18 S, T) rather than by spines as otherwise counted and drawn by Stammer (1936: Fig. 17 ).

Statoliths ( Fig. 11 B) composed of fluorite, diameter 96–157 µm; statolith formula 2 + (2–3) + (0–2) + (8–13) + (7–12) = 19–30. General form discoid, maximum height only about 50-70% maximum width. Flattened ellipsoidal in lateral view, subcircular in ventral view. Fundus and ambitus ventrally forming together a weakly vaulted structure.

Occurrence ( Fig. 12 ). Only known from subterranean freshwater lakes and canals in the karstic cave Vjetrenica, one of the world's highest biodiversity cave systems ( Culver & Sket 2000), 42.85N 017.98E, near the village Zavala in the karstic plain Popovo polje, Herzegovina, 12 km from the coast of the Adriatic Sea. Type locality is the Donje jezero ( Lower Lake ) within the Donja Vjetrenica ( Lower Vjetrenica ) in this system. According to Stammer (1936) this lake is 234 m above sea level.

Comparison. Already Stammer (1936) postulated some similarity but not a close relationship to the genus Diamysis Czerniavsky, 1882 . Ariani (1979) noted that certain Diamysis from the Adriatic basin share with Troglomysis (referring to Stammer’s description) the highest numbers of carpopropodal segments (three or five, respectively) in thoracic endopods 3, 4, and 8, in contrast to fewer in endopods 5–7. Most of our new data make this morphological similarity appear closer: antennal scale with apical segment bearing five setae, and sinus of telson without spines but with laminae. However, the lobes flanking the dactylus of the eighth thoracic endopods represent a newly discovered feature (besides the already known ones), supporting the status of Troglomysis Stammer, 1933 , as a separate genus.

Figures

FIGURE 7. Paramysis (Longidentia) adriatica sp. nov. (A, B) and Troglomysis vjetrenicensis Stammer, 1933 (C). A, B, ethanol fixed adult female with body length 11 mm, from the Adige River, paratype, in dorsal (A) and in lateral (B) view (MZH reg. no. HLA. 112100); C, ethanol fixed adult male 12.5 mm, from the type locality within the cave Donja Vjetrenica, lateral. A, B, photo M. Daneliya; C, photo A. P. Ariani.

FIGURE 11. Vaterite (A) and fluorite (B) statoliths in Mediterranean freshwater mysids. A, Paramysis adriatica sp. nov. from small creek at Split, oblique ventro-lateral view on right statolith of adult female with body length 8.8 mm; B, Troglomysis vjetrenicensis from the cave Donja Vjetrenica (type locality), ventral view on right statolith of adult male 12.5 mm (statolith somewhat deteriorated upon treatments related to SEM study and X-ray diffraction analysis by Ariani et al. 1993). A, B, SEMmicrographs by A. P. Ariani.

FIGURE 12. Distribution of five species of Mysinae (Mysidae) in tributaries and coastal waters of the Adriatic Sea. In part modified from Wittmann & Ariani (2012 b).

FIGURE 17. Diamysis lagunaris Ariani & Wittmann, 2000 (A – J), and D. hebraica Almeida Prado-Por, 1981 (K – Q). Materials from Lago di Caprolace (paratypes: A, C – E, G, J, Lazio coast of Tyrrhenian Sea), Étang de La Palme (B, Golfe du Lion, Mediterranean coast of France), coast of La Spezia (F, N-Tyrrhenian Sea), Lago di Ganzirri (H, Strait of Messina, Tyrrhenian Sea), and the coastal stream Nahal Tanninim (K – Q, Levantine Sea, coast of Israel). A, anterior body region of male with body length 5.6 mm, dorsal view on cephalothorax; B, eyes and anterior margin of carapace in female 5.3 mm, dorsal; C, exopod of first thoracopod in male 4.0 mm, caudal; D, tarsus (i. e. carpopropodus plus dactylus) of third thoracic endopod in female 6.1 mm, rostral; E, fourth pleopod of male 4.8 mm, rostral; F – H, posterior margin of sixth pleonite in females with 7.2 mm (F), 5.2 mm (G), or 5.1 mm (H) body length, lateral; J, telson of male 4.8 mm, dorsal; K, anterior body region of male 5.0 mm, dorsal view on cephalothorax; L, tarsus of third thoracic endopod, male 5.0 mm, rostral; M, exopod of sixth thoracopod in male 4.0 mm (paratype), rostral; N, exopod of fourth pleopod of male 5.0 mm, rostral; O, posterior margin of sixth pleonite, male 4.0 mm (paratype), lateral; P, the same for female 4.0 mm (holotype); Q, telson of male 5.0 mm, dorsal. A, K, pores on carapaces not to scale; A – J, from Ariani & Wittmann (2000); K – Q, original.

FIGURE 18. Troglomysis vjetrenicensis Stammer, 1933, from the cave Donja Vjetrenica (type locality). A, male with body length 9.9 mm, dorsal view on cephalothorax; B, left eye of male 12.5 mm, dorsal; C, right eye of female 12.0 mm, dorsal; D, antennal scale of male 12.5 mm; E – K, series of tarsi of thoracic endopods 3 – 8 in same male, setae omitted; L, eighth thoracopod with penis of same male; M – O, series of third to fifth pleopods in same male (M, O, views on outer = rostral face; N, inner = caudal face); P – R, posterior margin of sixth pleonite (lateral aspect turned by 90 ° to the left) in female 10.2 mm (P), female 10.4 mm (Q), and male 12.5 mm (R); S, telson of male 12.5 mm; T, distal third of telson in subadult female 12.0 mm.