Siriella vulgaris Hansen, 1910

Talbot, Suzette, 2009, A survey of Mysida from the Lizard Island area, Great Barrier Reef, Australia, Subfamily Siriellinae (Crustacea, Mysida, Mysidae), Zootaxa 2114, pp. 1-49 : 36-40

Siriella vulgaris Hansen, 1910

( Figures 23 , 24, 25)

Siriella suluhensis Czerniavsky, 1882: 108 . — Czerniavsky, 1887: 29.

Siriella vulgaris Hansen, 1910: 34 , pl. III, fig. 2a–k. — W.M. Tattersall, 1922: 454. — Colosi, 1924: 3. — W.M. Tattersall, 1928: 105. Illig, 1930: 562. — W.M. Tattersall, 1936a: 145. — W.M. Tattersall, 1936b: 279. — Coifmann, 1937: 3. — W.M. Tattersall, 1943: 65. — W.M. Tattersall, 1951: 62 –64, fig. 14. — Gordan, 1957: 381. — O.S. Tattersall, 1960: 166. — Ii, 1964: 94 –95. — Pillai, 1965: 1692, fig. 15. — O.S. Tattersall, 1965: 76. — Mauchline & Murano, 1977: 77. — Fenton, 1985: 37, 49 (key). — Bacescu, 1986: 19. — Murano, 1990: 193, fig. 5. — Muller, 1993: 45. — Fukuoka & Murano, 1997: 521, fig. 2F, G. — Fukuoka & Murano, 2002: 59, 98 (key). — Lowry & Stoddart, 2003: 469. — Yerman & Lowry, 2007: interactive key.

Type material. SYNTYPES: numerous specimens, Zoological Museum, University of Copenhagen, Denmark and Zoological Museum, University of Amsterdam, Netherlands.

Type locality. Indonesia: Bay of Kankamaraan, south coast of Kangeang (6°59’S 115°24.7’E), 22 m depth; north-east of Borneo (7°38’S 117°31’E), 640 m depth; north of Borneo (7°38’S 117°31’E), 10–0 m depth; Sailus Ketjil, Pulau Satengar (as Paternoster Islands), 27 m depth; between Bahluwang and Tambolugan Islands, south of Saleyer, 8–10 m depth; Makassar, 27–32 m depth; east of Borneo (4°57.4’S 119°2.8’E), 11–0 m depth; off Sawan, Siau Island, 27 m depth; off Kawai and Kamboling Islands, Karkaralong group, 23–31 m depth; north-east of Celebes (5°56.7’N 126°25’E); off Lawai, Palau Obi (as Obi Major), 23 m depth; between Gisser and Ceram Laut, 18 m depth; off Kilsuin, west coast of Kur Island, 18 m depth; west side of Taam Island, 9–36 m depth; between Nusa Besi and the north-east point of Timor, 27–54 m depth. Philippines: south-east of Pearl Bank, 15 m depth; off Kapul Island, 13 m depth; off Pulu Tongil, 13 m depth; Sulu Archipelago, off North Ubian (6°7.5’N 120°26’E), 16–23 m depth; Bay of Batjan, Batan Island; Samar Sea, north-east side of Daram Island, 49 m depth.

Material examined. One male, plankton tow, surface, Lizard Is. lagoon centre, 2034 hrs May 16 1976 (STL-76- NIO) AM P74066. 20 specimens, fixed trap, above Porites andrewsii, Lizard Is. lagoon, overnight, Jan. 13-14 1978 (STL-78-F5) AM P74067. 4 specimens, fixed trap, above Echinopora lamellosa, Lizard Is. lagoon, overnight, Jan. 13–14 1978 (STL-78-F6) AM P74068. 29 specimens, plankton tow, surface, Lizard Is. lagoon centre, 0 0 15 hrs Jan. 14 1978 (STL-78-N9) AM P74069. 7 specimens, plankton tow, surface, Lizard Is. lagoon centre, 0 0 33 hrs Jan. 14 1978 (STL-78-N10) AM P74070. 12 specimens, plankton tow, 5–6 m depth, Lizard Is. Lagoon centre, 0 0 57 hrs Jan. 14 1978 (STL-78-N11) AM P74071. 7 specimens, plankton tow, near surface, 2–4 km east of Yonge Reef, 1930 hrs Dec. 1 1978 (J.P.-78-3) AM P74072. 10 specimens, plankton tow, surface, Lizard Is. lagoon, 2130 hrs Dec. 1 1980 (Grindley #8) AM P74073. Total: 90 specimens.

Size range: 15 males, 5.1-7.0 mm. 1 immature male, 3.8 mm. 3 females, maximum of 11 young in marsupium, 6.2–6.6 mm. 3 females, marsupium empty, 5.0– 5.6 mm. 2 immature females, 3.7 & 4.5 mm. 66 juveniles, 1.5–2.5 mm.

Description. Head: eyes stalked, hemispherical, (diameter of adult male cornea, 0.4 mm), colour in Lizard Island specimens, red-brown. Rostrum short, terminating in a point barely reaching base of antennules, a small, blunt pseudo-rostral process projecting beneath it. Antennular peduncle with a long slender robust seta extending from the antero-medial border of the 2nd article almost to the end of the 3rd article, females with 2 stout, anteriorly directed robust setae in the angle between the antennular flagella, the larger being as long as the 3rd article of the peduncle ( Figs 23 A, B). Antennal scale slightly shorter than antennular peduncle, moderately broad (maximum width 0.3x length), spine on outer margin positioned at about 0.6x length of margin, terminal lobe long, apical suture present, with small apical lobe ( Fig. 23 C). Labrum with prominent anteriorly directed medial spiniform process, length more than 0.5x length of labrum proper ( Fig. 23 D). Mandibular palp with broadly expanded proximal article, maximum width 0.6x length ( Fig. 23 E). Maxillule and maxilla typical of the genus, maxilla strongly setose ( Figs 23 F, G). First thoracic somite fused with head, endopod of 1st thoracic limb fairly robust and moderately setose, functions as a gnathopod, exopod natatory, epipodite broad, leaf-like (Fig. 24A).

Pereon: endopod of 2nd thoracic limb not markedly robust, dactylus setose, probably functions as a gnathopod, exopod natatory (Fig. 24B), thoracic limbs 3–8 form pereopods, endopods slender, dactylus and nail elongate, genital organ at base of 8th thoracic limb in males (Fig. 24C).

Pleon: pleopods 2–5 biramous with spirally coiled pseudobranchiae, distal setae of pleopods 3 and 4 unmodified (Figs 24D, E). Tail fan with uropodal exopod slightly longer than endopod, proximal article of exopod with 5–7 robust setae at distal angle of outer margin ( Fig. 25 B), row of robust setae on inner margin of uropodal endopod consisting of about 10 long setae, interspersed with groups of 3 or 4 smaller setae, total number being 46–50 robust setae ( Fig. 25 A), telson linguiform, fairly narrow, rounded apex reaching beyond diaresis in uropodal exopod, 2 strong robust setae on either side of telson base, a diastema in each lateral margin forming a slight ‘waist’, more distally a series of marginal robust setae, increasing in length towards apex (19–21 on each side in Lizard Island specimens), the longest 2 flanking 3 small apical setae and 2 long delicate plumose setae ( Fig. 25 C).

Remarks. Siriella vulgaris is similar to S. australis , described by W. M. Tattersall (1927) from Gulf St Vincent, South Australia. Among the features that distinguish the Lizard Island specimens from the latter are the presence of an apical lobe in the antennal scale and a small pseudo-rostral process, both of which are FIGURE 24. Siriella vulgaris Hansen, 1910 . A, left 1st thoracic limb. B, 2nd thoracic limb. C, right 8th thoracic limb (male). D, 3rd pleopod (male). E, 4th pleopod (male). Scalebars = A–E: 0.2 mm

lacking in S. australis . The rostrum of S. vulgaris is slightly shorter than that of S. australis and much shorter than that of S. vulgaris rostrata , a variety of S. vulgaris recorded by W.M. Tattersall (1951) from the Philippines and Micronesia. In all three, the antennular peduncle's second article carries on its anterior margin a prominent dorsal seta that projects forward almost the entire length of the third article. The 3rd to 8th thoracic limbs of S. vulgaris are slender, with a long dactylus and nail. At their junction there is a thin bristle-like spine, unlike the prominent spine that Tattersall found in S. australis and that is also shown in his illustration of S. vulgaris rostrata .

Associated mysid species. A total of 20 other mysid species were captured with S. vulgaris . Anisomysis laticauda was represented in all 8 samples, Siriella inornata in 6, Anisomysis incisa in 5 and Anchialina penicillata Zimmer 1915 and Pseudanchialina inermis each in 4 of the 8 samples.

Habitat. Pelagic, sublittoral, on occasion taken in abundance at the surface at night ( W.M. Tattersall 1951).

Distribution Siriella vulgaris was described from Indonesia and the Philippines ( Hansen 1910). It has a widespread distribution in coastal waters in the tropical Indo-Pacific ( W.M. Tattersall 1951). In north-eastern Australian waters it is known from Princess Charlotte Bay ( W.M. Tattersall 1928) and the vicinity of Low Isles ( W.M. Tattersall 1936a). It has also been taken in Darwin harbour in the Northern Territory ( Bacescu 1986).

At Lizard Island small numbers were caught in the lagoon at night in 5 plankton tows, all but one of which were surface hauls, 24 were taken in 2 fixed traps placed above living coral overnight and 7 in an offshore plankton haul 2–4 km east of Yonge Reef.

Figures

FIGURE 23. Siriella vulgaris Hansen, 1910. A, cephalothorax (male, 6 mm). B, lateral view (female, 6.2 mm). C, antenna (male). D, labrum. E, right mandible. F, right maxillule. G, left maxilla. Scalebars = A: 0.5 mm; B: 0.1 mm; C – G: 0.2 mm.

FIGURE 25. Siriella vulgaris Hansen, 1910. A, endopod of left uropod, ventral view. B, telson and right uropod, dorsal view. C, telson. Scalebars = A – C: 0.2 mm.