Siriella vincenti W.M. Tattersall, 1927

Daneliya, Mikhail, Price, W. Wayne & Heard, Richard W., 2018, Revision of the Siriella brevicaudata species group (Crustacea: Mysida: Mysidae) from the West Indo-Pacific, European Journal of Taxonomy 426, pp. 1-80 : 63-69

Siriella vincenti W.M. Tattersall, 1927

Figs 29–31

Siriella vincenti W.M. Tattersall, 1927b: 239 , fig. 97.

Siriella vincenti – Hale 1929: 361, fig. 358 (adopted from Tattersall 1927b). — Illig 1930: 561 (key). — Dakin & Colefax 1940: 131, fig. 221 (questionable record). — Gordan 1957: 381 (catalogue). — Mauchline & Murano 1977: 77 (checklist). — Panampunnayil 1981: 90; 1995: 1949 (table). — Udrescu 1981: 31. — Băcescu & Udrescu 1984: 93. — Fenton 1986: 48, partim, fig. 2.12c–e (adopted from W.M. Tattersall 1927b: fig. 97a, e–f). — Müller 1993: 45 (catalogue). — Currie & Parry 1996: 138. — Parry et al. 1997: appendix 2b. — Lowry & Stoddart 2003: 469 (catalogue). — Deprez 2006: 354 (list). — Hanamura 2007: 37. — Yerman & Lowry 2007 (interactive key). — Murano & Fukuoka 2008: 35. — Anderson 2010: 23 (checklist).

Non Siriella vincenti – Talbot 2009: 33 , figs 21–22 (see S. talbotae sp. nov.).

Diagnosis

Carapace with anterodorsal margin angular, apically broadly rounded; lateral sides slightly concave. At least half of subrostral process covered by carapace. Carapace of female with dorsal tubercle and postcervical elevation. Telson 1.0–1.1 times as long as last abdominal somite, 2.0–2.1 times as long as wide anteriorly and 1.3 times as wide anteriorly as posteriorly. Lateral margins with three or four strong anterior spiniform setae and 10 to 15 posterior spiniform setae; terminal posterolateral pair of spiniform setae 0.11–0.13 times as long as telson and 0.9–1.0 times as long as subterminal pair of spiniform setae; subterminal 1.1–1.2 times as long as preceding pair of posterolateral spiniform setae. Apical margin without emargination; three apical spinules rather well-established, 0.2–0.3 times as long as subterminal pair of spiniform setae. Labrum with relatively long anterior spine, about 0.2 times as long as rest of labrum. Maxilla 1, outer ramus with apical smooth spiniform setae. Maxilla 2 endopod with three or four lateral setae. Pereopod 1 merus rather thin, 4.6–5.0 times as long as wide. Uropodal exopod 3.6–3.9 times as long as wide; segment 1 with three to six spiniform setae; segment 1 is 1.7–1.9 times as long as segment 2. Uropodal endopod with 15 to 22 medial spiniform setae in male and 19 to 25 in female; tip of terminal reaching apex of ramus.

Material examined

Syntypes (in total: 2 or 3 ♂♂, 5 ♀♀ (one subadult))

AUSTRALIA: 1 ♂ (without head and pereopodal endopods), 1 ♂ (head without one eye), 1 ♂, ca 7.5 mm long (without carapace and pereopodal endopods), 1 subadult ♀ (without head and pereopods), last abdominal segment with telson and uropods, likely belonging to an ovigerous ♀, 7.5 mm long, 1 ♀ (ovigerous), 7 mm long (with damaged carapace, but one pereopodal endopod left), 1 ♀, 7 mm long (with damaged carapace and without pereopods), 1 ♀, 7.5 mm long (with damaged carapace, but one endopod of pereopod 1 left), South Australia, “ 6 mi [miles] off Semaphore, G. [Gulf] of St. Vincent, 6–7 fm [= 10–13 m]”, H.M. Hale leg. ( SAM, C1615). Originally labeled as “types”, though Tattersall (1927b) himself called them syntypes. Tattersall also mentioned a total of 3 ♂♂ and 8 ♀♀. Thus, the description was based on an additional two–three specimens with unknown fate.

Other material

AUSTRALIA: Victoria: 1 ♂ (pereopod endopods missing), 8.5 mm long, Western Port, 38°29′20″ S, 145°21′37″ E, 6 m, sand-silt-clay, WBES, Benthic Survey, st. 1738, Smith McIntyre Grab, 26 Nov. 1973, Marine Studies Group, Ministry for Conservation and Noel Coleman leg., originally identified by Margaret M. Drummond ( MNV J4277); 1 subadult ♀, 5.5 mm long, 3 juveniles, 3.5–4.5 mm long, all in poor condition, Port Phillip Bay, eastern sandy region, 38°01.60′ S, 145°04.88′ E, 7.5 m, PPBES, st. 203.1, Smith MacIntyre Grab, 3 Apr. 1995, R.S. Wilson, G. Walker-Smith and S. Heislers leg., previously indentified by S. Heislers in 1996 ( MNV J43916 ); 1 subadult ♂, 5.5 mm long, Western Port, 38°24′22″ S, 145°14′40″ E, 20 m, sand, WBES, st. 1729, Smith-McIntyre grab, 21 Nov. 1973, Marine Studies Group, Ministry for Conservation and Noel Coleman leg., previously identified by Margaret M. Drummond ( MNV J4279); 1 subadult ♀, 6 mm long, Port Phillip Bay, Geelong arm, 38°09′18″ S, 144°29′18″ E, 9 m, sand, PPBES, R/V Melita, st. 952, Smith-McIntyre grab, 11 Jul. 1971, Marine Pollution Studies Group, Ministry for Conservation, Gary C. Poore, Sebastian F. Rainer et al. leg., Gary C. Poore det. in 1975 ( MNV J5470); 1 ♀, 7 mm long, Western Port, 38°15′19″ S, 145°22′23″ E, 0 m, intertidal, WBES, Benthic Survey, st. 1706, Smith-McIntyre grab, 8 Jan. 1974, Marine Studies Group, Ministry for Conservation and Noel Coleman leg., previously identified by Margaret M. Drummond ( MNV J4281); 2 ♀♀ (one without head), 7 mm long, Port Phillip Bay, off Werribee, 38°02′18″ S, 144°44′42″ E, 13 m, sand, PPBES, R/V Melita, st. 922, Smith- McIntyre grab, 10 Jun. 1971, Marine Pollution Studies Group, Ministry for Conservation, Gary C. Poore, Sebastian F. Rainer et al. leg., previously identified by Gary C. Poore ( MNV J5475); 1 ♂, 6 mm long, 1 juvenile, 3.5 mm long, Western Port, 38°29′18″ S, 145°22′50″ E, 6 m, WBES, st. 1741, Smith-McIntyre grab, 26 Nov. 1973, Noel Coleman leg., previously identified by Margaret M. Drummond ( MNV J4275). – New South Wales: 1 ♀, 7.5 mm long, N of Burrewarra Point, East Wall, 35°50′01″ S, 150°14′10″ E, 25 m, from macroalga Peyssonelia novahollandiae, bottom temperature 16°C, Invertebrate Biodiversity on Algal Substrates Project, Hermon Slade Batemans Bay Expedition, Investigator, R/V Connemara, st. NSW 1985, by hand during SCUBA, 25 Oct. 2002, G. Wilson, A. Millar and N. Yee leg. ( AM P.98725); 2 ♂♂, 9 ♀♀, 7 mm long, 7 subadults, Twofold Bay, Red Point, 37°06′07″ S, 149°57’04″ E, 12 m, algal turf on boulder, st. NSW 1118, airlift, 20 May 1995, K.B. Attwood leg. ( AM P.98736); 4 ♂♂, 6– 6.5 mm, 6 ♀♀, 6¯ 7.5 mm, 1 juvenile, E of gate between Tollgate Islands, Batemans Bay, 35°45.204′ S, 150°15.745′ E, 18.1 m, 22.2°C, rocky reef formed into ridges by angled bedding planes with gravel filled gutters at 18 m, fewer gutters at shallower depths, gravel, R/V Baragula and R/V Sula, st. NSW 2591, by hand during SCUBA, 26 Mar. 2004, P. Berents, K. Attwood, R. Johnson, S. Keable, S. Kiely, K. Monro, A. Murray, R. Springthorpe and J. Watson leg. ( AM P.98744); 1 ♂ (damaged), 5 ♀♀ (damaged), 2 juveniles (damaged), W of Tollgate Island, Batemans Bay, 35°44.827′ S, 150°15.42′ E, 7.8 m, 22.1°C, patches of reef, sand, stones and Ecklonia adiate, brown algae, R/V Baragula and R/V Sula, st. NSW 2648, airlift during SCUBA, 29 Mar. 2004, P. Berents, K. Attwood, R. Johnson, S. Keable, S. Kiely, K. Monro, A. Murray, R. Springthorpe and J. Watson leg. ( AM P.98732); 3 ♂♂ (damaged), 7 ♀♀ (5 damaged), 6 mm long, Forster, E of Red Head, 32°3.28′ S, 152°33.23′ E, 12.3 m, low profile rocky reef with sand gutter, encrusted rock surface with sediment and worm tubes, R/V Baragula, st. NSW 2265, airlift, 22 Mar. 2003, P.B. Berents, R.T. Johnson, S.J. Keable, A. Murray and R.T. Springthorpe leg. ( AM P.98727).

Description

Body length 5.5–8.5 mm. Female (syntypes)

CARAPACE. With anterodorsal margin angular, apically rounded, with slightly concave lateral margins; covering most of subrostral process, except for its very tip ( Fig. 29A ). Carapace with dorsal cephalic tubercle and postcervical elevation ( Fig. 29B ). Posterior margin of carapace not covering last two thoracic somites.

TELSON. About as long as last abdominal somite and 2.0–2.1 times as long as wide anteriorly; lateral margins with three strong anterior spiniform setae and 11 or 12 (15 in original description) posterior spiniform setae, distally becoming gradually longer; terminal posterolateral pair of spiniform setae 0.11–0.12 times as long as telson and 0.9 times as long as subterminal pair (as long in original illustration), which are 0.13–0.14 times as long as telson ( Fig. 29 C–D). Telson apically without emargination; three apical spinules rather well-established, with two long plumose setae between them.

HEAD APPENDAGES. Antennular peduncle segment 3 with one medial and three distomedial plumose setae ( Fig. 30A ). Antennal scale reaching distal margin of segment 3 of antenna 1 peduncle, with clear distal joint ( Fig. 30C ). Mandibular palp ( Fig. 30D ): segment 2 with nine dorsomedial setae (ventromedial missing); segment 3 with six long lateral setae, 0.8 times as long as segment 2. Labrum with relatively large anterior spine, 0.22 times as long as rest of labrum ( Fig. 30E ). Maxilla 1: apical spiniform setae of outer ramus smooth. Maxilla 2: endopod with three–four lateral setae.

MAXILLIPEDS. Maxilliped 1 as typical for the genus ( Fig. 30F ). Maxilliped 2 ( Fig. 31 A–B): ischium 1.5 times as long as wide; merus 2.4 times as long as wide; carpopropodus 2.8 times as long as wide and about as long as merus; dactylus 0.3 times as long as carpopropodus, with about five robust, serrated setae; unguis strong, 2.3 times as long as dactylus.

PEREOPODS. Pereopod 1 ( Fig. 31C ): preischium without setae; ischium 2.5 times as long as wide, with one lateral and numerous medial setae; merus 4.8 times as long as wide, with long and short medial setae; carpopropodus with barely established joint or without it, 6.3 times as long as wide and 0.9 times as long as merus; dactylus (including unguis) 0.4 times as long as carpopropodus; paradactylary setae thin, longer than dactylus, without serration; unguis with strong medial serration.

UROPODS. Uropodal exopod 3.8 times as long as wide. Segment 1 of uropodal exopod with three or four distolateral spiniform setae ( Fig. 29E ). Segment 2 of uropodal exopod 0.5 times as long as segment 1. Uropodal endopod with 19 to 25 medial spiniform setae; tip of terminal seta stretching beyond apical margin of ramus ( Fig. 29F ).

Male (syntypes)

Male process of antenna 1 rather long, conical; distally produced part about half as long as antennular segment 3 ( Fig. 30B ). Antennular inner flagellum normal, not dilated or meandering in proximal part. Antennal scale reaching distal margin of segment 3 of antenna 1 peduncle, without clear distal joint. Pleopods with 11–12-segmented rami ( Fig. 31D ). Segment 1 of uropodal exopod with five or six distolateral spiniform setae. Uropodal endopod with 19–22 medial spiniform setae.

Comparison

Siriella vincenti is the only species in the brevicaudata group in which the telson has a terminal posterolateral pair of spiniform setae that are shorter than (or rarely about as long as) the subterminal pair in both sexes (terminal longer than or occasionally as long as subterminal in at least males of other species). It has been confused with two newly described species, S. bassi sp. nov. and S. talbotae sp. nov., but is clearly distinguished from both (see relevant comparison sections for differences). Siriella vincenti is also distinguished by a number of characters from the related S. spinula (see differences in Comparison section for that species).

Distribution

Indian Ocean, South Australia: Gulf of St. Vincent (type locality), Spencer Gulf, the Dangerous Reef ( Băcescu & Udrescu 1984); Victoria: Portland Bay ( Parry et al. 1997), Port Phillip Bay ( Fenton 1986, confirmed in this study; Currie & Parry 1996); New South Wales: Twofold Bay, Batemans Bay, near Read Head (Forster) ( Figs 1–2 ), possibly also from Broken Bay ( Dakin & Colefax 1940). So far not confirmed from the Tasmanian coast, though mentioned from Margate Beach, North-West Bay and Darlington, Maria Island, by Fenton (1986). The specimens reported by Fenton (1986) and Talbot (2009) from Lizard Island do not belong to S. vincenti , but represent a new species, named here as S. talbotae sp. nov. (see above).

Habitat

Depth 0– 25 m. Bottom with sand, silt and clay (Victoria), on Peyssonelia novaehollandiae (Kütz.) Harv. , Ecklonia radiata (C.Agardh) J.Agardh and other macroalgae, sand, rocks and gravel (New South Wales). This species is seemingly distinguished ecologically from S. bassi sp. nov., which was discovered in the Bass Strait, and found at greater depths of 38–85 m (occasionally at 9–12 m).

Remarks

Siriella vincenti was originally described rather in detail (W.M. Tattersall 1927b), but not well enough for an adequate comparison with other related species. Based on the type series, S. vincenti is formally redescribed and illustrated in detail herein.

Tattersall (1927b) described the anterodorsal margin of the carapace as evenly rounded. However, judging from the illustration ( Tattersall 1927b: fig. 97a) and actual inspection of the syntypes, it appears to be rather angular, though with a rounded apex. The body lengths of the type specimens was originally described as up to 8 mm, which probably also included antennal scales. This evidently caused confusion in the discrimination between S. vincenti from S. spinula (cf. Panampunnayil 1995; Murano & Fukuoka 2008). The partial illustration of the telson and uropods of S. vincenti by Dakin & Colefax (1940) from Broken Bay in New South Wales, Australia, is insufficient to make a decision about the identity of the specimen; however, the terminal spiniform setae of the illustrated specimen are longer than the subterminal ones, thus suggesting that the specimen most probably belongs to another species.

We had an opportunity to examine a large collection from the Bass Strait, which separates the Australian mainland from Tasmania. This collection, which is deposited in the Museum Victoria, Melbourne, was previously identified by various researchers and also included in the dissertation of Fenton (1986) as S. vincenti . Besides S. vincenti , this collection also contained another undescribed member of the brevicaudata group, described herein as S. bassi sp. nov.

The specimens from Lizard Island in the Great Barrier Reef, Australia, identified by Talbot (2009) as S. vincenti , were compared with the redescribed type collection of S. vincenti and found to represent another new species within the brevicaudata group, S. talbotae sp. nov., described herein.

Figures

Fig. 29. Siriella vincenti W.M. Tattersall, 1927, syntype, ♀, length 7.5 mm, Gulf of St. Vincent, South Australia. A. Anterodorsal margin of carapace and subrostral process. B. Dorsal part of carapace, lateral view. C. Telson. D. Apical part of telson, dorsal view. E. Uropodal exopod, ventral view. F. Uropodal endopod, ventral view. Scale bars: A–C, E–F = 0.5 mm; D = 0.25 mm.

Fig. 30. Siriella vincenti W.M. Tattersall, 1927, syntypes, Gulf of St. Vincent, South Australia, Australia. A. Antenna 1 peduncle, dorsal view. B. Antenna 1 peduncle, dorsal view. C. Antenna 2 peduncle and antennal scale, ventral view. D. Mandibular palp, medial view. E. Labrum. F. Distal part of maxilliped 1 endopod, posterior view. A, C–F = ♀; B = ♂, length 7.5 mm. Scale bars: A–C = 0.5 mm; D–F = 0.25 mm.

Fig. 31. Siriella vincenti W.M. Tattersall, 1927, syntypes, Gulf of St. Vincent, South Australia, Australia. A. Maxilliped 2 endopod, posterior view. B. Distal part of maxilliped 2 endopod, posterior view. C. Pereopod 1 endopod, posterior view. D. Pleopod 4, posterior view. A–C = ♀, length 7.5 mm; D = ♂, length 7.5 mm. Scale bars: A, C–D = 0.5 mm; B = 0.25 mm.

Fig. 1. Distribution of species in the Siriella brevicaudata species group. Question mark (?) indicates published record requires verification.

Fig. 2. Distribution of species in the Siriella brevicaudata species group along the southern Australian coast.