Styela canopus ( Savigny, 1816 )

Lambert, Gretchen, Lee, Serina Siew-Chen & Teo, Serena Lay-Ming, 2021, Ascidians collected during the 2013 Singapore Strait International Marine Biodiversity Workshop, Zootaxa 4933 (1), pp. 1-38 : 26

Styela canopus ( Savigny, 1816)

Figure 10E

Specimens rarely more than 2 cm in length; siphons sometimes blackish, with reddish mottled and striped lining. Oral siphon at anterior end, atrial siphon a short distance behind. Siphonal lining with minute flattened and pointed spines or scales about 15 µm long by 11.5 µm wide at base which continue on the tunic surface outside the siphons (see Kott 1985). Dorsal tubercle a rounded U, opening anteriorly; ganglion directly posterior to dorsal tubercle. Numerous endocarps on body wall and on the gut loop. Two elongate gonads per side.

#0154B, two gonads per side though only one visible on each side in Fig. 10E . One gammarid amphipod in branchial sac.

#3784A, small, about 8 mm long x 10 mm wide in warty tunic. Twenty-nine oral tentacles. Anus with about a dozen rounded lobes. One small immature gonad visible on each side.

#3827C, four small specimens on a Polycarpa argentata .

#3850B, small, 1.7 cm across, but with large gonads.

Worldwide distribution: China, Hong Kong, Indonesia, Philippines, Singapore, Taiwan, Thailand, W. Indian Ocean, Okinawa, Marquesas Is., Japan, Palau, Guam, French Polynesia, Galápagos, Hawaii, southern California, Australia, New Caledonia, Majuro, Bahrain, Red Sea, S. Africa, West Indies, Martinique, SE U.S., Gulf of Mexico, Caribbean, Brazil, Mediterranean.

Detailed references with illustrations: Van Name (1945, as S. partita (Stimpson, 1852)) , Millar (1975), Tokioka & Nishikawa (1975), Kott & Goodbody (1982), Kott (1985), Nishikawa (1991), Abbott et al. (1997), Monniot C. et al. (2001), Monniot F. (2012, 2018b), Lee et al. (2013). Other references: Nishikawa (1984), Monniot C. (1983b, 1988, 2002), Monniot C. et al. (1985), Monniot C & Monniot F. (1987, 1994, 1997), Zheng (1995), Lambert (2002, 2003, 2019), Monniot F. & Monniot C. (2001, 2003), Lambert et al. (2005), Rocha & Kremer (2005), Rocha et al. (2005, 2012), Lee et al. (2016).

Figures

FIGURE 10. A: Polycarpa captiosa dorsal ganglion; B, C: Polycarpa cf. olitoria. B: right side in tunic, 5 cm in length; C: left side removed from tunic showing row of gonads. D: Polycarpa papillata right side, 7 cm in length; E: Styela canopus siphonal scales 15 µm in length; F, G: Symplegma brakenhielmi. F: live colony; G: single preserved zooid from same colony, 3 mm in length.