Symplegma brakenhielmi ( Michaelsen, 1904 )

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 : 26-27

Symplegma brakenhielmi ( Michaelsen, 1904) NEW RECORD

Figure 10F, G

Colonies usually somewhat translucent, variously colored in life but the colors fade or disappear in formalin. Zooids with 10-11 rows of stigmata, branchial sac with four longitudinal vessels per side. Atrial siphon dorsal, far from oral siphon. Variable number of stomach folds, large curved caecum on medial side of stomach. When mature, ovary and testis both present on each side. This species can be difficult to identify unless the gonads are fully mature. It has undoubtedly been common though unrecognized in Singapore for some time, based on its wide distribution in the tropical Indo-Pacific and its frequent appearance as fouling worldwide. See discussion by Monniot C. (1983b).

#1206, living colony very transparent, no pigment.

#2598, on a piece of dead coral. Very thin tunic, flat transparent zooids. About 10 stomach folds. Gonads with both ovary and branched testes.

#3827A, on a large Polycarpa argentata . Zooids greenish-brown at oral end, white at posterior end ( Fig. 4F ); color disappears in fixative ( Fig. 4G ). Zooids 3 mm in length.

Distribution: Hong Kong, Indonesia, Thailand, Bahrain, Fiji, Australia, New Caledonia, Palau, Guam, China, Noumea, Sri Lanka, Indian Ocean, Hawaii, Caribbean, French Guiana, Brazil, Martinique, Galápagos, Israel (Mediterranean).

Detailed references: Kott (1981, 1985 as S. oceania ; 2004), Monniot C. (1983b; 1988 as S. oceania Tokioka, 1961 ), Monniot C. et al. (1985 as S. oceania ), Monniot C. & Monniot F. (1987 as S. oceania ; 1997), Abbott et al. (1997 as S. oceania ), Monniot F. (2018b). Other references: Monniot F. & Monniot C. (2001, 2008), Rocha & Costa (2005), Rocha et al. (2005), Shenkar & Loya (2009), Lambert (2003, 2019), Monniot F. (2016).

Figures

FIGURE 4. A–D: Eudistoma laysani. A: whole living colony 3 cm across; B: one head; C: unhatched tadpole 800 µm in length; D: one head of preserved colony. E: Eudistoma regina, part of large colony; F: Aplidium cf. grisiatum colony 1.5 cm in width; G–H: Pseudodistoma fragile. G: whole living colony 4 cm across; H: single zooid 8 mm in length, somewhat contracted. Scale bar: E, 0.4 cm.

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.