Diplosoma velatum Kott, 2001

Page, M. J., 2018, Colonial ascidians from the Foveaux Strait region of New Zealand, Journal of Natural History (J. Nat. Hist.) 52 (17 - 20), pp. 1157-1180 : 1167

Diplosoma velatum Kott, 2001

( Figure 6a )

Material examined

New records. NEW ZEALAND, Bluff Harbour , Tiwai Point wharf piles (46.591°S, 168.349°E, 7 m, 21 August 2007, NIWA68092 , 1 colony) (46.591°S, 168.349°E, 9 m, 7 February 2011, NIWA87158 , 1 colony); Stewart Island, Glory Cove (46.971°S, 168.162°E, 10 m, 30 September 2006, NIWA169726 , 1 colony) .

Previously recorded. NEW ZEALAND, Fiordland (Crooked Arm Head, Only Island, Long Sound, Nine Fathom Passage, Dusky Sound, Thompson Sound ( Page et al. 2014); South Australia, (York Peninsula, Taipara Reef, Eyre Peninsula, Cathedral Rock and Kangaroo Island, Investigator Strait); Western Australia (Esperance, Oyster Harbour); Victoria (Western Port) (see Kott 1962, 1975, 1976, 2001).

Description

Pale orange colonies have characteristically large common cloacal apertures and zooids arranged in groups, suspended in test connectives visible through a semi-transparent gelatinous test ( Figure 6a ). The zooids are 1.8–2.0 mm long. The thorax has a large atrial aperture that exposes most of the branchial sac. The branchial sac has 4 rows, approximately 10 stigmata per half-row. There are 2 testis follicles,divided by a straight vas deferens.The larvae characteristic of this species are large, with 3 long, slender lateral ampullae on each side of adhesive papillae on long stalks.

Remarks

Diplosoma velatum colonies are common on wharf piles and natural substrata throughout Bluff Harbour. They are easily distinguishable from a co-occurring species, Diplosoma listerianum (Milne Edwards, 1841) , by their lobed, fleshy, sheet-like colonies.

Figures

Figure 6. In situ images of: (a) Diplosoma velatum (NIWA68092); (b) Polyclinum novaezealandiae (NIWA68097); (c) Synoicum stewartense (NIWA68089); (d) Aplidium benhami (NIWA68101); (e) Aplidium knoxi (NIWA68091); (f) Aplidium phortax (NIWA68109).