Ritterella sigillinoides (Brewin, 1958)

Page, M. J., Willis, T. J. & Handley, S. J., 2014, The colonial ascidian fauna of Fiordland, New Zealand, with a description of two new species, Journal of Natural History (J. Nat. Hist.) 48 (27 - 28), pp. 1653-1688 : 1676

Ritterella sigillinoides (Brewin, 1958)

Pesudodistoma sigillinoides Brewin, 1958a: p. 455 , fig. 2A 1, A 2, A 3, A 4 Pesudodistoma sigillinoides: Millar 1982: p. 47

Material examined

New Records: Edwardson Sound (45° 56.52’S, 166° 37.56’E, 14 m, 29 February 2009, NIWA 49948 , three colonies); Caswell Sound (45° 01.01’S, 167° 08.40’E, 18 m, 3 February 2009, NIWA 49989 , two colonies) .

Previously recorded: New Zealand, Stewart Island ( Brewin 1958a); east coast Stewart Island, 101 m ( Millar 1982).

Description

The colonies have numerous, small light-yellow capitate heads to 10 mm diameter on slender tapering, almost woody, sometimes branching stalks up to 40 mm high. As many as 20–30 zooids are embedded in a soft gelatinous test and open separately to the surface. The zooids are up to 14 mm long with atrial and branchial siphons that have six low indistinct lobes and a stomach with 11 broken folds. No larvae were present in specimens collected from Fiordland.

Remarks

This species is relatively uncommon in Fiordland and easily distinguished from other species by soft gelatinous colony heads. The branching character in the specimens collected in Fiordland agrees with the description by Millar (1982) collected from 135 m off Port Pegasus, Stewart Island. Deep emergent species are common in shallow water in Fiordland. The branching character seen in colonies here may be common to individuals in deeper environments.