Synoicum kuranui Brewin, 1950

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 : 1662-1663

Synoicum kuranui Brewin, 1950

( Figure 3F )

Synoicum kuranui Brewin, 1950c: p. 355 –356, fig. 1. Millar, 1960: p. 49 –51, fig. 8B.

Material examined

New records: Breaksea Sound, First Cove (45° 44.237’S, 166° 53.199’E, 15 m, 1 February, 2009, NIWA 49977 ) ; North Cape, Spirit’ s Bay (45° 44.237’S, 166° 53.199’E, 35 m, 12 March 2002, NIWA 49977 ) ; Whangarei Harbour (35° 18.8915’S, 174° 28.398’E, 10 m, 3 February 2003, WRE6058 ) .

Previously recorded: New Zealand; east coast Great Barrier Island ( Brewin 1950c: p. 355–356, text fig. 1); North Cape ( Millar 1960: p. 7, fig. 8b).

Description

The bright crimson (R 5/5) colonies of this species are usually numerous small capitate heads approximately 10 mm diameter on a low stalk of similar length arising from a common basal mat ( Figure 3F ). Zooids form several circular systems on each head. Each system is composed of approximately 10 zooids around a single cloacal aperture. This species is often found on low reef platforms in sandy environments. Zooids measure up to 9 mm long, the branchial aperture has six low rounded lobes and the atrial aperture is surmounted by a stout lappet with terminal teeth. The branchial sac has 10 rows of 14–15 stigmata per half row and the stomach is round with small areolations. Up to three ova can be found halfway down the post-abdomen anterior to an irregular double row of testis follicles.

Remarks

In sheltered environments of high tidal flow such as Whangarei Harbour ( WRE6058 ), aberrant cylindrical colonies of up to 1.2 m long and 20 mm diameter have been recorded. The morphology of the zooids examined is the same as Brewin’ s original description for the holotype, which has a distinct narrowing of the post-abdomen at its proximal end. The new records represent a southern extension to the known distribution of this species .

Figures

Figure 3. In situ images of: (A) Botryllus stewartensis (NIWA 49968); (B) Botrylloides leachii (NIWA 49998); (C) Botrylloides leachii (NIWA 49986); (D) Botrylloides sp. (NIWA 49967); (E) Botrylloides sp. (NIWA 68096); (F) Synoicum kuranui (NIWA 49977).