Polycitor translucidus Kott, 1957

Kott, Patricia, 2009, Taxonomic revision of Ascidiacea (Tunicata) from the upper continental slope off north-western Australia, Journal of Natural History 43 (31 - 32), pp. 1947-1986 : 1958-1959

Polycitor translucidus Kott, 1957

( Figure 1D )

Polycitor translucida Kott 1957, p. 81

Polycitor translucidus: Kott 1990, p. 177 and synonymy. Monniot F and C. 2001, p. 250 Polycitor crystallinus Monniot C. 1988, p. 209 .

Distribution

Previously recorded ( Kott 1990): western Australia (Shark Bay, Cockburn Sound); Victoria (Wilsons Promontory); Queensland (Maroochydore, Capricorn Group, Great Barrier Reef); French Polynesia; New Caledonia; Palau Is., Philippines. New record: CSIRO 05 / 06: western Australia (Station 003-020, Barrow Is., 21.00 S 114.13 E, 695 m? Camera tow, 9.6.07, QMG328573 ) .

Description

The colony consists of pillar-like upright lobes attached to firm and translucent basal test. In each lobe, about six zooids, lying parallel to each other and to the longitudinal axis of the colony lobe, open separately on the upper free surface. The branchial and atrial openings, each with six marginal lobes, are at the anterior end of the contracted zooid and longitudinal bands extend the length of the zooid outside an almost continuous coat of transverse muscles around the thorax. The stomach, near the posterior end of the abdomen, appears to have a smooth wall and the gut is very convoluted, the abdomen being contracted to about the same length as the thorax in this specimen.

Remarks

Both zooids and colony of Polycitor species can be readily confused, being variable and the zooids very contractile. In particular, of the three specimens assigned to P. circes Michaelsen, 1930 by Millar (1975) only one (from Marongas, 20.iii.14) appears to be conspecific with Michaelsen’s species. The other (19.iii.13) from the same location may belong to the present species, having similar zooids without folds in the stomach wall and relatively small larvae; the principal distinguishing characters of the present species. The third specimen Millar (1975) assigned to P. circes is very probably a specimen of a Pycnoclavella sp. (possibly P. diminuta ).

Key to the species of Polycitor reported from the tropical Indo-west Pacific

1. Stomach without folds...................... P. translucidus Kott, 1957 Stomach with folds............................................. 2

2. Stigmata in 8–10 rows; stomach folds 12–15......... P. annulus Kott, 1990 Stigmata in 18–23 rows; stomach folds 13–30.... P. circes Michaelsen, 1930

Figures

Figure 1. (A–B) Diazona fungia (QM G328570); (A) colony; (B) zooid. (C) Diazona textura (QM G328571) colony. (D) Polycitor translucidus (QM G328573) colony. (E–F) Sigillina mjöbergi (QM G328563); (E) colony; (F) zooid. Scales: A, C, D, 0.5 cm; B, 1.0 mm; E, 1.0 cm; F, 0.5 mm.