Polysyncraton magnetae Hastings, 1931

Kott, Patricia, 2007, New and little-known species of Didemnidae (Ascidiacea, Tunicata) from Australia (part 4), Journal of Natural History 41 (17 - 20), pp. 1163-1211 : 1172

Polysyncraton magnetae Hastings, 1931

( Figure 7A ) Polysyncraton magnetae Hastings 1931, p 100 ; Kott 2001, p 109 and synonymy; 2004a, p 741.

Distribution

Previously recorded (see Kott 2004a): Queensland (Great Barrier Reef). New record: Queensland (Great Barrier Reef: 18.615 ° S, 146.645 ° E, 30 m, QM G308818 ) .

Description

The newly recorded colony consists of large vertical lamellae with two sorts of spicules crowded throughout. Spicules, to 0.05 mm diameter, are both stellate (with 13–15 conical pointed rays) and globular (with rod-like, flat-tipped rays).

Zooids each have a large yellow egg at the posterior end of the abdomen and two loose coils of the vas deferens around seven or eight male follicles.

Remarks

Larger spicules (to 0.05 mm) are present than the 0.035 mm diameter previously recorded for this species. Also, the number of spicule rays in optical transverse section (15–17) that Kott (2001, Figure 162I) recorded appears to be too high. Other characteristics, including the yellow egg at the posterior end of the zooid, are reported previously for this species.

Figures

Figure 7. Scanning electron micrographs. (A) Polysyncraton magnetae (QM G308818); (B) Polysyncraton meandratum (QM G308849); (C) Polysyncraton otuetue (QM G308851); (D) Polysyncraton reticulum (QM G323330); (E) Polysyncraton scorteum (QM G323343); (F) Didemnum abradatum (QM G308870); (G) Didemnum astrum (QM G308857); (H) Didemnum candidum (QM G308765).