Observations on non-didemnid ascidians from Australian waters (1)
Author
Kott, Patricia
text
Journal of Natural History
2006
2006-04-26
40
3 - 4
169
234
http://dx.doi.org/10.1080/00222930600621601
journal article
10.1080/00222930600621601
1464-5262
5232431
Eudistoma anaematum
Kott, 1990
(
Figure 2G
)
Eudistoma anaematum
Kott 1990a
, p 196
.
Distribution
Previously recorded (see
Kott 1990a
):
Queensland
(Great Barrier Reef). New record:
Queensland
(Bowden Reef, AIMS 17693).
Description
The newly recorded colony has firm gelatinous test containing the usual long polycitorid zooids, which are arranged in circles with the long atrial siphons opening in the centre of the circle. Sand is not present either in or on the colony. The living colony was transparent and bluish beige. Dark, spherical pigment particles are scattered sparsely through the test of the preserved specimen. Zooids are robust, as previously described, with up to 30 stigmata in each of three rows and there is a long prestigmatal unperforated area in the pharynx. The almost spherical stomach is at the end of the long oesophageal neck, at the posterior end of the body. Zooids have up to two embryos developing in the atrial cavity. Larvae are similar to, although the trunk (
0.75 mm
long) is about half the length of the larval trunk of,
E. globosum
.
The three antero-median adhesive organs have wide platforms of adhesive cells on short thick stalks, each surrounded by a shallow epidermal cup; and three narrow, median, ectodermal ampullae alternate with the adhesive organs. A large oval yolk mass almost completely occupies the larval trunk. The tail winds about halfway around the trunk.
Remarks
The species is distinguished from others in this homogenous genus by its naked, sand-free, translucent colony. Its larva is described here for the first time.