Herdmania columna (Monniot C. & Monniot F., 1991)

Monniot, Francoise, 2021, New records of deep-sea ascidians (Tunicata, Ascidiacea) from the New Caledonia region, Zootaxa 4996 (3), pp. 443-468 : 459

Herdmania columna (Monniot C. & Monniot F., 1991)

Figure 16

Station: Kanacono DW 4728. Two specimens. (MNHN S2.HER 100).

Pyura columna Monniot C. & Monniot F. 1991 Figs 21I , 29. The body is 2 cm long on a peduncle of the same size ( Fig. 16B ). Both specimens have a cartilaginous tunic with few epibionts that contains the characteristic spicules of the genus. In one specimen there is a tunic papilla close to the oral aperture and two similar papillae at the anterior angle of the body. The muscular fibres are regularly crossed on the body sides. Twelve oral tentacles have ramifications of first order. The dorsal tubercle U-shaped opens in the prepharyngeal V. The dorsal lamina has long triangular languets. The branchial sac has 9 high folds on each side ( Fig. 15A ) and an additional half fold on the right side. The gut forms a wide open loop ( Fig.16C ) ending in an anus with two lips. A large hepatic gland covers the stomach ( Fig. 16C ). The gonads are long, straight and parallel to each other ( Fig. 16B, C ) six on the right side and two on the left, one in the gut loop and one above. The tubular ovary is covered by the testis vesicles, the common sperm duct follows the ovary length and opens with the oviduct but secondary successive male apertures arise erect on papillae ( Monniot & Monniot 1991 Fig. 29C).

The presence of needle-shaped spicules in with rods of spines justifies to place the species in the genus Herdmania , as well as the morphology of the gonads.

Very similar in the body shape and also present in the Caledonian area Herdmania colona Monniot F. & Monniot C., 2003 is a junior synonym of Herdmania fimbriata Kott, 2002 from South Australia. It differs by the musculature design, the presence of one gonad on each side, and different complex genital papillae.

Figures

FIGURE 15. Pyura viarecta. A, body ventrally opened; B, same body, branchial sac removed. Scale bars = 1cm.

FIGURE 16. Herdmania columna. A, branchial sac; B, body; C, gut and gonads. Scale bars = 1cm.

FIGURE 21. Culeolus sp. A, specimen; B, body without tunic; C, body ventrally opened without tunic. Scale bars = 1cm