Eusynstyela Michaelsen, 1904

Monniot, Françoise & Monniot, Claude, 2001, Ascidians from the tropical western Pacific, Zoosystema 23 (2), pp. 201-383 : 314-315

Genus Eusynstyela Michaelsen, 1904

Eusynstyela hartmeyeri Michaelsen, 1904 ( Fig. 126F )

Eusynstyela hartmeyeri Michaelsen, 1904: 38 , 114, pl. 1, fig. 1, Red Sea and Mozambique. — Monniot C. & Monniot F. 1997: 1639, Bahrain.

Polyandrocarpa violacea Sluiter, 1905: 10 , pl. 1, fig. 3.

Eusynstyela aliena Monniot C., 1991b: 18 , fig. 6, New Caledonia.

MATERIAL EXAMINED. — Hong Kong. SE Hong Kong Island, Swire Marine Lab, 22°12.53’N, 114°15.66’E, 5 m, 12.X.1994 ( MNHN S1 EUS 18).

DESCRIPTION

This species ( Fig. 126F ) makes thick crusts, with the zooids totally included in a common tunic. It was described from the Indian Ocean and Noumea Harbour. It is characterised by elongat- ed polycarps, erect in the cloacal cavity, with two testes of equal length. The stomach is elongated with a small, uncurved caecum.

REMARKS

Monniot C. (1991b) suggested that this species was imported into Noumea Harbour and that diverse populations described by previous authors from oyster cultures or mangroves may also belong to this species. The new collection from Hong Kong Harbour reinforces this hypothesis. Monniot C. & Monniot F. (1997: 1639) have considered the possible relationship between E. aliena and E. hartmeyeri Michaelsen, 1904 from the Red Sea and Arabian Gulf, both species that also make thick forms. The specimens of the present collection correspond perfectly to those from Noumea and the Indian Ocean. The synonymy of E. aliena and E. hartmeyeri is established here.

Eusynstyela latericius ( Sluiter, 1904) (Fig. 127A)

Gynandrocarpa latericius Sluiter, 1904: 94 , pl. 15, figs 8-11. Type locality: Indonesia. Synonymy and distribution: see Monniot C. 1991b: 14. — Monniot F. & Monniot C. 1996: 241, figs 49B-D; 50, pl. 8F, Indonesia.

MATERIAL EXAMINED. — Philippines. Bohol Sea, Camiguin Island, 9°12.89’N, 124°38.03’E, 7 m, 18.IV.1997 ( MNHN S1 EUS 20). — Bohol Sea, Camiguin Island, 9°12.89’N, 124°38.03’E, 25 m, 18.IV.1997 ( MNHN S1 EUS 21).

Papua New Guinea. Madang barrier reef pass N of Pig (Tab) Island, Rash Pass, 5°09.27’S, 145°49.82’E, 30 m, 22.XI.1993 ( MNHN S1 EUS 22).

Indonesia. N Sulawesi, West of Manado, 1°23.52’N, 124°32.64’E, 6 m, 14. V.1993 ( MNHN S1 EUS 15).

Fiji. SW Taveuni Island, 16°54.48’S, 179°55.30’E, 12 m, 2.XI.1996 ( MNHN S1 EUS 19).

Mariana Islands. Guam, fore reef of Merizo Channel, 5 m, 19.IX.1997 ( MNHN S1 EUS 26).

DESCRIPTION

The colonies form thin crusts. The tunic is thin and the zooids can be easily seen. The colour of the colonies may vary according to the extension of the lightest patches between the siphons (Fig. 127A). The species is characterised by a short globular stomach with a small caecum and round gonads lying on the body wall. According to the stage of development, the gonads are distributed along one row or two rows, or are sometimes irregular as in the type specimen. The dissection of this species is made difficult by elastic filaments uniting the tunic and the body wall.

REMARKS

This species is distributed throughout the tropical western Pacific Ocean.

Figures

FIG. 126. — A,?Phallusia obesa (Herdman, 1880); B, Phallusia philippinensis Millar, 1975; C, Phallusia sp.; D, Botryllus perspicuus (Herdman, 1886); E, Botryllus tyreus (Herdman, 1886); F, Eusynstyela hartmeyeri Michaelsen, 1904.