Ritterella mirifica Monniot and Monniot, 1983

Primo, Carmen & Vázquez, Elsa, 2007, Ascidians collected during the Spanish Antarctic expedition CIEMAR 99 / 00 in the Bransfield and Gerlache Straits, Journal of Natural History 41 (29 - 32), pp. 1775-1810 : 1786-1787

Ritterella mirifica Monniot and Monniot, 1983

( Figure 9 )

Ritterella mirifica Monniot and Monniot, 1983 .

Distribution

New record: Bransfield Strait (Station B7: one specimen). Previously recorded: Ross Sea ( Monniot and Monniot 1983); South Shetland Islands ( Monniot and Monniot 1983). From 142 to 365 m depth.

Description

We found only one very damaged stalked colony (50 mm height). Zooids with tubular siphons; the atrial one has numerous lobes ( Figure 9b ). Twelve to 13 rows of stigmata in the branchial sac. Stomach with five or six longitudinal folds. Testes slightly below the gut loop ( Figure 9a ). It was impossible to extract a complete postabdomen, so the length of zooids is unknown.

Remarks

The only Antarctic species of the genus Ritterella is R. mirifica , the paratype of which has been re-examined at the MNHN (MNHN A1 RIT 5). The characteristic atrial siphon, the grouped testes slightly below the gut loop, and the number of rows of stigmata are similar. The shape of the colonies is rather different (stalked here, globular in the holotype), but in both cases they are quite damaged.

Synoicum adareanum ( Herdman, 1902)

Polyclinum adareanum Herdman, 1902 ; Sluiter 1906.

Atopogaster elongata non Herdman, 1886 A. fuegiense ; Herdman, 1902.

Atopogaster incerta Hartmeyer, 1911 .

Macroclinum incertum: Hartmeyer 1909 .

Synoicum steineni Michaelsen, 1907 ; Hartmeyer 1921.

Amaroucium (Synoicum) steineni: Michaelsen 1921 .

? Oxycorynia mawsoni Harant and Vernières, 1938 .

Lissamaroucium magnum Sluiter, 1906 ; Hartmeyer 1911; Herdman 1912, 1915.

Macroclinum magnum Sluiter, 1914 .

Synoicum adareanum: Hartmeyer 1921 ; Van Name 1945; Kott 1954, 1969, 1971; Millar 1960, 1968; Monniot F 1970, 1978; Monniot and Monniot 1973, 1974, 1983, 1994; Vasseur 1974; Tatián et al. 1998a, 1998b, 2005; Ramos-Esplá et al. 2005.

Distribution

New record: Bransfield Strait (Station B3: one specimen; Station B5: 32 specimens; Station B6: 28 specimens; Station B7: 66 specimens). Previously recorded: Antarctic Region ( Millar 1960, 1968; Kott 1969, 1971; Monniot and Monniot 1983; Tatián et al. 2005; Ramos-Esplá et al. 2005); South Shetland Islands ( Tatián et al. 1998a, 1998b; Ramos-Esplá et al. 2005); Kerguelen Island ( Monniot and Monniot 1974). From 25 to 796 m depth.

Description

Although most of the specimens are immature, the colonies (from 18 to 230 mm height) have the characteristic aspect of the species: stalk with incrusted sand and rounded head, circular systems of zooids.

Remarks

Morphology of our specimens coincides with those described by F. Monniot (1970).

Figures

Figure 9. Ritterella mirifica, zooid.