Dicopia fimbriata Sluiter, 1905

Monniot, Françoise & López-Legentil, Susanna, 2017, Deep-sea ascidians from Papua New Guinea, Zootaxa 4276 (4), pp. 529-538 : 533

Dicopia fimbriata Sluiter, 1905

Sluiter, 1905: 05°46’S – 134°0’E, 1788 m, Indonesia Monniot C & Monniot F, 1991b, Loyalty Basin, New Caledonia Sanamyan K & Sanamyan N, 1999, Tasman Sea

Station CP 4480, 1 specimen (MNHN P 6 DIC13)

GenBank Accession Number: KY882283

The body measures 4.2 cm in height and 3 cm across the oral lobes ( Fig. 3 A, B). It was attached to the substrate by numerous thread-like filaments. The tunic is vitreous with a smooth surface, thin on the lips and with a cartilaginous consistency around the abdomen. The margin of the oral lobes is smooth and not rolled. The atrial aperture is a simple hole ( Fig. 3 D) that opens on the ventral side behind the ventral oral lobe. The oral musculature contains thin circular fibres that are crossed by thin short fibres at the top of the ventral lobe. Strong longitudinal muscular fibres lie on the dorsal oral lobe ( Fig. 3 C) with muscular bundles concentrated at the corners of the lips ( Fig. 3 A, B, C). Short longitudinal muscles are also present dorsally and ventrally to the mouth opening. The mouth is encircled with a sphincter. There is a ring of short filiform oral tentacles close to a prepharyngeal band with papillae. The branchial tissue is made of a few polygonal meshes without ciliae and there is a short dorsal lamina. The abdomen forms a compact mass with a closed intestinal loop and a hermaphroditic gonad. No morphological differences were noted when compare to previous descriptions of this species (Monniot & Monniot 1991b, Sanamyan & Sanamyan 1999).

There are only two other species with the genus Dicopia : D. antirrhinum Monniot, 1972 from the Atlantic Ocean has a tunic covered with papillae, giving it a velvet aspect and a different organization of the musculature. Dicopia japonica Oka, 1913 was described from Japan and is characterized by the presence of papillae on the tunic and a musculature on the oral lobes that is more developed than the one reported here.

Figures

FIGURE 3. Dicopia fimbriata. A, B both sides of a specimens with tunic, scale bar 1 cm. C, specimen without tunic. D, atrial siphon aperture.