Eudistoma magalhaensis Michaelsen 1907

• Main Authors: Sanamyan, Karen, Schories, Dirk
• Format: Other/Unknown Material
• Language: unknown
• Published: 2007
• Subjects: Biodiversity; Taxonomy; Animalia; Chordata; Ascidiacea; Enterogona; Polycitoridae; Eudistoma; Eudistoma magalhaensis; Pacific; Falso; Kamchatka
• Online Access: https://zenodo.org/record/6243399; https://doi.org/10.5281/zenodo.6243399

Eudistoma magalhaensis (Michaelsen, 1907) (Figures 1, 2) Paessleria magalhaensis Michaelsen, 1907: 69. Polycitor magalhaensis: Van Name, 1945: 132 and synonymy (only where it refers to the type material). Sigillina (Paessleria) magalhaensis: Kott, 1969: 39. Material examined: Chile, Guaitecas Islands (KBPIG 1316, 1317). Melinka, island in front of Falso Faro (KBPIG 1313, 1315); old landing stage, in front of the town (KBPIG 1314). Several specimens in each lot. The specimens were collected in 2004 and 2005 by scuba diving at 5–8 m depth by D. Schories. They are deposited in the Kamchatka Branch of the Pacific Institute of Geography (KBPIG). Description. The colonies consist of one to several small (about 1 cm diameter), rounded, semitransparent heads on short cylindrical stalks (0.5–1.5 cm long, 0.5 cm diameter) arising from common basal test. The stalked heads are unevenly distributed on the basal test (figure 2 B) and are never crowded. The heads are clear and soft, and are clearly demarcated from the supporting stalks by their greater diameter and the softer consistency of the test. This demarcation is especially evident between heads and stalks in living specimens with inflated heads, but can also be seen in preserved specimens. The stalks and basal tunic are firm and opaque and usually are covered by fine sediment, sparse sand grains and epibionts. Inner layers of the test may contain scattered minute sand grains but generally are free from embedded matter. The largest colony photographed in situ is about 10 cm in maximum extent, although preserved specimens are fragments less than 2–3 cm long (figure 2 A). Both living and preserved specimens are almost colourless, with a slight yellowish tint. Pigment granules were not detected in test, zooids or larvae. In preserved material contracted zooids are mostly located in the heads of the colony, and only occasionally abdomina extend down the stalk. Zooids are parallel to each other and open on the upper surface of the heads. Occasionally atrial siphons of two or ...