Eudendrium

Galea, Horia R. & Schories, Dirk, 2012, Some hydrozoans (Cnidaria) from Central Chile and the Strait of Magellan, Zootaxa 3296, pp. 19-67 : 26-27

Eudendrium sp. 1

(pl. 1A, B)

Material examined. Stn. GRU — 01.xi.2009, DS147 (20 m): a single, sterile colony, 4.5 cm high (MHNG-INVE- 79603).

Description. Colony arising from mesh-like hydrorhiza, composed of numerous branched, anastomosing stolonal fibers. Main stems and side branches strongly fascicled. Branching irregular, in all directions, side branches profusely given off at rather short intervals, slightly tortuous in shape. Perisarc of moderate thickness, horn-colored to dark brown basally, becoming progressively thinner and more colorless towards extremities, annulated at bases of branches and hydranth pedicels, with occasional irregularly-placed annulations elsewhere, but mostly smooth. Hydranths with basal part separated by groove from rest of body; 18–24 filiform tentacles. Gonophores absent. Nematocysts: microbasic euryteles in two size classes:

- small [(6.3–6.6)×(2.7–2.8) µm], pyriform capsules, abundant in tentacles, hydranth body and coenosarc of stem and branches;

- larger [(8.8–9.3)×(4.3–4.6) µm], ovoid capsules, abundant in the lower part of hydranth body above the basal groove, rare in the coenosarc.

Remarks. A reliable identification is impossible in the absence of gonophores. This species, as well as all those described below under the genus Eudendrium Ehrenberg, 1834 , are in need of a comprehensive study based on more abundant and fertile material of both sexes. Earlier Chilean records of Eudendrium species that are based on sterile material, or with no data on cnidome composition, should be taken with much reserve.

Distribution in Chile. The present material originates from Punta de Choros.

PLATE 1. A–B: Eudendrium sp. 1—shape of a colony and nematocysts (A); detail of the perisarc (B). C–F: Eudendrium sp. 2—colony on worm tube (C); female gonozooid and nematocysts (D); two gonophores (E); pedicels after the shedding of gonophores (F). G: Eudendrium sp. 3—female gonophores and nematocysts; two fertile stems (insert). H: Eudendrium sp. 4— shape of a colony and nematocysts. I: Eudendrium sp. 5—colony and nematocysts. J: Eudendrium sp. 6—several stems and nematocysts. Scale bars: 10 µm (all nematocysts); 100 µm (E, F); 300 µm (B, D, G); 1 cm (all colonies).