Rhysia halecii Hickson & Gravely 1907

• Main Author: Peña Cantero, Álvaro L.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2015
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Anthoathecata; Rhysiidae; Rhysia; Rhysia halecii; Antarc*; Antarctic; Ross Sea
• Online Access: https://doi.org/10.5281/zenodo.5671801; http://treatment.plazi.org/id/3D10878AFF88B45F10905DE3FCF33E85

Rhysia halecii (Hickson & Gravely, 1907) (Figs 9 A–D, 10A–C) Stylactis halecii Hickson & Gravely, 1907: 8 pl. 1 figs 5–6, pl. 4 fig. 33; Kramp, 1932: 7; Iwasa, 1934: 262, figs 15–16; Boero & Bouillon, 1993: 259; Peña Cantero, 2004: 768; Bouillon et al ., 2006: 157, fig. 88E, F. Halerella halecii — Stechow, 1925: 401; 1962: 417. Stylactaria halecii — Namikawa, 1991: 810. Not Stylactis halecii — Hirohito, 1988: 128, 131–132, fig. 48a, b. Material examined. Discovery Antarctic Expedition 1901-04: Type (NHM 1907.8.20.4), 28.II.1902, McMurdo Bay (Ross Sea), 20 fms, colony growing on Hydrodendron arboreum , with gonozooids. Description. Stolonal colony growing on stems of Hydrodendron arboreum (Fig. 9 A–D). ‘Encrusting hydrorhiza consisting of a dense mass of branching and anastomosing tubes (fig. 6). Each tube is covered with its own very thin sheath of perisarc (fig. 33) and there is no common sheath of coenosarc covering the hydrorhiza as a whole, … In the central parts of the hydrorhiza the tubes are closely packed, anastomose freely, and are disposed in several layers. At the periphery however the tubes are reduced to a single layer, become more dispersed, and anastomose slightly’ (Hickson & Gravely 1907: 9). Colony polymorphic, with gastrozooids, gonozooids and dactylozooids (Fig. 9 A–D). Gastrozooids (Fig. 9 C, 10A), c. 1050 µm high and c. 250 µm in maximum diameter, with conical hypostome and a distal crown of eight to nine filiform tentacles [six to ten according to Hickson & Gravely (1907)]. Nematocysts concentrated on their tips. Dactylozooids short (c. 200 µm high and 80 µm in maximum diameter), finger-shaped, distally swollen and with a high concentration of large nematocysts (Fig. 10 C). Dactylozooids covered by a perisarc sheath, except for distal pad. Gonozooids shorter than gastrozooids (c. 850 µm high and c. 370 µm in maximum diameter), with short, rounded hypostome, without tentacles or just with a few tentacle buds, without gonophores (gametes developing into body wall) (Figs 9 ...