Resomia convoluta Moser 1925

• Main Author: Pugh, P. R.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2006
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Siphonophorae; Resomiidae; Resomia; Resomia convoluta; Antarktis*; Weddell Sea
• Online Access: https://doi.org/10.5281/zenodo.5688261; http://treatment.plazi.org/id/038F8C6CFFDFD42F6314FB4C4ED8AFAC

Resomia convoluta (Moser, 1925) Diagnosis : Very young nectophores bearing no lateral digitate processes. Bracts with relatively small, triangular distal facet on upper surface; with bracteal canal ending at distal point below a cluster of nematocysts. Palpons without distal cluster of nematocysts. Material examined : Two specimens kindly loaned to me by Dr Francesc Pagès collected in the Weddell Sea (see Pagès and Kurbjeweit 1994) by the RV Polarstern during the Antarktis IX/2 cruise at Stations 67 (2.xii.1990, 66°27.9’S, 28°43.9’W) and 94 (10.xii. 1990, 68°49.1’S, 17°55.5’W). Both specimens were collected in the 1000– 500m depth range using a multiple opening/closing net system (0.25 m 2 mouth opening, 100µm mesh). Description : The description is based mainly on the specimen captured at St. 67, as the one from St. 94 is in relatively poor condition. Pneumatophore : The pneumatophore of the specimen from St. 67 (Fig. 4 A ) measured 1.88 mm in height and 0.55 mm in maximum diameter. It was quite featureless, apart from a darker patch of cells at the apex, which may have been pigmented in life. There had been some distortion as the base of the gas gland did not reach the base of the pneumatophore. The pneumatosaccus of the pneumatophore of the specimen from St. 94 (Fig. 4 B ) had clearly exploded due to gas expansion whilst being brought to the surface, as the expanded gas can be seen within the nectosome. It was greatly distorted and measured 2 mm in length and 0.95 mm in maximum diameter. The significance of this distortion is discussed below. Nectosome : Buds of nectophores and a single young one were attached at the base of the pneumatophore on the specimen from St. 67 (Fig. 4 A ), on the ventral side of the stem. Nectophore : Twenty six nectophores, at various stages of development, were found with the St. 67 specimen. They measured up to 15.7 mm in width and 13 mm in length. A photograph of a young one (3.1 mm wide, 2.8 mm long) is shown in Fig. 5 A . None of these young nectophores showed any signs of ...