Filellum undetermined

• Main Authors: Gil, Marta, Ramil, Fran
• Format: Text
• Language: unknown
• Published: Zenodo 2021
• Subjects: Biodiversity; Taxonomy; Animalia; Cnidaria; Hydrozoa; Leptothecata; Lafoeidae; Filellum; Filellum undetermined; Antarctic; Pena; Antarc*; antartic*; South Atlantic Ocean
• Online Access: https://dx.doi.org/10.5281/zenodo.5093684; https://zenodo.org/record/5093684

Filellum sp. Fig. 2F; Table 1 Material examined SOUTH ATLANTIC OCEAN • 2 colonies (1 growing on an antipatharian, 1 on Sertularella patagonica ), no coppinia; Vema Seamount, stn PT4; 31°39′43″–31°38′10″ S, 8°22′37″–8°23′42″ E; 50–108 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40003, SEAFO-2015-40033 • 4 colonies (3 growing on Campanularia hincksii , 1 on a bryozoan), no coppinia; Vema Seamount, stn Dive 3; 71–935 m depth; 31 Jan. 2015; SEAFO-2015 leg.; SEAFO-2015-40132, SEAFO-2015-40257, SEAFO-2015-40921 • 1 colony, growing on Amphisbetia distans , no coppinia; Vema Seamount, stn Dive 4; 91–95 m depth; 1 Feb. 2015; SEAFO-2015 leg.; SEAFO-2015-40661. Description Stolonal colonies arising from a filiform hydrorhiza creeping on other hydroids and a bryozoan. Hydrorhizal stolons give rise to small, tubular hydrothecae adnate for ca half their length; adnate part parallel to hydrorhiza, upper, free part provided with numerous and very faint striations on abcaulinar side, and bent upwards from hydrorhiza at an angle between 45° and 90°, although only occasionally perpendicular to the adnate part; aperture circular, rim even, only slightly everted; renovations have not been observed. Cnidome: two size classes of nematocysts, with small (10–12.5× 5–7.5 µm) and large (15–17.5 × 7.5–10 µm). Coppinia absent. Remarks The shape of the hydrothecae in the colonies studied herein resembles those of Filellum serratum (Clarke, 1879), Filellum antarcticum (Hartlaub, 1904) and Filellum magnificum Peña Cantero, Svoboda & Vervoort, 2004, due to the presence of numerous transversal striations of the adnate part. Nevertheless, the measurements of both hydrothecae and nematocysts do not match with those of the species mentioned above. In our material, the hydrothecae are smaller and the nematocysts larger than those of F. serratum , F. antarticum and F. magnificum . Based on these differences, we considered this material to be a different species, but the absence of coppinia prevents us from establishing a more accurate identification. : Published as part of Gil, Marta & Ramil, Fran, 2021, Hydroids (Cnidaria, Hydrozoa) from the Vema and Valdivia seamounts (SE Atlantic), pp. 49-96 in European Journal of Taxonomy 758 on page 56, DOI: 10.5852/ejt.2021.758.1425, http://zenodo.org/record/5088125 : {"references": ["Pena Cantero A. L., Svoboda A. & Vervoort W. 2004. Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R. V. Polarstern, with the description of a new species. Journal of Natural History 28: 2269 - 2303. https: // doi. org / 10.1080 / 00222930310001647361"]}