Schizotricha falcata Peña Cantero, 1998

Peña Cantero, A. L. & Vervoort, W., 2005, Species of Schizotricha Allman, 1883 (Cnidaria: Hydrozoa: Halopterididae) from US Antarctic expeditions with the description of two new species, Journal of Natural History 39 (11), pp. 795-818 : 803

Schizotricha falcata Peña Cantero, 1998

Schizotricha falcata: Peña Cantero and Vervoort 1999, p 361 –362 (synonymy).

Material examined. 6/436, several stem fragments up to 100 mm long, only one with a couple of hydrocladia ( USNM 1025574); 731/1944, one stem ca 165 mm high and one incipient stem ca 30 mm high ( USNM 1025575; RMNH-Coel. 30971).

Diagnosis. Colonies with unbranched stems. Main cauline tube divided into single hydrothecate internodes with two or three infrathecal nematothecae at different levels; cauline apophyses with one nematotheca. Hydrodadia strongly branched (hydrocladia up to seventh order reported). Normally, primary hydrocladium giving rise to secondary hydrocladia in its first, fourth and eighth internodes; secondary hydrocladium also giving third-order hydrocladia in its first, fourth and eighth internodes; first tertiary hydrocladium giving rise to fourth-order hydrocladia in its first and fifth internodes; finally, fifth-, sixth- and seventh-order hydrocladia forming from the first internodes of previous series. Hydrocladia divided into single hydrothecate internodes. Unforked hydrocladial internodes with a single infrathecal nematotheca. Hydrotheca low. Forked hydrocladial internodes with two or three infrathecal nematothecae at different levels; hydrocladial apophyses with one nematotheca. Gonothecae sickle-shaped.

Ecology and distribution. Schizotricha falcata is a shelf species, probably with a circalittoral distribution ( Peña Cantero and Vervoort 1999). It had been recorded from depths of 90 ( Blanco 1984) to 154 m (Peña Cantero 1998); our material was collected between 73 and 150 m. Fertile colonies were found in January (Peña Cantero 1998).

Schizotricha falcata seems to be endemic in West Antarctica ( Peña Cantero and Vervoort 1999), being known only off Low Island ( Blanco 1984) and King George Island (Peña Cantero 1998), in the South Shetland Islands area, off Astrolabe Island, Antarctic Peninsula, and off Anvers Island, Palmer Archipelago (present material).