Schizotricha trinematotheca Peña Cantero & Vervoort, 2005: 809–812, fig. 2; Peña Cantero, 2009: 1747, fig. 2g –h.
Material examined. TAN 0602/420, one stem 85 mm high and another at least 130 mm high, with immature gonothecae (NIWA 144243); TAN 0602/422, one stem 90 mm high (NIWA 144252); TAN 0602/430, one stem 230 mm high, with gonothecae (NIWA 144249).
Remarks. In the present material cauline internodes are provided with three infrahydrothecal nematothecae and, sometimes, one suprahydrothecal nematotheca. Intermediate ahydrothecate internodes, following cauline and hydrocladial apophyses, are provided with two to three nematothecae. Unforked hydrocladial internodes with two to four infrahydrothecal nematothecae and one to two suprahydrothecal nematothecae. Double internodes with three nematothecae below first hydrotheca, three nematothecae between both hydrothecae and one nematotheca above second hydrotheca. As typical, hydrocladia very long, with up to 47 hydrothecae.
Ecology and distribution. Schizotricha trinematotheca has been collected at depths from 70 to 579 m, on stones and gravel (Peña Cantero 2009); present material between 70 and 315 m. Gonothecae in February (Peña Cantero & Vervoort 2005) and March (Peña Cantero 2009; present material).
Peña Cantero & Vervoort (2005) reported it from off Buckle Island and Peña Cantero (2009) off Sturge, Buckle and Young islands; present material off Sturge and Buckle islands. Until the study by Peña Cantero (2019), who reported it from a seamount off Scott Island, it was considered endemic to the Balleny Islands.