Schizotricha Allman, 1883

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 : 799-800

Genus Schizotricha Allman, 1883

Schizotricha Allman 1883, p 28 ; type, by subsequent designation (Totton 1930, p 229): Schizotricha unifurcata Allman, 1883 .

Remarks. We have here amended the diagnosis of the genus presented by Peña Cantero and Vervoort (1999).

Diagnosis. Featherlike, colonial hydroids with branched or unbranched, polysiphonic stem. Hydrocaulus composed of main tube, divided into internodes bearing hydro- and nematothecae (ahydrothecate internodes also present in S. heteromera sp. nov.), and several undivided (accessory) tubes, only provided with nematothecae and accompanying main tube for almost all its length. Hydrothecate cauline internodes with one or more apophyses supporting hydrocladia, one hydrotheca at axil between each apophysis and stem, and several nematothecae associated with each hydrotheca: two flanking hydrothecal apertures and at least one infrathecal nematotheca; suprathecal nematothecae also present in some species. Cauline apophyses alternately arranged. Hydrocladia, except in S. profunda (Nutting, 1900) , branched once or several times, divided into internodes (with the exception of S. dichotoma Nutting, 1900 ), either all hydrothecate or also with ahydrothecate internodes provided with nematothecae. Branching usually taking place at first internode of previous hydrocladia. Forked hydrocladial internodes with one apophysis, supporting lower-order hydrocladium, one hydrotheca at axil of bifurcation and a variable number of nematothecae: two flanking hydrothecal aperture and at least one infrathecal nematotheca (occasionally also with suprathecal nematothecae). Unforked hydrothecate hydrocladial internodes with one or more hydrothecae and several associated nematothecae; two flanking hydrothecal aperture, at least one infrathecal nematotheca and, in certain species, also with suprathecal nematothecae. Cauline and hydrocladial apophyses usually provided with nematothecae. Hydrotheca cup-shaped, with smooth rim and completely adnate adcauline wall. Nematothecae two-chambered and movable. Colonies dioecious, with sexual dimorphism. Gonothecae inserting on hydrocladia between hydrothecal base and upper infrathecal nematotheca and provided with nematothecae. Cnidome composed of microbasic mastigophores, normally in two size classes.

The genus presently includes the following species:

Schizotricha anderssoni Jäderholm, 1904

Schizotricha crassa Peña Cantero and Vervoort, 2004

Schizotricha dichotoma Nutting, 1900

Schizotricha falcata Peña Cantero, 1998

Schizotricha frutescens (Ellis and Solander, 1786) (5 Sertularia frutescens Ellis and Solander, 1786 )

Schizotricha glacialis ( Hickson and Gravely, 1907) (5 Plumularia glacialis Hickson and Gravely, 1907 )

Schizotricha heteromera sp. nov.

Schizotricha jaederholmi Peña Cantero and Vervoort, 1996

Schizotricha multifurcata Allman, 1883

Schizotricha nana Peña Cantero, Svoboda and Vervoort, 1996

Schizotricha profunda (Nutting, 1900) (5 Plumularia profunda Nutting, 1900 )

Schizotricha southgeorgiae Peña Cantero and Vervoort, 2004

Schizotricha trinematotheca sp. nov.

Schizotricha turqueti Billard, 1906

Schizotricha unifurcata Allman, 1883

Schizotricha variabilis (Bonnevie, 1899) (5 Plumularia variabilis Bonnevie, 1899 )

Schizotricha vervoorti Peña Cantero, 1998

Description of the species