Schizotricha southgeorgiae Peña Cantero and Vervoort, 2004

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 : 809

Schizotricha southgeorgiae Peña Cantero and Vervoort, 2004

Schizotricha southgeorgiae Peña Cantero and Vervoort 2004a , 32–35, Figure 2 .

Material examined.? 000AG, one distal stem fragment ca 21 mm long ( USNM 1025595 ); 22/1536, five stem fragments (largest ca 380 mm long); possibly belonging to two stems (holotype, USNM 1012905 ; paratype, RMNH-Coel. 30918) .

Diagnosis. Colonies with unbranched stems. Main cauline tube with single hydrothecate internodes with two to five infrathecal nematothecae. Hydrocladia up to fourth order. Hydrocladia heteromerously divided into internodes; with ahydrothecate internode, provided with one nematotheca, following cauline and hydrocladial apophyses. Unforked hydrocladial internodes with one infrathecal nematotheca. Hydrotheca deep. Forked hydrocladial internodes with two infrathecal nematothecae.

Remarks. The material of this species was previously described and figured by Peña Cantero and Vervoort (2004a). The identity of material from Sta. 000AG is slightly doubtful since it differs from S. southgeorgiae in a few characters. Primarily, the occasional presence of one suprathecal nematotheca in the cauline internodes, usually when the following internode is shorter and provided with only two infrathecal nematothecae. Secondly, hydrocladia were unbranched, but note that this material consists of a single distal stem fragment. Thirdly, two infrathecal nematothecae occurred at different levels in the first hydrocladial internodes. Those internodes could be considered homologous to the first forked internodes of S. southgeorgiae that have two infrathecal nematothecae. In the remaining hydrocladial internodes with two infrathecal nematothecae, with a single exception, there is always an indication of reconstruction.

Ecology and distribution. Schizotricha southgeorgiae is known only from off South Georgia, where it was collected between 659 and 686 m depth in February ( Peña Cantero and Vervoort 2004a) .

Figures

Figure 2. Schizotricha trinematotheca sp. nov. (A) Hydrocladial branching and hydrothecal and gonothecal arrangement; (B) forked hydrocladial internode with apophysis supporting lower-order hydrocladium, hydrotheca, nematothecae, and intermediate ahydrothecate internode; (C–E) single unforked hydrocladial internodes with hydrothecae and nematothecae; (F) double unforked hydrocladial internode; (G) gonotheca (all drawings from the holotype). Scale bar: 2 mm (A); 450 Mm (B–G).