Schizotricha turqueti Billard, 1906

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 : 812-813

Schizotricha turqueti Billard, 1906

Schizotricha turqueti: Peña Cantero and Vervoort 1999, p 371 –372 (synonymy).

Material examined. 12/993, one fragmented stem (largest fragment ca 160 mm long) ( USNM 1025597); 27/1869, three stem fragments up to 80 mm long, with immature gonothecae ( USNM 1025598); 27/1896, five stem fragments up to 85 mm long, with gonothecae ( USNM 1025599); 32/2020, two distally broken stems without hydrocladia up to 75 mm long and one distal stem fragment ca 50 mm long ( USNM 1025600); 32/2054, one hydrocladium (in slide) ( USNM 1025601); 32/2121, three stem fragments up to 40 mm long, with immature gonothecae ( USNM 1025602); 32/2128, one stem ca 150 mm high and three stem fragments up to 90 mm long ( USNM 1025603); 575/052, five stems up to 215 mm high, with gonothecae ( USNM 1025604; RMNH-Coel. 30952; MNCN 2.03/331); 6/410, one stem fragment ca 25 mm long, with gonothecae ( USNM 1025605); 6/428, a few hydrocladia with gonothecae (on slide) ( USNM 1025606); 6/445, one fragmented stem (fragments up to 180 mm long), with gonothecae ( USNM 1025607; RMNH-Coel. 30957); 7/484, one stem ca 210 mm high, with gonothecae ( USNM 1025608); 702/464, four stems up to 210 mm high, with gonothecae ( USNM 1025609; RMNH-Coel. 30965; MNCN 2.03/332); 702/465, numerous stems up to 380 mm high, with male and female gonothecae ( USNM 1025610; RMNH-Coel. 30966; MNCN 2.03/ 333); 721/704, one stem ca 210 mm high, with gonothecae ( USNM 1025611); 721/774, two stems ca 250 and 55 mm high, with gonothecae ( USNM 1025612; RMNH-Coel. 30967); 721/775, four stems up to 230 mm high, with gonothecae ( USNM 1025613; RMNH-Coel. 30968; MNCN 2.03/334); 721/776, numerous stems up to 280 mm high, with gonothecae ( USNM 1025614; RMNH-Coel. 30969; MNCN 2.03/335); 721/777, several stems up to 280 mm high, with gonothecae ( USNM 1025615; RMNH-Coel. 30970; MNCN 2.03/336); 721/778, one stem ca 220 mm high, with gonothecae ( USNM 1025616); 721/816, one stem ca 60 mm high ( USNM 1025617); 731/1944, six stems up to 145 mm high, with gonothecae ( USNM 1025618; RMNH-Coel. 30972; MNCN 2.03/ 337); 8/612, several stem fragments up to 120 mm long, with female gonothecae ( USNM 1025619).

Diagnosis. Colonies with unbranched stems. Main cauline tube with single hydrothecate internodes, with one or two infrathecal nematothecae; cauline apophyses with one nematotheca. Hydrocladia up to sixth order. Hydrocladia regularly divided into hydrothecate internodes. Unforked hydrocladial internode with a single infrathecal nematotheca. Hydrotheca deep. Forked hydrocladial internodes with one or two infrathecal nematothecae; hydrocladial apophyses with one or two nematothecae.

Remarks. Occasionally in this species it is possible to find stems with false branching, due to previous fracture of the original stem. This is corroborated by the fact that the main stem is bifurcated, giving rise to two equally developed secondary stems; this does not constitute the branching pattern found in the typically branched species of Schizotricha .

The unforked hydrocladial internodes are typically provided with a single infrathecal nematotheca, though in the material from Sta. 721/704 there is occasionally a second infrathecal nematotheca in the first and sometimes in the second internode following the forked hydrocladial internodes.

The material from Sta. 32/2020, Sta. 721/775 and Sta. 731/1944 resembles Schizotricha glacialis ( Hickson and Gravely, 1907) in the frequent presence of double internodes. However, in the remaining features that material is closer to S. turqueti since up to sixthorder hydrocladia are present, whereas in S. glacialis only secondary hydrocladia have been reported. Moreover, only one nematotheca has been reported on the hydrocladial apophyses in S. glacialis , whereas one or two are present in S. turqueti , as also occurs in the material under discussion. Therefore, we conclude that double internodes sometimes occur in S. turqueti , so that this feature is not restricted to S. glacialis . In fact, double internodes also occur in S. crassa and S. trinematotheca sp. nov. For the moment, however, S. glacialis and S. turqueti are kept separate because in S. glacialis the hydrocladia are either unforked or have but a single ramification, even in fertile material (cf. Hickson and Gravely 1907; Peña Cantero et al. 1996).

Ecology and distribution. Schizotricha turqueti is a eurybathic species. It has been recorded from the intertidal level ( Billard 1906) to a depth of 330 m (Peña Cantero et al. 1996) on bottoms of gravel and pebbles with mud ( Peña Cantero and García Carrascosa 1995) and on muddy bottoms (Peña Cantero et al. 1996); our material was collected at depths from 40 to 1890 m, considerably increasing its bathymetric range, sometimes on pebbles. Fertile colonies have been reported previously only in January ( Peña Cantero and García Carrascosa 1995; Peña Cantero et al. 1996), whereas we observed gonothecae in colonies collected in January, February, March, May, and December. We found colonies of Antarctoscyphus sp., Clytia sp., Campanularia sp., and Lafoea sp. using S. turqueti as a substratum.

Previous to the present study, Schizotricha turqueti seemed to be endemic to West Antarctica, having been reported from Booth-Wandel Island by Billard (1906), off Elephant Island (South Shetland Islands) by Peña Cantero and García Carrascosa (1995) and Peña Cantero et al. (1996), and from the southern part of the Weddell Sea by Peña Cantero et al. (1996). However, our present material originates from both East and West Antarctica. In East Antarctica it has been found in the Ross Sea and off Victoria Land (off Franklin Island, Pennell Coast and Cape Adare). In West Antarctica, S. turqueti was collected off Anvers Island (Palmer Archipelago), Penguin Island (Antarctic Peninsula), Deception, King George, Livingston and Nelson islands (South Shetland Islands), Elephant Island, north of the South Orkney Islands, and off Bristol and Saunders islands (South Sandwich Archipelago).