Antarctic Science

Papers—Life Sciences and Oceanography

Ascidians (Tunicata, Ascidiacea) of Potter Cove, South Shetland Islands, Antarctica

M. Tatian a1, R.J. Sahade a1, M.E. Doucet a2 and G.B. Esnal a3
a1 Cátedra de Anatomía Comparada, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sársfield 299 (5000), Córdoba, Argentina
a2 Centro de Zoología Aplicada, Universidad Nacional de Córdoba, C.C. 122 (5000), Córdoba, Argentina
a3 Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina

Article author query
tatian m   [PubMed][Google Scholar] 
sahade r   [PubMed][Google Scholar] 
doucet m   [PubMed][Google Scholar] 
esnal g   [PubMed][Google Scholar] 


Certain physical factors, substrate type and ice action appear to be important determinants for ascidian distribution. Three different substrate types were sampled at depths between 0–30 m by SCUBA diving: soft bottoms, hard bottoms and moraine deposits. The species found were Aplidium radiatum, Synoicum adareanum, Distaplia cylindrica, Sycozoa gaimardi, Sycozoa sigillinoides, Tylobranchion speciosum, Corella eumyota, Ascidia challengeri, Cnemidocarpa verrucosa, Styela wandeli, Dicarpa insinuosa, Pyura bouvetensis, Pyura discoveryi, Pyura obesa, Pyura setosa, Molgula enodis and Molgula pedunculata. Highest diversity and patchy distribution was found in less stringent environments, where epibiosis is a commmon phenomenon on stolidobranch ascidians. Differences in stalk development were found in the most abundant species Molgula pedunculata and Cnemidocarpa verrucosa. Ice action may be the main factor that determines the absence of ascidians above 15 m in all the stations sampled.

(Received October 14 1997)
(Accepted March 10 1998)

Key Words: Antarctica; Ascidiacea; distribution; diversity, ice action; substrate types.