Diversity of Gammaridea (Amphipoda) from southern Tierra del Fuego, Argentina: preliminary results [Extended Abstract of the IBMANT/ANDEEP International Symposium and Workshop in 2003]

CHIESA, I.L.; ALONSO, G.M.; ZELAYA, D.G.

Berichte zur Polar- und Meeresforschung

Alfred Wegener Institute for Polar and Marine Research

Lugar: Bremerhaven; Año: 2005 vol. 507 p. 124 - 125

1618-3193

The Gammaridea are highly diversified in the Magellan Region were a total of 206 species have been reported. However, most of the studies deal with the fauna from Chile and just a few with that from Argentina. The objective of the present contribution is to analyse the diversity and the faunistic affinities of the Gammaridea from southern Tierra del Fuego, Argentina. Samples were collected in 7 stations, at about 30 m depth, along the Beagle Channel (between Bahía Ushuaia and San Pío Cape) and in Bahía Aguirre and Bahía Buen Suceso. A total of 3.823 specimens, including 18 families, 43 genera and 61 species, were identified. The following families showed the highest number of species (number of species in brackets): Corophiidae (8), Phoxocephalidae (7), Eusiridae (7), Gammarellidae (6), Iphimediidae (6) and Lysianassidae (5). Furthermore, Corophiidae, Stenothoidae, Lysianassidae, and Eusiridae were the most abundant families (1,010; 887, 565 and 458 specimens, respectively). Although Stenothoidae is the most specious in the Magellan Region, only 3 Probolisca species (all of them very abundant) were recognized during this study. The remaining 11 families exhibited a relatively low abundance and species diversity. Gondogeneia (Gammarellidae) and Gammaropsis (Corophiidae) were the most diversified genera, with 5 and 4 species, respectively. Cephalophoxoides and Parafoxiphalus (Phoxocephalidae), Ceradodocopsis (Gammaridae s.l.) and Photis (Corophiidae s.l.) are recorded for the first time in the Magellan Region. Moreover, 3 species belonging to the genera Atylus, Ischyrocerus, and Photis appear to be new to science. The Gammaridean fauna herein studied was compared with those from Antarctica, Scotia Sea, Sub-Antarctic Islands, and localities North to the Magellan Region in Argentina and Chile. The following results were obtained: 17 species (40.5%) are only known from the Magellan Region; 10 species (23.8%) present in the Magellan Region are also found in the Antarctic, Sub-Antarctic Island or Scotia Sea; 6 Species (14.3%) distribute from the Magellan Region towards the North; 4 species (9.5%) were reported from the Magellan Region both towards the North and South; and 5 species (11.9%) were also found in areas other than those herein analysed.