19.02.2013 - Common undescribed species of amphipods

19.02.2013 (Tuesday). In the morning, open sea with a few icefloes. The OFOS video camera provides pictures of the small shallow bank of Erebus and Terror Gulf, rising to 20 m depth. The top is rocky with some kelp and encrusting calcareous red algae, but otherwise quite bare. The slope looks muddy. Small stem-like gorgonians and a lot of small ophiurids can be seen on the video.

In the afternoon we go out for the trawling and and dredging operations. The sea remains open. It is cold and windy. We feel that we are already in the second part of the Antarctic summer. The content of the Agassiz trawl is not huge, but it is very rich in organisms, including amphipods. Amidst the common Epimeria aff. macrodonta, I found one specimen of the true E. macrodonta. It is amazing that such a common species with a very characteristic morphology and colour pattern as Epimeria aff macrodonta is still undescribed. This reflects the very poor state of knowledge of the Antarctic amphipods (mostly to the lack of funding for studying already existing collections). 

Immediately after the Agassiz trawl, we deploy the Rauschert dredge. It appears that one of the protective linoleum sheets of the dredge has been cut off. Too fragile... It will have to be replaced by a sheet of thicker rubber, but not right now (no time). Let's hope, that the second plastic sheet will survive until I can have an half free day for this reparation. When sieving the content of the dredge, it appears that the sediment is not true pure mud, but extremely fine sand mixed with some mud and gravel. The stones found in the trawl and the dredge are not brittle as in previous stations but consist of very hard basalt (it is almost impossible to remove encrusting organisms like bryozoans from them with a hammer and a chisel).  We get a very good catch with the dredge (a lot of small amphipods belonging to many species, often interesting for us as the brown and white "forms" of Eusirus bouvieri, again a problematic complex of species). We also get a giant barnacle, Bathylasma corolliforme (one of the very few species of Antarctic Cirripedia). Late in the evening the weather outside looks awful. Fine snow flying above the ice due to the strong wind. We work on the specimens from the dredge until 01:00. then we put the smallest species in a vial of alcohol (no time to sort out them right now).

Epimeria macrodonta (30 mm).

Epimeria aff macrodonta (30 mm). No need to be an amphipod specialist to see that its morphology and colour pattern are clearly different from that of the true Epimeria macrodonta (many specimens were examined and photographed). Yet this is an undescribed species and a common one. This is just an example amongst many others, which illustrates the poor state of knowledge of the Antarctic amphipod fauna, i.e. the most species rich animal group of Antarctic seas. This picture is not likely to improve very much in the coming years due to the lack of funding for studying museum collections..

(Cédric)