16
Study Area
Euphausiids also showed higher species
diversity at Pacific stations up until Cape
Froward (Guglielmo et al. 1991; Antezana et
al. 1992). Highest numbers were recorded
from lOO-200m. The species sampled
included Nematoscelis megalops, Stylocheiron maximum, Thysanoessa gregaria and
juvenile stages of Euphausia vallentini. Of
these, only E. vallentini was sampled within
the Straits. It was present in high numbers
especially near the bottom.
Eleven species of amphipods were
identified, seven of which were found only at
Pacific stations (Cyphocaris /aurei, Primno
macropa, Cyllopus magellanus, Hyperiella
dilatata, Scina borealis, S. unci pes and
Orchomene plebs) (Guglielmo et al. 1991;
Antezana et al. 1992). Temisto gaudichaudi
was the most important species reaching
maximum abundances in the area of Paso
Ancho and the Atlantic. This was the only
amphipod, together with Hyperoche mediterranea, sampled in this area.
Pelagic ostracods were collected at all
depths throughout the Straits with the
greatest abundances in the area of Paso
Ancho (Benassi et al. 1994). Eight species
were identified. Of these, Discoconchoecia
elegans and Obtusoecia antarctica were the
most common. Loricoecia loricata and
Metaconchoecia skogsbergi were confined to
Pacific areas whereas Pseudoconchoecia
serrulata was present only at Pacific and
Atlantic entrances to the Straits.
Note: A manual for the identification of Antarctic and sub-Antarctic copepods has recently
been published by Razouls (1994). Unfortunately, it has not been possible to mention this
work in our identification cards since it was published during the preparation of proofs of the
present Atlas.