3.39 Oithona atlantica Farran 1908
Oithona atlantica Farran, 1908: p. 500,
pI. 16 figs. 124-128, 131, pI. 17 fig. 137 -
Rosendorn, 1917: p. 12, fig. 2a-f-Nishida et
aI., 1977: p. 126, fig. 2a-h - Nishida, 1985: p.
17, figs. 3,4.
Oithona spinirostris Sars, 1918: p. 6, pIs. 1,2.
For more complete synonymy see Nishida
(1985).
Body length -
females: 1.16-1.39mm (47 specimens)
Female. Prosome fusiform in dorsal view,
2.5 times longer than wide, 1.1 times the
urosome. In dorsal view, head ending
anteriorly in pointed rostrum. Proportional
lengths of urosomites and furca 11: 32 : 15 :
14:17:11 = 100. PI-P4Rewith 1,1,2; 1,0,2;
1,0,1; 0,0,1 outer marginal spines and'I,I,4;
0,1,5; 0,1,5; 0,1,5 inner marginal setae.
Outer marginal spine of Re3 rather straight,
curved inwards at about 112 its length, and
about half as long as the terminal spine. P5
with one long seta attached directly to the
lateral process of Th5 and one moderately
long free segment with one long seta.
Order CYCLOPOIDA
Family Oithonidae
Remarks
O. atlantica is closely related to O. IOflgispina
but this latter species has not been found in
sub-Arctic and sub-Antarctic waters (Nishida
1985). Nishida (1985) reported that clear
differences distinguished O. ai/antica and O.
longispina in the North Pacific; however,
many specimens with intermediate features
occurred in the South Pacific. The specimens
collected in the Straits of Magellan concord
with O. atlantica as reported in the detailed
description by Nishida (1985).
Distribution
O. atlantica occurs in sub-Antarctic and
Antarctic waters of the Pacific Ocean (Nishida
1985). In the Atlantic Ocean it has been
recorded from cold-water areas (Sars 1918;
Farran 1926; Jespersen 1940) as well as from
the Mediterranean Sea (Razouls and Durand
1991). Ramirez (1969) reported O. atlantica as a poorly dominant species in the
Argentinian sector of the SW Atlantic. Marin
and Antezana (1985) and Hirakawa (1989)
reported O. atlantica in Chilean fjords. In the
present study, it was frequently sampled
throughout the Pacific and Central areas
of the Straits of Magellan; maximum
abundances were recorded from 50-tOO m.
Oithona atlantica Farran, 1908: p. 500,
pI. 16 figs. 124-128, 131, pI. 17 fig. 137 -
Rosendorn, 1917: p. 12, fig. 2a-f-Nishida et
aI., 1977: p. 126, fig. 2a-h - Nishida, 1985: p.
17, figs. 3,4.
Oithona spinirostris Sars, 1918: p. 6, pIs. 1,2.
For more complete synonymy see Nishida
(1985).
Body length -
females: 1.16-1.39mm (47 specimens)
Female. Prosome fusiform in dorsal view,
2.5 times longer than wide, 1.1 times the
urosome. In dorsal view, head ending
anteriorly in pointed rostrum. Proportional
lengths of urosomites and furca 11: 32 : 15 :
14:17:11 = 100. PI-P4Rewith 1,1,2; 1,0,2;
1,0,1; 0,0,1 outer marginal spines and'I,I,4;
0,1,5; 0,1,5; 0,1,5 inner marginal setae.
Outer marginal spine of Re3 rather straight,
curved inwards at about 112 its length, and
about half as long as the terminal spine. P5
with one long seta attached directly to the
lateral process of Th5 and one moderately
long free segment with one long seta.
Order CYCLOPOIDA
Family Oithonidae
Remarks
O. atlantica is closely related to O. IOflgispina
but this latter species has not been found in
sub-Arctic and sub-Antarctic waters (Nishida
1985). Nishida (1985) reported that clear
differences distinguished O. ai/antica and O.
longispina in the North Pacific; however,
many specimens with intermediate features
occurred in the South Pacific. The specimens
collected in the Straits of Magellan concord
with O. atlantica as reported in the detailed
description by Nishida (1985).
Distribution
O. atlantica occurs in sub-Antarctic and
Antarctic waters of the Pacific Ocean (Nishida
1985). In the Atlantic Ocean it has been
recorded from cold-water areas (Sars 1918;
Farran 1926; Jespersen 1940) as well as from
the Mediterranean Sea (Razouls and Durand
1991). Ramirez (1969) reported O. atlantica as a poorly dominant species in the
Argentinian sector of the SW Atlantic. Marin
and Antezana (1985) and Hirakawa (1989)
reported O. atlantica in Chilean fjords. In the
present study, it was frequently sampled
throughout the Pacific and Central areas
of the Straits of Magellan; maximum
abundances were recorded from 50-tOO m.