70
THE BIOLOGY O F EUPHAUSIIDS
Euphausia distinguenda Hansen, 191 1
E. distinguenda Hansen, 1911: 32; 1912: 248-250, pl. viii, fig. 3, a-f; Boden
et al., 1955: 344-345, fig. 30.
This species occurs in the tropical region of the eastern Pacific and
in the Indian Ocean but not in the Atlantic Ocean (Fig. 22). Its area of
distribution in the eastern Pacific contains the total area of distribution
of the related species, E. lamelligera which occurs closer to the coast.
E. distinguenda is found westwards in the North Equatorial Current as
far as 175"W. It occurs, along with E . tenera and E. eximia, in the Gulf
of California but, unlike these two species, it is only found infrequently in the California Current. The other centre of distribution is
in the Indian Ocean, being present in the Gulf of Oman, the Red Sea
and Gulf of Aden and throughout the Arabian Sea north of about 10"s.
The most eastern record is east of Ceylon a t about 85"E but it has not
been found to enter the distributional area of the other closely related
species, E . sibogae. Probably occurs a t about 300 m depth during the
day. Length 8-8.5 mm. (Illig, 1930; Torelli, 1934; Tattersall, 1939;
Brinton, 1962a; Ponomareva, 1963, 1964, 1968; Baker, 1965.)
Euphausia lamelligera Hansen, 191 1
E. lamelligera Hansen, 1911 : 32-33 ; 1912 : 250-252, pl. viii, fig. 4, a-e, pl. ix,
This species occupies two coastal areas, the waters off Peru with a
surface temperature of 18"-22"C and the waters off Central America
with a surface temperature of 26"-28"C (Fig. 22). It is more limited to
the coastal zone than the related species, E. distinguenda. Length
7-11 mm. (Brinton, 1962a.)
fig. 1, a; Boden et al., 1955: 345-347, fig. 31.
Euphausia gibba G. 0. Sars, 1883
E. gibba G. 0. Sars, 1883b : 17-18 ; 1885 : 91-93, pl. xvi, figs. 1-8.
The four species E. gibba, E. pseudogibba, E. paragibba and
E . hemigibba form a natural group, the " gibba group " but there is
some question as to whether E . gibba is indeed very closely related to
the other three species. E. gibba is restricted in distribution (Fig. 23)
t o the Central South Pacific extending from 15"s to 30's in the east
and from 13"s to 38"s in the west. It probably lives between 280 and
500m depth during the day, rising towards the surface at night.
Length 12-15 mm. (Brinton, 1962a.)
THE BIOLOGY O F EUPHAUSIIDS
Euphausia distinguenda Hansen, 191 1
E. distinguenda Hansen, 1911: 32; 1912: 248-250, pl. viii, fig. 3, a-f; Boden
et al., 1955: 344-345, fig. 30.
This species occurs in the tropical region of the eastern Pacific and
in the Indian Ocean but not in the Atlantic Ocean (Fig. 22). Its area of
distribution in the eastern Pacific contains the total area of distribution
of the related species, E. lamelligera which occurs closer to the coast.
E. distinguenda is found westwards in the North Equatorial Current as
far as 175"W. It occurs, along with E . tenera and E. eximia, in the Gulf
of California but, unlike these two species, it is only found infrequently in the California Current. The other centre of distribution is
in the Indian Ocean, being present in the Gulf of Oman, the Red Sea
and Gulf of Aden and throughout the Arabian Sea north of about 10"s.
The most eastern record is east of Ceylon a t about 85"E but it has not
been found to enter the distributional area of the other closely related
species, E . sibogae. Probably occurs a t about 300 m depth during the
day. Length 8-8.5 mm. (Illig, 1930; Torelli, 1934; Tattersall, 1939;
Brinton, 1962a; Ponomareva, 1963, 1964, 1968; Baker, 1965.)
Euphausia lamelligera Hansen, 191 1
E. lamelligera Hansen, 1911 : 32-33 ; 1912 : 250-252, pl. viii, fig. 4, a-e, pl. ix,
This species occupies two coastal areas, the waters off Peru with a
surface temperature of 18"-22"C and the waters off Central America
with a surface temperature of 26"-28"C (Fig. 22). It is more limited to
the coastal zone than the related species, E. distinguenda. Length
7-11 mm. (Brinton, 1962a.)
fig. 1, a; Boden et al., 1955: 345-347, fig. 31.
Euphausia gibba G. 0. Sars, 1883
E. gibba G. 0. Sars, 1883b : 17-18 ; 1885 : 91-93, pl. xvi, figs. 1-8.
The four species E. gibba, E. pseudogibba, E. paragibba and
E . hemigibba form a natural group, the " gibba group " but there is
some question as to whether E . gibba is indeed very closely related to
the other three species. E. gibba is restricted in distribution (Fig. 23)
t o the Central South Pacific extending from 15"s to 30's in the east
and from 13"s to 38"s in the west. It probably lives between 280 and
500m depth during the day, rising towards the surface at night.
Length 12-15 mm. (Brinton, 1962a.)