5.1 Boreomysis rostrata Illig, 1906
Boreomysis rostrata Illig, 1906: pp. 196, 197, fig.
2a-d- Illig, 1930: pp. 414-419, figs. 23-27- Tattersall, 1951: pp. 56-60, figs. 11-13 - Tattersall,
1955: pp. 68-71- Holmquist, 1957: pp. 5-10, fig.
la-t - li, 1964: pp. 20-23 - Mi.iller, 1993: p. 36
(world catalogue).
Boreomysis inermis Hansen, 1910: pp. 26, 27, pl.
2, fig 4a-c.
Boreomysis rostrata japonica Ii, 1964: pp. 23-28,
figs. 1, 2.
Boreomysis rostrata orientalis li, 1964: pp. 28-33,
figs. 3, 4.
Body length -
females: 18.5-20.8 mm (30 specimens)
males: 18.2-20.3 mm (30 specimens)
Female. Rostrum of carapace pointed and elongated, reaching distal margin of eyes. Lateral
margins of frontal plate convex and covering
basal parts of ocular peduncles. Eyes bearing
conspicuous ocular papilla. Antennules with
small 2nd article of peduncle, 1/2 as long as
wide. Distal margin of 3rd segment with small
tubercle bearing several fine setules. Antennal
scale about 4 times longer than wide, surpassing
distal margin of antennular peduncle by ca. 1/3.
Outer margin unarmed and terminating distally
with tooth; apex of scale slightly surpassing
tooth. Uropods long and slender; exopod longer
than endopod by 1/4; both are longer than telson. Exopods unarmed for short region in proximal area of outer margins. This region terminates with 2 small spines of unequallength.
Endopod bearing long, slender and recurved
spine on dorsal margin below statocysts. Telson
elongated and cleft; proximally wide and distally
- - - - - - - - - - - - - - - - - - - - - - -
Subphylum CRUSTACEA
Class MALACOSTRACA
Order MYSIDACEA
Suborder MYSIDA
Family Mysidae
Subfamily Boreomysinae
narrow. Proximal1/4 of lateral margins unarmed
whereas remaining 3/4 bearing series of long,
regularly distributed spines, with smaller spines
in between. Cleft narrow and deep, with characteristic dilation at base. Margins of cleft armed
with dense series of spinules, closely aposed to
one another.
Male. Similar to female except for the general
differences in the pleopods and a tuft oflong setules inserted on the antennule, at the base of the
2 flagella.
Remarks
1 agree with the description given by Tattersall
(1955) and Holmquist (1956, 1957). There are no
striking differences between females and males
except for the pleopods, which are more developed in males and bear a thick tuft of setules at
the base of the flagella of the antennular pedunele. The length of the rostrum is more or less the
same in both sexes; the specimens examined in
the present study had a somewhat longer rostrum, reaching the tip of the eyes in both females
and males.
Distribution
According to Holmquist (1957), the species is
confined to the Southern Oceans, south of the
Tropic ofCapricorn. It seems tobe a deep-dwelling species, and was sampled from 245-470 m
during the Lund University Chile Expedition
and as deep as 2000 m during the Valdivia Expedition. In the present study, it was the only species of mysid frequently sampled in the Straits,
especially in the Pacific sector, with very few
specimens collected in the Central area (Sts. 16
and 17).
Boreomysis rostrata Illig, 1906: pp. 196, 197, fig.
2a-d- Illig, 1930: pp. 414-419, figs. 23-27- Tattersall, 1951: pp. 56-60, figs. 11-13 - Tattersall,
1955: pp. 68-71- Holmquist, 1957: pp. 5-10, fig.
la-t - li, 1964: pp. 20-23 - Mi.iller, 1993: p. 36
(world catalogue).
Boreomysis inermis Hansen, 1910: pp. 26, 27, pl.
2, fig 4a-c.
Boreomysis rostrata japonica Ii, 1964: pp. 23-28,
figs. 1, 2.
Boreomysis rostrata orientalis li, 1964: pp. 28-33,
figs. 3, 4.
Body length -
females: 18.5-20.8 mm (30 specimens)
males: 18.2-20.3 mm (30 specimens)
Female. Rostrum of carapace pointed and elongated, reaching distal margin of eyes. Lateral
margins of frontal plate convex and covering
basal parts of ocular peduncles. Eyes bearing
conspicuous ocular papilla. Antennules with
small 2nd article of peduncle, 1/2 as long as
wide. Distal margin of 3rd segment with small
tubercle bearing several fine setules. Antennal
scale about 4 times longer than wide, surpassing
distal margin of antennular peduncle by ca. 1/3.
Outer margin unarmed and terminating distally
with tooth; apex of scale slightly surpassing
tooth. Uropods long and slender; exopod longer
than endopod by 1/4; both are longer than telson. Exopods unarmed for short region in proximal area of outer margins. This region terminates with 2 small spines of unequallength.
Endopod bearing long, slender and recurved
spine on dorsal margin below statocysts. Telson
elongated and cleft; proximally wide and distally
- - - - - - - - - - - - - - - - - - - - - - -
Subphylum CRUSTACEA
Class MALACOSTRACA
Order MYSIDACEA
Suborder MYSIDA
Family Mysidae
Subfamily Boreomysinae
narrow. Proximal1/4 of lateral margins unarmed
whereas remaining 3/4 bearing series of long,
regularly distributed spines, with smaller spines
in between. Cleft narrow and deep, with characteristic dilation at base. Margins of cleft armed
with dense series of spinules, closely aposed to
one another.
Male. Similar to female except for the general
differences in the pleopods and a tuft oflong setules inserted on the antennule, at the base of the
2 flagella.
Remarks
1 agree with the description given by Tattersall
(1955) and Holmquist (1956, 1957). There are no
striking differences between females and males
except for the pleopods, which are more developed in males and bear a thick tuft of setules at
the base of the flagella of the antennular pedunele. The length of the rostrum is more or less the
same in both sexes; the specimens examined in
the present study had a somewhat longer rostrum, reaching the tip of the eyes in both females
and males.
Distribution
According to Holmquist (1957), the species is
confined to the Southern Oceans, south of the
Tropic ofCapricorn. It seems tobe a deep-dwelling species, and was sampled from 245-470 m
during the Lund University Chile Expedition
and as deep as 2000 m during the Valdivia Expedition. In the present study, it was the only species of mysid frequently sampled in the Straits,
especially in the Pacific sector, with very few
specimens collected in the Central area (Sts. 16
and 17).