3.45 Oncaea englishi (Heron 1977)
Oncaea englishi Heron, 1977: p. 79, figs. 25n,
250,26,27.
Body length -
females: 0.78-0.88 mm (22 specimens)
male:
0.76 mm (1 specimen)
Female. Prosome 1.9 times longer than
wide, dilated at first somite, about 1.7 times
as long as urosome. Head narrow a~d
truncated in dorsal view. Rostral area wIth
thickened, rounded ventral margin. Posterior
points of fifth thoracic somite with slig~tly
curved tip. Proportional lengths of urOSOmItes
and furca 11 :53 :9:7:9: 11 = 100. Anal
somite with patch of spinules on dorsal distal
side· caudal ramus with very small spinules
on dorsal side. Second segment of maxilliped
with two spines on inner surface; proximal
spine short, distal spine elongated.' armed
with two longitudinal rows of dentIcles. P4
Re3 with two spines; the long terminal spine
longer than third segment. P5 with small free
segment, terminally bearing one seta and one
short setule.
Male. General shape resembling female,
with head narrow and truncated in dorsal
view. Proportional lengths of urosomites and
furca 8:61:4:4:4:9:10 = 100. Genital
somite ovoid in dorsal view. Anal somite and
Oncaea englishi
241
caudal rami with spinules. Maxilliped lacking
small segment proximal to claw on female;
second segment with several rows of setules
and denticles. Claw sinuous, with membranous flange on inner curvature, bearing
small setules.
Remarks
As discussed by Heron et al. (1984), O.
englishi closely resembles O. ornata
Giesbrecht, 1891, differing in the relative
lengths of the female urosomites, the terminal
endopod segments and the spinulation on P2
and P4. Malt (1983) discussed the differences
between the two species also on-the basis of
the pore signature pattern. Our specimens
closely agree with Herons' description except
for the size range, being smaller than those
reported by Heron (females 0.95-1.15mm;
males 0.85-1.00mm).
Distribution
O. englishi was described from specimens
sampled in the SW Pacific-Antarctic ar~a
(Heron 1977); it has also been recorded 10
Arctic waters, the NE Pacific Ocean and
Norvegian Sea (Heron et al. 1984). In the
present study, the species was widely distributed in the Pacific area. It was sampled at
all depths but with maximum abundances
from 4oo-500m. A few specimens were also
found from 300-400 m off Cape Froward.
Oncaea englishi Heron, 1977: p. 79, figs. 25n,
250,26,27.
Body length -
females: 0.78-0.88 mm (22 specimens)
male:
0.76 mm (1 specimen)
Female. Prosome 1.9 times longer than
wide, dilated at first somite, about 1.7 times
as long as urosome. Head narrow a~d
truncated in dorsal view. Rostral area wIth
thickened, rounded ventral margin. Posterior
points of fifth thoracic somite with slig~tly
curved tip. Proportional lengths of urOSOmItes
and furca 11 :53 :9:7:9: 11 = 100. Anal
somite with patch of spinules on dorsal distal
side· caudal ramus with very small spinules
on dorsal side. Second segment of maxilliped
with two spines on inner surface; proximal
spine short, distal spine elongated.' armed
with two longitudinal rows of dentIcles. P4
Re3 with two spines; the long terminal spine
longer than third segment. P5 with small free
segment, terminally bearing one seta and one
short setule.
Male. General shape resembling female,
with head narrow and truncated in dorsal
view. Proportional lengths of urosomites and
furca 8:61:4:4:4:9:10 = 100. Genital
somite ovoid in dorsal view. Anal somite and
Oncaea englishi
241
caudal rami with spinules. Maxilliped lacking
small segment proximal to claw on female;
second segment with several rows of setules
and denticles. Claw sinuous, with membranous flange on inner curvature, bearing
small setules.
Remarks
As discussed by Heron et al. (1984), O.
englishi closely resembles O. ornata
Giesbrecht, 1891, differing in the relative
lengths of the female urosomites, the terminal
endopod segments and the spinulation on P2
and P4. Malt (1983) discussed the differences
between the two species also on-the basis of
the pore signature pattern. Our specimens
closely agree with Herons' description except
for the size range, being smaller than those
reported by Heron (females 0.95-1.15mm;
males 0.85-1.00mm).
Distribution
O. englishi was described from specimens
sampled in the SW Pacific-Antarctic ar~a
(Heron 1977); it has also been recorded 10
Arctic waters, the NE Pacific Ocean and
Norvegian Sea (Heron et al. 1984). In the
present study, the species was widely distributed in the Pacific area. It was sampled at
all depths but with maximum abundances
from 4oo-500m. A few specimens were also
found from 300-400 m off Cape Froward.