6.8 Obtusoecia antarctica Miiller, 1906
Conchoecia obtusata Sars, 1866 var. antarctica
Mi.iller, 1906a: pp. 77, 78, pl. 16 figs. 10-23 -
Skogsberg, 1920: pp. 647,648- Ramirez and Moguilevsky, 1971: p. 656, pl. 11 figs. 1-3- Angel,
1981: p. 559, fig. 194/68.
Spinoecia obtusata var. antarctica? Poulsen,
1973: p. 123.
Conchoecia (Spinoecia) obtusata var. antarctica
Deevey, 1978: p. 53, fig. 8.
Obtusoecia antarctica Martens, 1979: p. 332, fig.
14a-e- Koch, 1992: pp. 79-82, fig. 20.
Conchoecia (Obtusoecia) antarctica Deevey,
1982: p. 148, fig. 18.
Carapace length -
females: 1.60 mm
males: 1.37 mm
Female. Carapace of medium size and subovate;
height about 1/2 the length; rostrum curved; incisure deep; dorsal margin straight below a rather long shoulder; posterior margin rounded,
proceeding smoothly into the nearly straight
ventral margin, which then curves smoothly towards the incisure. Both asymmetric glands in
the usual places; lateral corner glands absent; a
few long anterior glands below the incisure. Shell
smooth, inner list distinct. Cap of the frontal organ united with the stern, tip pointed; ornamented with numerous short hairs. Al with a dorsal
bristle; 5 end bristles, consisting of a long
smooth 'e' bristle and 4 short 'pipe' bristles.
Male. Carapace similar to that of the female but
smaller. Cap of the frontal organ separated from
its stern by a joint, finger-shaped, and densely
hirsute. Al 'e' bristle adorned with numerous
backwards-directed spines, distally these occur
in a double row but more proximally there is
only one row and they become smaller; 'b' and 'd'
bristles not as long and apparently smooth, 'c'
bristle a short sensory 'pipe' bristle, 'a' bristle
short and reflexed. A2 clasping joints strikingly
dimorphic (generic character); the right joint is
extraordinarily large, with a right-angled bend
at the elbow and then an obtuse-angled bend;
left joint rudimentary. Penis relatively short and
stout, with convex sides and a stepped top; numerous transverse muscle bands; seminal tube
simple but not straight, broadened at its base.
Remarks
Martens (1979) divided the species assigned by
Poulsen (1973) to Spinoecia into 2 natural units
to which he gave the new generic names Obtusoecia and Porroecia, thus clearing up a potential
taxonomie problem. Spinoecia (for which the
concept was too broad) then lapsed as an invalid
taxon because no type species had been designated.
Distribution
An gel ( 1981) regards this as an upper mesopelagic to epipelagic species in austral latitudes
and all southern oceans. Deevey (1983) gives the
latitudinal range as 36° to 68°S. Poulsen's questionable record is based on a single female in the
Dana collections from south of the Fiji Islands at
around 28°S. Benassi et al. (1994b) record earlier
unpublished data ofMcKenzie citing its presence
off southwestern Australia in samples collected
by SS Daimantina during the International Indi-
Conchoecia obtusata Sars, 1866 var. antarctica
Mi.iller, 1906a: pp. 77, 78, pl. 16 figs. 10-23 -
Skogsberg, 1920: pp. 647,648- Ramirez and Moguilevsky, 1971: p. 656, pl. 11 figs. 1-3- Angel,
1981: p. 559, fig. 194/68.
Spinoecia obtusata var. antarctica? Poulsen,
1973: p. 123.
Conchoecia (Spinoecia) obtusata var. antarctica
Deevey, 1978: p. 53, fig. 8.
Obtusoecia antarctica Martens, 1979: p. 332, fig.
14a-e- Koch, 1992: pp. 79-82, fig. 20.
Conchoecia (Obtusoecia) antarctica Deevey,
1982: p. 148, fig. 18.
Carapace length -
females: 1.60 mm
males: 1.37 mm
Female. Carapace of medium size and subovate;
height about 1/2 the length; rostrum curved; incisure deep; dorsal margin straight below a rather long shoulder; posterior margin rounded,
proceeding smoothly into the nearly straight
ventral margin, which then curves smoothly towards the incisure. Both asymmetric glands in
the usual places; lateral corner glands absent; a
few long anterior glands below the incisure. Shell
smooth, inner list distinct. Cap of the frontal organ united with the stern, tip pointed; ornamented with numerous short hairs. Al with a dorsal
bristle; 5 end bristles, consisting of a long
smooth 'e' bristle and 4 short 'pipe' bristles.
Male. Carapace similar to that of the female but
smaller. Cap of the frontal organ separated from
its stern by a joint, finger-shaped, and densely
hirsute. Al 'e' bristle adorned with numerous
backwards-directed spines, distally these occur
in a double row but more proximally there is
only one row and they become smaller; 'b' and 'd'
bristles not as long and apparently smooth, 'c'
bristle a short sensory 'pipe' bristle, 'a' bristle
short and reflexed. A2 clasping joints strikingly
dimorphic (generic character); the right joint is
extraordinarily large, with a right-angled bend
at the elbow and then an obtuse-angled bend;
left joint rudimentary. Penis relatively short and
stout, with convex sides and a stepped top; numerous transverse muscle bands; seminal tube
simple but not straight, broadened at its base.
Remarks
Martens (1979) divided the species assigned by
Poulsen (1973) to Spinoecia into 2 natural units
to which he gave the new generic names Obtusoecia and Porroecia, thus clearing up a potential
taxonomie problem. Spinoecia (for which the
concept was too broad) then lapsed as an invalid
taxon because no type species had been designated.
Distribution
An gel ( 1981) regards this as an upper mesopelagic to epipelagic species in austral latitudes
and all southern oceans. Deevey (1983) gives the
latitudinal range as 36° to 68°S. Poulsen's questionable record is based on a single female in the
Dana collections from south of the Fiji Islands at
around 28°S. Benassi et al. (1994b) record earlier
unpublished data ofMcKenzie citing its presence
off southwestern Australia in samples collected
by SS Daimantina during the International Indi-