6.6 Conchoecilla cf. chuni M iiller, 1906
Conchoecia chuni Mi.iller, 1906a: pp. 124, 125,
pl. 31 figs. 16-28- Mtiller, 1912: pp. 93, 94, fig. 25
- Angel, 1981: p. 557, fig. 194/27.
Conchoecilla chuni Poulsen, 1973: pp. 221-223,
figs. 112, 113.
Conchoecia (Conchoecilla) chuni Deevey, 1978:
pp. 68, 69, fig. 22- Deevey, 1982: p. 165, fig. 38.
Carapace length -
females: 2.15 mm
males: 1.40-1.55 mm (Mtiller, 1906a)
Female. Carapace large and boat-shaped; rostrum long and curved, asymmetrical, shorter in
the right than in the left valve, tip acuminate; incisure rather narrow and deep; dorsal margin
straight or weakly concave below the gently convex shoulders; right posterodorsal edge denticulate, tip pointed, left edge shorter with a blunted
tip; posterior margin convex making a smooth
curve with the ventral margin. Right asymmetrical gland located anteriorly below the incisure;
left asymmetric gland sited on the posterior
margin, dorsalwards of its smooth junction with
the ventral margin; additionally there are 5large
lateral glands on the posterior margin; medial
glands, however, are indistinct. Shell of our specimen smooth. Cap of the frontal organ united
with the stern and not much thicker, tip rounded;
ornamented ventrally with short hairs. Al with a
dorsal bristle; end bristles comprising a long
spinulose chief ('e') bristle and 4 shorter sensory
'pipe' bristles.
Male. Carapace much shorter than in the female,
not as produced posteriorly, and more distinctly
reticulate but otherwise similar. Cap of the frontal organ separated from the stern by a joint; finger-like, with a rounded tip, and smooth. Al 'e'
bristle carrying a double row of about 11-13
longish, slender, backwards-directed spines and
distally of these a small clump ofhairs, 'b' and 'd'
bristles nearly as long, 'c' bristle a short 'pipe'
bristle, 'a' bristle short and strongly reflexed. A2
clasping joints dimorphic; right joint larger with
a single basal protuberance and strongly recurved, left joint bent back at the elbow; both
joints have spinules at their tips. Penis almost
spatulate; broader distally, where it has a flat top,
than at its base; 6-7 weak transverse muscle
bands; seminal tube simple and slender (Mtiller
1906a).
Remarks
The genus Conchoecilla is easily recognized by a
relatively elongate carapace which is pointed
posteriorly in both valves ( the points unequal in
length), but more particularly by the position of
the right asymmetric gland which occurs anteriorly, below the incisure, in the right valve rather
than at or near the postero-ventral corner of this
valve as in most conchoeciines. The unusual
shape, the positions of the two asymmetric
glands and the distinctive lateral glands enable
this genus to be readily distinguished. As a rule,
the types and locations of asymmetric glands
and the presence/absence of lateral corner
glands, dorso-medial glands, and medial glands
are all very useful characters in defining the various conchoeciine genera.
Distribution
We have a single ovigerous female in sample 3 at
Station 10 (depth 400-500 m). Iles (1953) records
Conchoecia chuni Mi.iller, 1906a: pp. 124, 125,
pl. 31 figs. 16-28- Mtiller, 1912: pp. 93, 94, fig. 25
- Angel, 1981: p. 557, fig. 194/27.
Conchoecilla chuni Poulsen, 1973: pp. 221-223,
figs. 112, 113.
Conchoecia (Conchoecilla) chuni Deevey, 1978:
pp. 68, 69, fig. 22- Deevey, 1982: p. 165, fig. 38.
Carapace length -
females: 2.15 mm
males: 1.40-1.55 mm (Mtiller, 1906a)
Female. Carapace large and boat-shaped; rostrum long and curved, asymmetrical, shorter in
the right than in the left valve, tip acuminate; incisure rather narrow and deep; dorsal margin
straight or weakly concave below the gently convex shoulders; right posterodorsal edge denticulate, tip pointed, left edge shorter with a blunted
tip; posterior margin convex making a smooth
curve with the ventral margin. Right asymmetrical gland located anteriorly below the incisure;
left asymmetric gland sited on the posterior
margin, dorsalwards of its smooth junction with
the ventral margin; additionally there are 5large
lateral glands on the posterior margin; medial
glands, however, are indistinct. Shell of our specimen smooth. Cap of the frontal organ united
with the stern and not much thicker, tip rounded;
ornamented ventrally with short hairs. Al with a
dorsal bristle; end bristles comprising a long
spinulose chief ('e') bristle and 4 shorter sensory
'pipe' bristles.
Male. Carapace much shorter than in the female,
not as produced posteriorly, and more distinctly
reticulate but otherwise similar. Cap of the frontal organ separated from the stern by a joint; finger-like, with a rounded tip, and smooth. Al 'e'
bristle carrying a double row of about 11-13
longish, slender, backwards-directed spines and
distally of these a small clump ofhairs, 'b' and 'd'
bristles nearly as long, 'c' bristle a short 'pipe'
bristle, 'a' bristle short and strongly reflexed. A2
clasping joints dimorphic; right joint larger with
a single basal protuberance and strongly recurved, left joint bent back at the elbow; both
joints have spinules at their tips. Penis almost
spatulate; broader distally, where it has a flat top,
than at its base; 6-7 weak transverse muscle
bands; seminal tube simple and slender (Mtiller
1906a).
Remarks
The genus Conchoecilla is easily recognized by a
relatively elongate carapace which is pointed
posteriorly in both valves ( the points unequal in
length), but more particularly by the position of
the right asymmetric gland which occurs anteriorly, below the incisure, in the right valve rather
than at or near the postero-ventral corner of this
valve as in most conchoeciines. The unusual
shape, the positions of the two asymmetric
glands and the distinctive lateral glands enable
this genus to be readily distinguished. As a rule,
the types and locations of asymmetric glands
and the presence/absence of lateral corner
glands, dorso-medial glands, and medial glands
are all very useful characters in defining the various conchoeciine genera.
Distribution
We have a single ovigerous female in sample 3 at
Station 10 (depth 400-500 m). Iles (1953) records