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3.2 Abyssorchomene plebs Hurley, 1965
Orchomenella plebs Hurley, 1965: p. 109, figs. 1,
2- Emison, 1968: p. 202, fig. 10 tabs. 10- 12.
Orchomene plebs Thurston, 1974: p. 59- Andres,
1983: p. 203.
Abyssorchomene plebs De Broyer, 1983: pp. 146149, fig. 12a; Andres, 1990: p. 135, fig. 267.
Body length -
males: 6.6-12 mm (4 specimens)
Male. Eyes kidney-shaped, almost meeting in
midline. Al with accessory flagellum of 8 articles, the first of which ending at lst segment of
primary flagellum. AU articles are calceoliferous.
A2 much longer than Al, with articles of primary flagellum that are mainly calceoliferous. lst
segment of urosome notched anteriorly and posteriorly bearing a distinct, rounded hump. Coxal
plate of lst gnathopod characteristically narrower proximally and wider distally, resembling an
axe. 2nd gnathopod with very small dactyl, almost hidden by the setules. 2nd uropod not
notched. 3rd uropod with shorter internal than
external ramus; both rami bearing numerous
plumose setules along inner margin. 3rd epimeral plate rounded antero-distally and almost
forming right angle postero-distally.
Remarks
According to Hurley (1965), the peculiar axeshaped form of the coxal plate of the 1 st gnathopod allows for a rapid identification of the species. Only the congeneric species O. rossi (now A.
rossi) can be confused with O. plebs (now A.
plebs) but differs for the 3rd uropod. The inner
ramus is distinctly shorter than the lst segment
of the outer ramus in O. plebs (now A. plebs) and
both rami bear plumose setules; in O. rossi, (now
A. rossi) the inner ramus reaches at least the base
of the 2nd segment of the outer ramus which
never bears setules.
Distribution
A. plebs is a circum-Antarctic species and has
frequently been sampled under the sea ice in the
Ross Sea and off McMurdo Sound (Littlepage
and Pearse 1962). Its vertical depth range of distribution is included from 0-1000 m. In the
Straits of Magellan, the species shows a very irregular distribution, being absent from the Centrai areas. It was sampled only in the Primera
Angostura, in the Atlantic sector, and in the
are a of Tamar Island and off Carlos III Island, in
the Pacific sector. The species occurred in deep
layers from 400-600 m in the Pacific area and
at shallow depths from 20-40 m in the Atlantic
are a.
3.2 Abyssorchomene plebs Hurley, 1965
Orchomenella plebs Hurley, 1965: p. 109, figs. 1,
2- Emison, 1968: p. 202, fig. 10 tabs. 10- 12.
Orchomene plebs Thurston, 1974: p. 59- Andres,
1983: p. 203.
Abyssorchomene plebs De Broyer, 1983: pp. 146149, fig. 12a; Andres, 1990: p. 135, fig. 267.
Body length -
males: 6.6-12 mm (4 specimens)
Male. Eyes kidney-shaped, almost meeting in
midline. Al with accessory flagellum of 8 articles, the first of which ending at lst segment of
primary flagellum. AU articles are calceoliferous.
A2 much longer than Al, with articles of primary flagellum that are mainly calceoliferous. lst
segment of urosome notched anteriorly and posteriorly bearing a distinct, rounded hump. Coxal
plate of lst gnathopod characteristically narrower proximally and wider distally, resembling an
axe. 2nd gnathopod with very small dactyl, almost hidden by the setules. 2nd uropod not
notched. 3rd uropod with shorter internal than
external ramus; both rami bearing numerous
plumose setules along inner margin. 3rd epimeral plate rounded antero-distally and almost
forming right angle postero-distally.
Remarks
According to Hurley (1965), the peculiar axeshaped form of the coxal plate of the 1 st gnathopod allows for a rapid identification of the species. Only the congeneric species O. rossi (now A.
rossi) can be confused with O. plebs (now A.
plebs) but differs for the 3rd uropod. The inner
ramus is distinctly shorter than the lst segment
of the outer ramus in O. plebs (now A. plebs) and
both rami bear plumose setules; in O. rossi, (now
A. rossi) the inner ramus reaches at least the base
of the 2nd segment of the outer ramus which
never bears setules.
Distribution
A. plebs is a circum-Antarctic species and has
frequently been sampled under the sea ice in the
Ross Sea and off McMurdo Sound (Littlepage
and Pearse 1962). Its vertical depth range of distribution is included from 0-1000 m. In the
Straits of Magellan, the species shows a very irregular distribution, being absent from the Centrai areas. It was sampled only in the Primera
Angostura, in the Atlantic sector, and in the
are a of Tamar Island and off Carlos III Island, in
the Pacific sector. The species occurred in deep
layers from 400-600 m in the Pacific area and
at shallow depths from 20-40 m in the Atlantic
are a.