6.10 Philomedes eugeniae Skogsberg, 1920
Philomedes eugeniae Skogsberg, 1920: pp. 410413, fig. 74- Poulsen, 1962: p. 345 (key) - Kornicker, 1975: pp. 238-240, figs. 135-138.
Carapace length -
females: 1.37-1.75 mm (Kornicker, 1975)
males: unknown
Female. Carapace medium-sized, with a weak
subangular cauda; height about 2/3 the length;
rostrum prominent, with a flattened top; incisure deep; dorsal margin strongly curved, obliquely truncate posterodorsally; ventral margin
evenly rounded from weak cauda to the incisure.
Medial bristles on the rostral row numerous; on
the posterior list there are also some bristles,
partly arranged in groups; between the posterior
list and the valve margin are a few more bristles;
rostral selvage bearing short marginal hairs.
Carapace sculpture consisting of numerous subcircular and shallow pits. Colour whitish. 7th
limb with 3 dorsal and 2 ventral distal bell bristles, plus a total of 9-13 proxima! bell bristles.
Furca lamellar with 1 O claws decreasing m
length and strength from front to rear.
Male. Unknown for this species.
Remarks
We found five juveniles of this species. They are
referred to P. eugeniae because of the posterodorsal profile of the shell and the weak ca uda, the
Epibenthic Myodocopida
Family Philomedidae
presence of numerous shallow pits on the valves,
and the fact that, allowing for incremental
growth of around 25 % at each ecdysis, their
adult size would be within the size range given
by Kornicker (1975, see above). Our specimens
were collected at St. 21 (52°52'5, 70°30'W) and
St. 22 (52°40'5, 69°55 'W). The lateral profile of P.
eugeniae is more truncated postero-dorsally
than that of P. assimilis Brady, 1907 and the shell
has scattered shallow, subcircular pits rather
than the numerous punctae which characterize
that species (Kornicker 1975, figs. 129c, 138b ).
Another, and larger, individual has turned up in
the new samples from Magellan Straits.
Distribution
Our specimens were taken in samples from the
eastern end of Magellan Straits. Kornicker
(1975) gives the type locality for this species as
the Straits of Magellan at a depth of 7 m - material collected by the Swedish SS Eugeniae Expedition. This was the advice he received from the
curator of the type specimens at the Naturhistoriska Riksmuseet, Stockholm. The paratypes
were also collected in the same area, off Cape
Valentyn, at 270 m. Other material, examined by
Kornicker personally, was collected in Magellan
Straits by the RV Hero cruises 69-5 and 70-2. Indeed, this species is known only from the Magellanic subregion of the sub-Antarctic, whereas P.
assimilis, which has a similar shape but different
surface sculpture, is confined to the Antarctic, at
depths from 9 to 876 m (Kornicker 1975).
Philomedes eugeniae Skogsberg, 1920: pp. 410413, fig. 74- Poulsen, 1962: p. 345 (key) - Kornicker, 1975: pp. 238-240, figs. 135-138.
Carapace length -
females: 1.37-1.75 mm (Kornicker, 1975)
males: unknown
Female. Carapace medium-sized, with a weak
subangular cauda; height about 2/3 the length;
rostrum prominent, with a flattened top; incisure deep; dorsal margin strongly curved, obliquely truncate posterodorsally; ventral margin
evenly rounded from weak cauda to the incisure.
Medial bristles on the rostral row numerous; on
the posterior list there are also some bristles,
partly arranged in groups; between the posterior
list and the valve margin are a few more bristles;
rostral selvage bearing short marginal hairs.
Carapace sculpture consisting of numerous subcircular and shallow pits. Colour whitish. 7th
limb with 3 dorsal and 2 ventral distal bell bristles, plus a total of 9-13 proxima! bell bristles.
Furca lamellar with 1 O claws decreasing m
length and strength from front to rear.
Male. Unknown for this species.
Remarks
We found five juveniles of this species. They are
referred to P. eugeniae because of the posterodorsal profile of the shell and the weak ca uda, the
Epibenthic Myodocopida
Family Philomedidae
presence of numerous shallow pits on the valves,
and the fact that, allowing for incremental
growth of around 25 % at each ecdysis, their
adult size would be within the size range given
by Kornicker (1975, see above). Our specimens
were collected at St. 21 (52°52'5, 70°30'W) and
St. 22 (52°40'5, 69°55 'W). The lateral profile of P.
eugeniae is more truncated postero-dorsally
than that of P. assimilis Brady, 1907 and the shell
has scattered shallow, subcircular pits rather
than the numerous punctae which characterize
that species (Kornicker 1975, figs. 129c, 138b ).
Another, and larger, individual has turned up in
the new samples from Magellan Straits.
Distribution
Our specimens were taken in samples from the
eastern end of Magellan Straits. Kornicker
(1975) gives the type locality for this species as
the Straits of Magellan at a depth of 7 m - material collected by the Swedish SS Eugeniae Expedition. This was the advice he received from the
curator of the type specimens at the Naturhistoriska Riksmuseet, Stockholm. The paratypes
were also collected in the same area, off Cape
Valentyn, at 270 m. Other material, examined by
Kornicker personally, was collected in Magellan
Straits by the RV Hero cruises 69-5 and 70-2. Indeed, this species is known only from the Magellanic subregion of the sub-Antarctic, whereas P.
assimilis, which has a similar shape but different
surface sculpture, is confined to the Antarctic, at
depths from 9 to 876 m (Kornicker 1975).