The Isopods of Abyssal Depths in the Atlantic Ocean

Here two additional new abyssal species are de­
scribed from the South Atlantic abyss.
Figure 40. A—B: Storthyngura birsteini, n. sp.
A: dorsal view female holotype; B: uropod.
C-E: Storthyngura snanoi, n. sp. C: first antenna;
D: uropod; E: dorsal view female holotype.
A KEY TO THE SPECIES OF SYNEURYCOPE
(Modified from Menzies, 1956a, p. 6)
1. Dorsum of cephalon with spines . . . multispina, n. sp.
1. Dorsum of cephalon without spines 2
2. Mandibular palp small, unarmed 4
2. Mandibular palp well developed with 3-4 setae on
apical article 3
3. Maxilliped with coupling hooks . . parallela Hansen
3. Maxilliped without coupling
hooks hanseni Menzies
4. First peraeonal somite fused with
cephalon heezeni, n. sp.
4. First peraeonal somite separated from
cephalon capensis (Barnard)
Syneurycope heezeni, new species
Figure 41 A-E
Synonyms: None.
Diagnosis: Syneurycope with cephalon and first
ABYSSAL ATLANTIC ISOPODS 151
peraeonal somite fused. Dorsum of cephalon smooth,
frontal margin between first antennae concave.
Maxilliped without coupling hooks. Mandibular
palp without setae on apical article. Fifth peraeopods
with paddle-shaped terminal articles. Exopod of
uropod one-fourth as long as endopod. First pleonal
somite completely separated from pleon.
Measurements: Holotype female length 4.5 mm.,
width pleon 0.7 mm.
Type locality: South Atlantic, L.G.O. Biotrawl No.
200, types and one female paratype, cat. no. 1-227.
Distribution: Found also at L.G.O. Biotrawl No.
201, two females, two fragments, cat. no. 1-229,
and L.G.O. Biotrawl No. 220, one female, cat. no.
1-228.
Affinities:' This species is unique in having the
cephalon fused with the first peraeonal somite.
Syneurycope parallela Hansen
Figure 41 F
Synonyms: Syneurycope parallela Hansen, 1916, pp.
131-132, PI. 12.
Diagnosis: Syneurycope without spines on dorsum of
head. First pleonal somite clearly separated from
pleotelson. Maxilliped with three coupling hooks.
Uropodal exopod one-fifth the length of endopod.
Measurements: Length female 3.7 mm. (Hansen,
op. cit. p. 131).
Type locality: North Atlantic, southwest of Cape
Farewell, Ingolf Station 22, latitude 58° 10' N., longitude
48° 25' W., 3474 meters, temperature 1.4° C.,
one specimen (Hansen, op. cit.).
Distribution: Known only from type locality.
Affinities: Related to S. hanseni Menzies but with
coupling hooks on the maxilliped.
Syneurycope hanseni Menzies
Figure 42 A-D
Synonyms: Syneurycope hanseni Menzies, 1956a, pp.
6-7, Fig. 2.
Diagnosis: Syneurycope without spines on dorsum of
cephalon. First pleonal somite incompletely separated
from pleon. Maxilliped without coupling hooks.
Uropodal exopod one-third the length of endopod.
Mandibular palp well developed, terminal article
setiferous. Outer lobe at apex of male first pleopod
longer than inner lobe.
Measurements: Male length 3.75 mm., width
second peraeonal somite 0.65 mm.
Type locality: North Atlantic, L.G.O. Biotrawl
No. 1, type only, cat. no. 11758 A.M.N.H.
Distribution: Known only from type locality.
Affinities: This species is related to S. parallela
Hansen, from which it differs in lacking coupling
hooks.