The Isopods of Abyssal Depths in the Atlantic Ocean

168 ROBERT J. MENZIES
Genus: IANIRELLA Bonnier, 1896 Ion with a pair of spines. Each peraeonal somh-
and pleon with a pair of dorsal spines. Three later;
Synonym: lanirella Bonnier, 1896, p. 587; not projections on each side of pleon; each is rounded, r.. -
lanirella Sayce, 1900, p. 124. pointed. Cephalon with rostrum, but spines a:
Type species: lanirella nanseni Bonnier, 1896, p. 587, lacking from it
pi on ^
Measurements: None given.
Diagnosis: Same as for the family; coxal plates Type locality: North Atlantic, southeast of George
visible in dorsal view on peraeonal somites 5-7 Bank, ^ ^ < m Station 2571, 2480 meters, three spec -
inclusive. Uropoda with peduncle umramous. menS; cat nQ 3 8 % 7 j TJ. S. N - M.
Composition: The genus contains eight species, all Distribution: Southeast of Georges Bank, Albatr,
from the Atlantic Ocean. Three are known from station 2572, 3225 meters, and ,1/iafro* Station 257i
abyssal depths, the remainder from bathyal depths. Qiaf; meters
Two additional new abyssal species are described here. AffinUm . ' This spedes h unique m haying rQunde.
LIST OF THE SPECIES OF IANIRELLA
lateral borders of the somites.
Depth Range (Meters)
Species Least Greatest lanirella bifida, new species
1. nanseni Bonnier 950 950
2. lobata Richardson 2480 3225
3. spongicola Hansen 913 913 Synonyms: None.
4. laevis Hansen 2258 2702 Diagnosis: lanirella with lateral borders of peraec -
5. glabra Richardson 946 946 nal extensions sharply pointed. Dorsum of cephalo;
6. vemaeMenzies 5104 5122 peraeon, and pleon without spines. Lateral border
7. abyssicola Richardson
8 A St h
1205
1227
1205
1227
c , , ., , ,. . ,
pleon each with three stout apically spined pre-
9. caribbica Menzies 1169 1169 jections. Apex of pleon bluntly pointed. Cephalo:
A KEY TO THE SPECIES OF IANIRELLA
lacks rostrum, but frons has a medial pair of spine:
projections.
1. Lateral processes on peraeonites Measurements: Holotype, intersex, length 3.8 mm
rounded lobata Richardson width pleon 1.2 mm.
1. Lateral processes on peraeonites pointed . . . . 2 Typg locdity. South Atlantic, L.G.O. Biotrav,
2. Body with dorsal spines
o D J .u . A i
8
i
..T _„ ^ ^ T . or>
No. 53, type, cat. no. 1-183.
1. Body without dorsal spines 3 > /*- >
3. Lateral borders of pleon each with five major Distribution: Known only from type locality,
projections abyssicola Richardson Affinities: Related to vemae but with a bifid fron:
3. Lateral borders of pleon each with three projec- on the cephalon.
tions 4
4. Rostrum lacking 5
4. Rostrum present 6 lanirella laevis Hansen
5. Frons of cephalon rounded
5. Frons of cephalon bifid
vemae Menzies
bifida, n. sp.
-p- rf. ZQ p_p
6. Rostrum with apical spines 7
6. Rostrum without apical spines . . magnifrons, n. sp. Synonyms: lanirella laevis Hansen, 1916, p. 26, PI. I
7. Rostrum with four apical spines . . . . laevis Hansen Diagnosis: Ianirella with lateral borders of peraec-
7. Rostrum with three spines . . . . glabra Richardson rial extensions sharply pointed. Dorsum of cephaloi:
8. Submedian spines of 3-4
shorter than medial spine
peraeonal somite
9
peraeon, and pleon smooth.
. . , ,.
Lateral borders of pleo:
. , . .
8. Submedian spines of 3^ peraeonal somite
each WIth two stout a P lcalI y s P ined Projections, ape-
longer than medial spine nanseni Bonnier of pleon pointed. Cephalon with rostrum bearing
9. Medial spine at front of cephalon as wide four stout spines.
as long spongicola Hansen Measurements: Largest female length 4.0 mm
9. Medial spine at front of cephalon much longer fVt*r,*t*n r>n r!t \
^nauscii, op. cii.j.
10. Pleon^ith dorsal spines '.'.'.'.'. 'caribbica Menzies ^ localit y : North Atlantic > /^/Station 24
10. Pleon without dorsal spines . . . bonnieri Stephensen latitude 63° 06'N., longitude 56° 00'W., 2258 meters
temperature 2.4° C, seven specimens.
lanirella lobata Richardson Distribution: Also known from Ingolf Station no
Figure 52 C
36 > latitude 61° 50' N., longitude 56° 21' W., 270meters,
temperature 1.5° C., four specimens (Hansen
Synonyms: lanirella lobata Richardson, 1908, pp. op. cit.).
78-79, Figs. 8-11. Affinities: This species is allied to/, glabra Richard -
Diagnosis: lanirella with lateral borders of peraeo- son, from which it differs in having four spines, no:
nal extensions blunt and rounded. Dorsum of cepha- three, on the apex of the cephalic rostrum.