The Marine Fauna of New Zealand: Isopoda, Aegidae (Crustacea)

3 and 6 each occurring twice; lateral margin ( %)
or 2 (6 %) or 3 (28%); uropod endopod (n = 36)
mesial margin varied from 5 to 8 RS with 5 ( 4%), 6
(25%) and 7 (58%) the most frequent, 8 occurring once,
lateral margin with +2 (83%) with occasional damageinduced
variations of + and 0+ ; one specimen had
2+2. There is no discernable difference between males
and females.
Pereopods present a constant appearance, but no
detailed counts were made owing to the difficulty of
observing small setae under light microscopy without
dissection.
Recently (2006) collected and fresh material of this
species from the Chatham Rise (NIWA 25656, 25668,
25670, 2567 ) had bronze coloured eyes which are
very narrowly (less than the width of an ommatidium)
separated, this separation being less or not apparent in
long-preserved specimens.
remarks: The united eyes, acute and produced posterior
margins of coxal plates 2–4, wide frontal lamina
with the posterior margin forming a distinctly concave
blade, distinctive long and straight appendix masculina
in the males and the setation of robust setae on the
uropods and pleotelson all allow ready identification
of this species.
Aegiochus kakai sp. nov. shares a great many characters
with Aegiochus kanohi sp. nov., including the
general appearance and setation of the antennule,
antenna, pereopods, pleopods, uropods and posterior
margin of the pleotelson. In particular the general
morphology of the appendix masculina of the two species
is similar, both being basally swollen and distally
slender. Despite the overall similarity of appearance
there are numerous clear-cut points of difference and
the two species are easy to distinguish. Aegiochus kakai
has the eyes meeting medially, but the eyes themselves
are far smaller than in A. kanohi; the frontal lamina is
far wider than in A. kanohi and the posterior margin is
concave; the posteroventral angles of pereonite and
coxae 2 and 3 are acute and produced (truncate in A.
kanohi); and the appendix masculina is straight (sinuate
in A. kanohi). There are further differences in the
setation of the uropods and posterior margin of the
pleotelson, which is detailed in the ‘variation’ section
for each species.
Other superficially similar species from the southern
Indian Ocean are Aegiochus crozetensis Kussakin
and Vasina, 982 and A. uschakovi Kussakin, 967, but
these both have widely separated eyes.
prey: Not known. One sample (NIWA 23864) had
sponge tissue tangled up with the specimens suggesting
the possibility of at least temporary association
with hexactinellid sponges.
4
distribution: Recorded only from the Chatham Rise region,
off eastern South Island, New Zealand; at depths
from 757 to 080 metres.
etymoLogy: Kakai is a Mäori word meaning to nibble
or bite frequently; noun in apposition.
Aegiochus kanohi sp. nov. (Figs 65–68)
materiaL examined: Holotype: ♂ ( 4.8 mm), Chatham
Rise, 42°45.89’S, 79°59. 6’W, 9 April 200 , 800–757
m, coll. RV Tangaroa (NIWA 240 9).
Paratypes: 7 ♂ ( 0.5, .0, .5, 2.0, 2.5 dissected,
2.5, 3.0 mm), 2 ♀ (ovig. 4.0, 4.0, 5.0, 5.5, 5.5,
5.6, 6.0; non-ovig. .6, 2.5, 5.0, 5.0, 6.0 mm),
same data as holotype (NIWA 24020). ♀ (non-ovig
0.5 mm), Chatham Rise, 6 April 200 , 42°45.76’S,
79°59.29’W, 064–750, coll. RV Tangaroa (NIWA
2402 ). ♂ ( 2.0 mm), Chatham Rise, 5 April 200 ,
42°45.93’S, 79°59.34’W, 875–757 m, coll. RV Tangaroa
(NIWA 24022).
Additional material: ♂ (9.5 mm), ♀ ( 3.0 mm ovig),
manca (7.5 mm), north of Chatham Rise, 3 September
963, 43°04.00’S, 78°38.99’W, 549 m, stn. A9 0 (two
tubes) (NIWA 24023). ♀ ( 5.8 mm, ovig, v. poor condition),
vicinity of Hikurangi Trough, 5 September
987, 39°5 .90’S, 77°25. 9’E, 4 3 m (NIWA 24024).
New caledonia: 2 ♀ (ovig. 2.0, 3.2 mm), 24°39.3 ’S,
68°39.67’E, 29 October 986, 600 m, CHALCAL II, stn
DW75 (MNHN Is.59 ). 2 ♀ (non-ovig. 9.9, 2.9 mm),
New Caledonia, 24°54.5’S, 68°22.3’E, 28 October 986,
527 m, CHALCAL II, stn DW72 (MNHN Is.59 2).
desCription: Body 2.5 times as long as greatest width,
dorsal surfaces smooth, widest at pereonite 5, lateral
margins weakly ovate. Rostral point folded ventrally
and posteriorly. Eyes large, medially united (very narrow
gap present), anterior clear field 5% length of head,
posterior clear field 28% length of head; each eye made
up of ~ 5 transverse rows of ommatidia, each row
with ~9 ommatidia; eye colour black. Pereonite 1 and
coxae 2–3 each with posteroventral angle right-angled.
Coxae 5–7 with entire oblique carina (coxae 5–7 dorsal
margin concave); posterior margins straight, posterolateral
angle acute (less than 45°). Pleon with pleonite
visible in dorsal view; pleonite 4 with posterolateral
margins not extending to posterior margin of pleonite
5; pleonite 5 with posterolateral angles free, not overlapped
by lateral margins of pleonite 4. Pleotelson 0.9
times as long as anterior width, dorsal surface without
longitudinal carina; lateral margins convex, serrate or
notched, posterior margin converging to caudomedial
point, with 8– 0 RS.
Antennule peduncle articles 3 and 4 .0 as long
as combined lengths of articles and 2, article 3 3.4
times as long as wide (narrowing distally); flagellum