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

teral margin not digitate; endopods of pleopods 3–5
each with distolateral point; pleopods 2–4 peduncle
distolateral margin without prominent acute RS.
Uropod peduncle ventrolateral margin with RS,
posterior lobe about one-half as long as endopod.
Uropod rami apices narrowly rounded. Endopod
apically not bifid, lateral margin proximally convex
and distally straight, with prominent excision, positioned
about three-quarters along ramus, proximal
lateral margin with 6 RS, distal lateral margin with 4
RS, mesial margin weakly convex, with 3 RS. Exopod
extending beyond end of endopod, 3.5 times as long
as greatest width, apically not bifid; lateral margin
straight, with 9 RS; mesial margin sinuate, proximally
concave, with 4 RS.
femaLe: Similar to the male, but for the sexual characters;
no ovigerous females present.
size: Males 3 to 42 mm (mean = 35.5); female 28 to 25
mm; single manca (with pereopod 7 present but undeveloped)
22 mm; from a large damaged specimen the
species may reach an estimated size of up to 6 cm.
Variation: All four type specimens have received at
least some damage so it is not possible to quantify the
range in number of the robust setae. The shape and
proportion of the uropod rami is consistent between
specimens. Pleotelson RS potentially ranging from 4
to 8 (counted as 8+9, 7+9). Uropod exopod mesial
margin with 4 or 5 RS, lateral margin 8 or 9; uropod
endopod mesial margin varied from 3 to 6 RS, lateral
margin 6+3–6, once 7+5.
The robust setae on the merus of pereopods –3
present a constant pattern, with pereopod with 3+2
(all) pereopod 2 4+2 (all) and pereopod 3 merus had
4+2, 4+3 and 5+2; in the largest specimen (NIWA 7940)
the RS on pereopod 3 form a continuous row.
Fresh colour is a rich orange–brown, with dark
brown eyes; chromatophores not apparent. A conspicuous
feature of all the freshly caught specimens was the
dark brown colour of the robust setae on the pereopods,
uropodal rami and pleotelson.
remarks: Aegapheles mahana sp. nov. can be identified
by the following combination of characters: large eyes,
entirely united and extending almost fully to the anterior
margin of the head; anteriorly rounded frontal
lamina; pereopods –3 propodus palm without blade,
with small distal lobe; inferior margin of pereopod
merus with 3+2 robust setae, that of pereopods 2 and
3 with 4+2 robust setae; and the relatively slender and
distally acute uropodal rami with the exopod extending
distinctly beyond the posterior of the endopod; and
the lateral margin of the uropodal endopod with 6 or 7
setae proximal (or anterior) to the lateral notch.
79
Similar species in the region include Aegapheles
alazon Bruce, 2004, A. kixalles Bruce, 2004 and A. warna
Bruce, 2004. Aegapheles kixalles, known from the vicinity
of New Caledonia, is most similar in eye size and
shape, and in the shape and setation of the pereopods
and uropods, but is immediately distinguished by
having a narrow propodal blade on pereopods –3.
Aegapheles alazon is a widely distributed and sympatric
species which differs in having smaller eyes with
a much larger anterior clear field, pereopod 1 usually
with +2 robust setae on the merus (compared to 3+2)
and the uropodal endopod has only 2–4 robust setae
anterior to the lateral notch; in addition the lateral margins
of the frontal lamina are more strongly convex in
A. alazon. Aegapheles warna presents a similar pattern of
setation to the uropods, but the robust setae are larger,
more numerous and the exopod is wider than that of
A. mahana, extending only slightly beyond the endopod
while in A. mahana the exopod extends well beyond
the endopod apex and is noticeably more slender (3.5
times as long as wide) than that of A. warna (2.9 times
as long as wide).
prey: No records.
distribution: Northeastern New Zealand and in the
vicinity of the Chatham Islands; potentially at depths
between 365 and 40 metres (some dredge samples
covered substantial depth ranges up the sides of the
seamounts).
etymoLogy: The epithet, mahana, is a Mäori word
meaning warm, in reference to the volcanic activity of
these sea mounts.
Aegapheles rickbruscai (Bruce, 2004) comb. nov.
(Fig. 42)
Aega rickbruscai Bruce, 2004: 196, figs 40–44, 64.
materiaL examined: ♂ (44 mm), Cavalli Sea Mount, off
northern North Island, 34°07.2 ’S, 74°05.64’E, 6 April
2002, 554–549 m, NZOI stn Z 055, coll. S. O’Shea on
RV Kaharoa (NIWA 3444).
diagnosis (from Bruce 2004a): Eyes large, medially
united, anterior clear field 11% length of head, posterior
clear field 34% length of head; eye colour dark brown.
Pleonite 4 with posterolateral margins extending clearly
beyond posterior margin of pleonite 5; pleonite 5 with
posterolateral angles overlapped by lateral margins of
pleonite 4. Pleotelson 0.9 times as long as anterior width,
dorsal surface without longitudinal carina; lateral margins
convex, smooth, posterior margin with 0 RS.
Antennule peduncle article 2 without anterodistal
lobe; flagellum extending to mid-point of eye. An-