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

Aegiochus tara sp. nov. (Figs 88–90)
materiaL examined: Holotype, ♀ (non-ovig. 3 mm),
West Norfolk Ridge, 33°42.45’S, 67°27.03’E, 28 May
2003, 45 – 478 m, coll. NORFANZ, RV Tangaroa
(NIWA 7947).
Paratype. ♀ (non-ovig. 22 mm), Tasmania, 48 km east
of Cape Toureville, 42°00.25’S, 48°43.55’E, 30 October
980, 264 m, gravel with sandy mud, G.C.B. Poore &
co. (NMV J277 2).
Other material: Comparative material of Aegiochus
plebeia, see Appendix 2.
desCription: Body .6 times as long as greatest width,
dorsal surfaces polished in appearance and sparsely
punctate, widest at pereonite 5, lateral margins weakly
ovate. Rostral point folded ventrally and posteriorly.
Eyes large, not medially united, separated by about
4% width of head; each eye made up of ~ 2 transverse
rows of ommatidia, each row with ~22 ommatidia;
eye colour dark brown. Pereonite 1 and coxae 2–3 each
with posteroventral angle acute, posteriorly produced.
Coxae 5–7 with incomplete oblique carina; posterior
margins concave, posterolateral angle acute (less than
45°). Pleon with pleonite visible in dorsal view; pleonite
4 with posterolateral margins extending to but not
beyond 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 sinuate (posteriorly weakly
concave), smooth, posterior margin converging to
caudomedial point, with 4 RS (estimated).
Antennule peduncle articles 3 and 4 . times as long
as combined lengths of articles and 2, article 3 3.3
times as long as wide (narrowing distally); flagellum
with 9 articles, extending to posterior of pereonite .
Antenna peduncle article 4 2.5 times as long as wide,
.2 times as long as combined lengths of articles –3,
inferior margin 0 plumose setae, and short simple
seta; article 5 .0 times as long as article 4, 3.0 times
as long as wide, inferior margin with 0 palmate setae,
anterodistal angle with cluster of 2 short simple setae;
flagellum with 20 articles (terminal article/s missing),
extending to middle of pereonite 3.
Frontal lamina posterior margin free, downwardly
projecting, blade-like, wider than long, posteriorly
rounded, anterior margin acute, forming median angle,
posterior margin not abutting clypeus.
Mandible molar process present, small distinct flat
lobe; palp article 2 with 7 distolateral setae (simple and
biserrate; with distal submarginal row 7 simple setae),
palp article 3 with 25 setae (simple; distal most short,
next 3 markedly longer than remainder). Maxillule with
6 terminal RS (three largest being weakly hooked).
46
Maxilla mesial lobe with 3 RS (2 simple, serrate);
lateral lobe with 7 RS (4 hooked, 3 short and straight).
Maxilliped endite with 0 apical setae; palp article 2 with
3 RS; article 3 with 8 recurved RS (straight or weakly
recurved); article 4 with 4 hooked RS; article 5 with 4
RS (two longest of which are biserrate).
Pereopod 1 basis 2.8 times as long as greatest width
(narrowing distally); ischium 0.3 times as long as basis,
inferior margin with 0 RS, superior distal margin with
RS; merus inferior margin with 0 RS, superior distal
angle with 0 RS ( simple seta); carpus 0.7 as long as
merus, inferior margin with 0 RS; propodus 2.9 times as
long as proximal width, inferior margin with RS, propodal
palm with small distal lobe, dactylus smoothly
curved, .0 as long as propodus. Pereopod 2 ischium
inferior margin with 0 RS, superior distal margin with
RS; merus inferior margin with 3 RS (all small), set as
two groups, superior distal margin with 0 acute RS (2
simple setae); carpus similar in size to that of pereopod
, inferodistal angle with RS (large weakly curved).
Pereopod 3 similar to pereopod 2. Pereopods 5–7 inferior
margins of ischium–carpus with short RS. Pereopod 6
similar to pereopod 7. Pereopod 7 basis 4.4 times as long
as greatest width, inferior margins with 23 palmate
setae; ischium 0.4 as long as basis, inferior margin with
RS, superior distal angle with 4 RS, inferior distal
angle with 5 RS; merus .7 as long as ischium, 3.5 times
as long as wide, inferior margin with 5 RS (set as 2, 2
and ), superior distal angle with 4 RS, inferior distal
angle with 6 RS; carpus .3 as long as ischium, 3.7 times
as long as wide, inferior margin with 3 RS (set singly),
superior distal angle with RS, inferior distal angle
with 5 RS; propodus .0 as long as ischium, 4.6 times
as long as wide, inferior margin with 4 RS (set as ,
and 2), superior distal angle with slender seta (and
RS), inferior distal angle with 2 RS.
Pleopod 1 exopod .7 times as long as wide, distally
narrowly rounded, mesial margin weakly oblique,
lateral margin weakly convex, mesial margin strongly
convex, with PMS on distal one-third; lateral margin
strongly concave, with PMS on distal one-third, mesial
margin with PMS on distal half; peduncle .7 times as
wide as long, mesial margin with 9 coupling hooks.
Exopods of pleopods –3 each with distolateral margin
not digitate; endopods of pleopods 3–5 each with
distolateral point; pleopods 2–4 peduncle distolateral
margin with prominent acute RS.
Uropod peduncle ventrolateral margin with 2 RS,
posterior lobe about one-half as long as endopod.
Uropod rami extending beyond pleotelson. Endopod
apically not bifid, lateral margin straight, without
prominent excision, proximal lateral margin with RS,
distal lateral margin with 2 RS, mesial margin weakly
convex, with 7 RS. Exopod extending to end of endopod,
3.0 as long as greatest width, apically not bifid; lateral