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

Figure 60. Aegiochus insomnis sp. nov. Ovigerous female paratype 8.0 mm. A, maxilliped; B, maxilliped palp articles 3–5; C,
oostegite, sternite 5 (anterior to top of page); D, setae from mesial margin of oostegite; E, setae from anterolateral margin of
oostegite.
acute. Pleopod 3 exopod with ~40 PMS, endopod with
~6 PMS. Pleopod 4 exopod with ~37 PMS, endopod with
~5 PMS. Pleopod 5 exopod with ~37 PMS. Exopods of
pleopods –3 each with distolateral margin digitate;
endopods of pleopods 3–5 each without distolateral
point; pleopods 2–4 peduncle distolateral margin with
prominent acute RS.
Uropod peduncle ventrolateral margin with 3 RS,
posterior lobe about one-half as long as endopod.
Endopod apically deeply and equally bifid, lateral
margin straight, without prominent excision, proximal
lateral margin with 0 RS, distal lateral margin with
RS, mesial margin weakly convex, with 3 RS. Exopod
not extending to end of endopod, 2.4 times as long as
greatest width, apically deeply bifid, mesial process
prominent; lateral margin convex, with 7 RS; mesial
margin convex, with 3 RS.
femaLe: Similar to males, ovigerous females slightly
wider and slightly larger. Brood pouch composed of 5
pairs of oostegites arising from sternites –5, becoming
progressively larger towards the posterior, oostegite
5 extending to the posterior of sternite and bearing
plumose seta on the mesial margin, stout simple setae
along the posterior margin.
size: The single male measured 6.9 mm; ovigerous
females 7.2–9.5 mm (mean = 8.3 mm); non-ovigerous
females 6.5–9.0 mm (mean = 7.5 mm).
08
Variation: Pleotelson (n = 2) always without RS.
Uropod exopod mesial (n = 22) margin usually with 3
(82%), or 2 ( 8%) RS, lateral margin (n = 24) with 7 (88%)
or 8 ( 2%) RS; uropod endopod mesial margin (n = 24)
with 0 (38%), (33%) or 2 (29%) RS, lateral margin with
only (88%) or 0 ( 2%) RS distal to the pappose seta.
There is no discernable difference between males and
females. The distal robust setae are frequently small
and fine.
The relatively small size of the species precluded
making accurate direct counts of the robust setae on
pereopods and 2 although of the specimens examined
the pattern, number and size appears consistent.
remarks: Aegiochus insomnis sp. nov. is readily identified
by the relatively small eyes, diamond-shaped and
flat (‘Metacirolana-like’) frontal lamina, short pereopod
dactylus (about as long as the propodus), deeply serrated
pleopod exopods and the long acute appendix
masculina. There are two similar species in New Zealand:
Aegiochus nohinohi sp. nov. and Aegiochus gordoni
sp. nov. Both of those species have larger eyes, bladelike
posterior margin on the frontal lamina and have
a much longer dactylus on pereopod ( .2– .4 times
as long as the propodus).
prey: Not known.