Three new species of the family Aoridae collected from Sagami Bay, central Japan (Crustacea: Amphipoda)
Author
Ariyama, Hiroyuki
Osaka Museum of Natural History, Nagai Park, Higashi-Sumiyoshi, Osaka 546 - 0034 Japan.
Author
Kohtsuka, Hisanori
0000-0003-4440-2776
Misaki Marine Biological Station, Graduate School of Science, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Kanagawa 238 - 0025 Japan. kohtsuka @ g. ecc. u-tokyo. ac. jp; https: // orcid. org / 0000 - 0003 - 4440 - 2776
kohtsuka@g.ecc.u-tokyo.ac.jp
text
Zootaxa
2022
2022-06-30
5159
3
393
413
journal article
86215
10.11646/zootaxa.5159.3.5
30f2c59d-5818-461b-92b3-9072d705e757
1175-5326
6781795
F8C71493-291A-4C80-8A8B-197996E3399E
Aora
Krøyer, 1845
[Japanese name: Himeyumbo-sokoebi-zoku]
Aora
Krøyer, 1845: 335
.—
Myers & Moore, 1983: 167
(key).—
Myers, 1988: 187
.—J.L.
Barnard & Karaman, 1991: 161
.—
Myers & Lowry, 2003: 465
.
Type
species.
Aora typica
Krøyer, 1845
, fixed by monotypy.
Diagnostic description
[emended from J.L.
Barnard & Karaman (1991)
].
Body
laterally compressed, smooth.
Head
, rostrum short, ocular lobes short, anterodistal corner slightly or not projected; eyes small to large.
Urosomites
free.
Antenna 1
very long, slender; peduncular article 3 usually shorter than article 1; accessory flagellum 2- to 6- articulate.
Antenna 2
shorter than antenna 1, flagellum short, with 4–9 articles.
Mandible
, palp strong, slender, with 3 articles, article 3 longest, parallel-sided or semi-falciform, well setose; left molar traversed with parallel channels.
Maxilla 1
, inner plate triangular or conical, with apical seta; outer plate with 9–10 apical robust setae; palp biarticulate, with several robust setae distally.
Maxilla 2
broad, inner plate with mediofacial row of setae.
Maxilliped
, inner plate with several robust setae distally; outer plate with several marginal robust setae; palp consisting of 4 articles, article 4 bearing robust seta (nail) on tip.
Coxae
, male coxa 1 dilated, produced forward, male coxae 2–7 and all coxae in female ordinary to short, weakly overlapping; gills present on coxae 2–6; oostegites of female broad, present on coxae 2–5.
Male gnathopod 1
greatly enlarged, merochelate; merus produced into long distal tooth; carpus long, linear, propodus usually shorter than carpus.
Female gnathopod 1
smaller than that of male, subchelate; carpus shorter than propodus, palm oblique.
Gnathopod 2 of both sexes
smaller than gnathopod 1, subchelate; propodus shorter than or as long as carpus in male, length variable in female, palm oblique.
Pereopods 3, 4
similar to each other; bases slender.
Pereopods 5–7
similar to each other, progressively longer; bases broad.
Epimeral plates 1–3
usually each with notch on ventroposterior corner.
Uropods
biramous; uropod 1 peduncle shorter than or same length as rami, distal end of peduncle with long inter-ramal process, both rami subequal in length; uropod 2 shorter than uropod l, peduncle shorter than rami, distal end of peduncle with short or vestigial inter-ramal process, outer ramus slightly shorter than inner ramus; uropod 3 shortest, peduncle slightly elongate, shorter than rami, both rami subequal in length, outer ramus often with tiny second article.
Telson
entire, fleshy, usually with pair of hooked cusps.
Remarks.
This genus contains twenty species to date (Horton
et. al.
2022). But
Aora inermis
Appadoo & Myers, 2004
from
Mauritius
should be included in another genus (possibly
Tethylembos
), because this species has an acute anterodistal corner of the head, the non-merochelate (subchelate) male gnathopod 1, and the uropod 2 with a long inter-ramal process. The
Aora
species
share the merochelate gnathopod 1 and the smaller subchelate gnathopod 2 both in male with the
Aoroides
species
; however, the former can be distinguished from the latter by the 2–6 articulated accessory flagellum (rudimentary or absent in
Aoroides
) and the parallel-sided or semi-falciform article 3 of the maxillipedal palp (rod-shaped in
Aoroides
).