Taxonomic diversity of marine planktonic ‘ y-larvae’ (Crustacea: Facetotecta) from a coral reef hotspot locality (Japan, Okinawa), with a key to y-nauplii
Author
Olesen, Jørgen
6B569425-6BE7-4A73-B165-87E0C097715A
Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, DK- 2100 Copenhagen Ø, Denmark.
jolesen@snm.ku.dk&jolesen@snm.ku.dk&thecostracans@gmail.com
Author
Grygier, Mark J.
0A2FB16C-56B0-45E5-BB7B-61C3F0F7D46D
National Museum of Marine Biology & Aquarium, 2, Houwan Rd., Checheng, Pingtung 944401, Taiwan.
thecostracans@gmail.com&jolesen@snm.ku.dk&thecostracans@gmail.com
text
European Journal of Taxonomy
2024
2024-03-25
929
1
1
90
https://europeanjournaloftaxonomy.eu/index.php/ejt/article/download/2479/11077
journal article
293299
10.5852/ejt.2024.929.2479
f7dd08c6-e206-4d97-8c9d-7432c5df72b2
2118-9773
10876286
832192E7-A85A-4971-BA2F-D7420D299E8D
Hansenocaris aquila
Olesen & Grygier, 2022
Figs 2
,
9D–E
Hansenocaris aquila
Grygier &Olesen, 2022: 307
, fig. 6.
Hansenocaris aquila
–
Olesen
et al.
2024
: fig. 2.
Material examined
JAPAN
–
Okinawa
,
Sesoko I.
, laboratory pier,
26°38ʹ09.4ʺ N
,
127°51ʹ55.2ʺ E
•
2 LSN
; 1991–2005 (
Tables 1 and S1
).
Description
LAST-STAGE
NAUPLIUS (LSN)
. Lecithotrophic. Body spoon-shaped in dorso-ventral view; about twice as long as wide; cephalic shield broadly rounded, with sharp discontinuity in body outline leading into trunk. In lateral view, trunk axis bent downwards ca 40° with respect to cephalic axis. Length 400 µm (ventral view of mounted exuvia, without dorso-caudal spine), greatest width ca 210 µm, dorso-ventral thickness ca 120 µm. Labrum with goblet-shaped outline in ventral view, its free posterior margin extending into large medial spine (‘stem’ of ‘goblet’), preceded by four small spines on labral midline; labral surface divided into facets by cuticular ridges. Trunk dorsum with four longitudinal rows of spines. Caudal end attenuate, terminating in 100 µm long, robust dorso-caudal spine armed with many smaller spines and accompanied ventrally at base by pair of small, ca 5 µm long furcal spines; long axis of dorso-caudal spine upturned 15° with respect to trunk axis.
CYPRID VIEWED THROUGH CUTICLE OF LSN. No live specimens examined.
Identification and variation
Easily recognizable by its labrum with the posterior margin extended into a large, eagle-beak-like median spine preceded by ca four small spines on the midline; also distinguished by the four dorsal rows of longitudinal spines on the trunk and the very long, robust and distinctly spinose dorso-caudal spine.
Distribution
Japan
(Sesoko Island,
Okinawa
).