Hansenocaris undetermined

Olesen, Jørgen & Grygier, Mark J., 2024, Taxonomic diversity of marine planktonic ‘ y-larvae’ (Crustacea: Facetotecta) from a coral reef hotspot locality (Japan, Okinawa), with a key to y-nauplii, European Journal of Taxonomy 929 (1), pp. 1-90 : 34

publication ID

https://doi.org/ 10.5852/ejt.2024.929.2479

publication LSID

lsid:zoobank.org:pub:832192E7-A85A-4971-BA2F-D7420D299E8D

DOI

https://doi.org/10.5281/zenodo.10988690

persistent identifier

https://treatment.plazi.org/id/6515E623-0A16-1E24-39A3-66FAFD9694FF

treatment provided by

Plazi

scientific name

Hansenocaris undetermined
status

 

Y-nauplius Type V

Figs 2 View Fig , 12E–G View Fig

Type V – Dreyer et al. 2023a: figs 4, 5a, c, tables s1–s2.

Not Nauplius V – Hansen 1899: 47–49, table 3, fig. 6. — Schram 1970: 53, 64.

Material examined

JAPAN – Okinawa, Sesoko I. , laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 1 LSN; 1991–2005 GoogleMaps 2 LSN, 1 of which molted to a cyprid; 2018–2019 ( Tables 1 and S1 View Table 1 ).

Description

LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body narrowly ovate in dorso-ventral view; about 1.6 times as long as wide; lateral margins tapering gradually towards caudal end with indistinct concave transition between cephalic shield and trunk. In lateral view, body almost straight, with trunk axis downturned ca 10–15° with respect to cephalic axis. Length 340–370 µm (without dorso-caudal spine), greatest width ca 230 µm, greatest dorso-ventral thickness ca 100 µm. Labrum not examined in detail. Lateral margins of trunk with rows of 5–10 µm long spines. Caudal end rounded and terminating in fairly sharply pointed, 10–15 µm long dorso-caudal spine accompanied ventrally by similarly sharp pair of ca 10 µm long, triangular furcal spines.

CYPRID VIEWED THROUGH CUTICLE OF LSN. Body overall transparent, but rows of brown pigment spots present along lateral margins of cephalon early in cyprid development, with more extensive brownish coloration developing later on. Gut-like tube packed with yolk granules along most of its length. Lipid vesicles clustered in mouth/labrum region of cephalon, with a few more present anterior to nauplius eye. In early LSN, telson wider than long and about half as long as thorax, but more elongate in later-phase LSN.

Identification and variation

Easy recognizable by its overall disc-shaped body, spine-lined trunk margins and broadly rounded caudal end with a relatively small dorso-caudal spine. The two examined specimens differ somewhat in size ( Table S1 View Table 1 ), and only the larger one has rows of pigment spots along the margins of the developing cyprid’s cephalon.

Distribution

Japan (Sesoko Island, Okinawa).

Kingdom

Animalia

Phylum

Arthropoda

Class

Maxillopoda

Family

Hansenocarididae

Genus

Hansenocaris

Loc

Hansenocaris undetermined

Olesen, Jørgen & Grygier, Mark J. 2024
2024
Loc

Not Nauplius V

Schram T. A. 1970: 53
Hansen H. J. 1899: 47
1899
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