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 : 39-41

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.10988702

persistent identifier

https://treatment.plazi.org/id/6515E623-0A11-1E2D-39A8-62A7FD9690C6

treatment provided by

Plazi

scientific name

Hansenocaris undetermined
status

 

Y-nauplius Type AB

Figs 2 View Fig , 15G–M View Fig

Undescribed form-taxa of lecithotrophic y-larvae – Grygier et al. 2019 pars: 1228, fig. 3g.

Type AB – Dreyer et al. 2023a: figs 4, 5a, c, tables s1–s2. — Olesen et al. 2024: fig. 3b.

Material examined

JAPAN – Okinawa, Sesoko I. , laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 3 LSN; 1991–2005 GoogleMaps 9 LSN, 7 of which molted to cyprids; 2018–2019 ( Tables 1 and S1 View Table 1 ).

Description

LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body dipper-shaped/ovate in dorso-ventral view, about 1.6 times as long as wide; cephalic shield widely ovate, with sharp discontinuity in body outline leading into trunk. In lateral view, trunk axis downturned ca 50° with respect to cephalic axis. Length 210–240 µm (ventral view in life, without dorso-caudal spine), greatest width ca 150 µm, greatest dorso-ventral thickness ca 90–100 µm. Labrum elevated, spatulate in outline; surface divided into facets by cuticular ridges; with free posterior margin; pore pattern not examined in detail but one in midline posteriorly and a pair in postero-lateral corners. Caudal end obtuse, terminating in small, robust broad-conical, ca 5–10 µm long dorso-caudal spine, its axis upturned 20–30° with respect to trunk axis, this spine being accompanied ventrally by pair of even smaller, broad-conical furcal spines approximately 2–3 µm long.

CYPRID VIEWED THROUGH CUTICLE OF LSN. Body overall weakly brownish, but telson with brown/black spots arranged in rows and circles and gut-like tube packed with yellowish and orange yolk granules. Cephalic shield with lipid vesicles along lateral margins (3–4 on each side) and frontal margin (about 4).

Identification and variation

Easily recognizable by the combination of its compact form, spatulate labrum, short dorso-caudal spine and the brown-spotted pigmentation of the developing cyprid’s telson. At least one specimen has a larger dorso-caudal spine than the others.

Distribution

Japan (Sesoko Island, Okinawa).

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