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 : 30

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.10988684

persistent identifier

https://treatment.plazi.org/id/6515E623-0A2A-1E18-39AF-6528FD9694E4

treatment provided by

Plazi

scientific name

Hansenocaris undetermined
status

 

Y-nauplius Type W

Figs 2 View Fig , 11A–G View Fig

Material examined

JAPAN – Okinawa, Sesoko I. , laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 1 LSN; 1991–2005 GoogleMaps 9 LSN, 8 of which molted to cyprids; 2018–2019 ( Tables 1 and S1 View Table 1 ).

Description

LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body spoon-shaped in dorso-ventral view; about 1.8 times as long as wide; cephalic shield circular/ellipsoidal, with discontinuity in body outline leading into trunk. In lateral view, body axis bent downwards 30° with respect to cephalic axis. Length ca 250 µm (without dorso-caudal spine), greatest width ca 130 µm, greatest dorso-ventral thickness ca 80 µm. Labrum balloon-shaped, with surface divided into facets by cuticular ridges, midline produced into keel-like elevation, and free posterior margin bearing small median spine; pores not examined. Caudal end attenuate, terminating in 75–80 µm long, slightly dorsally curved dorso-caudal spine bearing small spines; spine upturned ca 20° to trunk axis and accompanied ventrally at base by pair of ca 10 µm long triangular furcal spines.

CYPRID VIEWED THROUGH CUTICLE OF LSN. Body overall weakly brownish-pigmented. Cephalon most often with two to four lipid vesicles along anterior margin and one to three laterally. Telson slightly longer than wide and about half as long as thorax, often with pair of distinct lipid vesicles.

Identification and variation

Recognizable by the combination of its general body shape, the balloon-shaped, keeled labrum with a spine on the posterior margin and the large, rather straight dorso-caudal spine flanked by relatively robust furcal spines. Variation is seen among nauplii in the form of the dorso-caudal spine (either broad-based and more or less straight or more slender and curved); in the morphology of the posterior margin of the labrum (spine sometimes absent/diminutive, margin sometimes weakly serrate); and among unmolted cyprids in the number of lipid vesicles.

Distribution

Japan (Sesoko Island, Okinawa).

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