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 : 48

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.10988722

persistent identifier

https://treatment.plazi.org/id/6515E623-0A18-1E2A-3996-64F1FD9695B0

treatment provided by

Plazi

scientific name

Hansenocaris undetermined
status

 

Y-nauplius Type AK

Figs 2 View Fig , 19A–E View Fig

Material examined

JAPAN – Okinawa, Sesoko I. , laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 1 LSN; 1991–2005 GoogleMaps 4 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 1.7 times as long as wide; lateral margins tapering gradually towards caudal end with very slight discontinuity at posterior end of cephalic shield. In lateral view, trunk axis downturned 35–40° with respect to cephalic axis. Length 330–350 µm (without dorso-caudal spine), greatest width ca 200 µm, greatest dorso-ventral thickness ca 100 µm. Labrum weakly produced as bell-shaped elevation; not clearly divided into facets; pores not examined in detail but at least three present, one in posterior midline and one pair in postero-lateral corners. Caudal end rounded, terminating in three almost identical, 20 µm long, narrow-conical, pointed caudal spines; among them, ventro-laterally situated furcal spines narrower at base than dorsal-caudal spine.

CYPRID VIEWED THROUGH CUTICLE OF LSN. Body overall weakly brownish, but terminal part of telson with distinct dark-brown pigmentation. Gut-like central tube in telson containing orange yolk granules. Telson about as long as wide, less than half as long as thorax.

Identification and variation

Easily recognizable by its general body form, especially the three equally long, thin caudal spines, and the brown pigmentation of the cyprid’s telson. Variation among specimens was insignificant but few specimens were examined.

Distribution

Japan (Sesoko Island, Okinawa).

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