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 : 41-43

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.10988706

persistent identifier

https://treatment.plazi.org/id/6515E623-0A1F-1E2F-39AB-6005FD969657

treatment provided by

Plazi

scientific name

Hansenocaris undetermined
status

 

Y-nauplius Type O*

Figs 2 View Fig , 16F–J View Fig

Type O* – Dreyer et al. 2023a: figs 3, 5a, c, tables s1–s2.

Material examined

JAPAN – Okinawa, Sesoko I. , laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 5 LSN; 1991–2005 GoogleMaps 66 LSN, 11 of which molted to cyprids; 2018–2019 ( Tables 1 and S1 View Table 1 ).

Description

LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body ovate in dorso-ventral view; about 1.6 times as long as wide, with lateral margins showing slight concavity at transition from cephalic shield to trunk. In lateral view, trunk axis downturned ca 40° with respect to cephalic axis. Length 240–280 µm (without dorso-caudal spine), greatest width ca 150 µm, greatest dorso-ventral thickness ca 100 µm. Labrum produced as sub-trapezoidal elevation divided into facets by cuticular ridges; pores not examined in detail, but at least two in posterior half of midline and one pair in postero-lateral corners. Caudal end nearly acute, terminating in smooth, pointed, ca 20 µm long dorso-caudal spine with axis upturned 25° relative to trunk axis, this spine being accompanied ventrally by pair of triangular, ca 5–10 µm long furcal spines.

CYPRID VIEWED THROUGH CUTICLE OF LSN. Body overall transparent but with weakly orange- or browncolored yolk granules in central gut-like tube. Typically with pair of transparent vesicles along anterior margin of cephalic shield. Telson approximately as long as wide and about half as long as thorax, with pair of transparent vesicles anteriorly.

Identification and variation

Recognizable by the combination of its ovate/triangular body shape and its small size, general transparency and small caudal spines. Some variation among specimens in body size, length-width ratio and precise size of the caudal spines suggests that this morphospecies may include more than one species.

Distribution

Japan (Sesoko Island, Okinawa).

Kingdom

Animalia

Phylum

Arthropoda

Class

Maxillopoda

SubClass

Facetotecta

Family

Hansenocarididae

Genus

Hansenocaris

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