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 : 23

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.10988672

persistent identifier

https://treatment.plazi.org/id/6515E623-0A21-1E13-39A0-663FFD969785

treatment provided by

Plazi

scientific name

Hansenocaris undetermined
status

 

Y-nauplius Type G

Figs 2 View Fig , 8E–G View Fig

Type G – 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 • 3 LSN; 1991–2005 GoogleMaps 21 LSN, 6 of which molted to cyprids; 2018–2019 ( Tables 1 and S1 View Table 1 ).

Description

LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body widely ovate in dorso-ventral view; about 1.2 times as long as wide; lateral margins tapering gradually towards caudal end with no marked discontinuity at posterior end of cephalic shield. In lateral view trunk axis downturned a full 90° relative to cephalic axis, with furcal spines directed anteriorly from end of trunk (i.e., anatomically ventrally but parallel to cephalic axis). Body length ca 300–320 µm (following body curvature in lateral view) (without dorso-caudal spine), greatest width 220 µm, greatest dorso-ventral thickness ca 100 µm. Labrum elevated, trapezoidal, about as long as wide with distinct posterior margin and with surface divided into facets by cuticular ridges; pore pattern not examined. Caudal end rounded, terminating in very short (8 µm), conical dorso-caudal spine and pair of long (40 µm), distally curved, talon-like furcal spines with pair of double-spines at (anatomically) dorsal base of each.

CYPRID VIEWED THROUGH CUTICLE OF LSN. Body weakly brown-pigmented. Many lipid vesicles present in dorsal part of cephalon, and, in some specimens, a dense concentration of yolk granules in central gut-like tube. Lateral margins of cephalic region with clusters of crystalline-like particles.

Identification and variation

Easily recognizable by the combination of its right-angle bend of the body, the large, talon-like furcal spines (‘medium talon’ in comparison to the most similar morphospecies, Types F and H), accompanied by small, basal double-spines, and the lateral clumps of crystalline particles within the margins of the cephalic shield (possibly remnant from the LSN).

Distribution

Japan (Sesoko Island, Okinawa).

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