Y-nauplius Type AP

Figs 2, 17L

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

Material examined

JAPAN – Okinawa, Sesoko I., laboratory pier, 26°38ʹ09.4ʺ N, 127°51ʹ55.2ʺ E • 1 LSN; 1991–2005 (Tables 1 and S1).

Description

LAST-STAGE NAUPLIUS (LSN). Lecithotrophic. Body shape not examined in dorso-ventral view, but cephalic shield apparently ovate with sharp discontinuity leading into trunk. In lateral view, trunk axis downturned 40° with respect to cephalic axis. Length 300 µm (lateral view of mounted exuvia) (without dorso-caudal spine), greatest width unknown, greatest dorso-ventral thickness ca 110 µm. Labrum strongly produced and divided into facets by cuticular ridges, with row of three successively longer spines on distal midline. Caudal end truncate, terminating in robust, conical, ca 30 µm long dorso-caudal spine, its axis upturned 35° relative to trunk axis. Thick, triangular furcal spines situated ventrally far from dorso-caudal spine, ca 5–10 µm long.

CYPRID VIEWED THROUGH CUTICLE OF LSN. No live specimen examined.

Identification and variation

Recognizable by its protruding labrum with three spines. This morphospecies resembles Type AF but is larger, slightly less stout and has a differently armed labrum (three spines instead of a single needle-like extension).

Distribution

Japan (Sesoko Island, Okinawa).