Fig. 5

SEM images of the lateral side of the cephalic region of Marsupenaeus japonicus: (a) the caudal part of the cephalic region, (b) the rostral part of the cephalic region, and (c, d, e, f) enlarged views of the highlighted areas in the previous images, showing the following structures: the cornea (C), the attached bony palate, the optic calathus (Oc) with wavy connections (CA), the basal segment (Bs), and the ocular plate (Op). The carapace (Ca) features two spines: the antennal spine (AS) and the orbital spine (OS). The antennule peduncle consists of a distal segment (DS), intermediate segment (MS), and proximal segment (PrS), extending into a thin medial flagellum (MF) and a thick lateral flagellum (LF). Other labeled structures include the scaphocerite (SCa), tapered end (Te), rostrum (Ro), apical part of the rostrum (AR), dorsal spines (DS), lateral groove (LG), median crest (MC), lateral ridges (LR), ventral spine (VS), mesial crest (MC), small simple setae (SS), short plumose setae (PLS), pores (P), pappose setae (PS), and nest-like structures (NS)