2019 Volume AA2019 Pages AA2019-1-
Two individuals of “monster larvae” belonging to the genus Cerataspis (Decapoda: Penaeoidea: Aristeidae) were collected in the western North Pacific in 2016. The smaller one (carapace length 7.3 mm) was collected by daytime plankton net operation towed at a shallow layer (25 m to the surface), and the larger one (carapace length 11.5 mm) was collected by a nighttime plankton net operation towed from 208 m to the surface. These larvae have a pair of large spines on the lateral surface of the carapace, and in this regard they agree with C. petiti Guérin-Méneville, 1844 reported from the Atlantic. However, the mitochondrial 16S rDNA sequences of these two individuals matched with those of C. monstrosus Gray, 1828, the senior synonym of the widely used name Plesiopenaeus armatus (Spence Bate, 1881), suggesting that the presence and absence of the spine might be intra-specific morphological plasticity or variations among different developmental stages.
