Chorionic membrane morphology of the eggs of Octopus bimaculoides and Octopus hubbsorum (Cephalopoda: Octopodidae)

Abstract

Recently spawned eggs of Octopus bimaculoides and O. hubbsorum are ovo-cylindrical in shape and have an average of 10.1±1.4 and 2.1±0.1 mm in length, respectively. The egg envelope consists of two main parts: the chorionic membrane (Chorion) and the chorionic peduncle. The chorion of O. bimaculoides eggs shows a single layer of 8 µm in thickness, with pores smaller than 1 µm in diameter, and the internal architecture of the chorion connects to the chorionic peduncle. The chorion of O. hubbsorum eggs has a thickness of 4 µm without pores, and the internal architecture of the chorion does not interconnect with the chorionic peduncle. The chorionic peduncle of O. hubbsorum eggs shows an annular width of 300 µm in the junction with the main body of the chorion. O. hubbsorum eggs have a micropyle shaped as a deep circular cavity, 15 µm in diameter in the center of the pole of the chorion. The micro-structure morphology of O. bimaculoides and O. hubbsorum eggs shows a differentiation between the chorion membranes, which is described in this study for the first time.