Ontogeny changes in carapace and appendages of ostracod Cypris pubera Müller, 1776

In this study, the postembryonic stages of Cypris pubera Müller, 1776 including eight instars and an adult are comprehensively described and compared with those of previously examined Cyprididae species. The first instar bivalved carapace of C. pubera became longer and calcified in subsequent instars until it reached adult form. The first instar of C. pubera has an oval shape and three pairs of naupliar limbs—i.e., antennule, antenna, and Anlage of mandible. The three naupliar appendages provide movement, sensation, and nutritional needs. From the first instar to adulthood, the numbers of setae on the last segment of the first antenna remain constant. During the molting process from the first to the second instar, claw g attached to the second antenna changes into a seta. The appendages are added at each instar, from the first to the sixth, with the exception of the third instar. L5s served as the walking leg, while in later instars, its morphology changed to serve as the feeding leg. As revealed in this study, L5s originated from the thoracic region, where there are two long setae on the protopod and exopod of the second antenna of the three first instars, and they serve as natatory setae.