Stone canal morphology in the brachiolaria larva of the asterinid sea star Parvulastra exigua

Here, we describe the morphology of the pore canal and the stone canal in late brachiolaria larvae of the asterinid P. exigua. We add to a previous report of the stone canal given in the account of the development of the primary podia in P. exigua (Morris et al. 2009). Larval development in P. exigua is abbreviated: the brachiolarian stage is reached without trace of a preceding bipinnarian feeding-stage and the adult rudiment starts to form within a few days of fertilization (Byrne 1995). The observations were made in a confocal laser-scanning microscope from whole-mounts of larvae made autofluorescent by glutaraldehyde fixation (Morris et al. 2009).