A critical review of ontogenetic development in Terebellidae (Polychaeta)

Abstract

AbstractGarraffoni, A.R.S. and Lana, P.C. 2009. A critical review of ontogenetic development in Terebellidae (Polychaeta). —Acta Zoologica (Stockholm) 91: 390–401.This study reviews the ontogenetic variability of the head, the first segments and the uncini in Terebellidae, based on primary literature and development series of four terebellid species. We test hypotheses on character homologies and indicate informative characters for future phylogenetic analyses. The prostomium, identified as the region above the prototroch band of the larva, in addition to being the region of origin of the buccal tentacles, contains a series of nerves originating from the cerebrum. The peristomium, which contains the mouth, is innervated by the stomogastric nerve and consists of upper and lower lips and an internal pharynx. The loss of the first notochaetae and neurochaetae in the course of development is a recurrent pattern in terebellids. The claviform chaetae disappear with age and growth, and can be used to define the larval stage. Chaetogenesis shows that the long shaft‐shaped manubrium and posterior process develop from different regions. The uncini terminology ‘double rows’ was reinterpreted and renamed ‘inverted rows’, which better reflects the inversion of chaetal positions during ontogenetic development.