preceded_by Platynereis life cycle stage early nectochaete stage mid nectochaete stage 75-6d mn At a temperature of 18 C this stages lasts from 75.00 hours till 96.00 hours. Developmental stage following Early nectochaete stage with the following key events: Formation of the antero-dorsal pair of tentacular cirri, anal cirri and antennal stubs. Body shape changes from torpedo-like into worm-like. Head distinguishable from the trunk due to a constriction. Adult eyes grow in size and are only separated by a medial constriction. Jaws start forming. Macromeres start to cellularize and begin to form midgut epithelium. Proctodeum develops a cylindrical tube shape. The stomodeum and proctodeum get in contact with the midgut (Hauenschild and Fischer, 1969). Pigmented spots at the base of the parapodia increase in size. Additional pigment appears in the head region. Brain grows. Additional serotonergic cells in the brain. Segmental nerves can be identified. Muscles and nerves of the antennae, tentacular cirri anal cirri become visible. PdumDv:0001200 platynereis_stage