Ontogenetic changes in gill morphology and potential significance for food acquisition in the scallop Placopecten magellanicus

摘要: Sources of mortality in both wild and cultured populations marine bivalves during postlarval stages remain largely unknown, but may be partly associated with the inability to meet energetic demands intense morphogenesis. The development gills postsettlement scallops (Placopecten magellanicus) from 0.35 14 mm shell height (SH) was investigated using scanning electron microscopy determine degree size-specific differentiation evaluate potential ontogenetic constraints food acquisition. Key transitional morphogenesis, likely exert pronounced effects on feeding function, were identified correlated scallop size. gill initially homorhabdic, unreflected inner demibranchs forming a basket-like structure maintained by ciliary junctions. Gill reflection, immediately followed accelerated proliferation filaments formation outer demibranchs, occurred at ~1 mm SH. Outer fully formed ~2 mm Suspension-feeding is probably rather inefficient prior attaining 1–2 mm sizes. onset heterorhabdic, adult form gill, which allows bidirectional particle transport for selection volume regulation ingested material fairly late development, ~3.3–5.0 mm Full plication delayed until attained ~7 mm. this species thus relatively protracted punctuated critical stages, important determining growth capacity populations.