Distribution, structure and importance of the cephalic dorsal hump, a new sensory organ in calanoid copepods

摘要: The occurrence, external morphology and internal ultrastructure of a cephalic integumental organ in calanoid copepods were studied, using the specimens from Pacific, Indian Atlantic Oceans. This is located on dorsoanterior surface cephalosome, name, dorsal hump (CDH) proposed. Externally, it usually has two pores, anterior apical, plate, thin cuticle along sides. CDH found only male Calanidae, Megacalanidae, Mecynoceridae Paracalanidae, showed some variation between species or groups both size shape. Transmission electron microscopy (TEM) Sagami Bay, Central Japan, revealed that Paracalanus parvus Calanus sinicus consists dermal glands receptor, which assumed to be chemosensory. A comparison distributions prehensile fifth legs suggests plays an important role mate recognition.