Abstract
The post-metamorphic female of Amazonicopeus elongatus gen. et sp. nov. (Copepoda: Poecilostomatoida) is described and Amazonicopeidae fam. nov. is proposed to contain this parasite.
The new form was found on the gill arches of Plagioscion squamosissimus (HECKEL) from the Amazon
River near Manaus, Brazil. The new family is unique in having a head with eyes, but no cephalothorax,
an elongate neck formed from head segments, a mouth distant from the head, located on the hindbody,
a protrusible mouth-tube and a divided abdomen with two free segments attached to each uropod.
These parasites burrow in to grasp the gill arch with their antennae. This penetration provokes an inflammatory reaction on the part of the host leading to cellular growth around the neck, followed by
fibrotic encapsulation and eventual calcification.
