EXTREMELY food-poor environments, such as the deep sea, place extraord
inary demands on organisms with respect to feeding, resulting in modif
ications of the feeding strategies found in shallow waters. A general
rule is that macrophagy becomes a better strategy than microphagous su
spension-feeding(1-3). The characteristics by which phyla are defined,
nonetheless; remain unchanged in these adaptations. We present here a
n apparently unique example of a fundamentally different body plan, de
rived from a pre-existing phylum, occurring in deep-sea sponges. We de
monstrate that the Cladorhizidae have evolved carnivory and capture sm
all crustaceans by means of filaments provided with raised hook-shaped
spicules. This adaptation to a food-poor deep-sea environment has res
ulted in the loss of the diagnostic characteristics of the phylum Pori
fera: an aquiferous system and choanocytes.