A New Highly Modified Species of Creagrutus (Characidae: Stevardiinae) Apparently Mimetic of Prodontocharax

A new species of Creagrutus of the subfamily Stevardiinae is described from the Rio Cachiyacu, a tributary of the Rio Huallaga in Peruvian Amazon. The species demonstrates a number of pronounced differences from the typical species of Creagrutus, most notably: the ventrally displaced jaws, the compressed, spatulate dentition and anterior portion of the neurocranium, along with modifications of the digestive system and the swimbladder. Its assignment to the genus is, nonetheless, supported by both morphological and molecular evidence. The new species is apparently mimetic of Prodontocharax melanotus, which also occurs at its type-locality. (AU)