A new synaphobranchid eel from the Brazilian continental slope is described herein as Synaphobranchus calvus. The species is distinguished from its congeners by the absence of scales on the head (vs. head scaled in other species) and its black to brown body with a deep blue belly (vs. body entirely black, gray, or brown in the remaining species). Further comments about the synaphobranchid eels of the western South Atlantic are given and a key with new characters to all species of Synaphobranchus are provided.