PRPRC 2006.10.001, the holotype specimen, is a nearly complete fossil, with the exception of some fins and a large amount of the skull, as well as an incomplete tail fin. Three other specimens reveal the rest of the tail. Most specimens at the Tumbler Ridge Museum in Tumbler Ridge, with one at the Royal Tyrrell Museum of Palaeontology.
Rebellatrix may have reached 1.30 metres (4 ft 3 in) in length. In addition to its uniquely forked (and symmetrical) tail fin, the posterior dorsal fin is behind the anal fin rather than opposite it. Rebellatrix is believed to have been a fast-swimming predator, since its tail is clearly built for speed, and modern coelacanths only use the tail fin when attacking prey, and would have been one of the first non-sharks to fill this niche.[2]