Polypterus was discovered, described, and named in 1802 by
Étienne Geoffroy Saint-Hilaire. Naturalists were initially unsure whether to regard it as a fish or an amphibian, and if it were to be classified as a fish, it was unclear whether it ought to be regarded as an Actinopterygian, Chondrichthyan, or Sarcopterygian. Around the time following its initial discovery, some entertained the idea of
Polypterus as a living fossil representing the "missing link" between fishes and tetrapods, illustrating a transitional form at the midpoint between finned and limbed vertebrates. Drawing on this work, in 1907,
E. S. Goodrich reported to the
British Association the then current state of evidence 'against'
Polypterus being a crossopterygian, placing it within the
palaeoniscids, the most primitive
actinopterygians. Much later, in 1946,
Romer confirmed this view, but he also wrote, "The weight of Huxley's [1861] opinion is a heavy one, and even today many a text continues to cite
Polypterus as a crossopterygian and it is so described in many a classroom, although students of
fish evolution have realized the falsity of this position for many years. ...
Polypterus ... is not a crossopterygian, but an actinopterygian, and hence can tell us nothing about crossopterygian anatomy and embryology." Hall (2001), relying on Patterson (1982) and Noack
et al. (1996), writes, "Phylogenetic analyses using both morphological and molecular data affirm
Polypterus as a living stem actinopterygian." Research is ongoing. Most of the conclusions drawn by Kerr from Budgett's specimens have been confirmed, but many questions remain. In 2014 researchers at McGill University (published in the journal Nature) turned to
Polypterus to help show what might have happened when fish first attempted to walk out of the water. The team of researchers raised juvenile
Polypterus on land for nearly a year, with the aim of revealing how these 'terrestrialized' fish looked and moved differently. == Recoil aspiration ==