diplopterus

from The Century Dictionary.

• noun In ichthyology, a genus of fossil fishes of the Old Red Sandstone, typical of the family Diplopteridœ: so called from the two dorsal fins.
• noun In ornithology, a genus of American ground-cuckoos, of the subfamily Saurotherinœ, sometimes giving name to a subfamily Diplopterinæ. D. næius is an example. D. phasianellus represents a different section of the same genus.