Hoplopteryx has a dorsal fin supported by nine unjointed, bony rays, deeply forked, homocercal tail, a moderately developed anal fin, and a pelvic fin located well forward. The snout is quite short, the eyes fairly large, and both jaws of the upturned mouth hold small teeth.
Habitat
Hoplopteryx was a marine fish, living in shallow chalk seas.
Size
Hoplopteryx was at a typical length 27 cm.
Sources
Fossils (Smithsonian Handbooks) by David Ward (Page 219)
Grandstaff, Barbara S.; Parris, David C. (2016). "A new species of Hoplopteryx from the Carlile Formation (Cretaceous) of South Dakota". Proceedings of the South Dakota Academy of Science. 95: 73–84.
