Martinavis is a genus of enantiornithine birds which existed in what is now southern France, North America and Salta Province, Argentina during the late Cretaceous period.

M. cruzyensis is known from the holotype ACAP-M 1957, a complete uncrushed right humerus, recovered from the Massecaps locality, Cruzy, which is in a Campanian/Maastrichtian-stage deposits in the Grès à Reptiles Formation of France.

In addition to size, the species differ slightly in proportions and qualitative features, making it unlikely the represent sexual or age variation.

These differ slightly in size but also in proportions, meaning M. saltariensis, while generally smaller, might nonetheless have had thicker legs, and thus match Soroavisaurus.

[3] As Yungavolucris is assumed to be a foot-propelled swimmer however the synonymity of at least some Martinavis specimens with it could explain the genus' prevalence in marine biomes.