Members of the subfamily are informally and collectively known as "plioplatecarpines" and have been recovered from all continents,[4] though the occurrences in Australia remain questionable.

The first plioplatecarpines appear in the Turonian and are among the oldest of mosasaurs, and the clade persists throughout the Maastrichtian, a period of approximately 24 million years.

Length of presacral series less than that of postsacral, neural spines of posterior caudal vertebrae at most only slightly elongated, do not form an appreciable fin.

Plioplatecarpinae was given a phylogenetic definition by Jack Conrad in 2008 as "all taxa sharing a more recent common ancestor with Plioplatecarpus marshi than with Tylosaurus proriger or Mosasaurus hoffmanni".

Polcyn and Bell (2005, p. 322[10]) have erected a more inclusive clade, the parafamily Russellosaurina, which includes the "subfamilies Tylosaurinae and Plioplatecarpini and their sister-clade containing the genera Tethysaurus, Russellosaurus, and Yaguarasaurus."

The cladogram below follows Simões et al. (2017)[11] Angolasaurus bocagei Selmasaurus johnsoni Ectenosaurus clidastoides Plesioplatecarpus planifrons Latoplatecarpus willistoni Platecarpus tympaniticus Plioplatecarpus In their 2024 description of the Moroccan plioplatecarpine Khinjaria, Longrich et al. performed a phylogenetic analysis, finding support for a clade of non-plioplatecarpin plioplatecarpines, named the Selmasaurini, which was recovered as the sister taxon to Plioplatecarpini.