page_title: Pliosauroidea
section_title: Phylogeny
hierarchical_section_title: Pliosauroidea / Classification / Phylogeny
caption_attribution_description: Cast of "Plesiosaurus" macrocephalus fossil found by Mary Anning, Muséum national d'histoire naturelle, Paris.
context_page_description: Pliosauroidea is an extinct clade of marine reptiles. Pliosauroids, also commonly known as pliosaurs, are known from the Jurassic and Cretaceous periods. The pliosauroids were crocodile-like short-necked plesiosaurs with large heads and massive toothed jaws. They were sauropterygian swimming reptiles, and were not dinosaurs. They originally included only members of the family Pliosauridae, of the order Plesiosauria, but several other genera and families are now also included, the number and details of which vary according to the classification used.
  The distinguishing characteristics are a short neck and an elongated head, with larger hind flippers compared to the fore flippers, the opposite of the plesiosaurs. They were carnivorous and their long and powerful jaws carried many sharp, conical teeth. Pliosaurs range from 4 to 15 metres and more in length. Their prey may have included fish, sharks, ichthyosaurs, dinosaurs and other plesiosaurs.
  The largest known species are Kronosaurus and Pliosaurus macromerus; other well known genera include Rhomaleosaurus, Peloneustes, and Macroplata.
context_section_description: Pliosauroidea is a stem-based taxon that was defined by Welles as "all taxa more closely related to Pliosaurus brachydeirus than to Plesiosaurus dolichodeirus". Pliosauridae and Rhomaleosauridae are stem-based taxa too. Pliosauridae is defined as "all taxa more closely related to Pliosaurus brachydeirus than to Leptocleidus superstes, Polycotylus latipinnis or Meyerasaurus victor". Rhomaleosauridae is defined as "all taxa more closely related to Meyerasaurus victor than to Leptocleidus superstes, Pliosaurus brachydeirus or Polycotylus latipinnis". The cladogram below follows a 2011 analysis by paleontologists Hilary F. Ketchum and Roger B. J. Benson, and reduced to genera only.
caption: Cast of "Plesiosaurus" macrocephalus found by Mary Anning, Muséum national d'histoire naturelle, Paris
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