Highly simplified pterosaur phylogeny – topology based on that recovered by Unwin [<b>57</b>] – to show phylogenetic content of clade names used in the text.

<p>Caelidracones, Breviquartossa and Lophocratia are all node-based clades named by Unwin <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058451#pone.0058451-Unwin5" target="_blank">[57]</a>. Novialoidea is a node-based clade named by Kellner <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058451#pone.0058451-Kellner1" target="_blank">[56]</a>; it is essentially identical in content and definition to Unwin’s Longchognatha <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058451#pone.0058451-Unwin5" target="_blank">[57]</a>. Pterodactyloidea was defined by Unwin <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058451#pone.0058451-Unwin5" target="_blank">[57]</a> as the node-based <i>Pteranodon longiceps</i>+<i>Quetzalcoatlus northropi</i> clade but by Kellner <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058451#pone.0058451-Kellner1" target="_blank">[56]</a> as the <i>Pterodactylus antiquus</i>+<i>Quetzalcoatlus northropi</i> clade. Neither definition is satisfactory since neither ‘captures’ all taxa in all topologies. Pterosaur silhouettes provided by Mark Witton.