File:Latitudinal biogeographic vicariance hypothesis in chasmosaurines.png

English: "Figure 3. Latitudinal biogeographic vicariance hypothesis in chasmosaurines: maps based on Lillegraven & Ostresh 1990. (A) Ancestral population of basal chasmosaurines in Laramidia. (B) Marine transgression divides ancestral chasmosaurines. (C) Allopatric speciation occurs amongst chasmosaurines, evolving into a northern Chasmosaurus lineage (in blue) and a southern Pentaceratops lineage (in red). (D) Marine regression occurs, reuniting both lineages, resulting in faunal exchange. Chasmosaurus lineage, Vagaceratops irvinensis. Pentaceratops lineage, Chasmosaurus russeli, CMN 8800. (E) Lineages further evolve. Chasmosaurus lineage, Kosmoceratops richardsoni. Pentaceratops lineage, Utahceratops gettyi. (F) Marine transgression occurs, Chasmosaurus lineage becomes extinct, leaving no further record after Kosmoceratops. Pentaceratops lineage becomes cosmopolitan along Laramidian lowlands. (G) Marine regression occurs, a Pentaceratops lineage subpopulation moves north. (H) Marine transgression occurs, producing second latitudinal biogeographic vicariance event, resulting in allopatric speciation between the northern Pentaceratops lineage (in yellow) and southern Pentaceratops lineage (in orange). (I) Northern Pentaceratops lineage, Anchiceratops ornatus. Southern Pentaceratops lineage, Arrhinoceratops brachyops. Marine regression occurs, which reunites both lineages. (J) Further marine transgression expands the Laramidian lowlands. Lineages further evolve. Southern Pentaceratops lineage, Triceratops. This lineage becomes cosmopolitan along the subcontinent. Northern Pentaceratops lineage, Regaliceratops peterhewsi."