A partial "Ceratosaurus" specimen indicates the presence of the genus in the Portuguese Porto Novo Member of the Lourinhã Formation. Many of the dinosaurs of the Lourinhã Formation are the same genera as those seen in the Morrison Formation, or have a close counterpart. Besides "Ceratosaurus", the researchers also noted the presence of "Allosaurus" and "Torvosaurus" in the Portuguese rocks are primarily known from the Morrison, while "Lourinhanosaurus" has so far only been reported from Portugal. Herbivorous dinosaurs from the Porto Novo Member include, among others, the sauropods "Dinheirosaurus" and "Zby", as well as the stegosaur "Miragaia". During the Late Jurassic, Europe had just been separated from North America by the still narrow Atlantic Ocean, and Portugal, as part of the Iberian Peninsula, was still separated from other parts of Europe. According to Mateus and colleagues, the similarity between the Portuguese and North American theropod faunas indicates the presence of a temporary land bridge, allowing for faunal interchange. Malafaia and colleagues, however, argued for a more complex scenario, as other groups, such as sauropods, turtles, and crocodiles, show clearly different species compositions in Portugal and North America. Thus, the incipient separation of these faunas could have led to interchange in some but allopatric speciation in other groups.