Early Cretaceous first appearances

Tarpon are fish of the genus Megalops. They are the only extant members of the family Megalopidae. Of the two species, one (M. atlanticus) is native to the Atlantic, and the other (M. cyprinoides) to the Indo-Pacific Oceans.

Peirosauridae is a Gondwanan family of mesoeucrocodylians that lived during the Cretaceous period. It was a clade of terrestrial crocodyliforms that evolved a rather dog-like skull, and were terrestrial carnivores. It was phylogenetically defined in 2004 as the most recent common ancestor of Peirosaurus and Lomasuchinae and all of its descendants. Lomasuchinae is a subfamily of peirosaurids that includes the genus Lomasuchus.

Uruguaysuchidae is a family of notosuchian crocodyliforms that lived in South America and Africa during the Cretaceous period. It was formally defined under the PhyloCode in 2024 as "the most inclusive clade containing Uruguaysuchus aznarezi but not Baurusuchus pachecoi, Peirosaurus torminni, Mahajangasuchus insignis, Notosuchus terrestris, and Crocodylus niloticus." Below is a modified cladogram that depicts the preferred reference phylogeny, chosen from Fernández Dumont et al. (2020):

Hylaeochampsidae is an extinct family of basal eusuchian crocodylomorphs thought to be closely related to the order Crocodylia.

thumb|160px|right|Fossil specimen of Jeholodens jenkinsi, [[National Museum of Nature and Science, Tokyo]]

Polyglyphanodontia, also known as the Borioteiioidea, is an extinct clade of Cretaceous lizards. Polyglyphanodontians were the dominant group of lizards in North America and Asia during the Late Cretaceous.

Asioryctitheria ("Asian digging beasts") is an extinct order of early eutherians.

Lycoptera is an extinct genus of fish that lived from Lower Cretaceous, Barremian to Aptian in present-day China, North Korea, Mongolia and Siberia. Although there is record from Jurassic Formation in Siberia, its age remains questionable. It is known from abundant fossils representing sixteen species, which serve as important index fossil used to date geologic formations in China. Along with the genus Peipiaosteus, Lycoptera has been considered a defining member of the Jehol Biota, a prehistoric ecosystem famous for its feathered dinosaurs, which flourished for 20 million years during the Ear

Gobiosuchidae is a family of Cretaceous crocodyliforms known from Mongolia and Spain.