Maastrichtian first appearances

The southern frogs form the Leptodactylidae, a name that comes from Greek meaning a bird or other animal having slender toes. They are a diverse family of frogs that most likely diverged from other hyloids during the Cretaceous. The family has undergone major taxonomic revisions in recent years, including the reclassification of the former subfamily Eleutherodactylinae into its own family the Eleutherodactylidae; the Leptodactylidae now number 206 species in 13 genera distributed throughout Mexico, the Caribbean, and Central and South America. The family includes terrestrial, burrowing, aquati

The Ceratophryidae, also known as common horned frogs, are a family of frogs found in South America. It is a relatively small family with three extant genera and 12 species. Despite the common name, not all species in the family have the horn-like projections at the eyes. They have a relatively large head with big mouth, and they are ambush predators able to consume large prey, including lizards, other frogs, and small mammals. They inhabit arid areas and are seasonal breeders, depositing many small eggs in aquatic habitats. Tadpoles are free-living and carnivorous (Ceratophrys and Lepidobatra

Taeniodonta ("banded teeth") is an extinct order of eutherian mammals, that lived in North America and Europe from the late Cretaceous (Maastrichtian) to the middle Eocene. They were among the first mammals to evolve large body sizes (comparable to a modern wild boar or American black bear), as well as ever-growing teeth for eating tough plants.

Gondwanatheria is an extinct group of mammaliaforms that lived in parts of Gondwana, including Madagascar, India, South America, Africa, and Antarctica during the Upper Cretaceous through the Miocene (and possibly much earlier, if Allostaffia is a member of this group). Until recently, they were known only from fragmentary remains. They are generally considered to be closely related to the multituberculates and likely the euharamiyidians, well known from the Northern Hemisphere, with which they form the clade Allotheria.

Dyrosauridae is a family of extinct neosuchian crocodyliforms that lived from the Campanian to the Eocene. Dyrosaurid fossils are globally distributed, having been found in Africa, Asia, Europe, North America and South America. Over a dozen species are currently known, varying greatly in overall size and cranial shape. A majority were aquatic, some terrestrial and others fully marine (see locomotion below), with species inhabiting both freshwater and marine environments. Ocean-dwelling dyrosaurids were among the few marine reptiles to survive the Cretaceous–Paleogene extinction event.

Kogaionidae is a family of fossil mammals within the extinct order Multituberculata. Representatives are known from the Upper Cretaceous and the Paleocene of Europe. Having started as island endemics on Hațeg Island during the Upper Cretaceous, where they were in fact the dominant mammal group and diverged into rather unique ecological niches, they expanded across Europe in the Paleocene, where they briefly became a major component of its mammal fauna before their extinction. They are considered to be basal members of Cimolodonta.

Andinichthyidae is a prehistoric family of basal catfishes from the Cretaceous to Eocene of South America.