New Zealand, and Antarctica, and the Neotropic shares many plant and animal lineages with these other continents, including marsupial mammals and the Antarctic flora. After the final breakup of the Gondwana about 110 million years ago, South America was separated from Africa and drifted north and west. 66 million years ago, the Cretaceous–Paleogene extinction event altered local flora and fauna. Much later, about two to three million years ago, South America was joined with North America by the formation of the Isthmus of Panama, which allowed a biotic exchange between the two continents, the Great American Interchange. South American species like the ancestors of the Virginia opossum (Didelphis virginiana) and the armadillo moved into North America, and North Americans like the ancestors of South America's camelids, including the llama (Lama glama), moved south. The long-term effect of the exchange was the extinction of many South American species, mostly by outcompetition by northern species. Endemic animals and plants Animals There are 31 bird families that are endemic to the Neotropical realm, over twice the number of any other realm. They include tanagers, rheas, tinamous, curassows, antbirds, ovenbirds, toucans, and seriemas. Bird families originally unique to the Neotropics include hummingbirds (family Trochilidae) and wrens (family Troglodytidae). Mammal groups originally unique to the Neotropics include: Order Xenarthra: anteaters, sloths, and armadillos New World monkeys Solenodontidae, the solenodons Caviomorpha rodents, including capybaras, guinea pigs, hutias and chinchillas American opossums (order Didelphimorphia) and shrew opossums (order Paucituberculata) There are 63 fish families and subfamilies are endemic to the Neotropical realm, more than any other realm. Neotropical fishes include more than 5,700 species, and represent at least 66 distinct lineages in continental freshwaters (Albert and Reis, 2011). The well-known red-bellied piranha is endemic to the Neotropic realm, occupying a larger geographic area than any other piranha species. Some fish groups originally unique to the Neotropics include: Order Gymnotiformes: Neotropical electric fishes Family Characidae: tetras and allies Family Loricariidae: armoured catfishes Subfamily Cichlinae: Neotropical cichlids Subfamily Poeciliinae: guppies and relatives Examples of other animal groups that are entirely or mainly restricted to the Neotropical region include: Caimans New World coral snakes Poison dart frogs Dactyloidae ("anoles") Rock iguanas (Cyclura) Preponini and Anaeini butterflies (including Agrias) Brassolini and Morphini butterflies (including Caligo and Morpho) Callicorini butterflies Heliconiini butterflies Ithomiini butterflies Riodininae butterflies Eumaeini butterflies Firetips or firetail skipper butterflies Euglossini bees Augochlorini bees Pseudostigmatidae ("giant damselflies") Mantoididae (short-bodied