How little we know about Earth’s biodiversity from a 2017 discovery: At the time, experts working with Eric Mezarda described a new species of great apes from the island of Sumatra: the Tapanoli orangutan (Pongo tapanulinsis). And by no means is it just large vertebrate species that have been scientifically rediscovered in recent years. A study by Mario Maura and Walter Jetz in “Nature Ecology and Evolution” reported that the possibilities are currently greatest for discovering new terrestrial vertebrate species and for recording them taxonomically.
Not surprisingly, many of these hotspots can be found in well-known centers of biodiversity in the tropics. The northern Andes, the Atlantic rainforest of Brazil, the mountains of East Africa, the mountain rainforest of Madagascar, Indochina, and the islands of the Philippines and Indonesia as well as New Guinea are therefore the most beneficial destinations for explorers. Some recent new details have come from there. About a quarter of unknown species are distributed in four countries, two biologists write: Brazil and Colombia, Madagascar and Indonesia. And half the species probably live in tropical rainforests.
For their study, Maura and Jetz recorded data on the size, residence, distribution, and other properties of 32,000 terrestrial vertebrates in computer models. They then calculated how likely it is that a species with different combinations of traits has been discovered or is still to be discovered and where it is most likely to be the case. By the existence of known species, he said where the unknown species may be and what properties they may have. Large mammals with a large distribution area on land are therefore most likely already discovered on a large scale (for the exceptions seen above), while small frogs are not frequent in wooded mountain valleys in Colombia.
Two scientists therefore expect several new descriptions of small reptiles and amphibians over the next few years, rodents and bats in mammals, but also some primates. In birds, on the other hand, the number of undesirable species is small, and they are mainly distributed among small songbirds or owls. Surprisingly, it cannot be denied here: A single study from Indonesia in 2020 produced five newly recorded songbird species (and five subspecies) at once.
The study should not have only theoretical value. Many of the described areas are among the areas on Earth most affected by natural degradation. To record species from extinction – and to be able to protect them as best as possible – taxonomy should focus more on local ecosystems. For example, the Tapanoli orangutan may have been documented in time just before it disappeared: the reservoir may soon flood parts of its habitat.