Discoveries of new species continue to be reported regularly in scientific journals and the popular media, but how distinct are these new species from known species? In a new paper led by Deon Lum, a former research assistant in our lab, we explored this question for birds. We drew on multiple existing sources to build a robust avian phylogenetic tree, and explored how much each discovery of a new bird species over the last 250 years has added to our knowledge of phylogenetic diversity.
Our main finding is that newly discovered species are increasingly similar to known species. Around the turn of the 19th century, novel species discoveries included the Tawny Frogmouth and the Australian Owlet-nightjar, each of which represented a new taxonomic order and contributed roughly 60 Myr to known phylogenetic diversity at the time. In contrast, the most novel discoveries in recent decades have contributed only about 10% as much to our knowledge. One exception proves the rule: the discovery of the Udzungwa Forest Partridge in the 1990s was by far the most novel species in recent decades, but its novel contribution to known phylogenetic diversity was only about 20 Myr—one third that of the earliest decades’ most novel species. We conclude that our knowledge of the avian tree of life is mostly complete.
Deon recently moved to the UK, where he is starting his PhD in the Department of Earth and Environmental Sciences at the University of Manchester. The paper was also authored by Frank Rheindt of our department’s Avian Evolution Lab.