The new hominid, named Homo luzonensis after the island of Luzon, in the Philippines, where its bones were found, stood less than 4ft tall and probably still spent time swinging from trees.
In 2003, fossils of another island-dwelling species - Homo floresiensis, dubbed the "Hobbit" due to its diminutive size - were unearthed in a cave on the Indonesian island of Flores, some 3,000 km from the Luzon site.
Scientists have discovered a long-lost cousin of modern humans by analyzing fossil teeth and bones found in the Philippines.
Florent Détroit, of the Natural History Museum in Paris and the paper's first author, also said the discovery provided the latest challenge to the fairly straightforward prevalent narrative of human evolution. But he said the Philippines discovery gives new credence to an alternate view: Maybe some unknown creature other than H. erectus also slipped out of Africa and into Europe and Asia, and later gave rise to both island species.
This undated photo provided by the Callao Cave Archaeology Project in April 2019 shows the right upper teeth of the individual CCH6 of the newly discovered species Homo luzonensis.
There's no sign that H. luzonensis encountered any other member of the Homo group, Détroit said in an email.
"As for the fate of luzonensis, it is too early to say whether the spread of Homo sapiens into the region at least 50,000 years ago might have been a factor in its disappearance", he said.
But some human relative was on Luzon more than 700,000 years ago, as indicated by the presence of stone tools and a butchered rhino dating to that time, he said. It might have been the newfound species or an ancestor of it, he said in an email.
As per the Guardian, it was once thought that humans only left Africa about 1.5 million years ago, when a large-bodied ancient human called Homo erectus set off on a dispersal that ultimately allowed it to occupy territory spanning Africa and Spain, China and Indonesia.
"Arrival by accident ... is favored by many scholars, but this is mainly because of arguments like "Homo erectus were not clever enough to cross the sea on purpose", said Détroit.
H. erectus is generally considered the first Homo species to have expanded beyond Africa, and it plays a prominent role in the conventional wisdom about evolution outside that continent.
The discovery of Homo luzonensis "provides yet more evidence that hints that H. erectus might not have been the only globe-trotting early hominin", wrote Tocheri.
It also raises questions, including how the species arrived on the island and who its ancestors were.
After all, he said in an interview, remains of the hobbits and H. luzonensis show a mix of primitive and more modern traits that differ from what's seen in H. erectus.
Michael Petraglia of the Max Planck Institute for the Science of Human History in Jena, Germany, said the Luzon find "shows we still know very little about human evolution, particularly in Asia".