Researchers have identified a fossilized leg bone discovered in 2009 at Liang Bua cave on Flores Island as belonging to a new extinct megapode species. The bone, dated to 190,000 to 120,000 years ago, represents the first megapode fossil ever found in Wallacea, a biogeographic region spanning eastern Indonesia, Melanesia, the Philippines and Australia.
Hanneke Meijer, a professor and curator of osteology at the University Museum of Bergen, led the identification. The researchers named the species Megapodius rokusi after Rokus Due Awe, the individual who first recognized the bones of Homo floresiensis at the same cave site and later identified this fossil as a bird bone.
The leg bone came from one of Liang Bua's deepest layers, the same location that held the remains of H. floresiensis. Researchers compared the fossil to living and extinct megapode species and found it did not match any known species. Its toe joints differed in shape and position from other megapodes, and its size indicated M. rokusi was notably large for its genus.
M. rokusi weighed approximately 3.9 kilograms, making it the largest Megapodius ever found. Today's orange-footed scrubfowl, the current megapode species on Flores Island, weighs only 0.5 to 1.2 kilograms.
The study, published in Alcheringa: An Australasian Journal of Palaeontology, notes that without wing bones, it remains uncertain whether M. rokusi could fly. The fossil may have vanished around the same time as other extinct Liang Bua animals, including the giant stork, dwarf Stegodon, H. floresiensis and vultures, though an earlier extinction is also possible.
Meijer noted that bird fossils have been historically overlooked in favor of mammal bones and expects more megapode fossils remain undiscovered in Wallacea.