Temporal range: Late Pleistocene,
|CCH1, a 67,000 year old fossil third metatarsal bone attributed to Homo luzonensis.|
Détroit et al., 2019
Homo luzonensis is an extinct species of archaic humans in the genus Homo. In 2007, a third metatarsal bone (MT3) was discovered in Callao Cave, Luzon, Philippines by Philip J. Piper and initially identified as modern human by Florent Détroit. This find was dated using uranium series ablation to an age of 66,700 ± 1000 years before present, while associated faunal remains and a hominin tooth found in 2011 delivered dates of around 50,000 years ago.
In 2019, Florent Détroit et al. described the subsequent discovery of "twelve additional hominin elements that represent at least three individuals that were found in the same stratigraphic layer of Callao Cave as the previously discovered metatarsal" and identified the fossils as belonging to a newly discovered species, Homo luzonensis, on the basis of differences from previously identified species in the genus Homo. This included H. floresiensis and H. sapiens. However, some scientists think additional evidence is required to confirm the fossils as a new species, rather than a locally adapted population of other Homo populations, such as H. erectus or Denisovan.
Although the initial hypothesis of human migration to the Philippines proposed the use of land bridges during the last ice age, modern bathymetric readings of the Mindoro Strait and Sibutu Passage suggest that neither would have been fully closed (which correlates with the Philippines being biogeographically separated from Sundaland by the Wallace Line[note 1]) and a sea crossing has always been necessary to reach Luzon and other oceanic islands of the Philippines.
The small sizes of the hominins' molars suggest that it may have undergone island dwarfing, similar to H. floresiensis, although no estimate of its height is currently possible. An expert not associated with the study commented that the curvature of its digits suggests it may have climbed trees.
The fossil human remains were associated with the remains of deer (Cervus mariannus), wild pig, and an extinct bovine. Some of the animal bones exhibit potential cut marks, suggesting that they were butchered. Much earlier stone tools and the almost complete fossilized skeleton of a butchered rhinoceros dating back to c. 700,000 years ago were found by Thomas Ingicco and colleagues in the nearby San Pedro site in Rizal, Kalinga.
On May 5, 2007, a research team from the Philippines, France, and Australia discovered a third metatarsal bone during the excavation of Callao Cave. The morphological characteristics of the fossil were unequivocally classified as belonging to the genus Homo, making it the oldest evidence of the presence of the genus in the Philippines at the time. The scientific description of the fossil in 2010 identified the fossil as belonging to H. sapiens. In 2011, fossil phalanges from the finger and toe, along with five fossil molars, were discovered and were also attributed to H. sapiens.
In April 2019, in a study by Florent Détroit et al., the fossils were attributed to a distinct species of archaic human, dubbed Homo luzonensis. The fossils are currently housed in the National Museum of the Philippines.
The 2019 Nature article describing H. luzonensis noted that: "The presence of another and previously unknown hominin species east of the Wallace Line during the Late Pleistocene epoch underscores the importance of island Southeast Asia in the evolution of the genus Homo."