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Callao Man - Homo luzonensis
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Callao Man - Homo luzonensis

Temporal range: Late Pleistocene, 0.07–0.065 Ma 

Scientific classification
Kingdom:  Animalia
Phylum:  Chordata
Class:  Mammalia
Order:  Primates
Family:  Hominidae
Tribe:  Hominini
Genus:  Homo
Species:  Homo luzonensis  Détroit et al., 2019

Callao Man (Homo luzonensis; Ilocano: Tao ti Callao; Filipino: Taong Callao) refers to fossilized hominid remains discovered in Callao Cave, Peñablanca, Cagayan, Luzon in the Philippines in 2007 by Armand Salvador Mijares. Specifically, the initial find consisted of a single 61-millimeter metatarsal which, when dated using uranium series ablation, was found to be about 67,000 years old, dating to the Late Pleistocene.
In 2019, an article in the academic journal Nature 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 previous identified species in the genus Homo, including H. floresiensis and H. sapiens.

[Image: Homo_luzonensis-novataxa_2019-D%25C3%25A...0OVPAA.jpg]

Description
Although the initial theory 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. Therefore, the theory at present is that Callao Man and his contemporaries in Luzon arrived from Sundaland by raft.
The small size of the hominin's molars suggest that it may have undergone island dwarfing, similar to Homo floresiensis; the curvature of its digits suggest it climbed trees.
Butchered animal remains were also found in the same layer of sediment, which indicates that the Callao Man had a degree of knowledge in the use of tools, although no stone tools were found. The bones of the animals were from deer (Cervus mariannus), pigs, and an extinct type of cattle. Given that stone tools and butchered rhinos dating back to 700,000 years ago have been found in the area, this lineage may have been isolated on the island for nearly a million years.



New species of early human found in the Philippines


by The Australian National University

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CT scan and the structure of the right maxillary P3 - M2 of Homo luzonensis from Callao Cave Credit: Callao Cave Research Project

An international team of researchers have uncovered the remains of a new species of human in the Philippines, proving the region played a key role in hominin evolutionary history.
The new species, Homo luzonensis is named after Luzon Island, where the more than 50,000 year old fossils were found during excavations at Callao Cave.
Co-author and a lead member of the team, Professor Philip Piper from The Australian National University (ANU) says the findings represent a major breakthrough in our understanding of human evolution across Southeast Asia.
The researchers uncovered the remains of at least two adults and one juvenile within the same archaeological deposits.
"The fossil remains included adult finger and toe bones, as well as teeth. We also recovered a child's femur. There are some really interesting features – for example, the teeth are really small," Professor Piper said.
"The size of the teeth generally, though not always, reflect the overall body-size of a mammal, so we think Homo luzonensiswas probably relatively small. Exactly how small we don't know yet. We would need to find some skeletal elements from which we could measure body-size more precisely.
"It's quite incredible, the extremities, that is the hand and feet bones are remarkably Australopithecine-like. The Australopithecines last walked the earth in Africa about 2 million years ago and are considered to be the ancestors of the Homogroup, which includes modern humans.
"So, the question is whether some of these features evolved as adaptations to island life, or whether they are anatomical traits passed down to Homo luzonensis from their ancestors over the preceding 2 million years."
While there are still plenty of questions around the origins of Homo luzonensis, and their longevity on the island of Luzon, recent excavations near Callao Cave produced evidence of a butchered rhinoceros and stone tools dating to around 700,000 years ago.
"No hominin fossils were recovered, but this does provide a timeframe for a hominin presence on Luzon. Whether it was Homo luzonensis butchering and eating the rhinoceros remains to be seen," Professor Piper said.



"It makes the whole region really significant. The Philippines is made up of a group of large islands that have been separated long enough to have potentially facilitated archipelago speciation. There is no reason why archaeological research in the Philippines couldn't discover several species of hominin. It's probably just a matter of time."
Homo luzonensis shares some unique skeletal features with the famous Homo floresiensis or 'the hobbit', discovered on the island of Flores to the south east of the Philippine archipelago.
In addition, stone tools dating to around 200,000 years ago have been found on the island of Sulawesi, meaning that ancient hominins potentially inhabited many of the large islands of Southeast Asia.

[Image: 5cadb06a48ee0.jpg]
Right Upper teeth of the individual CCH6, the type specimen of the new species Homo luzonensis. From left to right: two premolars and 3 molars, in lingual view. Credit: Callao Cave Archaeology Project

The project team was led by Dr. Armand Mijares of the University of the Philippines, and includes Dr. Florent Détroit of the National Museum of Natural History in Paris and researchers from the University of Bordeaux, Paul Sabatier University and the University of Poitiers in France, as well as Griffith University in Australia.
The research has been published in the journal Nature.

https://phys.org/news/2019-04-species-ea...pines.html



Journal Reference:

Florent Détroit, Armand Salvador Mijares, Julien Corny, Guillaume Daver, Clément Zanolli, Eusebio Dizon, Emil Robles, Rainer Grün and Philip J. Piper. 2019. A New Species of Homo from the Late Pleistocene of the Philippines. Nature. 568; 181–186. DOI: 10.1038/s41586-019-1067-9


Abstract
A hominin third metatarsal discovered in 2007 in Callao Cave (Northern Luzon, the Philippines) and dated to 67 thousand years ago provided the earliest direct evidence of a human presence in the Philippines. Analysis of this foot bone suggested that it belonged to the genus Homo, but to which species was unclear. Here we report the 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. These specimens display a combination of primitive and derived morphological features that is different from the combination of features found in other species in the genus Homo (including Homo floresiensis and Homo sapiens) and warrants their attribution to a new species, which we name Homo luzonensis. 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.

https://www.nature.com/articles/s41586-019-1067-9
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