''Homo luzonensis'', also locally called "Ubag" after a mythical caveman, is an extinct, possibly
pygmy
In anthropology, pygmy peoples are ethnic groups whose average height is unusually short. The term pygmyism is used to describe the phenotype of endemic short stature (as opposed to disproportionate dwarfism occurring in isolated cases in a pop ...
, species of
archaic human
A number of varieties of '' Homo'' are grouped into the broad category of archaic humans in the period that precedes and is contemporary to the emergence of the earliest early modern humans (''Homo sapiens'') around 300 ka. Omo-Kibish I (Omo I) f ...
from the
Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of ...
of
Luzon
Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as ...
, the Philippines. Their remains, teeth and
phalanges, are known only from
Callao Cave
Callao Cave () is one of 300 limestone caves located in the Barangays of Magdalo and Quibal in the municipality of Peñablanca, about northeast of Tuguegarao City, the capital of Cagayan province within the Peñablanca Protected Landscape and ...
in the northern part of the island dating to before 50,000 years ago. They were initially identified as belonging to modern humans in 2010, but in 2019, after the discovery of more specimens, they were placed into a new species based on the presence of a wide range of traits similar to modern humans as well as to ''
Australopithecus
''Australopithecus'' (, ; ) is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genus ''Homo'' (which includes modern humans) emerged within ''Australopithecus'', as sister to e.g. ''Austral ...
'' and early ''Homo''.
Their ancestors, who may have been Asian ''
H. erectus
''Homo erectus'' (; meaning "upright man") is an extinct species of archaic human from the Pleistocene, with its earliest occurrence about 2 million years ago. Several human species, such as '' H. heidelbergensis'' and '' H. antecessor' ...
'' or some other even earlier ''
Homo
''Homo'' () is the genus that emerged in the (otherwise extinct) genus ''Australopithecus'' that encompasses the extant species ''Homo sapiens'' ( modern humans), plus several extinct species classified as either ancestral to or closely relate ...
'', would have needed to have made a sea crossing of several miles at minimum to reach the island. Human presence on Luzon dates to at latest 771,000 to 631,000 years ago.
The inhabitants of the cave dragged in mainly
Philippine deer
The Philippine deer (''Rusa marianna''), also known as the Philippine sambar or Philippine brown deer, is a vulnerable deer species endemic to the Philippines. It was first described from introduced populations in the Mariana Islands, hence t ...
carcasses, and used tools for butchering.
Taxonomy
![Callao Cave](https://upload.wikimedia.org/wikipedia/commons/3/3c/Callao_Cave.jpg)
The first remains were discovered in 2007 in
Callao Cave
Callao Cave () is one of 300 limestone caves located in the Barangays of Magdalo and Quibal in the municipality of Peñablanca, about northeast of Tuguegarao City, the capital of Cagayan province within the Peñablanca Protected Landscape and ...
in Northern
Luzon
Luzon (; ) is the largest and most populous island in the Philippines. Located in the northern portion of the Philippines archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as ...
, the Philippines. In 2010, French anthropologist Florent Détroit and Filipino archaeologist
Armand Mijares and colleagues identified them as belonging to modern humans.
In 2019, after the discovery of 12 new specimens and based on the apparent presence of both modern-humanlike and primitive ''
Australopithecus
''Australopithecus'' (, ; ) is a genus of early hominins that existed in Africa during the Late Pliocene and Early Pleistocene. The genus ''Homo'' (which includes modern humans) emerged within ''Australopithecus'', as sister to e.g. ''Austral ...
''-like features, they reassigned the remains (and other
hominin
The Hominini form a taxonomic tribe of the subfamily Homininae ("hominines"). Hominini includes the extant genera ''Homo'' (humans) and '' Pan'' (chimpanzees and bonobos) and in standard usage excludes the genus ''Gorilla'' (gorillas).
The ...
findings from the cave) to a new species, ''Homo luzonensis'', the specific name deriving from the name of the island.
The
holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...
, CCH6, comprises the upper right
premolar
The premolars, also called premolar teeth, or bicuspids, are transitional teeth located between the canine and molar teeth. In humans, there are two premolars per quadrant in the permanent set of teeth, making eight premolars total in the mouth ...
s and
molars
The molars or molar teeth are large, flat teeth at the back of the mouth. They are more developed in mammals. They are used primarily to grind food during chewing. The name ''molar'' derives from Latin, ''molaris dens'', meaning "millstone to ...
. The
paratype
In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype nor a syntype). Of ...
s are: CCH1, a right
third metatarsal bone
The third metatarsal bone is a long bone in the foot. It is the second longest metatarsal. The longest being the second metatarsal. The third metatarsal is analogous to the third metacarpal bone in the hand
As the four other metatarsals bones it ...
of the foot; CCH2 and CCH5, two
phalanges of the fingers; CCH3 and CCH4, two phalanges of the foot; CCH4, a left premolar; and CCH9, a right third molar. CCH7 represents a juvenile
femoral shaft. These represent at least three individuals. The specimens are kept at the
National Museum of the Philippines
The National Museum of the Philippines ( fil, Pambansang Museo ng Pilipinas}) is an umbrella government organization that oversees a number of national museums in the Philippines including ethnographic, anthropological, archaeological, and vis ...
, Manila.
The exact taxonomic placement of ''H. luzonensis'' is unknown, and, like for other tropical hominins, DNA extraction failed.
It is possible that—like what is hypothesized for ''
H. floresiensis
''Homo floresiensis'' also known as "Flores Man"; nicknamed "Hobbit") is an extinct species of small archaic human that inhabited the island of Flores, Indonesia, until the arrival of modern humans about 50,000 years ago.
The remains of an ...
'' from
Flores
Flores is one of the Lesser Sunda Islands, a group of islands in the eastern half of Indonesia. Including the Komodo Islands off its west coast (but excluding the Solor Archipelago to the east of Flores), the land area is 15,530.58 km2, and th ...
, Indonesia—''H. luzonensis'' descended from an early ''
H. erectus
''Homo erectus'' (; meaning "upright man") is an extinct species of archaic human from the Pleistocene, with its earliest occurrence about 2 million years ago. Several human species, such as '' H. heidelbergensis'' and '' H. antecessor' ...
'' dispersal across Southeast Asia. It is also possible that these two insular archaic humans descend from an entirely different ''Homo'' species possibly earlier than ''H. erectus''.
[ The bones were dated to before 50,000 years ago,] and there is evidence of hominin activity on the island as early as 771,000 – 631,000 years ago.
Anatomy
Like other endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
fauna on Luzon, as well as ''H. floresiensis'', ''H. luzonensis'' may have shrunk in size due to insular dwarfism
Insular dwarfism, a form of phyletic dwarfism, is the process and condition of large animals evolving or having a reduced body size when their population's range is limited to a small environment, primarily islands. This natural process is disti ...
. However, more complete remains are needed to verify size. Much like ''H. floresiensis'', ''H. luzonensis'' presents a number of characteristics more similar to ''Australopithecus'' and early ''Homo'' than to modern humans and more recent ''Homo''.
The teeth of ''H. luzonensis'' are small and mesiodistally (the length between the two ends of the tooth) shortened. The molars are smaller than those of ''H. floresiensis''. Like other recent ''Homo'' and modern humans, the molars decrease in size towards the back of the mouth, and the enamel-dentin
Dentin () (American English) or dentine ( or ) (British English) ( la, substantia eburnea) is a calcified tissue of the body and, along with enamel, cementum, and pulp, is one of the four major components of teeth. It is usually covered by ena ...
juncture lacks well defined wavy crenulations. The enamel-dentine juncture is most similar to that of Asian ''H. erectus''. The premolars are oddly large compared to the molars, with more similar proportions to '' Paranthropus'' than any other ''Homo'', though ''H. luzonensis'' postcanine teeth differ greatly from those of ''Paranthropus'' in size and shape. ''H. luzonensis'' premolars share many characteristics with those of ''Australopithecus'', ''Paranthropus'', and early ''Homo''.
The finger bones are long, narrow, and curved, which is seen in ''Australopithecus'', ''H. floresiensis'', and sometimes modern humans. They are dorso-palmarly (from the palm to the back of the hand) compressed, and have well developed flexor sheath attachment, which are seen in ''Australopithecus'' and the early ''H. habilis
''Homo habilis'' ("handy man") is an extinct species of archaic human from the Early Pleistocene of East and South Africa about 2.31 million years ago to 1.65 million years ago (mya). Upon species description in 1964, ''H. habilis'' was highly c ...
''. Unique to ''H. luzonensis'', the dorsal beak near the knuckle was strongly developed and angled towards the wrist rather than the finger. The foot bones are morphologically unique among ''Homo'', and are more or less indistinguishable from those of '' A. africanus'' and '' A. afarensis''. ''Australopithecus'' limbs are generally interpreted as being adaptations for bipedalism
Bipedalism is a form of terrestrial locomotion where an organism moves by means of its two rear limbs or legs. An animal or machine that usually moves in a bipedal manner is known as a biped , meaning 'two feet' (from Latin ''bis'' 'double' a ...
and potentially suspensory behavior Suspensory behaviour is a form of arboreal locomotion or a feeding behavior that involves hanging or suspension of the body below or among tree branches. This behavior enables faster travel while reducing path lengths to cover more ground when trav ...
in the trees, but the fragmentary record of ''H. luzonensis'' limits extrapolation of locomotory behavior.
Since the remains are so fragmentary, it is difficult to make accurate estimates of actual size for this species, but they may have been within the range of modern day Philippine Negritos, who average in height for males and for females.
Culture
Because Luzon has always been an island in the Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
, the ancestors of ''H. luzonensis'' would have had to have made a substantial sea crossing over the Huxley Line.
About 90% of the bone fragments from Callao Cave belong to the Philippine deer
The Philippine deer (''Rusa marianna''), also known as the Philippine sambar or Philippine brown deer, is a vulnerable deer species endemic to the Philippines. It was first described from introduced populations in the Mariana Islands, hence t ...
, which suggests that deer carcasses were periodically brought into the cave. With the exception of Palawan
Palawan (), officially the Province of Palawan ( cyo, Probinsya i'ang Palawan; tl, Lalawigan ng Palawan), is an archipelagic province of the Philippines that is located in the region of Mimaropa. It is the largest province in the country in ...
(where there were tiger
The tiger (''Panthera tigris'') is the largest living cat species and a member of the genus '' Panthera''. It is most recognisable for its dark vertical stripes on orange fur with a white underside. An apex predator, it primarily preys on u ...
s), there is no evidence of large carnivores ever inhabiting the Philippines during the Pleistocene, which attributes these remains to human activity. The Philippine warty pig
The Philippine warty pig (''Sus philippensis'') is one of four known species in the pig genus ('' Sus'') endemic to the Philippines. The other three endemic species are the Visayan warty pig (''S. cebifrons''), Mindoro warty pig (''S. oliveri'') ...
and an extinct bovid
The Bovidae comprise the biological family of cloven-hoofed, ruminant mammals that includes cattle, bison, buffalo, antelopes, and caprines. A member of this family is called a bovid. With 143 extant species and 300 known extinct species, ...
were also present. There are cut marks on a deer tibia, and a lack of tools in the cave could either have resulted from the use of organic material for tools rather than stone, or the processing of meat away from the cave.
The Minori Cave, in the Cagayan Valley
Cagayan Valley ( ilo, Tanap ti Cagayan; fil, Lambak ng Cagayan), is an administrative region in the Philippines, located in the northeastern section of Luzon Island. It is composed of five Philippine provinces: Batanes, Cagayan, Isabela, ...
of northern Luzon (excavated much earlier) yielded an almost complete skeleton of a rhino (the extinct ''Rhinoceros philippinensis
''Nesorhinus philippinensis'' is a Pleistocene-aged species of rhinoceros endemic to the Philippine islands. Fossil remains were found in modern day Metro Manila and Kalinga. It is estimated to have weighed around or less than 800kg, or at leas ...
''), which had been butchered dating to 771–631,000 years ago. In 1981, six lithic core
In archaeology, a lithic core is a distinctive artifact that results from the practice of lithic reduction. In this sense, a core is the scarred nucleus resulting from the detachment of one or more flakes from a lump of source material or too ...
s, forty-nine lithic flake
In archaeology, a lithic flake is a "portion of rock removed from an objective piece by percussion or pressure,"Andrefsky, W. (2005) ''Lithics: Macroscopic Approaches to Analysis''. 2d Ed. Cambridge, Cambridge University Press and may also be refe ...
s, and two hammerstone
In archaeology, a hammerstone is a hard cobble used to strike off lithic flakes from a lump of tool stone during the process of lithic reduction. The hammerstone is a rather universal stone tool which appeared early in most regions of the wo ...
s, were found at Minori Cave, which are similar to the chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a prec ...
industry from the Lower Paleolithic
The Lower Paleolithic (or Lower Palaeolithic) is the earliest subdivision of the Paleolithic or Old Stone Age. It spans the time from around 3 million years ago when the first evidence for stone tool production and use by hominins appears in ...
Arubo 1 site in central Luzon. Also present were the remains of the elephant ''Stegodon
''Stegodon'' ("roofed tooth" from the Ancient Greek words , , 'to cover', + , , 'tooth' because of the distinctive ridges on the animal's molars) is an extinct genus of proboscidean, related to elephants. It was originally assigned to the fami ...
'', the Philippine deer, freshwater turtles, and monitor lizard
Monitor lizards are lizards in the genus ''Varanus,'' the only extant genus in the family Varanidae. They are native to Africa, Asia, and Oceania, and one species is also found in the Americas as an invasive species. About 80 species are recogn ...
s.
See also
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References
External links
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{{Good article
Hominini
Early species of Homo
Paleontology in the Philippines
Prehistory of the Philippines
History of Cagayan
2007 archaeological discoveries
Fossil taxa described in 2019