Hadropithecus
Encyclopedia
Hadropithecus is a medium-sized, extinct genus of lemur
, or strepsirrhine primate
, from Madagascar
that includes a single species, Hadropithecus stenognathus. Due to its rarity and lack of sufficient skeletal remains, it is one of the least understood of the extinct lemurs. Both it and Archaeolemur
are collectively known as "monkey lemur
s" or "baboon lemurs" due to body plan
s and dentition
that suggest a terrestrial
lifestyle and a diet similar to that of modern baboon
s. Hadropithecus had extended molars and a short, powerful jaw, suggesting that it was both a grazer
and a seed predator
.
The monkey lemurs are considered to be most closely related to the living indri
ids and the recently extinct sloth lemurs, although recent finds had caused some dispute over a possible closer relation to living lemurid
s. Genetic tests, however, have reaffirmed the previously presumed relationship. Hadropithecus lived in open habitat in the Central Plateau
, South, and Southwest regions of Madagascar. It is known only from subfossil
or recent remains and is considered to be a modern form of Malagasy lemur. It died out around 444–772 CE
, shortly after the arrival of humans on the island.
s" and "baboon lemurs", come from their dental and locomotor adaptations, which resemble that of modern African baboon
s. The genus Hadropithecus is derived from the Greek
words αδρος, hadros, meaning "stout" or "large", and πίθηκος, pithekos, meaning "ape". The species name derives from the Greek root στενο-, steno-, meaning "narrow", and γναθος, gnathos, meaning "jaw" or "mouth".
Archaeolemuridae. This family in turn belongs to the infraorder Lemuriformes, which includes all the Malagasy lemurs. The species was formally described in 1899 from a mandible
(lower jaw) found at Andrahomana cave in southeastern Madagascar by paleontologist Ludwig Lorenz von Liburnau, who thought it represented an ape
. A year later, Lorenz von Liburnau also described Pithecodon sikorae based on photographs of a skull, which upon further review turned out to be a juvenile version of Hadropithecus stenognathus. In a publication from 1902, he declared that Hadrophithecus stenognathus was not an ape, but a lemur. Over 100 years later, the rarity of its skeletal remains has made this species one of the least understood species of subfossil lemur
.
Based on similarities in their skull and teeth, it was later thought that monkey lemurs (Hadropithecus and Archaeolemur) were a sister group to the living indri
ids and the recently extinct sloth lemurs (family Palaeopropithecidae). However, there was some debate over whether the monkey lemurs or the sloth lemurs were more closely related to today's indriids. The monkey lemurs had skulls that more closely resembled the indriids, but their teeth were very specialized and unlike those of the indriids. The sloth lemurs, on the other hand, had teeth like the indriids, but very specialized skulls. The matter was settled with the discovery of new skeletons of Babakotia
and Mesopropithecus
, two genera of sloth lemur, both of which had indriid-like skulls and teeth. More recently, postcrania
l remains of Hadropithecus found in the early 2000s prompted the suggestion that the monkey lemurs were more closely related to the lemurid
s. However, DNA sequencing
has reaffirmed the sister group status of the monkey lemurs to indriids and sloth lemurs.
than a baboon. It may also have been less agile than Old World monkey
s. Both lemurs were quadrupedal (walked on four legs). There is no evidence of cursorial
ity (adaptations specifically for running) in either species, and although Hadropithecus could have climbed trees, it lacked adaptations for leaping or suspension
.
Although fewer postcranial remains have been discovered for Hadropithecus than for Archaeolemur, what has been found indicates that both were adapted for a terrestrial
or semi-terrestrial lifestyle, an unusual trait for lemurs. Both genera had short limbs and a powerful build. Due to its specialized dentition and likely diet, Hadropithecus is thought to have been the more terrestrial of the two, since Archaeolemur may have sent more time foraging and sleeping in the trees. Both genera also have shortened hands and feet, an adaptation for walking on the ground.
The face of Hadropithecus was shortened and adapted to heavy stress from chewing. The monkey lemurs had highly specialized teeth, but Hadropithecus went further by specializing in strong grinding. It had expanded molar
s that wore down quickly, much like those of ungulate
s, and its posterior premolars acted like molars to extend the grinding surface. It also had a robust mandible
to facilitate crushing hard objects. Even the strepsirrhine toothcomb
was reduced in this species. Its dental formula was
The skulls of both Hadropithecus and Archaeolemur indicate that monkey lemurs had relatively large brains compared to the other subfossil lemurs, with Hadropithecus having an estimated endocranial
volume of 115 ml.
, and it has been shown to be the only subfossil lemur to consume both C3
and C4
(or CAM) plants, an indication that it lived in more open habitats and had a varied diet. Its physiology and dentition
suggest that it may have been much like the Gelada Baboon
in locomotion and diet, acting as a manual grazer
(picking grass with the hands) since its teeth were well-adapted for grinding either grass or seeds. Microwear patterns on its teeth, as well as its overly large molars, indicate it processed hard objects like nuts or seeds, making it a seed predator
. More recent microwear analysis suggests differences between Gelada Baboons and Hadropithecus, indicating that this extinct lemur may not have been a grazer, but strictly a hard object processor.
, introduced pigs
, and spreading human populations than its more generalized cousin. The last known record was radiocarbon dated
to around 444–772 CE
.
Lemur
Lemurs are a clade of strepsirrhine primates endemic to the island of Madagascar. They are named after the lemures of Roman mythology due to the ghostly vocalizations, reflective eyes, and the nocturnal habits of some species...
, or strepsirrhine primate
Primate
A primate is a mammal of the order Primates , which contains prosimians and simians. Primates arose from ancestors that lived in the trees of tropical forests; many primate characteristics represent adaptations to life in this challenging three-dimensional environment...
, from Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
that includes a single species, Hadropithecus stenognathus. Due to its rarity and lack of sufficient skeletal remains, it is one of the least understood of the extinct lemurs. Both it and Archaeolemur
Archaeolemur
Archaeolemur is an extinct genus of lemurs that includes two species, Archaeolemur edwardsi and A. majori.The genus was widespread throughout Madagascar through much of the Holocene epoch, and its remains are often abundant at fossil sites across the island. The wide geographical and temporal range...
are collectively known as "monkey lemur
Monkey lemur
The Monkey lemurs or Baboon lemurs are an extinct type of lemurs that includes one family, Archaeolemuridae, two genera and three species. Despite their common names, members of Archaeolemuridae were not as closely related to monkeys as they were to other lemurs....
s" or "baboon lemurs" due to body plan
Body plan
A body plan is the blueprint for the way the body of an organism is laid out. An organism's symmetry, its number of body segments and number of limbs are all aspects of its body plan...
s and dentition
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...
that suggest a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
lifestyle and a diet similar to that of modern baboon
Baboon
Baboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. There are five species, which are some of the largest non-hominoid members of the primate order; only the mandrill and the drill are larger...
s. Hadropithecus had extended molars and a short, powerful jaw, suggesting that it was both a grazer
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
and a seed predator
Seed predation
Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores feed on the seeds of plants as a main or exclusive food source, in many cases leaving the seeds damaged and not viable...
.
The monkey lemurs are considered to be most closely related to the living indri
Indri
The indri , also called the babakoto, is one of the largest living lemurs. It is a diurnal tree-dweller related to the sifakas and, like all lemuroids, it is native to Madagascar.- Etymology :...
ids and the recently extinct sloth lemurs, although recent finds had caused some dispute over a possible closer relation to living lemurid
Lemuridae
Lemuridae is a family of prosimian primates native to Madagascar, and one of five families commonly known as lemurs. These animals were thought to be the evolutionary predecessors of monkeys and apes, but this is no longer considered correct...
s. Genetic tests, however, have reaffirmed the previously presumed relationship. Hadropithecus lived in open habitat in the Central Plateau
Central Highlands (Madagascar)
The Central Highlands, Central High Plateau, or Hauts-Plateaux are a mountainous biogeographical region in central Madagascar. They include the contiguous part of the island's interior above 800 m altitude...
, South, and Southwest regions of Madagascar. It is known only from subfossil
Subfossil
Subfossil refers to remains whose fossilization process is not complete, either for lack of time or because the conditions in which they were buried were not optimal for fossilization....
or recent remains and is considered to be a modern form of Malagasy lemur. It died out around 444–772 CE
Common Era
Common Era ,abbreviated as CE, is an alternative designation for the calendar era originally introduced by Dionysius Exiguus in the 6th century, traditionally identified with Anno Domini .Dates before the year 1 CE are indicated by the usage of BCE, short for Before the Common Era Common Era...
, shortly after the arrival of humans on the island.
Etymology
The common names that Hadropithecus shares with Archaeolemur, "monkey lemurMonkey lemur
The Monkey lemurs or Baboon lemurs are an extinct type of lemurs that includes one family, Archaeolemuridae, two genera and three species. Despite their common names, members of Archaeolemuridae were not as closely related to monkeys as they were to other lemurs....
s" and "baboon lemurs", come from their dental and locomotor adaptations, which resemble that of modern African baboon
Baboon
Baboons are African and Arabian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. There are five species, which are some of the largest non-hominoid members of the primate order; only the mandrill and the drill are larger...
s. The genus Hadropithecus is derived from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
words αδρος, hadros, meaning "stout" or "large", and πίθηκος, pithekos, meaning "ape". The species name derives from the Greek root στενο-, steno-, meaning "narrow", and γναθος, gnathos, meaning "jaw" or "mouth".
Classification and phylogeny
Hadropithecus stenognathus is classified as the sole member of the genus Hadropithecus and belongs to the familyFamily (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Archaeolemuridae. This family in turn belongs to the infraorder Lemuriformes, which includes all the Malagasy lemurs. The species was formally described in 1899 from a mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
(lower jaw) found at Andrahomana cave in southeastern Madagascar by paleontologist Ludwig Lorenz von Liburnau, who thought it represented an ape
Ape
Apes are Old World anthropoid mammals, more specifically a clade of tailless catarrhine primates, belonging to the biological superfamily Hominoidea. The apes are native to Africa and South-east Asia, although in relatively recent times humans have spread all over the world...
. A year later, Lorenz von Liburnau also described Pithecodon sikorae based on photographs of a skull, which upon further review turned out to be a juvenile version of Hadropithecus stenognathus. In a publication from 1902, he declared that Hadrophithecus stenognathus was not an ape, but a lemur. Over 100 years later, the rarity of its skeletal remains has made this species one of the least understood species of subfossil lemur
Subfossil lemur
Subfossil lemurs are lemurs from Madagascar that are represented by recent remains dating from nearly 26,000 years ago to approximately 560 years ago. They include both living and extinct species, although the term more frequently refers to the extinct giant lemurs...
.
Based on similarities in their skull and teeth, it was later thought that monkey lemurs (Hadropithecus and Archaeolemur) were a sister group to the living indri
Indri
The indri , also called the babakoto, is one of the largest living lemurs. It is a diurnal tree-dweller related to the sifakas and, like all lemuroids, it is native to Madagascar.- Etymology :...
ids and the recently extinct sloth lemurs (family Palaeopropithecidae). However, there was some debate over whether the monkey lemurs or the sloth lemurs were more closely related to today's indriids. The monkey lemurs had skulls that more closely resembled the indriids, but their teeth were very specialized and unlike those of the indriids. The sloth lemurs, on the other hand, had teeth like the indriids, but very specialized skulls. The matter was settled with the discovery of new skeletons of Babakotia
Babakotia
Babakotia is a medium-sized, extinct genus of lemur, or strepsirrhine primate, from Madagascar that contains a single species, Babakotia radofilai. Together with Palaeopropithecus, Archaeoindris, and Mesopropithecus, it forms the family Palaeopropithecidae, commonly known as the sloth lemurs...
and Mesopropithecus
Mesopropithecus
Mesopropithecus is an extinct genus of small to medium-sized lemur, or strepsirrhine primate, from Madagascar that includes three species, M. dolichobrachion, M. globiceps, and M. pithecoides. Together with Palaeopropithecus, Archaeoindris, and Babakotia, it is part of the sloth...
, two genera of sloth lemur, both of which had indriid-like skulls and teeth. More recently, postcrania
Postcrania
Postcrania[p] in zoology and vertebrate paleontology refers to all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g...
l remains of Hadropithecus found in the early 2000s prompted the suggestion that the monkey lemurs were more closely related to the lemurid
Lemuridae
Lemuridae is a family of prosimian primates native to Madagascar, and one of five families commonly known as lemurs. These animals were thought to be the evolutionary predecessors of monkeys and apes, but this is no longer considered correct...
s. However, DNA sequencing
DNA sequencing
DNA sequencing includes several methods and technologies that are used for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA....
has reaffirmed the sister group status of the monkey lemurs to indriids and sloth lemurs.
Anatomy and physiology
Hadropithecus stenognathus has been estimated to have weighed between 27 and 35 kg (59.5 and 77.2 lb) and to have been roughly as large as Archaeolemur, although more gracile. Newer subfossil finds, however, suggest that Hadropithecus may have been more robust, and more like a gorillaGorilla
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies...
than a baboon. It may also have been less agile than Old World monkey
Old World monkey
The Old World monkeys or Cercopithecidae are a group of primates, falling in the superfamily Cercopithecoidea in the clade Catarrhini. The Old World monkeys are native to Africa and Asia today, inhabiting a range of environments from tropical rain forest to savanna, shrubland and mountainous...
s. Both lemurs were quadrupedal (walked on four legs). There is no evidence of cursorial
Cursorial
Cursorial is a biological term that describes an organism as being adapted specifically to run. It is typically used in conjunction with an animal's feeding habits or another important adaptation. For example, a horse can be considered a "cursorial grazer", while a wolf may be considered a...
ity (adaptations specifically for running) in either species, and although Hadropithecus could have climbed trees, it lacked adaptations for leaping or suspension
Suspensory behavior
Suspensory Behavior, exhibited by primates, is a form of arboreal locomotion or a feeding behavior which involves hanging or suspension of the body below or among the branches, rather than moving or sitting on top of the branches...
.
Although fewer postcranial remains have been discovered for Hadropithecus than for Archaeolemur, what has been found indicates that both were adapted for a terrestrial
Terrestrial animal
Terrestrial animals are animals that live predominantly or entirely on land , as compared with aquatic animals, which live predominantly or entirely in the water , or amphibians, which rely on a combination of aquatic and terrestrial habitats...
or semi-terrestrial lifestyle, an unusual trait for lemurs. Both genera had short limbs and a powerful build. Due to its specialized dentition and likely diet, Hadropithecus is thought to have been the more terrestrial of the two, since Archaeolemur may have sent more time foraging and sleeping in the trees. Both genera also have shortened hands and feet, an adaptation for walking on the ground.
The face of Hadropithecus was shortened and adapted to heavy stress from chewing. The monkey lemurs had highly specialized teeth, but Hadropithecus went further by specializing in strong grinding. It had expanded molar
Molar (tooth)
Molars are the rearmost and most complicated kind of tooth in most mammals. In many mammals they grind food; hence the Latin name mola, "millstone"....
s that wore down quickly, much like those of ungulate
Ungulate
Ungulates are several groups of mammals, most of which use the tips of their toes, usually hoofed, to sustain their whole body weight while moving. They make up several orders of mammals, of which six to eight survive...
s, and its posterior premolars acted like molars to extend the grinding surface. It also had a robust mandible
Mandible
The mandible pronunciation or inferior maxillary bone forms the lower jaw and holds the lower teeth in place...
to facilitate crushing hard objects. Even the strepsirrhine toothcomb
Toothcomb
A toothcomb is an anatomical structure found in strepsirrhine primates, which includes lemurs, lorises and galagos. A toothcomb consists of long, flat forward-angled teeth, and includes the lower incisors and the canine teeth...
was reduced in this species. Its dental formula was
The skulls of both Hadropithecus and Archaeolemur indicate that monkey lemurs had relatively large brains compared to the other subfossil lemurs, with Hadropithecus having an estimated endocranial
Endocranium
For internal cast of the cranium, see Endocast.The endocranium in comparative anatomy is a part of the skull base in vertebrates and represent the basal, inner part of the cranium. The term is also applied to the outer layer of the dura mater in human anatomy.-Basic structure:Structurally, the...
volume of 115 ml.
Ecology
Like all other lemurs, Hadropithecus was endemic to Madagascar. Because it died out only recently and is only known from subfossil remains, it is considered to be a modern form of Malagasy lemur. It once ranged across the Central Plateau, South, and Southwest regions of Madagascar. Within its original range, there were few other lemurs to overlap its ecological nicheEcological niche
In ecology, a niche is a term describing the relational position of a species or population in its ecosystem to each other; e.g. a dolphin could potentially be in another ecological niche from one that travels in a different pod if the members of these pods utilize significantly different food...
, and it has been shown to be the only subfossil lemur to consume both C3
C3 carbon fixation
carbon fixation is a metabolic pathway for carbon fixation in photosynthesis. This process converts carbon dioxide and ribulose bisphosphate into 3-phosphoglycerate through the following reaction:...
and C4
C4 carbon fixation
C4 carbon fixation is one of three biochemical mechanisms, along with and CAM photosynthesis, used in carbon fixation. It is named for the 4-carbon molecule present in the first product of carbon fixation in these plants, in contrast to the 3-carbon molecule products in plants. fixation is an...
(or CAM) plants, an indication that it lived in more open habitats and had a varied diet. Its physiology and dentition
Dentition
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, the characteristic arrangement, kind, and number of teeth in a given species at a given age...
suggest that it may have been much like the Gelada Baboon
Gelada
The gelada , sometimes called the gelada baboon, is a species of Old World monkey found only in the Ethiopian Highlands, with large populations in the Semien Mountains...
in locomotion and diet, acting as a manual grazer
Grazing
Grazing generally describes a type of feeding, in which a herbivore feeds on plants , and also on other multicellular autotrophs...
(picking grass with the hands) since its teeth were well-adapted for grinding either grass or seeds. Microwear patterns on its teeth, as well as its overly large molars, indicate it processed hard objects like nuts or seeds, making it a seed predator
Seed predation
Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores feed on the seeds of plants as a main or exclusive food source, in many cases leaving the seeds damaged and not viable...
. More recent microwear analysis suggests differences between Gelada Baboons and Hadropithecus, indicating that this extinct lemur may not have been a grazer, but strictly a hard object processor.
Extinction
Because of the low number of subfossil finds, Hadropithecus is thought to have been rare, and it died out sooner than its sister taxon, Archaeolemur. Both disappeared shortly after the arrival of humans to the island, but being a large, specialized, terrestrial grazer, Hadropithecus would have faced more pressure from domestic livestockLivestock
Livestock refers to one or more domesticated animals raised in an agricultural setting to produce commodities such as food, fiber and labor. The term "livestock" as used in this article does not include poultry or farmed fish; however the inclusion of these, especially poultry, within the meaning...
, introduced pigs
PIGS
PIGS is a four letter acronym that can stand for:* PIGS , Phosphatidylinositol glycan anchor biosynthesis, class S, a human gene* PIGS , the economies of Portugal, Italy , Greece and Spain...
, and spreading human populations than its more generalized cousin. The last known record was radiocarbon dated
Radiocarbon dating
Radiocarbon dating is a radiometric dating method that uses the naturally occurring radioisotope carbon-14 to estimate the age of carbon-bearing materials up to about 58,000 to 62,000 years. Raw, i.e. uncalibrated, radiocarbon ages are usually reported in radiocarbon years "Before Present" ,...
to around 444–772 CE
Common Era
Common Era ,abbreviated as CE, is an alternative designation for the calendar era originally introduced by Dionysius Exiguus in the 6th century, traditionally identified with Anno Domini .Dates before the year 1 CE are indicated by the usage of BCE, short for Before the Common Era Common Era...
.