''Pachylemur'' is an
extinct, giant lemur most closely related to the
ruffed lemur
The ruffed lemurs of the genus ''Varecia'' are strepsirrhine primates and the largest extant lemurs within the family Lemuridae. Like all living lemurs, they are found only on the island of Madagascar. Formerly considered to be a monotypic genus ...
s of
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''Varecia''. Two species are known, ''Pachylemur insignis'' and ''Pachylemur jullyi'', although there is some doubt as to whether or not they may actually be the same species. ''Pachylemur'' is sometimes referred to as the giant ruffed lemur, because although it and the living ruffed lemurs had similar teeth and skeletons, ''Pachylemur'' was more robust and as much as three to four times larger.
DNA studies have confirmed a
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
relationship between these two types of
lemur
Lemurs ( ) (from Latin ''lemures'' – ghosts or spirits) are Strepsirrhini, wet-nosed primates of the Superfamily (biology), superfamily Lemuroidea (), divided into 8 Family (biology), families and consisting of 15 genera and around 100 exist ...
. Like living ruffed lemurs, ''Pachylemur'' specialized in eating fruit, and was therefore an important
seed disperser
In Spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant.
Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...
, possibly for tree species with seeds too large for even ruffed lemurs to swallow. In the
spiny thickets of southwestern
Madagascar
Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...
, they were also likely to have dispersed seeds evolved to attach to fur and be carried away. Unlike ruffed lemurs, the fore- and hindlimbs of ''Pachylemur'' were nearly the same length, and therefore it was likely to be a slow, deliberate climber. However, both used
hindlimb suspension to reach fruit on small branches below them.
Like other lemurs, ''Pachylemur'' was only found on the island of Madagascar, and its
subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
remains have been found primarily at sites in the central and southwestern parts of the island. Fragmentary and indeterminate remains have also been found in northern Madagascar. ''Pachylemur'' once lived in diverse lemur
communities
A community is a Level of analysis, social unit (a group of living things) with commonality such as place (geography), place, Norm (social), norms, religion, values, Convention (norm), customs, or Identity (social science), identity. Communiti ...
within its range, but in many of these locations, 20% or fewer of the original lemur species remain. ''Pachylemur'' went into decline following the arrival of humans in Madagascar around 350
BCE
Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the or ...
.
Habitat loss
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
,
forest fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...
, and
bushmeat
Bushmeat is meat from wildlife species that are hunted for human consumption, most often referring to the meat of game in Africa. Bushmeat represents
a primary source of animal protein and a cash-earning commodity for inhabitants of humid tropi ...
hunting are thought to have been the reasons for its disappearance. ''Pachylemur'' is thought to have gone
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
between 680–960
CE, although subfossil remains found in a cave pit in southwestern Madagascar may indicate that it survived up until 500 years ago.
''Pachylemur'' remains were first described in 1895 by French zoologist
Henri Filhol Henri Filhol
Henri Filhol (13 May 1843 – 28 April 1902) was a French medical doctor, malacologist and naturalist born in Toulouse. He was the son of Édouard Filhol (1814-1883), curator of the Muséum de Toulouse.
After receiving his early e ...
and were originally included in the genus ''Lemur'', along with the
ring-tailed lemur
The ring-tailed lemur (''Lemur catta'') is a large strepsirrhine primate and the most recognized lemur due to its long, black and white ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the ''Lemur'' ge ...
and other close relatives currently classified within the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Lemuridae
Lemuridae is a family of strepsirrhine primates native to Madagascar and the Comoros. They are represented by the Lemuriformes in Madagascar with one of the highest concentration of the lemurs. One of five families commonly known as lemurs. These ...
. In 1948, French
paleontologist
Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...
Charles Lamberton
Charles Lamberton (23 April 18768 October 1960) was a French paleontologist who lived and studied on the island of Madagascar between 1911 and 1948 and specialized in the recently extinct subfossil lemurs. He made significant contributions towa ...
placed the species in the
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
''Pachylemur'', which was recognized as a genus by 1979. However, due to earlier uses of the name ''Pachylemur'', the
priority of an alternative genus name proposed by
Guillaume Grandidier
Guillaume Grandidier (1 July 1873 – 13 September 1957) was a French geographer, ethnologist, zoologist who studied the island of Madagascar.
He was the son of the wealthy industrialist Alfred Grandidier also a zoologist and expert on Madagasca ...
in 1905, and errors in Lamberton's 1948 description of the genus, the
availability
In reliability engineering, the term availability has the following meanings:
* The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at a ...
of the name under the rules of
zoological nomenclature
The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the In ...
was considered questionable. In 2011, a petition was filed with the
International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries.
Orga ...
to preserve the name.
Evolutionary history
''Pachylemur'' was similar to but significantly larger and more robust than living
ruffed lemur
The ruffed lemurs of the genus ''Varecia'' are strepsirrhine primates and the largest extant lemurs within the family Lemuridae. Like all living lemurs, they are found only on the island of Madagascar. Formerly considered to be a monotypic genus ...
s (
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''Varecia''). In addition to their general
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
* Morphology (archaeology), study of the shapes or forms of artifacts
* Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...
, studies of their teeth (
dental anatomy
Dental anatomy is a field of anatomy dedicated to the study of human tooth structures. The development, appearance, and classification of teeth fall within its purview. (The function of teeth as they contact one another falls elsewhere, under den ...
) also suggest a close relation. In 1953,
William Charles Osman Hill
Dr William Charles Osman Hill FRSE FZS FLS FRAI (13 July 1901 – 25 January 1975) was a British anatomist, primatologist, and a leading authority on primate anatomy during the 20th century. He is best known for his nearly completed eight-vol ...
noted that the skull of both ''P. insignis'' and ''P. jullyi'' (then called ''Lemur insignis'' and ''L. jullyi'') resembled that of ruffed lemurs more so than the rest of the
lemurs classified in the genus ''Lemur'' at that time.
Because of the similarities, ''Pachylemur'' is sometimes referred to as a giant ruffed lemur. In addition to the morphological similarities,
molecular studies also support a close relationship. Based on studies of their
DNA, ''Pachylemur'' and ruffed lemurs form the
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and t ...
relative to the rest of the lemurs in the family
Lemuridae
Lemuridae is a family of strepsirrhine primates native to Madagascar and the Comoros. They are represented by the Lemuriformes in Madagascar with one of the highest concentration of the lemurs. One of five families commonly known as lemurs. These ...
. This sister group itself forms a sister group with the
clade
A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
(related group) containing
brown lemurs (''Eulemur''), the
ring-tailed lemur
The ring-tailed lemur (''Lemur catta'') is a large strepsirrhine primate and the most recognized lemur due to its long, black and white ringed tail. It belongs to Lemuridae, one of five lemur families, and is the only member of the ''Lemur'' ge ...
(''Lemur''), the
greater bamboo lemur
The greater bamboo lemur (''Hapalemur simus''), also known as the broad-nosed bamboo lemur and the broad-nosed gentle lemur, is a species of lemur endemic to the island of Madagascar.
Taxonomy
Originally described as ''Hapalemur (Prolemur) s ...
(''Prolemur''), and the lesser
bamboo lemur
The bamboo lemurs or gentle lemurs are the lemurs in genus ''Hapalemur''. These medium-sized primates live exclusively on Madagascar.
Etymology
Bamboo lemurs were first described by French zoologist Isidore Geoffroy Saint-Hilaire in 1851. Compar ...
s (''Hapalemur'').
Taxonomic classification
French zoologist
Henri Filhol Henri Filhol
Henri Filhol (13 May 1843 – 28 April 1902) was a French medical doctor, malacologist and naturalist born in Toulouse. He was the son of Édouard Filhol (1814-1883), curator of the Muséum de Toulouse.
After receiving his early e ...
was the first to scientifically describe a species of ''Pachylemur''; he named ''Lemur insignis'' and ''Lemur intermedius'' in 1895 on the basis of a few
subfossil
A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...
bones. Descriptions of other species now placed in ''Pachylemur'' quickly followed. In 1899,
Guillaume Grandidier
Guillaume Grandidier (1 July 1873 – 13 September 1957) was a French geographer, ethnologist, zoologist who studied the island of Madagascar.
He was the son of the wealthy industrialist Alfred Grandidier also a zoologist and expert on Madagasca ...
named a new
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
and species, ''Palaeochirogalus jullyi'', on the basis of two teeth from
Antsirabe
Antsirabe () is the third largest city in Madagascar and the capital of the Vakinankaratra region, with a population of 265,018 in 2014.
In Madagascar, Antsirabe is known for its relatively cool climate (like the rest of the central region), it ...
, central Madagascar, which he thought similar to
dwarf lemur
The dwarf lemurs are the lemurs of the genus ''Cheirogaleus''. All of the species in this genus, like all other lemurs, are native to Madagascar.
Description
Measuring 19–27 cm in body length with a tail about 16–17 cm, they are ...
s (''Cheirogaleus''). In 1903,
Grafton Elliot Smith
Sir Grafton Elliot Smith (15 August 1871 – 1 January 1937) was an Australian-British anatomist, Egyptologist and a proponent of the hyperdiffusionist view of prehistory. He believed in the idea that cultural innovations occur only once and ...
placed this species in the genus ''Lemur'' (as ''Lemur jullyi''), and in 1905, Grandidier himself considered the species a
synonym
A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...
of ''Lemur insignis''.
Meanwhile, in 1904,
Herbert F. Standing
Herbert Fox Standing (5 July 1857 – 24 December 1943) was an English paleontologist and Quaker medical missionary in Madagascar. He was the author of the book ''The Children of Madagascar'' (1887) and the Headmaster of the Boys' High School of ...
had named a different species using the same name, ''Lemur jullyi'', and named another species ''Lemur maziensis''. He noted similarities between this group and the ruffed lemurs, then considered a single species, ''Lemur varius''. In 1908, Standing named another species in the group, ''Lemur majori'', and included his ''Lemur maziensis'' in ''L. jullyi''. The name ''Pachylemur'' was introduced for these animals in 1948 by
Charles Lamberton
Charles Lamberton (23 April 18768 October 1960) was a French paleontologist who lived and studied on the island of Madagascar between 1911 and 1948 and specialized in the recently extinct subfossil lemurs. He made significant contributions towa ...
, who grouped ''Lemur insignis'', ''Lemur majori'', and ''Lemur jullyi'' in a
subgenus
In biology, a subgenus (plural: subgenera) is a taxonomic rank directly below genus.
In the International Code of Zoological Nomenclature, a subgeneric name can be used independently or included in a species name, in parentheses, placed between t ...
of the genus ''Lemur''.
Since 1979, ''Pachylemur'' has generally been regarded as a distinct genus, but some classifications include the genus in ''Lemur'' or the ruffed lemur genus ''Varecia''. In a 1982 review,
Ian Tattersall
Ian Tattersall (born 1945) is a British-born American paleoanthropologist and a curator emeritus with the American Museum of Natural History in New York City, New York. In addition to human evolution, Tattersall has worked extensively with lemur ...
recognized two species, ''Lemur insignis'' and ''Lemur jullyi''. He did not regard ''Pachylemur'' as a distinct genus or even subgenus. As Tattersall noted, ''Lemur jullyi'' Standing, 1904, is
preoccupied
The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently.
* In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linn ...
by ''Palaeochirogalus jullyi'' Grandidier, 1899, and thus
invalid
Invalid may refer to:
* Patient, a sick person
* one who is confined to home or bed because of illness, disability or injury (sometimes considered a politically incorrect term)
* .invalid, a top-level Internet domain not intended for real use
As t ...
. However, both names are based on material from the central plateau of Madagascar and Tattersall therefore presumed that they belong to the same species, which he could continue to call ''Lemur jullyi''. Recent classifications recognize ''Pachylemur'' as a valid genus with two species—''P. insignis'' (Filhol, 1895) and ''P. jullyi'' (Grandidier, 1899)—but express doubt about the distinction between the two species.
There are several
nomenclatural
Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. The principles of naming vary from the relatively informal conventions of everyday speech to the internationally ag ...
problems with the current use of the name ''Pachylemur''. First, Filhol had himself used the name ''Pachylemur'' in 1874 for a group of primitive primates, including ''
Adapis
''Adapis'' is an extinct adapiform primate from the Eocene of Europe. While this genus has traditionally contained five species (''A. magnus, A. bruni, A. collinsonae, A. parisiensis,'' and ''A. sudrei''), recent research has recognized at least ...
'', that he considered intermediate between
pachyderms and lemurs. Several other authors mentioned this name in the 19th and early 20th centuries, but it is questionable that any rendered the name
available
In reliability engineering, the term availability has the following meanings:
* The degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at a ...
under the rules of
zoological nomenclature
The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the In ...
. Still, this name potentially renders ''Pachylemur'' Lamberton, 1948, invalid under the
Principle of Homonymy. In addition, the generic name ''Palaeochirogalus'' Grandidier, 1899, predates ''Pachylemur'' Lamberton, 1948, by half a century and thus takes precedence under the
Principle of Priority
270px, '' valid name.
Priority is a fundamental principle of modern botanical nomenclature and zoological nomenclature. Essentially, it is the principle of recognising the first valid application of a name to a plant or animal. There are two asp ...
, and ''Pachylemur'' Lamberton is itself unavailable because Lamberton failed to select a
type species
In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...
. To conserve the name ''Pachylemur'', Jelle Zijlstra,
Colin Groves
Colin Peter Groves (24 June 1942 – 30 November 2017) was a British-Australian biologist and anthropologist. Groves was Professor of Biological Anthropology at the Australian National University in Canberra, Australia.
Education
Born in Englan ...
, and Alex Dunkel submitted a petition to the
International Commission on Zoological Nomenclature
The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries.
Orga ...
in 2011. The petition asks the Commission to suppress the names ''Pachylemur'' Filhol, 1874, ''Pachylemur'' Palmer, 1904 (based on Filhol's name), and ''Palaeochirogalus'' Grandidier, 1899, and to make ''Pachylemur'' Lamberton, 1948, retroactively available with ''Lemur insignis'' as its type species.
Anatomy and physiology
''Pachylemur'' resembled the living ruffed lemurs but was three or four times larger, with an estimated body mass of for ''P. insignis'' and for the larger ''P. jullyi''. In addition, the skeleton is more robust.
![Pachylemur insignis skull 001](https://upload.wikimedia.org/wikipedia/commons/6/68/Pachylemur_insignis_skull_001.jpg)
The
dental formula
Dentition pertains to the development of teeth and their arrangement in the mouth. In particular, it is the characteristic arrangement, kind, and number of teeth in a given species at a given age. That is, the number, type, and morpho-physiolo ...
is , as in all
lemurids. The
toothcomb
A toothcomb (also tooth comb or dental comb) is a dental structure found in some mammals, comprising a group of front teeth arranged in a manner that facilitates grooming, similar to a hair comb. The toothcomb occurs in lemuriform primates ( ...
—a comblike structure formed by the lower front teeth, characteristic of lemurs and
lorisoids—is similar to that of other lemurids. The two halves of the
mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower tooth, teeth in place. The mandible sits beneath the maxilla. It is the only movabl ...
(lower jaw) do not fuse at the
mandibular symphysis
In human anatomy, the facial skeleton of the skull the external surface of the mandible is marked in the median line by a faint ridge, indicating the mandibular symphysis (Latin: ''symphysis menti'') or line of junction where the two lateral halves ...
. However, there are some differences in tooth morphology from the living brown and ring-tailed lemurs, similar to those between the ruffed lemurs and the other genera. In ''Pachylemur'', the
talonid
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 ...
basin (a basin at the back end of the lower
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 ...
) is more elongate, and it is not lined by an
entoconid
Many different terms have been proposed for features of the tooth crown in mammals.
The structures within the molars receive different names according to their position and morphology. This nomenclature was developed by Henry Fairfield Osborn i ...
cusp. In the first two upper molars, the
lingual cingulum (a shelf on the inner, or lingual, side of the tooth) is expanded towards the front. The two species differ in details of tooth morphology. ''P. insignis'' had narrower lower
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, and the buccal (outer) cusps on these teeth are located to the front of their lingual counterparts. Relative to the ruffed lemurs, ''Pachylemur'' has more massive jaws and larger molars.
The skull of ''Pachylemur'' is relatively broad, but the
orbit
In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a p ...
s (eye sockets) are smaller and oriented more towards the front than in the ruffed lemurs. In the
postcranial skeleton Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...
, the most distinctive traits of ''Pachylemur'' are found. It had shorter and more robust limbs than the ruffed lemurs, and the fore- and hindlimbs were closer in length (
intermembral index The intermembral index is a ratio used to compare limb proportions, expressed as a percentage. It is equal to the length of forelimbs (humerus plus radius) divided by the length of the hind limbs (femur plus tibia) multiplied by 100, otherwise writt ...
of approximately 97).
Compared to the
axial skeleton
The axial skeleton is the part of the skeleton that consists of the bones of the head and trunk (anatomy), trunk of a vertebrate. In the human skeleton, it consists of 80 bones and is composed of six parts; the human skull, skull (22 bones), als ...
of ruffed lemurs, the vertebrae of ''Pachylemur'' had shorter
vertebral bodies
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic ...
and the
spinous process
The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...
had less anticliny. The
head of its femur (thigh bone) was also relatively large. As of 2001, no bones of the
digits had been found for either species.
Behavior
Based on dental wear and the presence of
dental caries
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
, ''Pachylemur'' was likely a
fruit specialist, just like the closely related ruffed lemurs, but unlike most of the other
leaf-eating
In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (1 ...
,
extinct, giant lemurs of Madagascar. Although it primarily ate fruit, it may have supplemented its diet with leaves and other foliage seasonally. Its teeth were similar in appearance to that of ruffed lemurs, while its
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 ...
and uneven dental wear suggest that it ate fewer leaves and more hard fruits and stems than today's brown lemur species.
![Baobab 04](https://upload.wikimedia.org/wikipedia/commons/f/f7/Baobab_04.jpg)
Because it ate larger, harder, more fibrous fruits than ruffed lemurs, ''Pachylemur'' was likely an important
seed disperser
In Spermatophyte plants, seed dispersal is the movement, spread or transport of seeds away from the parent plant.
Plants have limited mobility and rely upon a variety of dispersal vectors to transport their seeds, including both abiotic vectors, ...
compared to the more folivorous extinct giant lemurs. Within the
spiny thickets of southwest Madagascar, only ''P. insignis'' and ''
Archaeolemur majori
''Archaeolemur'' ("ancient lemur" from Ancient Greek From Ancient Greek ἀρχαῖος (arkhaîos), "Ancient" + Modern Latin lemur, "lemur") is an extinct genus of subfossil lemurs known from the Holocene epoch of Madagascar. ''Archaeolemur'' i ...
'', a type of extinct
monkey lemur
The monkey lemurs or baboon lemurs (Archaeolemuridae) are a recently extinct family of lemurs known from skeletal remains from sites on Madagascar dated to 1000 to 3000 years ago.
The monkey lemur family is divided into two genera, ''Hadropith ...
, are suspected of having been large-seed dispersers, particularly for plants that use a form of
photosynthesis
Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored i ...
known as
C3 carbon fixation. The plants that may have depended on these giant extinct lemurs include ''
Adansonia
''Adansonia'' is a genus made up of eight species of medium-to-large deciduous trees known as baobabs ( or ). They are placed in the Malvaceae family, subfamily Bombacoideae. They are native to Madagascar, mainland Africa, and Australia.Tropic ...
'' (baobabs), ''
Cedrelopsis'', ''
Commiphora
The genus of the myrrhs, ''Commiphora'', is the most species-rich genus of flowering plants in the frankincense and myrrh family, Burseraceae. The genus contains approximately 190 species of shrubs and trees, which are distributed throughout th ...
'', ''
Delonix
''Delonix'' is a genus of flowering plants in the family Fabaceae, subfamily Caesalpinioideae. It contains trees that are native to Madagascar and East Africa. By far the best known species is the Royal Poinciana ('' D. regia'').
The name o ...
'', ''
Diospyros
''Diospyros'' is a genus of over 700 species of deciduous and evergreen trees and shrubs. The majority are native to the tropics, with only a few species extending into temperate regions. Individual species valued for their hard, heavy, dark tim ...
'', ''
Grewia
''Grewia'' is a large flowering plant genus in the mallow family Malvaceae, in the expanded sense as proposed by the Angiosperm Phylogeny Group. Formerly, Grewia was placed in either the family Tiliaceae or the Sparrmanniaceae. However, these ...
'', ''
Pachypodium
''Pachypodium'' is a genus of succulent spine-bearing trees and shrubs, native to Madagascar and Africa. It belongs to the family Apocynaceae.
Genus characteristics
All ''Pachypodium'' are succulent plants that exhibit, to varying degrees, the ...
'', ''
Salvadora'', ''
Strychnos
''Strychnos'' is a genus of flowering plants, belonging to the family Loganiaceae (sometimes Strychnaceae). The genus includes about 100 accepted species of trees and lianas, and more than 200 that are as yet unresolved. The genus is widely dis ...
'', ''
Tamarind
Tamarind (''Tamarindus indica'') is a Legume, leguminous tree bearing edible fruit that is probably indigenous to tropical Africa. The genus ''Tamarindus'' is monotypic taxon, monotypic, meaning that it contains only this species. It belongs ...
us'', and ''
Uncarina
''Uncarina'' is a genus of plant in the family Pedaliaceae found in Madagascar.
Etymology
The genera name is derived from the Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece, a country in Southern Europe:
*Greeks, a ...
''.
Black-and-white ruffed lemur
The black-and-white ruffed lemur (''Varecia variegata'') is an endangered species of ruffed lemur, one of two which are endemic to the island of Madagascar. Despite having a larger range than the red ruffed lemur, it has a much smaller populati ...
s can swallow seeds with a diameter up to , which is larger than any other living lemur. Having been more than twice as large, ''Pachylemur'' would have been capable of swallowing even larger seeds. In the case of baobabs, the fruits have large seeds surrounded by a nutritious pulp and may have required
seed dispersal through ingestion. In western Madagascar, the
genetic diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is dis ...
of ''
Commiphora guillaminii'' suggests it had more widespread seed dispersal in the past, but today shows signs of more localized diversity when compared to African
species within the same genus that have not lost their seed dispersers.
Many small trees and shrubs in the spiny thickets, such as
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 ...
''Uncarina'', conserve water by producing seeds with hooks and spines rather than fleshy fruits. These seeds attach themselves to the skin and fur of passing animals for dispersal, and are still dispersed by living lemur species as well as
introduced species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...
such as cattle. ''Pachylemur'' may also have helped disperse seeds in this fashion.
For many years,
palaeoanthropologists thought that ''Pachylemur'' was a
ground-dwelling lemur due to its robust
postcranial skeleton Postcrania (postcranium, adjective: postcranial) in zoology and vertebrate paleontology is all or part of the skeleton apart from the skull. Frequently, fossil remains, e.g. of dinosaurs or other extinct tetrapods, consist of partial or isolated sk ...
. Yet more recent analysis of its axial and
appendicular skeleton
The appendicular skeleton is the portion of the skeleton of vertebrates consisting of the bones that support the appendages. There are 126 bones. The appendicular skeleton includes the skeletal elements within the limbs, as well as supporting shou ...
—particularly the vertebrae and femur—suggests that it was a tree-dweller (
arboreal
Arboreal locomotion is the Animal locomotion, locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally, but others are exclusively arboreal. Th ...
). Like the ruffed lemurs, ''Pachylemur'' was also an arboreal
quadruped
Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor' ...
that frequently exhibited
hindlimb suspension in order to reach fruit and leaves on smaller branches. However, ''Pachylemur'' was a slow, deliberate climber unlike the ruffed lemurs, which leap and bound through the upper
canopy
Canopy may refer to:
Plants
* Canopy (biology), aboveground portion of plant community or crop (including forests)
* Canopy (grape), aboveground portion of grapes
Religion and ceremonies
* Baldachin or canopy of state, typically placed over an a ...
. Like both the living and extinct lemurs, ''Pachylemur'' likely conserved energy because of its diet, small brain, and slow climbing.
Because its eyes were comparable in size to those of modern day-living (
diurnal) lemurs, ''Pachylemur'' was probably diurnal as well, as were most of the giant, extinct lemurs. However, compared to similarly sized
anthropoid
Anthropoid means 'ape/human feature' and may refer to:
* Simian, monkeys and apes (anthropoids, or suborder Anthropoidea, in earlier classifications)
*Anthropoid apes - apes that are closely related to humans (e.g., former family Pongidae and some ...
primates, its
visual acuity
Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal ...
was relatively poor.
Distribution and habitat
The subfossil remains of ''Pachylemur'' have been found in all
regions of Madagascar
Madagascar is divided into 23 regions (''faritra''). These formerly second-tier administrative divisions became first-level administrative divisions when the former six provinces were dissolved on 4 October 2009.
Elections
Elections for the ...
, except in the
eastern rainforests where no
subfossil sites are known. The two species are typically found in the
spiny thickets and
succulent woodlands of southern/southwestern Madagascar (''P. insignis'') and the
subhumid forests of the
central highlands (''P. jullyi''), although other indeterminate or fragmentary remains have been discovered at Ankilitelo Cave in southwestern Madagascar, as well as in the
dry deciduous forests at
Amparihingidro in the northwest (possibly ''P. insignis'') and
Ankarana
Ankarana Special Reserve in northern Madagascar was created in 1956. It is a small, partially vegetated plateau composed of 150-million-year-old middle Jurassic limestone. With an average annual rainfall of about , the underlying rocks have been e ...
in the northern tip of the island (possibly ''P. jullyi'').
Subfossil sites with ''P. insignis'' include
Andolonomby, Beloha (near
Anavoha),
Bemafandry,
Andrahomana,
Manombo-Toliara,
Ambolisatra,
Ambararata-Mahabo,
Ampoza-Ankazoabo,
Belo-sur-mer,
Lamboharana,
Taolambiby,
Tsiandroina, and
Tsirave in south and southwestern Madagascar. ''P. jullyi'' has been recorded at
Ampasambazimba
Ampasambazimba is a mountain peak and subfossil site in Madagascar, most known for being the site of the remains of the extinct giant sloth lemur ''Archaeoindris''.
Ampasambazimba is located at 1,036 meters above sea level. It was discovered i ...
,
Antsirabe
Antsirabe () is the third largest city in Madagascar and the capital of the Vakinankaratra region, with a population of 265,018 in 2014.
In Madagascar, Antsirabe is known for its relatively cool climate (like the rest of the central region), it ...
, and
Morarano-Betafo in the central highlands of Madagascar.
In general, lemur diversity has declined since the arrival of humans due to
habitat loss
Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...
,
forest fragmentation
Habitat fragmentation describes the emergence of discontinuities (fragmentation) in an organism's preferred environment (habitat), causing population fragmentation and ecosystem decay. Causes of habitat fragmentation include geological processes ...
, and
bushmeat
Bushmeat is meat from wildlife species that are hunted for human consumption, most often referring to the meat of game in Africa. Bushmeat represents
a primary source of animal protein and a cash-earning commodity for inhabitants of humid tropi ...
hunting. At some subfossil sites, ''Pachylemur'' lived alongside as many as 19 or 20 other lemur species, but now as few as 20% of those species remain in those areas.
Extinction
![Pachylemur insignis 7](https://upload.wikimedia.org/wikipedia/commons/3/35/Pachylemur_insignis_7.JPG)
Humans arrived in Madagascar around 350
BCE
Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian calendar), the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the or ...
, but did not cause the extinction of ''Pachylemur'' and the other giant lemurs immediately. Instead, many human-related factors, such as habitat loss, forest fragmentation, bushmeat hunting, and the introduction of invasive species, along with the gradual desiccation of certain parts of the island, caused their decline and eventual extinction over more than a millennium. The same factors threaten all
living lemur species today.
The initial decline of ''Pachylemur'' began within 500 years of human colonization, but prior to the establishment of large human settlements. Hunting in the Central Highlands and the spiny thickets likely caused a substantial drop in its population. Large lemurs, including ''Pachylemur'', survived in the Central Highlands, succulent woodlands, and spiny thickets until around 950 CE. Based on
radiocarbon dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon.
The method was dev ...
of subfossil remains collected as of 2010, the most recent remains of ''P. insignis'' out of 17 dated specimens came from Ankilibehandry in the succulent woodlands and dated between 680 and 780
CE. Of eight dated specimens, the most recent remains of ''P. jullyi'' came from Ampasambazimba in the Central Highlands and dated between 620 and 680 CE. ''Pachylemur'' is generally thought to have gone extinct between 680–960 CE, but remains of ''P. insignis'' have been found in Ankilitelo Cave (a pit cave in southwestern Madagascar), which is assumed to be less than 500 years old.
Notes
References
Literature cited
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{{Taxonbar, from=Q292027
Subfossil lemurs
Prehistoric primate genera
†Pachylemur
Holocene extinctions
Fossil taxa described in 1948