107-498: The Duke Lemur Center is a non-invasive research center housing over 200 lemurs and bush babies across 13 species. It is located at Duke University in Durham, North Carolina . According to the Center, it houses the most diverse population of lemurs outside of their native Madagascar . The center is open to the public through tours, for which visitors must make an appointment. In 1966,
214-435: A grooming claw on the second toe of each foot for scratching in areas that are inaccessible to the mouth and tongue. Adapiforms may have had a grooming claw, but there is little evidence of this. The toothcomb consists of either two or four procumbent lower incisors and procumbent lower canine teeth followed by a canine-shaped premolar . It is used to comb the fur during oral grooming. Shed hairs that accumulate between
321-488: A prehensile tail , a trait found only in New World monkeys , particularly atelids , among primates. Lemurs also rely heavily on their sense of smell, a trait shared with most other mammals and early primates, but not with the visually oriented higher primates. This sense of smell is important in terms of marking territory as well as provide an indication of whether or not another lemur is a viable breeding partner. Lemurs are
428-490: A prosimian colony of approximately 90 individuals, belonging to John Buettner-Janusch , was relocated from the Center for Prosimian Biology at Yale University to Duke University, creating the Duke Lemur Center ( DLC ). Through the 1970s, the colony grew to approximately 700 individuals representing 33 species. The current colony ranges between 200 and 250 animals, representing approximately 13 species. Originally called
535-493: A rhinarium (or "wet nose"); a fully functional vomeronasal organ , which detects pheromones ; a postorbital bar and the lack of postorbital closure (a wall of thin bone behind the eye); orbits (bony sockets that enclose the eye) that are not fully facing forward; left and right mandible (lower jaw) bones that are not fully fused; and a small brain-to-body mass ratio . Additional traits shared with other prosimian primates (strepsirrhine primates and tarsiers ) include
642-613: A toothcomb , a specialized set of teeth in the front, lower part of the mouth mostly used for combing fur during grooming . Many of today's living strepsirrhines are endangered due to habitat destruction , hunting for bushmeat , and live capture for the exotic pet trade. Both living and extinct strepsirrhines are behaviorally diverse, although all are primarily arboreal (tree-dwelling). Most living lemuriforms are nocturnal , while most adapiforms were diurnal . Both living and extinct groups primarily fed on fruit , leaves , and insects . The taxonomic name Strepsirrhini derives from
749-410: A bicornuate (two-horned) uterus and epitheliochorial placentation . Because their thumbs are only pseudo-opposable, making their movement less independent of the other fingers, their hands are less than perfect at grasping and manipulating objects. On their feet, they have a widely abducted hallux (first toe) which facilitates the grasping of tree limbs. A common misconception is that lemurs have
856-406: A central core which houses common resources like laboratories, exam rooms, food prep, bathrooms, and storage spaces. Both buildings are designed for low water and electricity use, and are LEED registered. The total cost of the two-buildings, designed by architects Lord, Aeck & Sargent of Chapel Hill, North Carolina , was $ 10.4 million. The children's television show Zoboomafoo , produced by
963-610: A cercamoniine, but also may have been a stem lemuriform. Azibiids from Algeria date to roughly the same time and may be a sister group of the djebelemurids . Together with Plesiopithecus from the late Eocene Egypt, the three may qualify as the stem lemuriforms from Africa. Molecular clock estimates indicate that lemurs and the lorisoids diverged in Africa during the Paleocene, approximately 62 mya. Between 47 and 54 mya, lemurs dispersed to Madagascar by rafting . In isolation,
1070-452: A different ocean gyre , producing currents that ran counter to what they are today. The ocean currents were shown to be even stronger than today, which would have pushed a raft along faster, shortening the trip to 30 days or less—short enough for a small mammal to survive easily. As the continental plates drifted northward, the currents gradually changed, and by 20 mya the window for oceanic dispersal had closed, effectively isolating
1177-479: A diverse group of primates in terms of morphology and physiology. Some lemurs, such as the sportive lemurs and indriids , have longer hind limbs than forelimbs , making them excellent leapers . Indriids also have a specialized digestive system for folivory , exhibiting enlarged salivary glands , a spacious stomach , and an elongated caecum (lower gut) that facilitates fermentation . The hairy-eared dwarf lemur ( Allocebus trichotis ) reportedly has
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#17328553901121284-439: A four-tooth toothcomb due to the loss of either a pair of canines or incisors. Because the lower canine is either included in the toothcomb or lost, the lower dentition can be difficult to read, especially since the first premolar (P2) is often shaped like a canine (caniniform) to fill the canine's role. In folivorous (leaf-eating) lemurs, except for indriids, the upper incisors are greatly reduced or absent. Used together with
1391-474: A functional strepsirrhine toothcomb. In the case of the aye-aye, the morphology of the deciduous incisors, which are lost shortly after birth, indicates that its ancestors had a toothcomb. These milk teeth are lost shortly after birth and are replaced by open-rooted, continually growing ( hypselodont ) incisors. The toothcomb in lemurs normally consists of six teeth (four incisors and two canines), although indriids, monkey lemurs, and some sloth lemurs only have
1498-487: A highly mobile, filiform (filament-shaped) middle finger for extracting food from tiny holes; large, bat -like ears for detecting hollow spaces within trees; and use of self-generated acoustical cues to forage. Lemurs are unusual since they have great variability in their social structure, yet generally lack sexual dimorphism in size and canine tooth morphology. However, some species tend towards having larger females, and two species of true lemur (genus Eulemur ),
1605-497: A more specialized and younger branch of adapiform primarily from Europe. Scandentia (treeshrews) Dermoptera (colugos) † Plesiadapiformes Simians Tarsiers † Omomyiformes † Adapiformes Lorisoids Lemurs Lemurs rafted from Africa to Madagascar between 47 and 54 mya, whereas the lorises split from the African galagos around 40 mya and later colonized Asia. The lemuriforms, and particularly
1712-435: A more thorough analysis. Lemurs vary greatly in size. They include the smallest primates in the world and, until recently, also included some of the largest. They currently range in size from about 30 g (1.1 oz) for Madame Berthe's mouse lemur ( Microcebus berthae ) up to 7–9 kg (15–20 lb) for the indri ( Indri indri ) and diademed sifaka ( Propithecus diadema ). One recently extinct species rivaled
1819-459: A new suborder, Simiolemuriformes, to suggest that strepsirrhines are more closely related to simians than tarsiers. However, no clear relationship between the two had been demonstrated by the early 2000s. The idea reemerged briefly in 2009 during the media attention surrounding Darwinius masillae (dubbed "Ida"), a cercamoniine from Germany that was touted as a " missing link between humans and earlier primates" (simians and adapiforms). However,
1926-655: A sister group to the living strepsirrhines. They are included in Strepsirrhini, and are considered basal members of the clade. Although their status as true primates is not questioned, the questionable relationship between adapiforms and other living and fossil primates leads to multiple classifications within Strepsirrhini. Often, adapiforms are placed in their own infraorder due to anatomical differences with lemuriforms and their unclear relationship. When shared traits with lemuriforms (which may or may not be synapomorphic) are emphasized, they are sometimes reduced to families within
2033-533: A smaller brain than comparably sized simians , large olfactory lobes for smell, a vomeronasal organ to detect pheromones , and a bicornuate uterus with an epitheliochorial placenta . Their eyes contain a reflective layer to improve their night vision , and their eye sockets include a ring of bone around the eye, but they lack a wall of thin bone behind it. Strepsirrhine primates produce their own vitamin C , whereas haplorhine primates must obtain it from their diets. Lemuriform primates are characterized by
2140-429: A specialized dental structure called a "toothcomb", with the exception of the aye-aye, in which the structure has been modified into two continually growing (hypselodont) incisors (or canine teeth ), similar to those of rodents . Often, the toothcomb is incorrectly used to characterize all strepsirrhines. Instead, it is unique to lemuriforms and is not seen among adapiforms. Lemuriforms groom orally, and also possess
2247-415: A very long tongue , allowing it to feed on nectar . Likewise, the red-bellied lemur ( Eulemur rubriventer ) has a feathery brush-shaped tongue, also uniquely adapted to feed on nectar and pollen. The aye-aye has evolved some traits that are unique among primates, making it stand out among the lemurs. Such traits include continuously growing, rodent-like front teeth for gnawing through wood and hard seeds;
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#17328553901122354-435: A wide variety of fruits and leaves, while some are specialists. Two species of lemurs may coexist in the same forest due to different diets. Lemur research during the 18th and 19th centuries focused on taxonomy and specimen collection. Modern studies of lemur ecology and behavior did not begin in earnest until the 1950s and 1960s. Initially hindered by political issues on Madagascar during the mid-1970s, field studies resumed in
2461-541: Is a suborder of primates that includes the lemuriform primates, which consist of the lemurs of Madagascar , galagos ("bushbabies") and pottos from Africa , and the lorises from India and southeast Asia . Collectively they are referred to as strepsirrhines. Also belonging to the suborder are the extinct adapiform primates which thrived during the Eocene in Europe, North America, and Asia, but disappeared from most of
2568-409: Is a synapomorphy (shared, derived trait) seen among lemuriforms, although it is frequently and incorrectly used to define the strepsirrhine clade. Strepsirrhine primates are also united in possessing an epitheliochorial placenta . Unlike the tarsiers and simians, strepsirrhines are capable of producing their own vitamin C and do not need it supplied in their diet. Further genetic evidence for
2675-551: Is a 14,922-square-foot (1,386.3 m) facility (including exterior animal runs) with 7,056 square feet (655.5 m) of interior space. It can house up to 60 animals that can be released into the 69-acre (28 ha) Duke Forest if weather permits. The second building was completed in 2010 and is a 20,637-square-foot (1,917.2 m) facility (including exterior animal runs) with 9,883 square feet (918.2 m) of interior space. Together, they are able to house 140 lemurs. The buildings are designed with animal housing wings radiating from
2782-655: Is basal to all Lemuriformes, and in 2008, Russell Mittermeier, Colin Groves, and others ignored addressing higher-level taxonomy by defining lemurs as monophyletic and containing five living families, including Daubentoniidae. Relationships among lemur families have also proven to be problematic and have yet to be definitively resolved. To further complicate the issue, several Paleogene fossil primates from outside Madagascar, such as Bugtilemur , have been classified as lemurs. However, scientific consensus does not accept these assignments based on genetic evidence, and therefore it
2889-595: Is generally accepted that the Malagasy primates are monophyletic. Another area of contention is the relationship between the sportive lemurs and the extinct koala lemurs (Megaladapidae). Formerly grouped in the same family due to similarities in dentition, they are no longer considered to be closely related due to genetic studies. More taxonomic changes have occurred at the genus level, although these revisions have proven more conclusive, often supported by genetic and molecular analysis. The most noticeable revisions included
2996-670: Is highest in the rainforests of the east coast. Despite their adaptations for weathering extreme adversity, habitat destruction and hunting have resulted in lemur populations declining sharply, and their diversity has diminished, with the recent extinction of at least 17 species in eight genera, known collectively as the subfossil lemurs . Most of the approximately 100 species and subspecies of lemur are either threatened or endangered. Unless trends change, extinctions are likely to continue. Until recently, giant lemurs existed on Madagascar. Now represented only by recent or subfossil remains, they were modern forms that were once part of
3103-516: Is now used in the colloquial sense in reference to all Malagasy primates. Lemur taxonomy is controversial, and not all experts agree, particularly with the recent increase in the number of recognized species. According to Russell Mittermeier , the president of Conservation International (CI), taxonomist Colin Groves , and others, there are nearly 100 recognized species or subspecies of extant (or living) lemur, divided into five families and 15 genera. Because genetic data indicates that
3210-506: Is smaller than that of anthropoid primates. As with all strepsirrhine primates, they have a "wet nose" ( rhinarium ). Lemurs are generally the most social of the strepsirrhine primates, living in groups known as troops. They communicate more with scents and vocalizations than with visual signals. Lemurs have a relatively low basal metabolic rate , and as a result may exhibit dormancy such as hibernation or torpor . They also have seasonal breeding and female social dominance . Most eat
3317-474: Is still used to illustrate the behavioral ecology of tarsiers relative to the other primates. In addition to the controversy over tarsiers, the debate over the origins of simians once called the strepsirrhine clade into question. Arguments for an evolutionary link between adapiforms and simians made by paleontologists Gingerich, Elwyn L. Simons , Tab Rasmussen , and others could have potentially excluded adapiforms from Strepsirrhini. In 1975, Gingerich proposed
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3424-624: The Duke University Primate Center ( DUPC ), the center's name was changed in April 2006 after a refocusing of the scientific goals and overall mission. Specimens from its scientific collection may thus be assigned the code DPC . The mission of the Duke University Lemur Center is to "promote research and understanding of prosimians and their natural habitat as a means of advancing the frontiers of knowledge, to contribute to
3531-456: The Eocene (56 to 34 mya ) or Paleocene (66 to 56 mya). Adapiforms, however, lack a specialized arrangement of teeth, known as a toothcomb , which nearly all living strepsirrhines possess. A more recent hypothesis is that lemurs descended from lorisoids (loris-like) primates. This is supported by comparative studies of the cytochrome b gene and the presence of the strepsirrhine toothcomb in both groups. Instead of being
3638-716: The Greek στρέψις strepsis "a turning round" and ῥίς rhis "nose, snout, (in pl.) nostrils" ( GEN ῥινός rhinos ), which refers to the appearance of the sinuous (comma-shaped) nostrils on the rhinarium or wet nose. The name was first used by French naturalist Étienne Geoffroy Saint-Hilaire in 1812 as a subordinal rank comparable to Platyrrhini ( New World monkeys ) and Catarrhini ( Old World monkeys ). In his description , he mentioned " Les narines terminales et sinueuses " ("Nostrils terminal and winding"). When British zoologist Reginald Innes Pocock revived Strepsirrhini and defined Haplorhini in 1918, he omitted
3745-657: The International Union for Conservation of Nature (IUCN) considers lemurs to be the world's most endangered mammals, noting that as of 2013 up to 90% of all lemur species confront the threat of extinction in the wild within the next 20 to 25 years. Ring-tailed lemurs are an iconic flagship species . Collectively, lemurs exemplify the biodiverse fauna of Madagascar and have facilitated the emergence of eco-tourism . In addition, conservation organizations increasingly seek to implement community-based approaches to save lemur species and promote sustainability. Carl Linnaeus ,
3852-583: The Mozambique Channel , a deep channel between Africa and Madagascar with a minimum width of about 560 km (350 mi). In 1915, paleontologist William Diller Matthew noted that the mammalian biodiversity on Madagascar (including lemurs) can only be accounted for by random rafting events , where very small populations rafted from nearby Africa on tangled mats of vegetation, which get flushed out to sea from major rivers. This form of biological dispersal can occur randomly over millions of years. In
3959-463: The Northern Hemisphere as the climate cooled. Adapiforms are sometimes referred to as being "lemur-like", although the diversity of both lemurs and adapiforms does not support this comparison. Strepsirrhines are defined by their "wet" (moist) rhinarium (the tip of the snout) – hence the colloquial but inaccurate term "wet-nosed" – similar to the rhinaria of canines and felines. They also have
4066-765: The Public Broadcasting Service (PBS), was filmed at the Duke Lemur Center. In order to film the show, a custom-made animal sound stage was constructed on the Duke University campus. One of the show's hosts Martin Kratt , holds a degree in Zoology from Duke University. On 10 November 2014, Jovian , the Coquerel's sifaka who portrayed Zoboomafoo in the series of the same name , died of renal failure in his home at
4173-471: The gorilla in size, at 160–200 kg (350–440 lb) for Archaeoindris fontoynonti . Like all primates, lemurs have five divergent digits with nails (in most cases) on their hands and feet. Most lemurs possess a laterally compressed, elongated nail, called a toilet-claw , on the second toe and use it for scratching and grooming. In addition to the toilet-claw, lemurs share a variety of other traits with other strepsirrhine primates, which include
4280-416: The gray-headed lemur ( E. albocollaris ) and the red lemur ( E. rufus ), exhibit size differences in canine teeth. True lemurs show sexual dichromatism (sexual differences in fur coloration), but the difference between the genders varies from strikingly obvious, as in the blue-eyed black lemur ( E. macaco ), to nearly imperceptible in the case of the common brown lemur ( E. fulvus ). Crypsis , or
4387-500: The toothcomb of extant lemuriforms; however, this view is not strongly supported due to a lack of clear transitional fossils. Instead, lemuriforms may be descended from a very early branch of Asian cercamoniines or sivaladapids that migrated to northern Africa. Until discoveries of three 40 million-year-old fossil lorisoids ( Karanisia , Saharagalago , and Wadilemur ) in the El Fayum deposits of Egypt between 1997 and 2005,
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4494-449: The toothcomb of most lemurs, the bottom incisors and canine teeth are procumbent (face forward rather than up) and finely spaced, thus providing a tool for either grooming or feeding. For instance, indri use their toothcomb not only for grooming, but also to pry out the large seeds from the tough epicarp of Beilschmiedia fruits, while fork-marked lemurs use their relatively long toothcomb to cut through tree bark to induce
4601-525: The 1940s, American paleontologist George Gaylord Simpson coined the term "sweepstakes hypothesis" for such random events. Rafting has since been the most accepted explanation for the lemur colonization of Madagascar, but until recently, this trip was thought to be very unlikely because strong ocean currents flow away from the island. In January 2010 , a report demonstrated that around 60 mya both Madagascar and Africa were 1,650 km (1,030 mi) south of their present-day positions, placing them in
4708-709: The 1980s. Lemurs are important for research because their mix of ancestral characteristics and traits shared with anthropoid primates can yield insights on primate and human evolution . Most species have been discovered or promoted to full species status since the 1990s; however, lemur taxonomic classification is controversial and depends on which species concept is used. Many lemur species remain endangered due to habitat loss and hunting. Although local traditions, such as fady , generally help protect lemurs and their forests, illegal logging , economic privation and political instability conspire to thwart conservation efforts. Because of these threats and their declining numbers,
4815-482: The 30-gram (1.1 oz) mouse lemur to the 9-kilogram (20 lb) indri . Since the arrival of humans on the island around 2,000 years ago, over a dozen species of " giant lemurs " larger than living lemur species have become extinct, including the gorilla-sized Archaeoindris . Lemurs share many common basal primate traits, such as divergent digits on their hands and feet, and nails instead of claws (in most species). However, their brain-to-body size ratio
4922-562: The Duke Lemur Center at the age of 20. 35°59′42″N 78°57′37″W / 35.9949°N 78.9604°W / 35.9949; -78.9604 Lemur Lemurs ( / ˈ l iː m ər / LEE -mər ; from Latin lemures lit. ' ghosts ' or ' spirits ' ) are wet-nosed primates of the superfamily Lemuroidea ( / l ɛ m j ʊ ˈ r ɔɪ d i ə / lem-yuurr- OY -dee-ə ), divided into 8 families and consisting of 15 genera and around 100 existing species . They are endemic to
5029-461: The Early to Middle Eocene, evidence from genetics and recent fossil finds both suggest they may have been present during the early adaptive radiation . The origin of the earliest primates that the simians and tarsiers both evolved from is a mystery. Both their place of origin and the group from which they emerged are uncertain. Although the fossil record demonstrating their initial radiation across
5136-463: The Northern Hemisphere is very detailed, the fossil record from the tropics (where primates most likely first developed) is very sparse, particularly around the time that primates and other major clades of eutherian mammals first appeared. Lacking detailed tropical fossils, geneticists and primatologists have used genetic analyses to determine the relatedness between primate lineages and
5243-479: The Prosimii-Anthropoidea taxonomy is familiar and frequently seen in the research literature and textbooks. Strepsirrhines are traditionally characterized by several symplesiomorphic (ancestral) traits not shared with the simians, particularly the rhinarium. Other symplesiomorphies include long snouts , convoluted maxilloturbinals , relatively large olfactory bulbs , and smaller brains. The toothcomb
5350-412: The academic literature provides a basic framework for primate taxonomy, usually including several potential taxonomic schemes. Although most experts agree upon phylogeny , many disagree about nearly every level of primate classification. The most commonly recurring debate in primatology during the 1970s, 1980s, and early 2000s concerned the phylogenetic position of tarsiers compared to both simians and
5457-417: The adjacent image. Lemur taxonomy has changed significantly since the first taxonomic classification of lemurs by Carl Linnaeus in 1758. One of the greatest challenges has been the classification of the aye-aye, which has been a topic of debate up until very recently. Until Richard Owen published a definitive anatomical study in 1866, early naturalists were uncertain whether the aye-aye (genus Daubentonia )
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#17328553901125564-470: The amount of time since they diverged . Using this molecular clock , divergence dates for the major primate lineages have suggested that primates evolved more than 80–90 mya, nearly 40 million years before the first examples appear in the fossil record. The early primates include both nocturnal and diurnal small-bodied species, and all were arboreal, with hands and feet specially adapted for maneuvering on small branches. Plesiadapiforms from
5671-468: The arrival of humans roughly 1500 to 2000 years ago, lemurs were found all across the island. However, early settlers quickly converted the forests to rice paddies and grassland through slash-and-burn agriculture (known locally as tavy ), restricting lemurs to approximately 10% of the island's area, ~60,000 km (23,000 sq mi). Today, the diversity and complexity of lemur communities increases with floral diversity and precipitation and
5778-539: The aye-aye (Daubentoniidae) in its own infraorder, Chiromyiformes. In some cases, plesiadapiforms are included within the order Primates, in which case Euprimates is sometimes treated as a suborder, with Strepsirrhini becoming an infraorder, and the Lemuriformes and others become parvorders. Regardless of the infraordinal taxonomy, Strepsirrhini is composed of three ranked superfamilies and 14 families, seven of which are extinct. Three of these extinct families included
5885-526: The aye-aye, and the extinct sloth lemurs , monkey lemurs , and koala lemurs have reduced dentitions, having lost incisors, canines, or premolars. The ancestral deciduous dentition is 2.1.3 2.1.3 , but young indriids, aye-ayes, koala lemurs, sloth lemurs, and probably monkey lemurs have fewer deciduous teeth. There are also noticeable differences in dental morphology and tooth topography between lemurs. Indri , for instance, have teeth that are perfectly adapted for shearing leaves and crushing seeds. In
5992-462: The case of lemurs, natural selection has driven this isolated population of primates to diversify significantly and fill a rich variety of ecological niches , despite their smaller and less complex brains compared to simians. The divergence between strepsirrhines, simians, and tarsiers likely followed almost immediately after primates first evolved. Although few fossils of living primate groups – lemuriforms, tarsiers, and simians – are known from
6099-455: The case of mouse lemurs, the gray mouse lemur ( M. murinus ), golden-brown mouse lemur ( M. ravelobensis ), and Goodman's mouse lemur ( M. lehilahytsara ) were considered the same species until recently, when genetic tests identified them as cryptic species. The lemur dentition is heterodont (having multiple tooth morphologies) and derives from an ancestral primate permanent dentition of 2.1.3.3 2.1.3.3 . Indriids, sportive lemurs,
6206-451: The center's inhabitants were born on site." In 1997, the center began a program to reintroduce black-and-white ruffed lemurs into the 5,500-acre (2,200 ha) Betampona Natural Reserve in Madagascar , the first return of any prosimian primates to the island nation. In 2009 and 2010, the center completed two new buildings for housing lemurs. The first building was completed in 2009 and
6313-548: The cladistic analysis was flawed and the phylogenetic inferences and terminology were vague. Although the authors noted that Darwinius was not a "fossil lemur", they did emphasize the absence of a toothcomb, which adapiforms did not possess. † Adapiformes stem lemuriforms Daubentoniidae other lemurs lorises galagos Within Strepsirrhini, two common classifications include either two infraorders (Adapiformes and Lemuriformes) or three infraorders (Adapiformes, Lemuriformes, Lorisiformes). A less common taxonomy places
6420-520: The climate cooled: The last of the adapiforms died out at the end of the Miocene (~7 mya). Adapiform primates are extinct strepsirrhines that shared many anatomical similarities with lemurs. They are sometimes referred to as lemur-like primates, although the diversity of both lemurs and adapiforms do not support this analogy. Like the living strepsirrhines, adapiforms were extremely diverse, with at least 30 genera and 80 species known from
6527-455: The direct ancestors of lemurs, the adapiforms may have given rise to both the lemurs and lorisoids, a split that would be supported by molecular phylogenetic studies. The later split between lemurs and lorises is thought to have occurred approximately 62 to 65 mya according to molecular studies, although other genetic tests and the fossil record in Africa suggest more conservative estimates of 50 to 55 mya for this divergence. However,
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#17328553901126634-562: The early Paleocene are sometimes considered "archaic primates", because their teeth resembled those of early primates and because they possessed adaptations to living in trees, such as a divergent big toe ( hallux ). Although plesiadapiforms were closely related to primates, they may represent a paraphyletic group from which primates may or may not have directly evolved, and some genera may have been more closely related to colugos , which are thought to be more closely related to primates. The first true primates (euprimates) do not appear in
6741-401: The early Eocene, although their most basal members share enough dental similarities to suggest that they diverged during the Paleocene (66–55 mya). Lemuriform origins are unclear and debated. American paleontologist Philip Gingerich proposed that lemuriform primates evolved from one of several genera of European adapids based on similarities between the front lower teeth of adapids and
6848-555: The educational development of future leaders in international scholarship and conservation and to enhance the human condition by stimulating intellectual growth and sustaining global biodiversity." According to Duke University, the Lemur Center, the only university-based facility in the world devoted to the study of strepsirrhine primates, "is home to the world's largest colony of endangered primates – including more than 200 lemurs , bush babies and lorises .... More than 85 percent of
6955-564: The environment. Lemurs have adapted to fill many open ecological niches since making their way to Madagascar. Their diversity in both behavior and morphology (outward appearance) rivals that of the monkeys and apes found elsewhere in the world. Ranging in size from the 30 g (1.1 oz) Madame Berthe's mouse lemur , the world's smallest primate, to the recently extinct 160–200 kg (350–440 lb) Archaeoindris fontoynonti , lemurs evolved diverse forms of locomotion, varying levels of social complexity, and unique adaptations to
7062-631: The extinct adapiforms and the lemuriform primates, which include lemurs and lorisoids ( lorises , pottos , and galagos ). Strepsirrhines diverged from the haplorhine primates near the beginning of the primate radiation between 55 and 90 mya. Older divergence dates are based on genetic analysis estimates, while younger dates are based on the scarce fossil record . Lemuriform primates may have evolved from either cercamoniines or sivaladapids , both of which were adapiforms that may have originated in Asia. They were once thought to have evolved from adapids ,
7169-472: The family Adapidae, which was divided into two or three subfamilies: Adapinae, Notharctinae, and sometimes Sivaladapinae. All North American adapiforms were lumped under Notharctinae, while the Old World forms were usually assigned to Adapinae. Around the 1990s, two distinct groups of European "adapids" began to emerge, based on differences in the postcranial skeleton and the teeth. One of these two European forms
7276-543: The family Prosimia (Prosimii) in 1811. The use of the tarsier-galago classification continued for many years until 1898, when Dutch zoologist Ambrosius Hubrecht demonstrated two different types of placentation (formation of a placenta ) in the two groups. English comparative anatomist William Henry Flower created the suborder Lemuroidea in 1883 to distinguish these primates from the simians, which were grouped under English biologist St. George Jackson Mivart 's suborder Anthropoidea (=Simiiformes). According to Flower,
7383-416: The flow of tree sap . The toothcomb is kept clean by the sublingua or "under-tongue", a specialized structure that acts like a toothbrush to remove hair and other debris. The sublingua extends below the tip of the tongue and is tipped with keratinized , serrated points that rake between the front teeth. Only the aye-aye, the extinct giant aye-aye , and the largest of the extinct giant sloth lemurs lack
7490-478: The fossil record as of the early 2000s. They diversified across Laurasia during the Eocene, some reaching North America via a land bridge . They were among the most common mammals found in the fossil beds from that time. A few rare species have also been found in northern Africa. The most basal of the adapiforms include the genera Cantius from North America and Europe and Donrussellia from Europe. The latter bears
7597-639: The fossil record until the early Eocene (~55 mya), at which point they radiated across the Northern Hemisphere during a brief period of rapid global warming known as the Paleocene–Eocene Thermal Maximum . These first primates included Cantius , Donrussellia , Altanius , and Teilhardina on the northern continents, as well as the more questionable (and fragmentary) fossil Altiatlasius from Paleocene Africa. These earliest fossil primates are often divided into two groups, adapiforms and omomyiforms . Both appeared suddenly in
7704-402: The fossil record without transitional forms to indicate ancestry, and both groups were rich in diversity and were widespread throughout the Eocene. The last branch to develop were the adapiforms, a diverse and widespread group that thrived during the Eocene (56 to 34 million years ago [ mya ]) in Europe, North America, and Asia. They disappeared from most of the Northern Hemisphere as
7811-466: The founder of modern binomial nomenclature , gave lemurs their name as early as 1758. With his declaration of the genus Lemur in the 10th edition of Systema Naturae , he included three species: Lemur tardigradus (the red slender loris , now known as Loris tardigradus ), Lemur catta (the ring-tailed lemur ), and Lemur volans (the Philippine colugo , now known as Cynocephalus volans ). Although
7918-421: The full range of lemur sizes. Daubentoniidae Lemuridae Indriidae Lepilemuridae Cheirogaleidae Daubentoniidae Lepilemuridae Cheirogaleidae Lemuridae † Megaladapidae Indriidae † Palaeopropithecidae † Archaeolemuridae From a taxonomic standpoint, the term "lemur" originally referred to the genus Lemur , which currently contains only the ring-tailed lemur . The term
8025-459: The general term "strepsirrhine", along with oversimplified anatomical comparisons and vague phylogenetic inferences, can lead to misconceptions about primate phylogeny and misunderstandings about primates from the Eocene, as seen with the media coverage of Darwinius . Because the skeletons of adapiforms share strong similarities with those of lemurs and lorises, researchers have often referred to them as "primitive" strepsirrhines, lemur ancestors, or
8132-411: The genus Lemur into two genera: Prosimia for the lemurs, colugos, and tarsiers and Tardigradus for the lorises. Ten years later, É. Geoffroy and Georges Cuvier grouped the tarsiers and galagos due to similarities in their hindlimb morphology , a view supported by German zoologist Johann Karl Wilhelm Illiger , who placed them in the family Macrotarsi while placing the lemurs and tarsiers in
8239-550: The gradual split of a broadly defined genus Lemur into separate genera for the ring-tailed lemur , ruffed lemurs , and brown lemurs due to a host of morphological differences. Due to several taxonomic revisions by Russell Mittermeier, Colin Groves, and others, the number of recognized lemur species has grown from 33 species and subspecies in 1994 to approximately 100 in 2008. With continuing cytogenetic and molecular genetic research, as well as ongoing field studies , particularly with cryptic species such as mouse lemurs,
8346-425: The inability of humans to visually distinguish between two or more distinct species, has recently been discovered among lemurs, particularly within the sportive lemurs ( Lepilemur ) and mouse lemurs ( Microcebus ). With sportive lemurs, subspecies were traditionally defined based on slight morphological differences, but new genetic evidence has supported giving full species status to these regional populations. In
8453-428: The infraorder Lemuriformes (or superfamily Lemuroidea). The first fossil primate described was the adapiform Adapis parisiensis by French naturalist Georges Cuvier in 1821, who compared it to a hyrax (" le Daman "), then considered a member of a now obsolete group called pachyderms . It was not recognized as a primate until it was reevaluated in the early 1870s. Originally, adapiforms were all included under
8560-456: The island of Madagascar . Most existing lemurs are small, have a pointed snout, large eyes, and a long tail. They chiefly live in trees and are active at night . Lemurs share resemblance with other primates , but evolved independently from monkeys and apes . Due to Madagascar's highly seasonal climate, lemur evolution has produced a level of species diversity rivaling that of any other primate group. Living lemurs range in weight from
8667-431: The lemuriform divergence from the other primates and the subsequent lemur-lorisoid split both predate the appearance of adapiforms in the early Eocene. New calibration methods may reconcile the discrepancies between the molecular clock and the fossil record, favoring more recent divergence dates. The fossil record suggests that the strepsirrhine adapiforms and the haplorhine omomyiforms had been evolving independently before
8774-460: The lemurs and the rest of the terrestrial Malagasy fauna from mainland Africa. Isolated on Madagascar with only a limited number of mammalian competitors, the lemurs did not have to compete with other evolving arboreal mammalian groups, such as squirrels . They were also spared from having to compete with monkeys , which evolved later. The intelligence, aggression, and deceptiveness of monkeys gave them an advantage over other primates in exploiting
8881-579: The lemurs diversified and filled the niches often filled by monkeys and apes today. In Africa, the lorises and galagos diverged during the Eocene, approximately 40 mya. Unlike the lemurs in Madagascar, they have had to compete with monkeys and apes, as well as other mammals. The taxonomy of strepsirrhines is controversial and has a complicated history. Confused taxonomic terminology and oversimplified anatomical comparisons have created misconceptions about primate and strepsirrhine phylogeny , illustrated by
8988-407: The lemurs of Madagascar, are often portrayed inappropriately as " living fossils " or as examples of " basal ", or "inferior" primates. These views have historically hindered the understanding of mammalian evolution and the evolution of strepsirrhine traits, such as their reliance on smell ( olfaction ), characteristics of their skeletal anatomy, and their brain size, which is relatively small. In
9095-769: The local climate. Lemurs lack any shared traits that make them stand out from all other primates. Different types of lemurs have evolved unique combinations of unusual traits to cope with Madagascar's harsh, seasonal climate. These traits can include seasonal fat storage, hypometabolism (including torpor and hibernation ), small group sizes, low encephalization (relative brain size), cathemerality (activity both day and night), and strict breeding seasons . Extreme resource limitations and seasonal breeding are also thought to have given rise to three other relatively common lemur traits: female social dominance , sexual monomorphism, and male–male competition for mates involving low levels of agonism , such as sperm competition . Before
9202-405: The media attention surrounding the single "Ida" fossil in 2009. Strepsirrhine primates were first grouped under the genus Lemur by Swedish taxonomist Carl Linnaeus in the 10th edition of Systema Naturae published in 1758. At the time, only three species were recognized, one of which (the colugo) is no longer recognized as a primate. In 1785, Dutch naturalist Pieter Boddaert divided
9309-401: The most ancestral traits , so it is often considered a sister group or stem group of the other adapiforms. Adapiforms are often divided into three major groups: The relationship between adapiform and lemuriform primates has not been clearly demonstrated, so the position of adapiforms as a paraphyletic stem group is questionable. Both molecular clock data and new fossil finds suggest that
9416-467: The nose and reinstated the use of the suborder Strepsirrhini, while also moving the tarsiers and the simians into a new suborder, Haplorhini. It was not until 1953, when British anatomist William Charles Osman Hill wrote an entire volume on strepsirrhine anatomy, that Pocock's taxonomic suggestion became noticed and more widely used. Since then, primate taxonomy has shifted between Strepsirrhini-Haplorhini and Prosimii-Anthropoidea multiple times. Most of
9523-445: The number of recognized lemur species is likely to keep growing. However, the rapid increase in the number of recognized species has had its critics among taxonomists and lemur researchers. Since classifications ultimately depend on the species concept used, conservationists often favor definitions that result in the splitting of genetically distinct populations into separate species to gain added environmental protection. Others favor
9630-477: The oldest known lemuriforms had come from the early Miocene (~20 mya) of Kenya and Uganda . These newer finds demonstrate that lemuriform primates were present during the middle Eocene in Afro-Arabia and that the lemuriform lineage and all other strepsirrhine taxa had diverged before then. Djebelemur from Tunisia dates to the late early or early middle Eocene (52 to 46 mya) and has been considered
9737-484: The oldest lemur fossils on Madagascar are actually subfossils dating to the Late Pleistocene . Once part of the supercontinent Gondwana , the island of Madagascar has been isolated since it broke away from eastern Africa (~160 mya), Antarctica (~80–130 mya), and India (~80–90 mya). Since ancestral lemurs are thought to have originated in Africa around 62 to 65 mya, they must have crossed
9844-512: The other prosimians. Tarsiers are most often placed in either the suborder Haplorhini with the simians or in the suborder Prosimii with the strepsirrhines. Prosimii is one of the two traditional primate suborders and is based on evolutionary grades (groups united by anatomical traits) rather than phylogenetic clades, while the Strepsirrhini-Haplorrhini taxonomy was based on evolutionary relationships. Yet both systems persist because
9951-416: The preferred taxonomic division. Yet tarsiers still closely resemble both strepsirrhines and simians in different ways, and since the early split between strepsirrhines, tarsiers and simians is ancient and hard to resolve, a third taxonomic arrangement with three suborders is sometimes used: Prosimii, Tarsiiformes, and Anthropoidea. More often, the term "prosimian" is no longer used in official taxonomy, but
10058-532: The recently extinct giant lemurs of Madagascar, many of which died out within the last 1,000 years following human arrival on the island. When Strepsirrhini is divided into two infraorders, the clade containing all toothcombed primates can be called "lemuriforms". When it is divided into three infraorders, the term "lemuriforms" refers only to Madagascar's lemurs, and the toothcombed primates are referred to as either "crown strepsirrhines" or "extant strepsirrhines". Confusion of this specific terminology with
10165-417: The recently extinct subfossil lemurs were closely related to living lemurs, an additional three families, eight genera, and 17 species can be included in the total. In contrast, other experts have labeled this as taxonomic inflation , instead preferring a total closer to 50 species. The classification of lemurs within the suborder Strepsirrhini is equally controversial, although most experts agree on
10272-411: The relationship between tarsiers and simians as a haplorhine clade is the shared possession of three SINE markers . Because of their historically mixed assemblages which included tarsiers and close relatives of primates, both Prosimii and Strepsirrhini have been considered wastebasket taxa for "lower primates". Regardless, the strepsirrhine and haplorrhine clades are generally accepted and viewed as
10379-601: The rest of the lemurs were placed in Lemuriformes and the lorisoids in Lorisiformes. Although it is generally agreed that the aye-aye is the most basal member of the lemur clade, the relationship between the other four families is less clear since they diverged during a narrow 10 to 12 million-year window between the Late Eocene (42 mya) and into the Oligocene (30 mya). The two main competing hypotheses are shown in
10486-640: The rich lemur diversity that has evolved in isolation. Some of their adaptations were unlike those seen in their living relatives. All 17 extinct lemurs were larger than the extant (living) forms, some weighing as much as 200 kg (440 lb), and are thought to have been active during the day. Not only were they unlike the living lemurs in both size and appearance, they also filled ecological niches that either no longer exist or are now left unoccupied. Large parts of Madagascar, which are now devoid of forests and lemurs, once hosted diverse primate communities that included more than 20 lemur species covering
10593-451: The same phylogenetic tree . In one taxonomy, the infraorder Lemuriformes contains all living strepsirrhines in two superfamilies, Lemuroidea for all lemurs and Lorisoidea for the lorisoids ( lorisids and galagos). Alternatively, the lorisoids are sometimes placed in their own infraorder, Lorisiformes, separate from the lemurs. In another taxonomy published by Colin Groves, the aye-aye was placed in its own infraorder, Chiromyiformes, while
10700-441: The second "r" from both ("Strepsi r hini" and "Haplo r hini" instead of "Strepsi rr hini" and "Haplo rr hini"), although he did not remove the second "r" from Platyrrhini or Catarrhini, both of which were also named by É. Geoffroy in 1812. Following Pocock, many researchers continued to spell Strepsirrhini with a single "r" until primatologists Paulina Jenkins and Prue Napier pointed out the error in 1987. Strepsirrhines include
10807-403: The suborder Lemuroidea contained the families Lemuridae (lemurs, lorises, and galagos), Chiromyidae ( aye-aye ), and Tarsiidae (tarsiers). Lemuroidea was later replaced by Illiger's suborder Prosimii. Many years earlier, in 1812, É. Geoffroy first named the suborder Strepsirrhini, in which he included the tarsiers. This taxonomy went unnoticed until 1918, when Pocock compared the structure of
10914-599: The term lemur was first intended for slender lorises , it was soon limited to the endemic Malagasy primates, which have been known as collectively "lemurs" ever since. The name lemur is derived from the Latin term lemures , which refers to specters or ghosts that were exorcised during the Lemuria festival of ancient Rome. Linnaeus was familiar with the works of Virgil and Ovid , both of whom mentioned lemures. Seeing an analogy that fit with his naming scheme, he adapted
11021-906: The term lemur was selected because of the nocturnal activity and slow movements of the red slender loris: Lemures dixi hos, quod noctu imprimis obambulant, hominibus quodanmodo similes, & lento passu vagantur. I call them lemurs, because they go around mainly by night, in a certain way similar to humans, and roam with a slow pace. Lemurs are primates belonging to the suborder Strepsirrhini . Like other strepsirrhine primates , such as lorises , pottos , and galagos , they share ancestral (or plesiomorphic ) traits with early primates. In this regard, lemurs are popularly confused with ancestral primates; however, lemurs did not give rise to monkeys and apes ( simians ). Instead, they evolved independently in isolation on Madagascar . All modern strepsirrhines including lemurs are traditionally thought to have evolved from early primates known as adapiforms during
11128-515: The term "lemur" for these nocturnal primates. It was noted in 2012 that many sources had commonly and falsely assumed that Linnaeus was referring to the ghost-like appearance, reflective eyes , and ghostly cries of Madagascar's lemurs when he selected the name. Up until then, it had also been speculated that Linnaeus may also have known that some Malagasy people believed that lemurs were the souls of their ancestors . However, both claims were discredited since according to Linnaeus' own explanation,
11235-786: The toothcomb on the mandible (lower jaw), this complex is reminiscent of an ungulate browsing pad . Lemurs are unusual among primates for their rapid dental development, particularly among the largest species. For example, indriids have relatively slow body growth but extremely fast tooth formation and eruption . By contrast, anthropoid primates exhibit slower dental development with increased size and slower morphological development. Lemurs are also dentally precocious at birth, and have their full permanent dentition at weaning . Strepsirrhini † Adapiformes Lemuriformes (See text) sister: Haplorhini Strepsirrhini or Strepsirhini ( / ˌ s t r ɛ p s ə ˈ r aɪ n i / ; STREP -sə- RY -nee )
11342-416: Was a primate , rodent , or marsupial . However, the placement of the aye-aye within the order Primates remained problematic until very recently. Based on its anatomy, researchers have found support for classifying the genus Daubentonia as a specialized indriid , a sister group to all strepsirrhines, and as an indeterminate taxon within the order Primates. Molecular tests have now shown Daubentoniidae
11449-528: Was identified as cercamoniines, which were allied with the notharctids found mostly in North America, while the other group falls into the traditional adapid classification. The three major adapiform divisions are now typically regarded as three families within Adapiformes (Notharctidae, Adapidae and Sivaladapidae), but other divisions ranging from one to five families are used as well. All lemuriforms possess
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