Lemuriformesis the soleextantinfraorderofprimatethat falls under the suborderStrepsirrhini.It includes thelemursofMadagascar,as well as thegalagosandlorisidsof Africa and Asia, although a popular alternative taxonomy places thelorisoidsin their own infraorder, Lorisiformes.[a]
| Lemuriformes | |
|---|---|
| |
| A sample of lemuriform diversity;[a]8 biological genera are depicted (from top, left to right):Lemur,Propithecus,Daubentonia,Varecia,Microcebus,Nycticebus,Loris,Otolemur. | |
Scientific classification
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Primates |
| Suborder: | Strepsirrhini |
| Infraorder: | Lemuriformes Gray,1821 |
| Superfamilies | |
|
Lemuroidea | |
Lemuriformprimates are characterized by atoothcomb,a specialized set of teeth in the front, lower part of the mouth mostly used for combing fur during grooming.[4]
Evolutionary history
editLemuriform origins are unclear and debated. AmericanpaleontologistPhilip Gingerichproposed that lemuriform primates evolved from one of several genera of European adapids based on similarities between the front lower teeth of adapids and thetoothcombof extant lemuriforms; however, this view is not strongly supported due to a lack of clear transitional fossils.[5]Instead, lemuriforms may be descended from a very early branch of Asian cercamoniines or sivaladapids that immigrated to northern Africa.[6][7]
| Lemuriform phylogeny[8][9] | ||||||||||||||||||||||||||||||
|
Until discoveries of three 40-million-year-old fossil lorisoids (Karanisia,Saharagalago,andWadilemur) in theEl Fayum depositsof Egypt between 1997 and 2005, the oldest known lemuriforms had come from the early Miocene (~20 mya) ofKenyaandUganda.These newer finds demonstrate that lemuriform primates were present during the middleEocenein Afro-Arabia and that the lemuriform lineage and all other strepsirrhine taxa had diverged before then.[10][11][12]DjebelemurfromTunisiadates to the late early or early middle Eocene (52 to 46 mya) and has been considered a cercamoniine,[13]but also may have been a stem lemuriform.[6]AzibiidsfromAlgeriadate to roughly the same time and may be a sister group of thedjebelemurids.Together withPlesiopithecusfrom the late Eocene Egypt, the three may qualify as the stem lemuriforms from Africa.[7]
Molecular clock estimates indicate that lemurs and the lorisoids diverged in Africa during thePaleocene,approximately 62 mya. Between 47 and 54 mya, lemurs dispersed to Madagascar byrafting.[11]In isolation, the lemurs diversified and filled the niches often filled by monkeys and apes today.[14]In Africa, the lorises and galagos diverged during the Eocene, approximately 40 mya.[11]Unlike the lemurs in Madagascar, they have had to compete with monkeys and apes, as well as other mammals.[15]
Taxonomic classification
editMost of the academic literature provides a basic framework for primate taxonomy, usually including several potential taxonomic schemes.[16]Although most experts agree uponphylogeny,[17]many disagree about nearly every level of primate classification.[16]
Within Strepsirrhini, two common classifications include either two infraorders (Adapiformes and Lemuriformes)[18]or three infraorders (Adapiformes, Lemuriformes, Lorisiformes).[19]A less common taxonomy places theaye-aye(Daubentoniidae) in its own infraorder, Chiromyiformes.[20]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.[21]Regardless of the infraordinal taxonomy, crown strepsirrhines are composed of 10 families, three of which are extinct.[18]These three extinct families included thegiant lemursof Madagascar,[22]many of which died out within the last 1,000 years following human arrival on the island.[23]
| 2 infraorders[1][2] | 3 infraorders[3] | 4 infraorders[24] |
|---|---|---|
|
|
|
When Strepsirrhini is divided into two infraorders, the clade containing all toothcombed primates can be called "lemuriforms".[18]When it is divided into three infraorders, the term "lemuriforms" refers only to Madagascar's lemurs,[14]and the toothcombed primates are referred to as either "crown strepsirrhines"[25]or "extant strepsirrhines".[26]Confusion of this specific terminology with 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 ofDarwinius.[27]Because the skeletons of adapiforms share strong similarities with those of lemurs and lorises, researchers have often referred to them as "primitive" strepsirrhines,[28]lemur ancestors, or a sister group to the living strepsirrhines. They are included in Strepsirrhini,[26]and are considered basal members of the clade.[29]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 the infraorder Lemuriformes (or superfamily Lemuroidea).[30]
Notes
edit- ^abcAlthough themonophyletic relationshipbetween lemurs and lorisoids is widely accepted, their clade name is not. The term "lemuriform" is used here because it derives from one popular taxonomy that clumps thecladeof toothcombed primates into oneinfraorderand the extinct, non-toothcombedadapiformsinto another, both within thesuborderStrepsirrhini.[1][2]However, another popular alternative taxonomy places thelorisoidsin their own infraorder, Lorisiformes.[3]
References
edit- ^abSzalay & Delson 1980,p. 149.
- ^abCartmill 2010,p. 15.
- ^abHartwig 2011,pp. 20–21.
- ^Cartmill & Smith 2011,pp. 89–90.
- ^Rose 2006,p. 182 & 186.
- ^abGodinot 2006,p. 446.
- ^abTabuce et al. 2009,pp. 4091–4092.
- ^Janečka et al. 2007,fig. 2.
- ^Asher, Bennett & Lehmann 2009,p. 856.
- ^Hartwig 2011,p. 24–25.
- ^abcVaughan, Ryan & Czaplewski 2011,pp. 170–171.
- ^Rose 2006,p. 187.
- ^Rose 2006,p. 185.
- ^abCartmill & Smith 2011,p. 89.
- ^Hartwig 2011,p. 29.
- ^abHartwig 2011,pp. 20 & 22.
- ^Sussman 2003,p. 45.
- ^abcCartmill & Smith 2011,p. 90.
- ^Hartwig 2011,p. 20.
- ^Groves 2005,p. 121.
- ^Rose 2006,p. 166.
- ^Godfrey & Jungers 2002,p. 106.
- ^Godfrey & Jungers 2002,p. 97.
- ^Groves 2005.
- ^Rose 2006,p. 186.
- ^abVaughan, Ryan & Czaplewski 2011,p. 169.
- ^Williams et al. 2010,p. 567.
- ^Rose 2006,p. 181.
- ^Covert 2002,p. 18.
- ^Rose 2006,p. 179.
Literature cited
edit- Asher, R. J.; Bennett, N.; Lehmann, T. (2009-07-06)."The new framework for understanding placental mammal evolution".BioEssays.31(8): 853–864.doi:10.1002/bies.200900053.PMID19582725.
- Cartmill, M. (2010)."Primate Classification and Diversity".In Platt, M.; Ghazanfar, A (eds.).Primate Neuroethology.Oxford University Press. pp. 10–30.ISBN978-0-19-532659-8.
- Cartmill, M.; Smith, F. H. (2011).The Human Lineage.John Wiley & Sons.ISBN978-1-118-21145-8.
- Godinot, M. (2006). "Lemuriform origins as viewed from the fossil record".Folia Primatologica.77(6): 446–464.doi:10.1159/000095391.PMID17053330.S2CID24163044.
- Groves, C. P.(2005)."Strepsirrhini".InWilson, D. E.;Reeder, D. M. (eds.).Mammal Species of the World: A Taxonomic and Geographic Reference(3rd ed.). Baltimore: Johns Hopkins University Press. p. 111.ISBN0-801-88221-4.OCLC62265494.
- Hartwig, Walter Carl (2002). Hartwig, W. C (ed.).The primate fossil record.Cambridge University Press. p. 544.Bibcode:2002prfr.book.....H.ISBN978-0-521-66315-1.
- Covert, H. H. (2002)."Chapter 3: The earliest fossil primates and the evolution of prosimians: Introduction".The Primate Fossil Record.pp. 13–20.Bibcode:2002prfr.book.....H.ISBN9780521663151.
- Godfrey, L. R.; Jungers, W. L. (2002)."Chapter 7: Quaternary fossil lemurs".The Primate Fossil Record.pp. 97–121.Bibcode:2002prfr.book.....H.ISBN9780521663151.
- Hartwig, W. (2011). "Chapter 3: Primate evolution". In Campbell, C. J.; Fuentes, A.; MacKinnon, K. C.; Bearder, S. K.; Stumpf, R. M (eds.).Primates in Perspective(2nd ed.). Oxford University Press. pp. 19–31.ISBN978-0-19-539043-8.
- Janečka, J.E.; Miller, W.; Pringle, T.H.; Wiens, F.; Zitzmann, A.; Helgen, K.M.; Springer, M.S.; Murphy, W.J. (2007)."Molecular and genomic data identify the closest living relative of primates"(PDF).Science.318(5851): 792–794.Bibcode:2007Sci...318..792J.doi:10.1126/science.1147555.PMID17975064.S2CID12251814.
- Rose, K. D. (2006).The Beginning of the Age of Mammals.Johns Hopkins University Press.ISBN978-0-8018-8472-6.
- Sussman, R. W. (2003).Primate Ecology and Social Structure.Pearson Custom Publishing.ISBN978-0-536-74363-3.
- Szalay, F.S.; Delson, E. (1980).Evolutionary History of the Primates.Academic Press.ISBN978-0126801507.OCLC893740473.
- Tabuce, R.; Marivaux, L.; Lebrun, R.; Adaci, M.; Bensalah, M.; Fabre, P. -H.; Fara, E.; Gomes Rodrigues, H.; Hautier, L.; Jaeger, J. -J.; Lazzari, V.; Mebrouk, F.; Peigne, S.; Sudre, J.; Tafforeau, P.; Valentin, X.; Mahboubi, M. (2009)."Anthropoid versus strepsirhine status of the African Eocene primatesAlgeripithecusandAzibius:Craniodental evidence ".Proceedings of the Royal Society B: Biological Sciences.276(1676): 4087–4094.doi:10.1098/rspb.2009.1339.PMC2821352.PMID19740889.
- "African Origin Of Anthropoid Primates Called Into Question With New Fossil Discovery".ScienceDaily.17 September 2009.
- Vaughan, T.; Ryan, J.; Czaplewski, N. (2011)."Chapter 12: Primates".Mammalogy(5th ed.). Jones & Bartlett Learning.ISBN978-0-7637-6299-5.
- Williams, B. A.; Kay, R. F.; Christopher Kirk, E.; Ross, C. F. (2010)."Darwinius masillaeis a strepsirrhine—a reply to Franzenet al.(2009) "(PDF).Journal of Human Evolution.59(5): 567–573, discussion 573–9.doi:10.1016/j.jhevol.2010.01.003.PMID20188396.Archived fromthe original(PDF)on 2013-05-17.