sloth lemur
{{Short description|Extinct family of lemurs}}
{{Automatic taxobox
| name = Sloth lemur
| fossil_range = {{fossilrange|Pleistocene|Northgrippian|earliest=Late Miocene|PS=(Possible Late Miocene record)}}
| taxon = Palaeopropithecidae
| authority = Tattersall, 1973{{cite book|last1=McKenna|first1=MC|last2=Bell|first2=SK|title=Classification of Mammals: Above the Species Level|publisher=Columbia University Press|page=335|year=1997|isbn=978-0-231-11013-6}}
| image = Babakotia skull 001.jpg
| image_caption = Babakotia radofilai skull
| subdivision_ranks = Genera
| subdivision = {{plainlist|
- {{extinct}}Archaeoindris
- {{extinct}}Babakotia
- {{extinct}}Mesopropithecus
- {{extinct}}Palaeopropithecus}}
}}
The sloth lemurs (Palaeopropithecidae) comprise an extinct family of lemurs that includes four genera.{{cite book | author = Mittermeier, Russell A.| title = Lemurs of Madagascar | edition = 2nd | pages = 44–45 | publisher = Conservation International | year = 2006 | isbn=978-1-881173-88-5|display-authors=etal}}{{cite book | last = Nowak | first = Ronald M. | title = Walker's Primates of the World | pages = [https://archive.org/details/walkersprimateso0000nowa/page/89 89–91] | publisher = Johns Hopkins University Press | year = 1999 | isbn = 978-0-8018-6251-9 | url-access = registration | url = https://archive.org/details/walkersprimateso0000nowa/page/89 }} The common name can be misleading, as members of Palaeopropithecidae were not closely related to sloths. This clade has been dubbed the ‘‘sloth lemurs’’ because of remarkable postcranial convergences with South American sloths.{{cite journal|title = Molar microwear of subfossil lemurs: improving the resolution of dietary inferences| doi=10.1006/jhev.2002.0592|pmid=12457853|volume=43|issue = 5 |date=November 2002|journal=J. Hum. Evol.|pages=645–57 | last1 = Rafferty | first1 = KL | last2 = Teaford | first2 = MF | last3 = Jungers | first3 = WL| bibcode=2002JHumE..43..645R}} Despite postcranial similarities, the hands and feet show significant differences. Sloths possess long, curved claws, while sloth lemurs have short, flat nails on their distal phalanges like most primates.{{Cite journal|journal = Proceedings of the National Academy of Sciences of the United States of America|volume = 94|issue = 22|pages = 11998–12001|jstor = 43006|last1 = Jungers|first1 = William L.|title = Phalangeal curvature and positional behavior in extinct sloth lemurs (Primates, Palaeopropithecidae)|last2 = Godfrey|first2 = Laurie R.|last3 = Simons|first3 = Elwyn L.|last4 = Chatrath|first4 = Prithijit S.|year = 1997|doi = 10.1073/pnas.94.22.11998|pmid = 11038588|pmc = 23681|bibcode = 1997PNAS...9411998J|doi-access = free}}
Diet
Members of the family Palaeopropithecidae appear to have eaten a mix of fruit, nuts, and foliage.{{Cite journal|title = Dental use wear in extinct lemurs: evidence of diet and niche differentiation|journal = Journal of Human Evolution|date = 2004-09-01|pages = 145–169|volume = 47|issue = 3|doi = 10.1016/j.jhevol.2004.06.003|first1 = Laurie R.|last1 = Godfrey|first2 = Gina M.|last2 = Semprebon|first3 = William L.|last3 = Jungers|first4 = Michael R.|last4 = Sutherland|first5 = Elwyn L.|last5 = Simons|first6 = Nikos|last6 = Solounias|pmid=15337413| bibcode=2004JHumE..47..145G }} The sloth lemurs were mixed-feeders rather than specialized browsers who ate a mixed diet based on seasonality. On the basis of highly robust mandible, Palaeopropithecus and Archaeoindris can be considered highly folivorous. The family Palaeopropithecidae exhibited molar megadonty, small deciduous teeth with low occlusal length ratios, and a decoupling of the speed of dental and body growth with acceleration of dental development relative to body growth. These attributes were observed in conjunction with the finding that Palaeopropithecidae experienced prolonged periods of gestation.{{Cite journal|journal = Proceedings of the National Academy of Sciences of the United States of America|volume = 99|issue = 9|pages = 6124–6129|jstor = 3058636|last1 = Schwartz|first1 = Gary T.|title = Dental microstructure and life history in subfossil Malagasy lemurs|last2 = Samonds|first2 = Karen E.|last3 = Godfrey|first3 = Laurie R.|last4 = Jungers|first4 = William L.|last5 = Simons|first5 = Elwyn L.|year = 2002|doi = 10.1073/pnas.092685099|pmid = 11983905|pmc = 122913|bibcode = 2002PNAS...99.6124S|doi-access = free}}
Distribution and diversity
Postcranial measurements and anatomy suggest that three of the four genera, Palaeopropithecus, Babakotia, and Mesopropithecus were primarily arboreal and suspensory. The family was isolated due to river systems which formed a bio-geographical boundary, and likely attributed to the speciation of the family into four genera.{{Cite journal|title = Nouvelle découverte dans le Nord-Ouest de Madagascar et répartition géographique des espèces du genre Palaeopropithecus|journal = Annales de Paléontologie|date = 2004-10-01|pages = 279–286|volume = 90|issue = 4|doi = 10.1016/j.annpal.2004.07.001|first1 = Dominique|last1 = Gommery|first2 = Sabine|last2 = Tombomiadana|first3 = Frédérique|last3 = Valentin|first4 = Beby|last4 = Ramanivosoa|first5 = Raulin|last5 = Bezoma}}
Taxonomy
Traditionally the family Palaeopropithecidae has been considered most closely related to members of the extant family Indriidae based on morphology. Recently, DNA from extinct giant lemurs has confirmed this, as well as the fact that Malagasy primates in general share a common ancestor.{{Cite journal|title = Ancient DNA from Giant Extinct Lemurs Confirms Single Origin of Malagasy Primates|journal = Proceedings of the National Academy of Sciences of the United States of America|date = 2005-04-05|pages = 5090–5095|volume = 102|issue = 14|first1 = K. Praveen|last1 = Karanth|first2 = Thomas|last2 = Delefosse|first3 = Berthe|last3 = Rakotosamimanana|first4 = Thomas J.|last4 = Parsons|first5 = Anne D.|last5 = Yoder|first6 = Elwyn L.|last6 = Simons|doi=10.1073/pnas.0408354102|jstor=3375184|pmid=15784742|pmc=555979|bibcode = 2005PNAS..102.5090K|doi-access = free}} The post-canine teeth of sloth lemurs are similar in number (two premolars, three molars) and general design to living indriids. Babakotia and Mesopropithecus preserve the typical indriid-like toothcomb, but Palaeopropithecus and Archaeoindris have replaced it with four short and stout teeth of unknown functional significance. The vertebrae formation supports the theory that three of the four genera were suspensory/arboreal, while Babakotia was more likely antipronograde.{{Cite journal|title = Lumbar vertebral morphology of flying, gliding, and suspensory mammals: Implications for the locomotor behavior of the subfossil lemurs Palaeopropithecus and Babakotia|journal = Journal of Human Evolution|date = 2014-10-01|pages = 40–52|volume = 75|doi = 10.1016/j.jhevol.2014.06.011|first1 = Michael C.|last1 = Granatosky|first2 = Charlotte E.|last2 = Miller|first3 = Doug M.|last3 = Boyer|first4 = Daniel|last4 = Schmitt|pmid=25216795| bibcode=2014JHumE..75...40G }}
Extinction
The extinction of Palaeopropithecus (as well as other giant lemurs) has been linked to climate change and the subsequent collapse of ecosystems that come with rapid climate shift. Recent findings also indicate that human hunting is partly responsible for the extinction of giant lemurs. It is likely not the only cause and cannot be applied to the entire island of Madagascar, but does explain patterns in certain regions of human settlement.{{Cite journal|title = Paleoenvironment of Ankilitelo Cave (late Holocene, southwestern Madagascar): implications for the extinction of giant lemurs|journal = Journal of Human Evolution|date = 2010-04-01|pages = 338–352|volume = 58|issue = 4|doi = 10.1016/j.jhevol.2010.01.005|first = Kathleen M.|last = Muldoon|pmid=20226497| bibcode=2010JHumE..58..338M }} Long bones have been discovered with cuts characteristic of butchering, either by dismembering and skinning or by filleting.{{Cite journal|title = The extinct sloth lemurs of Madagascar|journal = Evolutionary Anthropology: Issues, News, and Reviews|date = 2003-01-01|issn = 1520-6505|pages = 252–263|volume = 12|issue = 6|doi = 10.1002/evan.10123|first1 = Laurie R.|last1 = Godfrey|first2 = William L.|last2 = Jungers|s2cid = 4834725}} Thorough scrutiny has led scientists to believe these marks to be from hunting by early humans.{{Cite journal|title = Evidence of early butchery of giant lemurs in Madagascar|journal = Journal of Human Evolution|date = 2005-12-01|pages = 722–742|volume = 49|issue = 6|doi = 10.1016/j.jhevol.2005.08.004|first1 = Ventura R.|last1 = Perez|first2 = Laurie R.|last2 = Godfrey|first3 = Malgosia|last3 = Nowak-Kemp|first4 = David A.|last4 = Burney|first5 = Jonah|last5 = Ratsimbazafy|first6 = Natalia|last6 = Vasey|pmid=16225904| bibcode=2005JHumE..49..722P }}
File:Archaeoindris fontoynonti.jpg|Archaeoindris fontoynonti
File:Babakotia radofilai.jpg|Babakotia radofilai
File:Mesopropithecus globiceps skull 001.jpg|Mesopropithecus globiceps
References
{{Reflist}}
External links
- {{Commons category-inline|Palaeopropithecidae|Palaeopropithecidae}}
{{Strepsirrhini|L.}}
{{Taxonbar|from=Q15982606}}