Based on similarities in their skull and teeth, it was later thought that monkey lemurs (Hadropithecus and Archaeolemur) were a sister group to the living indriids and the recently extinct sloth lemurs (family Palaeopropithecidae). However, there was some debate over whether the monkey lemurs or the sloth lemurs were more closely related to today's indriids. The monkey lemurs had skulls that more closely resembled the indriids, but their teeth were very specialized and unlike those of the indriids. The sloth lemurs, on the other hand, had teeth like the indriids, but very specialized skulls. The matter was settled with the discovery of new skeletons of Babakotia and Mesopropithecus, two genera of sloth lemur, both of which had indriid-like skulls and teeth. More recently, postcranial remains of Hadropithecus found in the early 2000s prompted the suggestion that the monkey lemurs were more closely related to the lemurids. However, DNA sequencing has reaffirmed the sister group status of the monkey lemurs to indriids and sloth lemurs.
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Palmer, T. (1904). "Index generum mammalium: a list of the genera and families of mammals". North American Fauna. 23: 1–984. doi:10.3996/nafa.23.0001. pp. 80–81, 539, 645, 648. https://books.google.com/books?id=WdnPAAAAMAAJ
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Lorenz von Liburnau, L. (1899). "Herr Custor Dr. Ludwig v. Lorenz berichtet über einen fossilen Anthropoiden von Madagascar". Anzeigen der Kaiserlichen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Classe, Wien. 27: 255–257. https://books.google.com/books?id=xkQUAAAAYAAJ&q=Hadropithecus&pg=PA255
Lorenz von Liburnau, L. (1902). "Über Hadropithecus stenognathus Lz., nebst Bemerkungen zu einigen anderen ausgestorbenen Primaten von Madagaskar". Denkschriften der Kaiserlichen Akademie der Wissenschaften, Mathematisch-naturwissenschaftliche Klasse, Wien. 72: 243–254. https://www.biodiversitylibrary.org/item/31611#315
Ryan, T.M.; Burney, D.A.; Godfrey, L.R.; Göhlich, U.B.; Jungers, W.L.; Vasey, N.; Ramilisonina; Walker, A.; Weber, G.W. (2008). "A reconstruction of the Vienna skull of Hadropithecus stenognathus" (PDF). PNAS. 105 (31): 10699–10702. Bibcode:2008PNAS..10510699R. doi:10.1073/pnas.0805195105. PMC 2488384. PMID 18663217. Retrieved 19 February 2010. http://www.pnas.org/content/105/31/10699.full.pdf
Horvath, J.; et al. (2008). "Development and application of a phylogenomic toolkit: Resolving the evolutionary history of Madagascar's lemurs" (PDF). Genome Research. 18 (3): 489–99. doi:10.1101/gr.7265208. PMC 2259113. PMID 18245770. Retrieved 2009-09-02. http://www.biology.duke.edu/yoderlab/reprints/2008Horvath_etalGR.pdf
Orlando, L.; Calvignac, S.; Schnebelen, C.; Douady, C.J.; Godfrey, L.R.; Hänni, C. (2008). "DNA from extinct giant lemurs links archaeolemurids to extant indriids". BMC Evolutionary Biology. 8 (1): 121. Bibcode:2008BMCEE...8..121O. doi:10.1186/1471-2148-8-121. PMC 2386821. PMID 18442367. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2386821
Godfrey, L.R.; Jungers, W.L. (2003). "Subfossil Lemurs". In Goodman, S.M.; Benstead, J.P (eds.). The Natural History of Madagascar. University of Chicago Press. pp. 1247–1252. ISBN 978-0-226-30306-2. 978-0-226-30306-2
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Simons, E.L. (1997). "Chapter 6: Lemurs: Old and New". In Goodman, S.M.; Patterson, B.D (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 142–166. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Godfrey, L.R.; Jungers, W.L.; Burney, D.A.; Vasey, N.; Ramilisonina, S.J.; Wheeler, W.; Lemelin, P.; Shapiro, L.J.; et al. (2006). "New discoveries of skeletal elements of Hadropithecus stenognathus from Andrahomana Cave, southeastern Madagascar". Journal of Human Evolution. 51 (4): 395–410. Bibcode:2006JHumE..51..395G. doi:10.1016/j.jhevol.2006.04.012. PMID 16911817. /wiki/Bibcode_(identifier)
Orlando, L.; Calvignac, S.; Schnebelen, C.; Douady, C.J.; Godfrey, L.R.; Hänni, C. (2008). "DNA from extinct giant lemurs links archaeolemurids to extant indriids". BMC Evolutionary Biology. 8 (1): 121. Bibcode:2008BMCEE...8..121O. doi:10.1186/1471-2148-8-121. PMC 2386821. PMID 18442367. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2386821
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Godfrey, L.R.; Jungers, W.L.; Schwartz, G.T. (2006). "Chapter 3: Ecology and Extinction of Madagascar's Subfossil Lemurs". In Gould, L.; Sauther, M.L (eds.). Lemurs: Ecology and Adaptation. Springer. pp. 41–64. ISBN 978-0-387-34585-7. 978-0-387-34585-7
Ryan, T.M.; Burney, D.A.; Godfrey, L.R.; Göhlich, U.B.; Jungers, W.L.; Vasey, N.; Ramilisonina; Walker, A.; Weber, G.W. (2008). "A reconstruction of the Vienna skull of Hadropithecus stenognathus" (PDF). PNAS. 105 (31): 10699–10702. Bibcode:2008PNAS..10510699R. doi:10.1073/pnas.0805195105. PMC 2488384. PMID 18663217. Retrieved 19 February 2010. http://www.pnas.org/content/105/31/10699.full.pdf
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Godfrey, L.R.; Jungers, W.L.; Schwartz, G.T. (2006). "Chapter 3: Ecology and Extinction of Madagascar's Subfossil Lemurs". In Gould, L.; Sauther, M.L (eds.). Lemurs: Ecology and Adaptation. Springer. pp. 41–64. ISBN 978-0-387-34585-7. 978-0-387-34585-7
Ryan, T.M.; Burney, D.A.; Godfrey, L.R.; Göhlich, U.B.; Jungers, W.L.; Vasey, N.; Ramilisonina; Walker, A.; Weber, G.W. (2008). "A reconstruction of the Vienna skull of Hadropithecus stenognathus" (PDF). PNAS. 105 (31): 10699–10702. Bibcode:2008PNAS..10510699R. doi:10.1073/pnas.0805195105. PMC 2488384. PMID 18663217. Retrieved 19 February 2010. http://www.pnas.org/content/105/31/10699.full.pdf
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Simons, E.L. (1997). "Chapter 6: Lemurs: Old and New". In Goodman, S.M.; Patterson, B.D (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 142–166. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Simons, E.L. (1997). "Chapter 6: Lemurs: Old and New". In Goodman, S.M.; Patterson, B.D (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 142–166. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Godfrey, L.R.; Jungers, W.L.; Reed, K.E.; Simons, E.L.; Chatrath, P.S. (1997). "Chapter 8: Subfossil Lemurs". In Goodman, S.M.; Patterson, B.D. (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 218–256. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Godfrey, L.R.; Jungers, W.L.; Reed, K.E.; Simons, E.L.; Chatrath, P.S. (1997). "Chapter 8: Subfossil Lemurs". In Goodman, S.M.; Patterson, B.D. (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 218–256. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Ryan, T.M.; Burney, D.A.; Godfrey, L.R.; Göhlich, U.B.; Jungers, W.L.; Vasey, N.; Ramilisonina; Walker, A.; Weber, G.W. (2008). "A reconstruction of the Vienna skull of Hadropithecus stenognathus" (PDF). PNAS. 105 (31): 10699–10702. Bibcode:2008PNAS..10510699R. doi:10.1073/pnas.0805195105. PMC 2488384. PMID 18663217. Retrieved 19 February 2010. http://www.pnas.org/content/105/31/10699.full.pdf
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Godfrey, L.R.; Jungers, W.L.; Schwartz, G.T. (2006). "Chapter 3: Ecology and Extinction of Madagascar's Subfossil Lemurs". In Gould, L.; Sauther, M.L (eds.). Lemurs: Ecology and Adaptation. Springer. pp. 41–64. ISBN 978-0-387-34585-7. 978-0-387-34585-7
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Mittermeier, R.A.; Tattersall, I.; Konstant, W.R.; Meyers, D.M.; Mast, R.B. (1994). Lemurs of Madagascar. Illustrated by S.D. Nash (1st ed.). Conservation International. pp. 33–48. ISBN 1-881173-08-9. OCLC 32480729. 1-881173-08-9
Sussman, R.W. (2003). "Chapter 4: The Nocturnal Lemuriformes". Primate Ecology and Social Structure. Pearson Custom Publishing. pp. 107–148. ISBN 978-0-536-74363-3. 978-0-536-74363-3
Simons, E.L. (1997). "Chapter 6: Lemurs: Old and New". In Goodman, S.M.; Patterson, B.D (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 142–166. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Godfrey, L.R.; Jungers, W.L.; Schwartz, G.T. (2006). "Chapter 3: Ecology and Extinction of Madagascar's Subfossil Lemurs". In Gould, L.; Sauther, M.L (eds.). Lemurs: Ecology and Adaptation. Springer. pp. 41–64. ISBN 978-0-387-34585-7. 978-0-387-34585-7
Godfrey, L.R.; Jungers, W.L.; Reed, K.E.; Simons, E.L.; Chatrath, P.S. (1997). "Chapter 8: Subfossil Lemurs". In Goodman, S.M.; Patterson, B.D. (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 218–256. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Ryan, T.M.; Burney, D.A.; Godfrey, L.R.; Göhlich, U.B.; Jungers, W.L.; Vasey, N.; Ramilisonina; Walker, A.; Weber, G.W. (2008). "A reconstruction of the Vienna skull of Hadropithecus stenognathus" (PDF). PNAS. 105 (31): 10699–10702. Bibcode:2008PNAS..10510699R. doi:10.1073/pnas.0805195105. PMC 2488384. PMID 18663217. Retrieved 19 February 2010. http://www.pnas.org/content/105/31/10699.full.pdf
Simons, E.L. (1997). "Chapter 6: Lemurs: Old and New". In Goodman, S.M.; Patterson, B.D (eds.). Natural Change and Human Impact in Madagascar. Smithsonian Institution Press. pp. 142–166. ISBN 978-1-56098-682-9. 978-1-56098-682-9
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7
Nowak, R.M. (1999). "Family Archaeolemuridae: Baboon Lemurs". Walker's Mammals of the World (6th ed.). Johns Hopkins University Press. pp. 91–92. ISBN 978-0-8018-5789-8. 978-0-8018-5789-8
Mittermeier, R.A.; Konstant, W.R.; Hawkins, F.; Louis, E.E.; et al. (2006). Lemurs of Madagascar. Illustrated by S.D. Nash (2nd ed.). Conservation International. pp. 37–51. ISBN 1-881173-88-7. OCLC 883321520. 1-881173-88-7