Archaeoindris
Archaeoindris Temporal range: Pleistocene-Holocene
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Archaeoindris fontoynontii skull | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Mammalia |
Order: | Primates |
Suborder: | Strepsirrhini |
Family: | †Palaeopropithecidae |
Genus: | †Archaeoindris Standing, 1909 |
Species: | †A. fontoynontii
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Binomial name | |
†Archaeoindris fontoynontii Standing, 1909
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Subfossil sites forArchaeoindris fontoynontii[1] | |
Synonyms[2] | |
Lemuridotherium madagascariense Standing, 1910 |
Archaeoindris fontoynontii is an extinct giant lemur and the largest primate known to have evolved on Madagascar, comparable in size to a male gorilla. It belonged to a family of extinct lemurs known as "sloth lemurs" (Palaeopropithecidae) and, because of its extremely large size, it has been compared to the ground sloths that once roamed North and South America. It was most closely related to Palaeopropithecus, the second largest type of sloth lemur. Along with the other sloth lemurs, Archaeoindris was related to the living indri, sifakas, and woolly lemurs, as well as the recently extinct monkey lemurs (Archaeolemuridae). The genus, Archaeoindris, translates to "ancient indri-like lemur", even though it probably became extinct recently, around 350 BCE.
Archaeoindris was first described by
The skeleton of Archaeoindris was massive and robust, and shared many traits with that of Palaeopropithecus. The arms were longer than the legs, but no hand or foot bones have been found for comparison with the other sloth lemurs. Size estimates based on the limited remains have varied widely, ranging as high as 244 kilograms (538 pounds), but the most thorough statistical investigation using
Misattributions and limited remains have resulted in varying opinions about the way Archaeoindris moved in its environment, ranging from tree-dwelling to ground-dwelling. Its skeleton suggests it was a deliberate climber that visited the ground to travel.
The diet of Archaeoindris was mostly leaves, and its habitat—prior to human arrival—was a mix of
Etymology
The generic name Archaeoindris, meaning "ancient indri-like lemur", is derived from the Greek word ἀρχαῖος (archaios, or "ancient") and indris, a common variation of the generic name Indri.[3] The species name, fontoynontii (sometimes spelled fontoynonti), was selected in honor of Antoine Maurice Fontoynont, the president of the Académie Malgache (Malagasy Academy) at the time. Fontoynont was reported to have been supervising the excavation when it was discovered.[4]
Evolutionary history
Archaeoindris was a type of sloth lemur (family Palaeopropithecidae), a recently extinct family of giant lemurs (known as subfossil lemurs) native to Madagascar. Its ancestors were likely arboreal (tree-dwelling), and this giant sloth lemur has been compared to the extinct giant ground sloths of North and South America.[5]
Phylogeny of Archaeoindris and its closest lemur relatives[6][7] | |||||||||||||||||||||||||||||||||||||||
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Archaeoindris was most closely related to Palaeopropithecus,[1] a genus containing the second largest of the sloth lemurs and specialized for suspensory behavior in its arboreal habitat.[8] Traits of the postcranium (skeleton below the skull) indicate that Babakotia was the next most closely related sloth lemur to Archaeoindris and Palaeopropithecus, followed by Mesopropithecus,[1] the smallest of the sloth lemurs.[9]
All four genera of sloth lemurs are known to be a
However, other anatomical and developmental traits suggested that monkey lemurs might be more closely related to family Lemuridae, which include five genera of lemur, including the ring-tailed lemur (Lemur catta). Molecular analysis has shown strong support for the former, placing the monkey lemurs in a clade with the sloth lemurs and indriids.[1]
Taxonomic classification
The family Palaeopropithecidae contained a large number of species compared to most other subfossil lemur families. It included four known genera and seven species, all of which are now extinct.[10] Among these was the genus Archaeoindris, one of only a few monotypic lemur taxa.[11]
Archaeoindris fontoynontii was first described by Herbert F. Standing in 1909 from two fragments of a maxilla (upper jaw) and a complete mandible (lower jaw).[12][13] These type specimens—AM-6239 (maxillae) and AM-6237 (mandible)—are stored in the collection at the University of Antananarivo.[14] The mandible contains a complete set of upper teeth, the left maxillary fragment contains the last premolar (P4) and all three molars (M1–M3), and the right maxillary fragment bears both premolars (P2 and P4) and the first molar (M1).[13]
At the time, Standing noted similarities with the
Only six postcranial specimens of Archaeoindris have been found. Two of these belonged to an adult and include a damaged humerus (upper arm bone) and an almost complete femur (thigh bone). The other four come from an immature individual and include a damaged humerus, a damaged ulna (lower arm bone), and two femurs, both lacking the epiphyses (rounded end of the bone) on both ends.
Archaeoindris is one of the least common of the subfossil lemurs, and the few known specimens were all found at
Historically, some remains from other subfossil lemurs have been mistakenly attributed to Archaeoindris, resulting in incorrect interpretations of its anatomy and behavior.[12] In 1934, Lamberton missed earlier attribution errors[16] and incorrectly labeled a tibia and two fibulae (lower leg bones) from a species of koala lemur (Megaladapis grandidieri) as belonging to Archaeoindris. Because of these misattributions and Lamberton's use of the immature bones, his reconstruction was inaccurate.[12][17]
In 1936, Alice Carleton corrected Lamberton by identifying the tibia and fibulae as belonging to a koala lemur. Carleton's corrections were later confirmed and other misattributions were corrected in the 1960s and 1970s by Alan Walker and William L. Jungers.[12][18]
In 1910, twenty-four years before Lamberton's monograph on Archaeoindris, Standing identified a massive right femur from Ampasambazimba as a new species, Lemuridotherium madagascariense. Although Standing recognized the strong similarities between Lemuridotherium and Archaeoindris, he placed them in separate genera due to what he perceived as a great size difference.[18] Lamberton was also persuaded by the size difference, partly because he failed to recognize the smaller tibia and fibulae as belonging to the smaller Megaladapis grandidieri. Furthermore, Lamberton did not realize that the smaller femurs he assigned to Archaeoindris belonged to a juvenile.[19]
Although some later authors considered Lemuridotherium a
Anatomy and physiology
Though similar to Palaeopropithecus, Archaeoindris was significantly larger and more robust.[5][14] Archaeoindris was one of the largest primates to ever evolve,[10] and was the largest-known strepsirrhine primate,[13] weighing an estimated 160 kg (350 lb).[2] It was roughly the size of an adult male gorilla,[12] which was first noted by Lamberton.[20]
Since its discovery, size estimates have varied from "larger than a human" to "possibly the largest primate ever". In a study by Jungers from 1990, the area of its molar teeth predicted a mass of 230.5 kg (508 lb), while the
Like all three species of Palaeopropithecus, Archaeoindris exhibited
Unlike Palaeopropithecus the rims of the orbits (eye sockets) were not as thick.[25] The area of the orbit was 946 mm2 (1.466 sq in), comparable to that of gorillas. Based on the ratio of its orbit area to the size of its optic canal, Archaeoindris had low retinal summation, meaning its eyes were less sensitive to light (like living diurnal lemurs). Yet the ratio was not as low as in comparably sized apes, suggesting Archaeoindris had low visual acuity and lacked trichromatic color vision.[28]
The jaw exhibited a long, robust
Most bones of the postcranial skeleton, including the bones of the hands, feet, vertebral column, ribs,
In the adult, the humerus was significantly longer than the femur, while in the immature specimen, both the humerus and ulna were much longer than the femur,[33] making the arms considerably longer than the legs, as also seen in Palaeopropithecus. The relative length of the arms to the legs was shorter in Archaeoindris, so although its intermembral index was over 100, it was lower than that of Palaeopropithecus.[2][34]
Behavior
Archaeoindris is thought to have been a leaf-eater (folivorous),[5] a view supported by wear patterns on its teeth.[35] Its fused mandibular symphyses and the likelihood of accelerated dental development suggest that it began processing fibrous foods in the mouth with thorough chewing.[29] Its diet may also have included some fruits and seeds.[36] Like most of the other giant lemurs, Archaeoindris is thought to have been diurnal because of its relatively small orbits, which are comparable to those of gorillas.[37]
Both Standing and Lamberton assumed Archaeoindris to be a slow-moving tree-dweller like Megaladapis, primarily due to the misattributed bones. Lamberton also speculated that it would have resembled a ground sloth—a view later supported by Jungers in 1980 after several misattributions had been corrected and having considered its gorilla-like size. Jungers went on to propose that it would have spent most of its time on the ground (terrestrial).
However, the functional morphology of its hip joint indicates a degree of mobility typically seen in more arboreal animals.[33] Other traits shared with Palaeopropithecus, particularly seen in the femur, suggest that Archaeoindris spent considerable time in the trees for feeding and possibly nesting,[25][38] although it also would have visited the ground to feed and travel. It is described as a deliberate, scansorial (climbing) browser, and it is unknown whether it was like Palaeopropithecus in performing hang-feeding since hand and foot bones are missing. Given its bulky size, this would be unexpected.[33]
Distribution and habitat
Archaeoindris is known from only one subfossil site, Ampasambazimba, in central Madagascar, and all remains date to the Late
Extinction
Despite being the most species-rich family among the giant lemurs, all four genera of sloth lemur, including Archaeoindris, have gone extinct.[35] Radiocarbon dating of the stratigraphic level of some of the Archaeoindris remains were dated to 8000 BP,[5] while two other specimens were dated to 2362–2149 BP (412–199 BCE) and 2711–2338 BP (761–388 BCE).[43] From these dates, it is likely that Archaeoindris was still alive on the high plateau in 350 BCE when the first humans reached the west coast of Madagascar,[44] despite being rare by that time. Consequently, it would have been especially vulnerable to hunting and habitat loss.[5]
References
- ^ a b c d Godfrey, Jungers & Burney 2010, p. 354.
- ^ a b c d e f g h i j k Godfrey, Jungers & Burney 2010, p. 356.
- ^ Dunkel, Zijlstra & Groves 2011–2012, p. 68.
- ^ Standing 1909, p. 9.
- ^ a b c d e f g Nowak 1999, p. 91.
- ^ Orlando et al. 2008, p. 4 of 9.
- ^ a b Godfrey & Jungers 2003a, p. 1252.
- ^ Mittermeier et al. 2010, pp. 37–40.
- ^ Mittermeier et al. 2010, pp. 39–40.
- ^ a b Jungers, Demes & Godfrey 2008, p. 343.
- ^ Godfrey & Jungers 2003a, p. 1248.
- ^ a b c d e f g Godfrey & Jungers 2002, p. 101.
- ^ a b c d Vuillaume-Randriamanantena 1988, p. 379.
- ^ a b c d e Godfrey & Jungers 2002, p. 112.
- ^ Vuillaume-Randriamanantena 1988, p. 390.
- ^ a b Godfrey & Jungers 2003b, p. 255.
- ^ Godfrey, Jungers & Burney 2010, p. 361.
- ^ a b c Vuillaume-Randriamanantena 1988, p. 380.
- ^ Vuillaume-Randriamanantena 1988, pp. 381–382.
- ^ a b Jungers, Demes & Godfrey 2008, p. 344.
- ^ a b Jungers, Demes & Godfrey 2008, p. 345.
- ^ Jungers, Demes & Godfrey 2008, p. 347.
- ^ Jungers, Demes & Godfrey 2008, p. 350.
- ^ Jungers 1990, p. 114.
- ^ a b c d Godfrey & Jungers 2003b, p. 256.
- ^ a b Godfrey, Jungers & Burney 2010, p. 355.
- ^ a b Tattersall 1982, p. 224.
- ^ Godfrey, Jungers & Schwartz 2006, p. 53–55.
- ^ a b c Godfrey & Jungers 2002, p. 103.
- ^ Jungers et al. 2001, p. 388.
- ^ Tattersall 1982, p. 225.
- ^ Vuillaume-Randriamanantena 1988, p. 387.
- ^ a b c Godfrey & Jungers 2002, p. 102.
- ^ Vuillaume-Randriamanantena 1988, p. 389.
- ^ a b Godfrey, Jungers & Schwartz 2006, p. 49.
- ^ Godfrey & Jungers 2003b, p. 257.
- ^ Godfrey, Jungers & Schwartz 2006, p. 53.
- ^ Jungers et al. 2001, p. 393.
- ^ Godfrey, Jungers & Burney 2010, pp. 356–357.
- ^ MacPhee, Burney & Wells 1985, p. 467.
- ^ MacPhee, Burney & Wells 1985, p. 463.
- ^ Godfrey & Jungers 2002, p. 118.
- ^ Godfrey, Jungers & Burney 2010, p. 353.
- ^ Mittermeier et al. 2010, pp. 37 & 39.
Literature cited
- Dunkel, A. R.; Zijlstra, J. S.; Groves, C. P. (2011–2012). "Giant rabbits, marmosets, and British comedies: etymology of lemur names, part 1" (PDF). Lemur News. 16: 64–70. ISSN 1608-1439. Archived from the original(PDF) on 2016-11-06. Retrieved 2012-08-19.
- Godfrey, L. R.; Jungers, W. L. (2002). "Quaternary fossil lemurs". In Hartwig, W. C (ed.). The Primate Fossil Record. ISBN 978-0-521-66315-1.
- Godfrey, L. R.; Jungers, W. L. (2003a). "Subfossil Lemurs". In Goodman, S. M.; Benstead, J. P (eds.). The Natural History of Madagascar. ISBN 978-0-226-30306-2.
- Godfrey, L. R.; Jungers, W. L. (2003b). "The extinct sloth lemurs of Madagascar" (PDF). Evolutionary Anthropology: Issues, News, and Reviews. 12 (6): 252–263. S2CID 4834725. Archived from the original(PDF) on 2012-03-20. Retrieved 2012-08-21.
- Godfrey, L. R.; Jungers, W. L.; Burney, D. A. (2010). "Subfossil Lemurs of Madagascar". In Werdelin, L.; Sanders, W. J (eds.). Cenozoic Mammals of Africa. ISBN 978-0-520-25721-4.
- Godfrey, L. R.; Jungers, W. L.; Schwartz, G. T. (2006). "Ecology and Extinction of Madagascar's Subfossil Lemurs". In Gould, L.; Sauther, M. L. (eds.). Lemurs: Ecology and Adaptation. Developments in Primatology: Progress and Prospect. Springer. pp. 41–64. ISBN 978-0-387-34585-7.
- Jungers, W. L. (1990). "Problems and methods in reconstructing body size in fossil primates". In Damuth, J.; MacFadden, B. J (eds.). Body Size in Mammalian Paleobiology: Estimation and Biological Implications. Cambridge University Press. pp. 103–118. ISBN 978-0-521-36099-9.
- Jungers, W. L.; Demes, B.; Godfrey, L. R. (2008). "How Big were the "Giant" Extinct Lemurs of Madagascar?". In Fleagle, J. G.; Gilbert, C. C. (eds.). Elwyn Simons: A Search for Origins. Developments in Primatology: Progress and Prospects. pp. 343–360. ISBN 978-0-387-73895-6.
- Jungers, W. L.; Godfrey, L. R.; Simons, E. L.; Wunderlich, R. E.; Richmond, B. G.; Chatrath, P. S. (2001). "Ecomorphology and Behavior of Giant Extinct Lemurs from Madagascar". In Plavcan, J. M.; Kay, R. F.; Jungers, W. L.; van Schaik, C. P. (eds.). Reconstructing Behavior in the Primate Fossil Record (PDF). Springer. pp. 371–411. ISBN 978-0-306-46604-5. Archived from the original(PDF) on 2006-09-09.
- MacPhee, R. D. E.; Burney, D. A.; Wells, N. A. (1985). "Early Holocene chronology and environment of Ampasambazimba, A Malagasy subfossil lemur site". International Journal of Primatology. 6 (5): 463–489. S2CID 44449535.
- OCLC 670545286.
- Nowak, R. M. (1999). Walker's Mammals of the World (6th ed.). ISBN 978-0-8018-5789-8.
- 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 (121): 121. PMID 18442367.
- Standing, H. F. (1909). "Subfossiles provenant des fouilles d'Ampasambazimba". Bulletin de l'Académie Malgache (in French). 6: 9–11.
- Tattersall, I. (1982). The Primates of Madagascar. ISBN 978-0-231-04704-3.
- Vuillaume-Randriamanantena, M. (1988). "The taxonomic attributions of giant subfossil lemur bones from Ampasambazimba: Archaeoindris and Lemuridotherium". Journal of Human Evolution. 17 (4): 379–391. .