Recent fieldwork in Argentina has resulted in the recovery of numerous new specimens of palaeothe... more Recent fieldwork in Argentina has resulted in the recovery of numerous new specimens of palaeothentid marsupials, an important component of the Deseadan-Santacrucian (Oligocene-middle Miocene) mammalian fauna of Patagonia. The 1994 collections include a new genus and species from the early Miocene Pinturas Formation at Estancia La Cafnada and the first complete lower dentition ofAcdestis oweni from a locality in the Santa Cruz Formation along the Rio Chalia. Specimens from the La Cafiada locality, an isolated ml and two dentary fragments, represent a new genus and species of a very large palaeothentine, here named Titanothentes simpsoni, new genus and species. Several dental features distinguish the new form from its closest relatives. Chiefamong
The Faywn Prim.ate Forest Revisited In Oligocene times, the Fayum area of northern Egypt was a su... more The Faywn Prim.ate Forest Revisited In Oligocene times, the Fayum area of northern Egypt was a subtropical to tropical lowland coastal plain with damp soils and seasonal rainfall that supported an abundance and variety of vegetation, including lianes (large vines), tall trees, and possibly mangroves, and a large and varied vertebrate fauna. The Oligocene marine strandline was close by and principal Jebel Qatrani Formation streams were probably brackish several kilometers inland due to tidal incursions. Sediments of the Jebel Qatrani Formation were deposited by several large meandering streams, associated with minor but sometimes extensive flood basin ponds. These rocks provide no evidence for the former existence, in early Tertiary time, of a "Proto-Nile" River. Large accumulations of silicified fossil logs in the Jebel Qatrani Formation are autochthonous and the logs were transported only a short distance before burial. The Oligocene higher primates A•~g;Ptopithecus, Propliopithecus, Parapithecus, and Apidium lived in this paleoenvironment and postcranial remains of Aeg;ptopithecus and Apidium demonstrate that these animals were arboreal. This scenario for the paleoenvironment of the Fayum area in Oligocene times differs greatly from the nearly treeless, sparsely vegetated, semiarid sahtlien Oligocene Fayum paleoenvironment populated by terrestrial primates that ,vas recently proposed by Kortlandt (1980).
Over the past century, numerous vertebrate fossils collected near the town of Ramnagar, India, ha... more Over the past century, numerous vertebrate fossils collected near the town of Ramnagar, India, have proven to be important for understanding the evolution and biogeography of many mammalian groups. Primates from Ramnagar, though rare, include a number of hominoid specimens attributable to Sivapithecus, as well as a single published mandibular fragment preserving the P 4-M 1 of the Miocene adapoid Sivaladapis palaeindicus. Since 2010, we have renewed fossil prospecting in the Lower Siwalik deposits near Ramnagar in an attempt to better understand the evolution, biogeographic timing, and paleoclimatic context of mammalian radiations in Asia, with a particular focus on primates. Our explorations have resulted in the identification of new fossil localities, including the site of Sunetar. The age of Sunetar and the Ramnagar region, in general, is tentatively dated between 14 and 11 Ma. In 2014, a partial right mandible of a sivaladapid primate was recovered at Sunetar, preserving the corpus with P 4 roots and worn M 1-M 3 dentition. Although sivaladapids are known by numerous specimens of two genera (Sivaladapis and Indraloris) at Lower Siwalik sites on the Potwar Plateau (Pakistan) and at the Middle Siwalik locality of Haritalyangar (India), this new specimen is just the second sivaladapid recovered from the Ramnagar region. Our analyses suggest that the new specimen is distinct from all other sivaladapids, and we therefore describe it as a new genus and species close to the base of the Sivaladapinae.
''tarsirotators'' in contrast to ''tarsifulcrumating'' galagos and tarsiers. Sizerelated variatio... more ''tarsirotators'' in contrast to ''tarsifulcrumating'' galagos and tarsiers. Sizerelated variation in hindlimb kinematics is surprisingly limited within the sample of indriid leapers, although acceleration time (the duration of the push off) does increase with increasing body size. In addition, forelimb kinematics reveal a clear size-related pattern; the smallest indriid species leaps with its arms tucked into the chest-like tarsiers and galagos-and the larger-bodied indriid species use their arms during acceleration for take off as well as to initiate body rotation while airborne. The small-bodied species rely exclusively on their tails for this same purpose. Whereas relative tail length decreases with increasing body size in vertical clingers and leapers, the relative weight of the forelimbs increases and makes their action more effective.
American Journal of Physical Anthropology, Nov 1, 1978
Micropithecus clarki, from Miocene sediments of Napak. Uganda, is the smallest known hominoid pri... more Micropithecus clarki, from Miocene sediments of Napak. Uganda, is the smallest known hominoid primate, living or fossil. In facial morphology i t is very similar to extant gibbons. Dentally, it is most similar to t h e small apes from t h e Miocene of Kenya, Dendropithecus and Limnopithecus. All of t h e apes from t h e early Miocene of East Africa seem to represent a single phyletic group t h a t could be easily derived from t h e Oligocene apes known from the Fayum of Egypt. Pliopithecus from t h e Miocene of Europe is more closely allied with t h e Oligocene radiation than with t h e later East African radiation.
The provenance and age of two Homo sapiens fossils (Omo I and Omo II) from the Kibish Formation i... more The provenance and age of two Homo sapiens fossils (Omo I and Omo II) from the Kibish Formation in southern Ethiopia have been much debated. Here we confirm that Omo I and the somewhat more primitive-looking Omo II calvariae are from similar stratigraphic levels in Member I of the Kibish Formation. Based on 40 Ar/ 39 Ar age measurements on alkali feldspar crystals from pumice clasts in the Nakaa'kire Tuff, a tuffaceous bed in Member I just below the hominin levels, we place an older limit of 198 AE 14 ka (weighted mean age ¼ 196 AE 2 ka) for the hominins. A younger limit of 104 AE 7 ka (weighted mean age ¼ 104 AE 1 ka) is provided by feldspars separated from pumice clasts in the Aliyo Tuff in Member III. Geological evidence indicates rapid deposition of each member of the Kibish Formation, concurrent with deposition of sapropels in the Mediterranean Sea. The 40 Ar/ 39 Ar age measurements, together with correlations with sapropels, indicate that the hominin fossils are close in age to the older limit. Our preferred estimate of the age of the hominins is 195 AE 5 ka, making them the earliest welldated anatomically modern humans yet described.
Recent palrontological fieldlvork in southern Argentina has g~vwratr~d many new primate fossils f... more Recent palrontological fieldlvork in southern Argentina has g~vwratr~d many new primate fossils from the early-middle I2liocenc Pintnuh Formation in the northwestern part of Santa (:rux Provincr. This paper describes three new species-a small species of the previousi! dcsrrihvd genus, .Sorincebus, and two species of a new, larger genus more similar to Homunt~ulus. A fbssil primate from Colhurhuapian deposits at thr G~GI Barranca in nearby Chubut Province, previousI> assigned to I/omuntu/u.~. ih provisionally placrd in the grnus .Soriacebus. All of the fossil platyrrhincs from Santa Crux Province have been repeatedly shown to ha\c phrnrti~~ similarities to .lotu.r. Ca//icebu.c and pithcciinrs, hut their phylttic wlatir~rru arr far from rewlvcd.
Proceedings of the National Academy of Sciences of the United States of America, Feb 2, 1999
Numerous biomolecular studies from the past 20 years have indicated that the large African monkey... more Numerous biomolecular studies from the past 20 years have indicated that the large African monkeys Papio, Theropithecus, and Mandrillus have a diphyletic relationship with different species groups of mangabeys. According to the results of these studies, mandrills and drills (Mandrillus) are most closely related to the torquatus-galeritus group of mangabeys placed in the genus Cercocebus, whereas baboons (Papio) and geladas (Theropithecus) are most closely related to the albigena-aterrimus mangabeys, now commonly placed in the genus Lophocebus. However, there has been very little morphological evidence linking mandrills on the one hand and baboons and geladas on the other with different groups of mangabeys. In a study of mangabey locomotion and skeletal anatomy, we have identified features of the postcranial skeleton and the dentition that support the molecular phylogeny and clearly link mandrills with Cercocebus and Papio with Lophocebus. Moreover, the features linking Cercocebus and Mandrillus accord with ecological studies of these species indicating that these two genera are a cryptic clade characterized by unique adaptations for gleaning insects, hard nuts, and seeds from the forest f loor.
Proceedings of the National Academy of Sciences, 2021
Significance The Paleogene dispersals of monkeys and rodents from Africa to South America permane... more Significance The Paleogene dispersals of monkeys and rodents from Africa to South America permanently and profoundly altered the composition of mammalian communities in the Neotropics, but the timing of these colonization events remains uncertain. Through a combination of geochronological analyses (detrital zircon dating of the Santa Rosa fossil locality in eastern Perú) and phylogenetic biochronological analyses (tip-dating age estimation of caviomorph rodents), we demonstrate that the oldest known primates and rodents of South America are unlikely to be older than Early Oligocene in age and are not Eocene in age as previously postulated. There are no grounds for rejecting the possibility of an earlier arrival for either clade, but at present the fossil record provides no evidence for earlier dispersals.
Proceedings of the Royal Society B: Biological Sciences, 2020
The fossil record of ‘lesser apes’ (i.e. hylobatids = gibbons and siamangs) is virtually non-exis... more The fossil record of ‘lesser apes’ (i.e. hylobatids = gibbons and siamangs) is virtually non-existent before the latest Miocene of East Asia. However, molecular data strongly and consistently suggest that hylobatids should be present by approximately 20 Ma; thus, there are large temporal, geographical, and morphological gaps between early fossil apes in Africa and the earliest fossil hylobatids in China. Here, we describe a new approximately 12.5–13.8 Ma fossil ape from the Lower Siwaliks of Ramnagar, India, that fills in these long-standing gaps with implications for hylobatid origens. This ape represents the first new hominoid species discovered at Ramnagar in nearly a century, the first new Siwalik ape taxon in more than 30 years, and likely extends the hylobatid fossil record by approximately 5 Myr, providing a minimum age for hylobatid dispersal coeval to that of great apes. The presence of crown hylobatid molar features in the new species indicates an adaptive shift to a more ...
Objectives: Extant primate crania represent a small subset of primate crania that have existed. T... more Objectives: Extant primate crania represent a small subset of primate crania that have existed. The main objective here is to examine how the inclusion of fossil crania changes our understanding of primate cranial diversity relative to analyses of extant primates. We hypothesize that fossil taxa will change the major axes of cranial shape, occupy new areas of morphospace, change the relative diversity of major primate clades, and fill in notable gaps separating major primate taxa/ clades. Materials and Methods: Eighteen 3D landmarks were collected on 157 extant and fossil crania representing 90 genera. Data were subjected to a Generalized Procrustes Analysis then principal components analysis. Relative diversity between clades was assessed using an F-statistic. Results: Fossil taxa do not significantly alter major axes of cranial shape, but they do occupy unique areas of morphospace, change the relative diversity between clades, and fill in notable gaps in primate cranial evolution. Strepsirrhines remain significantly less diverse than anthropoids. Fossil hominins fill the gap in cranial morphospace between extant great apes and modern humans. Discussion: The morphospace outlined by living primates largely includes that occupied by fossil taxa, suggesting that the cranial diversity of living primates generally encompasses the total diversity that has evolved in this Order. The evolution of the anthropoid cranium was a significant event allowing anthropoids to achieve significantly greater cranial diversity compared to strepsirrhines. Fossil taxa fill in notable gaps within and between clades, highlighting their transitional nature and eliminating the appearance of large morphological distances between extant taxa, particularly in the case of extant hominids.
Recent fieldwork in Argentina has resulted in the recovery of numerous new specimens of palaeothe... more Recent fieldwork in Argentina has resulted in the recovery of numerous new specimens of palaeothentid marsupials, an important component of the Deseadan-Santacrucian (Oligocene-middle Miocene) mammalian fauna of Patagonia. The 1994 collections include a new genus and species from the early Miocene Pinturas Formation at Estancia La Cafnada and the first complete lower dentition ofAcdestis oweni from a locality in the Santa Cruz Formation along the Rio Chalia. Specimens from the La Cafiada locality, an isolated ml and two dentary fragments, represent a new genus and species of a very large palaeothentine, here named Titanothentes simpsoni, new genus and species. Several dental features distinguish the new form from its closest relatives. Chiefamong
The Faywn Prim.ate Forest Revisited In Oligocene times, the Fayum area of northern Egypt was a su... more The Faywn Prim.ate Forest Revisited In Oligocene times, the Fayum area of northern Egypt was a subtropical to tropical lowland coastal plain with damp soils and seasonal rainfall that supported an abundance and variety of vegetation, including lianes (large vines), tall trees, and possibly mangroves, and a large and varied vertebrate fauna. The Oligocene marine strandline was close by and principal Jebel Qatrani Formation streams were probably brackish several kilometers inland due to tidal incursions. Sediments of the Jebel Qatrani Formation were deposited by several large meandering streams, associated with minor but sometimes extensive flood basin ponds. These rocks provide no evidence for the former existence, in early Tertiary time, of a "Proto-Nile" River. Large accumulations of silicified fossil logs in the Jebel Qatrani Formation are autochthonous and the logs were transported only a short distance before burial. The Oligocene higher primates A•~g;Ptopithecus, Propliopithecus, Parapithecus, and Apidium lived in this paleoenvironment and postcranial remains of Aeg;ptopithecus and Apidium demonstrate that these animals were arboreal. This scenario for the paleoenvironment of the Fayum area in Oligocene times differs greatly from the nearly treeless, sparsely vegetated, semiarid sahtlien Oligocene Fayum paleoenvironment populated by terrestrial primates that ,vas recently proposed by Kortlandt (1980).
Over the past century, numerous vertebrate fossils collected near the town of Ramnagar, India, ha... more Over the past century, numerous vertebrate fossils collected near the town of Ramnagar, India, have proven to be important for understanding the evolution and biogeography of many mammalian groups. Primates from Ramnagar, though rare, include a number of hominoid specimens attributable to Sivapithecus, as well as a single published mandibular fragment preserving the P 4-M 1 of the Miocene adapoid Sivaladapis palaeindicus. Since 2010, we have renewed fossil prospecting in the Lower Siwalik deposits near Ramnagar in an attempt to better understand the evolution, biogeographic timing, and paleoclimatic context of mammalian radiations in Asia, with a particular focus on primates. Our explorations have resulted in the identification of new fossil localities, including the site of Sunetar. The age of Sunetar and the Ramnagar region, in general, is tentatively dated between 14 and 11 Ma. In 2014, a partial right mandible of a sivaladapid primate was recovered at Sunetar, preserving the corpus with P 4 roots and worn M 1-M 3 dentition. Although sivaladapids are known by numerous specimens of two genera (Sivaladapis and Indraloris) at Lower Siwalik sites on the Potwar Plateau (Pakistan) and at the Middle Siwalik locality of Haritalyangar (India), this new specimen is just the second sivaladapid recovered from the Ramnagar region. Our analyses suggest that the new specimen is distinct from all other sivaladapids, and we therefore describe it as a new genus and species close to the base of the Sivaladapinae.
''tarsirotators'' in contrast to ''tarsifulcrumating'' galagos and tarsiers. Sizerelated variatio... more ''tarsirotators'' in contrast to ''tarsifulcrumating'' galagos and tarsiers. Sizerelated variation in hindlimb kinematics is surprisingly limited within the sample of indriid leapers, although acceleration time (the duration of the push off) does increase with increasing body size. In addition, forelimb kinematics reveal a clear size-related pattern; the smallest indriid species leaps with its arms tucked into the chest-like tarsiers and galagos-and the larger-bodied indriid species use their arms during acceleration for take off as well as to initiate body rotation while airborne. The small-bodied species rely exclusively on their tails for this same purpose. Whereas relative tail length decreases with increasing body size in vertical clingers and leapers, the relative weight of the forelimbs increases and makes their action more effective.
American Journal of Physical Anthropology, Nov 1, 1978
Micropithecus clarki, from Miocene sediments of Napak. Uganda, is the smallest known hominoid pri... more Micropithecus clarki, from Miocene sediments of Napak. Uganda, is the smallest known hominoid primate, living or fossil. In facial morphology i t is very similar to extant gibbons. Dentally, it is most similar to t h e small apes from t h e Miocene of Kenya, Dendropithecus and Limnopithecus. All of t h e apes from t h e early Miocene of East Africa seem to represent a single phyletic group t h a t could be easily derived from t h e Oligocene apes known from the Fayum of Egypt. Pliopithecus from t h e Miocene of Europe is more closely allied with t h e Oligocene radiation than with t h e later East African radiation.
The provenance and age of two Homo sapiens fossils (Omo I and Omo II) from the Kibish Formation i... more The provenance and age of two Homo sapiens fossils (Omo I and Omo II) from the Kibish Formation in southern Ethiopia have been much debated. Here we confirm that Omo I and the somewhat more primitive-looking Omo II calvariae are from similar stratigraphic levels in Member I of the Kibish Formation. Based on 40 Ar/ 39 Ar age measurements on alkali feldspar crystals from pumice clasts in the Nakaa'kire Tuff, a tuffaceous bed in Member I just below the hominin levels, we place an older limit of 198 AE 14 ka (weighted mean age ¼ 196 AE 2 ka) for the hominins. A younger limit of 104 AE 7 ka (weighted mean age ¼ 104 AE 1 ka) is provided by feldspars separated from pumice clasts in the Aliyo Tuff in Member III. Geological evidence indicates rapid deposition of each member of the Kibish Formation, concurrent with deposition of sapropels in the Mediterranean Sea. The 40 Ar/ 39 Ar age measurements, together with correlations with sapropels, indicate that the hominin fossils are close in age to the older limit. Our preferred estimate of the age of the hominins is 195 AE 5 ka, making them the earliest welldated anatomically modern humans yet described.
Recent palrontological fieldlvork in southern Argentina has g~vwratr~d many new primate fossils f... more Recent palrontological fieldlvork in southern Argentina has g~vwratr~d many new primate fossils from the early-middle I2liocenc Pintnuh Formation in the northwestern part of Santa (:rux Provincr. This paper describes three new species-a small species of the previousi! dcsrrihvd genus, .Sorincebus, and two species of a new, larger genus more similar to Homunt~ulus. A fbssil primate from Colhurhuapian deposits at thr G~GI Barranca in nearby Chubut Province, previousI> assigned to I/omuntu/u.~. ih provisionally placrd in the grnus .Soriacebus. All of the fossil platyrrhincs from Santa Crux Province have been repeatedly shown to ha\c phrnrti~~ similarities to .lotu.r. Ca//icebu.c and pithcciinrs, hut their phylttic wlatir~rru arr far from rewlvcd.
Proceedings of the National Academy of Sciences of the United States of America, Feb 2, 1999
Numerous biomolecular studies from the past 20 years have indicated that the large African monkey... more Numerous biomolecular studies from the past 20 years have indicated that the large African monkeys Papio, Theropithecus, and Mandrillus have a diphyletic relationship with different species groups of mangabeys. According to the results of these studies, mandrills and drills (Mandrillus) are most closely related to the torquatus-galeritus group of mangabeys placed in the genus Cercocebus, whereas baboons (Papio) and geladas (Theropithecus) are most closely related to the albigena-aterrimus mangabeys, now commonly placed in the genus Lophocebus. However, there has been very little morphological evidence linking mandrills on the one hand and baboons and geladas on the other with different groups of mangabeys. In a study of mangabey locomotion and skeletal anatomy, we have identified features of the postcranial skeleton and the dentition that support the molecular phylogeny and clearly link mandrills with Cercocebus and Papio with Lophocebus. Moreover, the features linking Cercocebus and Mandrillus accord with ecological studies of these species indicating that these two genera are a cryptic clade characterized by unique adaptations for gleaning insects, hard nuts, and seeds from the forest f loor.
Proceedings of the National Academy of Sciences, 2021
Significance The Paleogene dispersals of monkeys and rodents from Africa to South America permane... more Significance The Paleogene dispersals of monkeys and rodents from Africa to South America permanently and profoundly altered the composition of mammalian communities in the Neotropics, but the timing of these colonization events remains uncertain. Through a combination of geochronological analyses (detrital zircon dating of the Santa Rosa fossil locality in eastern Perú) and phylogenetic biochronological analyses (tip-dating age estimation of caviomorph rodents), we demonstrate that the oldest known primates and rodents of South America are unlikely to be older than Early Oligocene in age and are not Eocene in age as previously postulated. There are no grounds for rejecting the possibility of an earlier arrival for either clade, but at present the fossil record provides no evidence for earlier dispersals.
Proceedings of the Royal Society B: Biological Sciences, 2020
The fossil record of ‘lesser apes’ (i.e. hylobatids = gibbons and siamangs) is virtually non-exis... more The fossil record of ‘lesser apes’ (i.e. hylobatids = gibbons and siamangs) is virtually non-existent before the latest Miocene of East Asia. However, molecular data strongly and consistently suggest that hylobatids should be present by approximately 20 Ma; thus, there are large temporal, geographical, and morphological gaps between early fossil apes in Africa and the earliest fossil hylobatids in China. Here, we describe a new approximately 12.5–13.8 Ma fossil ape from the Lower Siwaliks of Ramnagar, India, that fills in these long-standing gaps with implications for hylobatid origens. This ape represents the first new hominoid species discovered at Ramnagar in nearly a century, the first new Siwalik ape taxon in more than 30 years, and likely extends the hylobatid fossil record by approximately 5 Myr, providing a minimum age for hylobatid dispersal coeval to that of great apes. The presence of crown hylobatid molar features in the new species indicates an adaptive shift to a more ...
Objectives: Extant primate crania represent a small subset of primate crania that have existed. T... more Objectives: Extant primate crania represent a small subset of primate crania that have existed. The main objective here is to examine how the inclusion of fossil crania changes our understanding of primate cranial diversity relative to analyses of extant primates. We hypothesize that fossil taxa will change the major axes of cranial shape, occupy new areas of morphospace, change the relative diversity of major primate clades, and fill in notable gaps separating major primate taxa/ clades. Materials and Methods: Eighteen 3D landmarks were collected on 157 extant and fossil crania representing 90 genera. Data were subjected to a Generalized Procrustes Analysis then principal components analysis. Relative diversity between clades was assessed using an F-statistic. Results: Fossil taxa do not significantly alter major axes of cranial shape, but they do occupy unique areas of morphospace, change the relative diversity between clades, and fill in notable gaps in primate cranial evolution. Strepsirrhines remain significantly less diverse than anthropoids. Fossil hominins fill the gap in cranial morphospace between extant great apes and modern humans. Discussion: The morphospace outlined by living primates largely includes that occupied by fossil taxa, suggesting that the cranial diversity of living primates generally encompasses the total diversity that has evolved in this Order. The evolution of the anthropoid cranium was a significant event allowing anthropoids to achieve significantly greater cranial diversity compared to strepsirrhines. Fossil taxa fill in notable gaps within and between clades, highlighting their transitional nature and eliminating the appearance of large morphological distances between extant taxa, particularly in the case of extant hominids.
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Papers by John Fleagle