The assembly of Africa’s iconic C 4 grassland ecosystems is central to evolutionary interpretatio... more The assembly of Africa’s iconic C 4 grassland ecosystems is central to evolutionary interpretations of many mammal lineages, including hominins. C 4 grasses are thought to have become ecologically dominant in Africa only after 10 million years ago (Ma). However, paleobotanical records older than 10 Ma are sparse, limiting assessment of the timing and nature of C 4 biomass expansion. This study uses a multiproxy design to document vegetation structure from nine Early Miocene mammal site complexes across eastern Africa. Results demonstrate that between ~21 and 16 Ma, C 4 grasses were locally abundant, contributing to heterogeneous habitats ranging from forests to wooded grasslands. These data push back the oldest evidence of C 4 grass–dominated habitats in Africa—and globally—by more than 10 million years, calling for revised paleoecological interpretations of mammalian evolution.
Extended Data Fig. 10 | Phylogenetic relationships of A. hui and selected mammaliaforms. Strict c... more Extended Data Fig. 10 | Phylogenetic relationships of A. hui and selected mammaliaforms. Strict consensus tree of 16 equally parsimonious trees (tree length = 2,315,consistency index = 0.3015 and retention index = 0.7001) derived from analysis of 84 cynodont taxa and 530 characters,with multistate characters unordered and unweighted.Bremer values are listed next to the nodes.Adalatherium is highlighted in red.Allotheria—consisting of Cifelliodon, Euharamiyida,Gondwanatheria (including Adalatherium) and Multituberculata—is highlighted in blue.Taxon and character lists,the data matrix,limitations and assumptions,phylogenetic methods and a more detailed explanation of the results are provided in the Supplementary Information.
Extended Data Fig. 6 | Enamel microstructure of A. hui holotype (UA 9030). a–d, Scanning electron... more Extended Data Fig. 6 | Enamel microstructure of A. hui holotype (UA 9030). a–d, Scanning electron micrographs of single postcanine tooth enamel fragment sectioned in various planes.a, Transverse section of entire enamel band from the enamel–dentine junction (EDJ) to the outer enamel surface (OES) (about 0.4-mm thick) showing single layer of radial enamel and absence of distinct layer of prismless external enamel.Prism size increases from,on average,2.3 to 2.8 Μm from the enamel–dentine junction to the outer enamel surface.Prisms close to the enamel–dentine junction are intersected by interprismatic matrix at slightly higher angles than towards the outer enamel surface.b, Transverse section showing the clear distinction between enamel prisms and interprismatic matrix. c, Radial section showing radial enamel in outer zone with prisms surrounded by interprismatic matrix and some cross-sections of prisms showing tubules.d, Radial,but slightly oblique, section showing enamel of inner zon...
Fig. 4 | Key stages in plate tectonic history of Madagascar. a, Position of Madagascar before rif... more Fig. 4 | Key stages in plate tectonic history of Madagascar. a, Position of Madagascar before rifting between West Gondwana (South America and Africa) and East Gondwana (Madagascar,Seychelles,Indian subcontinent, Sri Lanka,Antarctica and Australia) at 183 Myr ago (Early Jurassic epoch). b, Separation of Indo-Madagascar from Antarctica and Australia at 124 Myr ago (mid-Early Cretaceous epoch).c, Separation of Indian subcontinent from Madagascar at 88 Myr ago (mid-Late Cretaceous epoch).d, Approximate time of deposition of Maevarano Formation at 66 Myr ago (latest Cretaceous period).Solid black lines indicate current coastlines of Madagascar and east Africa; brown represents Precambrian terranes;and yellow indicates sedimentary basins along west coast of Madagascar.The discovery site of UA 9030 is indicated by red star in d. Scale bars,500 km.Maps adapted from Earthworks (www.reeves.nl/gond.com).
Extended Data Fig. 3 | Cranium of A. hui holotype (UA 9030). a–e, Photographs of external surface... more Extended Data Fig. 3 | Cranium of A. hui holotype (UA 9030). a–e, Photographs of external surfaces of cranium in right lateral (a), left lateral (b), dorsal (c), ventral (d) and anterior (e) views.a'–e', Labelled ΜCT images of cranium in the same views as in a–e, respectively.f, Labelled ΜCT image of medial view of right side of nasal cavity.aC,alveolus for upper canine; as, alisphenoid;eo, exoccipital; fr,frontal;ID,distal upper incisor;IM,mesial upper incisor; ju, jugal; la, lacrimal;mx, maxilla; na, nasal;os/ps, orbitosphenoid/presphenoid complex;PC,upper postcanine tooth;pe, petrosal;pmx,premaxilla;pt,pterygoid;smx,septomaxilla;sq, squamosal; v,vomer.
Extended Data Fig. 4 | Inner ear of A. hui holotype (UA 9030). a, Ventral view of reconstructed c... more Extended Data Fig. 4 | Inner ear of A. hui holotype (UA 9030). a, Ventral view of reconstructed cranium, with petrosal fragment bounded by red line enlarged in a'. b–e, Reconstructed cochlear canal in dorsomedial (b), ventrolateral (c) and posteroventromedial (d, e) views,with the view in d being slightly more posterior and the view in e slightly more medial.In e, only the medial aspect of cochlear canal in grey is shown, to reveal primary bony lamina and cochlear nerve foramina.Semi-transparent grey,cochlear canal;yellow, cochlear nerve;blue, secondary canal.
Extended Data Fig. 5 | Lower jaw of A. hui holotype (UA 9030). Photographs of left dentary in lef... more Extended Data Fig. 5 | Lower jaw of A. hui holotype (UA 9030). Photographs of left dentary in left column; photographs of right dentary in right column. a, b, Lateral views.c, d, Dorsal (occlusal) views.e, f, Medial views.i, lower incisor;pc, lower postcanine tooth.
Extended Data Fig. 2 | Bivariate plots of body mass estimates for A. hui. a, Relationship between... more Extended Data Fig. 2 | Bivariate plots of body mass estimates for A. hui. a, Relationship between cranial length and body mass in 423 extant mammals, plus estimated body mass in the gondwanatherians A.hui and Vintana sertichi. b, Relationship between cranial width and body mass in 423 extant mammals, plus the estimated body mass in A. hui and V.sertichi. c, Relationship between cranial size and body mass in 423 extant mammals,plus the estimated body mass in A.hui and V.sertichi. d, Relationship between humeral length and body mass in 187 extant therian mammals,plus the estimated body mass in A.hui. e, Relationship between femoral length and body mass in 184 extant species of therian mammal,plus the estimated body mass in A.hui. f, Relationship between stylopodial diaphyseal circumference and body mass as calculated for a sample of 245 tetrapod species45 (data points shown for mammals only, n = 200),plus the estimated body mass in A.hui. Regression lines in a–e are from ordinary leas...
Fig. 3 | Skeleton of A. hui holotype (UA 9030). a–g, Digitally reconstructed skeleton in left lat... more Fig. 3 | Skeleton of A. hui holotype (UA 9030). a–g, Digitally reconstructed skeleton in left lateral view,highlighting the left scapulocoracoid in lateral view (a), thoracic vertebra 6 and lumbar vertebra 7 in anterior and dorsal views (missing parts mirrored and rendered as semi-transparent) (b), the left femur in distal and anterior views (c), the left humerus in anterior and distal views (d), the left astragalus and navicular in anterior view,and left calcaneus in medial and dorsal views (e), left hind foot in dorsal view (f), and the left tibia in lateral and anterior views (g). L,lumbar vertebra; T,thoracic vertebra.Scale bars,5 cm (main skeleton),1 cm (a–d, f, g), 5 mm (e).
Proceedings of the National Academy of Sciences, 2019
Significance Almost nothing is known about the origin and evolution of Old World monkeys (cercopi... more Significance Almost nothing is known about the origin and evolution of Old World monkeys (cercopithecoids) because the first ∼12 million years of their fossil record is documented by only two isolated teeth. We describe a new primitive monkey from Kenya that dates from ∼22 million years ago and reveals a previously unknown stage of evolution. Comparisons between this monkey and other cercopithecoids offer detailed insights into the development of the novelties associated with the evolution of the cercopithecoid dentition, and particularly bilophodonty. Results suggest that this fossil monkey exhibited dental adaptations for frugivory and perhaps hard object feeding. Bilophodonty, the dental trait that unites all living cercopithecoids, evolved later, likely in response to the inclusion of leaves in the diet.
ABSTRACT—The cranium of Vintana sertichi preserves the first associated upper dentition of a gond... more ABSTRACT—The cranium of Vintana sertichi preserves the first associated upper dentition of a gondwanatherian mammal. Gondwanatherians are known almost exclusively from isolated teeth, particularly molariforms. As such, referral of V. sertichi to the Gondwanatheria, differentiation of V. sertichi from other gondwanatherians, and determination of the relationships of V. sertichi to other gondwanatherians must rely heavily on dental morphology. The hypsodont nature, gross morphology, enamel microstructure, and wear pattern of its molariform teeth serve to unequivocally identify the cranium of V. sertichi as that of a sudamericid gondwanatherian. Based on available morphology, V. sertichi appears to have had an upper dental formula of 2.0.1.4. There are two long, curved alveoli in each premaxilla for enlarged, buccolingually compressed, procumbent incisors that were well separated from the cheek teeth by a long diastema. There is no evidence of a canine. The single premolariform tooth appears to have been small and two-rooted, but neither the left nor the right crowns are preserved. Of the eight upper molariform alveoli, four are preserved with teeth in situ, three in the left maxilla (antepenultimate, penultimate, and ultimate) and one in the right (penultimate). The molariform cheek teeth have several salient characteristics: large size, hypsodont crowns, roughly quadrangular outlines, occlusal surfaces worn essentially flat, numerous cementum-filled infundibula, cementum-filled furrows that invaginate from the buccal side but do not extend to the base of the crown, and multiple, short root apices. The relative amounts of wear on the molariform cheek teeth of V. sertichi indicate a mesial-to-distal eruption sequence. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP
The assembly of Africa’s iconic C 4 grassland ecosystems is central to evolutionary interpretatio... more The assembly of Africa’s iconic C 4 grassland ecosystems is central to evolutionary interpretations of many mammal lineages, including hominins. C 4 grasses are thought to have become ecologically dominant in Africa only after 10 million years ago (Ma). However, paleobotanical records older than 10 Ma are sparse, limiting assessment of the timing and nature of C 4 biomass expansion. This study uses a multiproxy design to document vegetation structure from nine Early Miocene mammal site complexes across eastern Africa. Results demonstrate that between ~21 and 16 Ma, C 4 grasses were locally abundant, contributing to heterogeneous habitats ranging from forests to wooded grasslands. These data push back the oldest evidence of C 4 grass–dominated habitats in Africa—and globally—by more than 10 million years, calling for revised paleoecological interpretations of mammalian evolution.
Extended Data Fig. 10 | Phylogenetic relationships of A. hui and selected mammaliaforms. Strict c... more Extended Data Fig. 10 | Phylogenetic relationships of A. hui and selected mammaliaforms. Strict consensus tree of 16 equally parsimonious trees (tree length = 2,315,consistency index = 0.3015 and retention index = 0.7001) derived from analysis of 84 cynodont taxa and 530 characters,with multistate characters unordered and unweighted.Bremer values are listed next to the nodes.Adalatherium is highlighted in red.Allotheria—consisting of Cifelliodon, Euharamiyida,Gondwanatheria (including Adalatherium) and Multituberculata—is highlighted in blue.Taxon and character lists,the data matrix,limitations and assumptions,phylogenetic methods and a more detailed explanation of the results are provided in the Supplementary Information.
Extended Data Fig. 6 | Enamel microstructure of A. hui holotype (UA 9030). a–d, Scanning electron... more Extended Data Fig. 6 | Enamel microstructure of A. hui holotype (UA 9030). a–d, Scanning electron micrographs of single postcanine tooth enamel fragment sectioned in various planes.a, Transverse section of entire enamel band from the enamel–dentine junction (EDJ) to the outer enamel surface (OES) (about 0.4-mm thick) showing single layer of radial enamel and absence of distinct layer of prismless external enamel.Prism size increases from,on average,2.3 to 2.8 Μm from the enamel–dentine junction to the outer enamel surface.Prisms close to the enamel–dentine junction are intersected by interprismatic matrix at slightly higher angles than towards the outer enamel surface.b, Transverse section showing the clear distinction between enamel prisms and interprismatic matrix. c, Radial section showing radial enamel in outer zone with prisms surrounded by interprismatic matrix and some cross-sections of prisms showing tubules.d, Radial,but slightly oblique, section showing enamel of inner zon...
Fig. 4 | Key stages in plate tectonic history of Madagascar. a, Position of Madagascar before rif... more Fig. 4 | Key stages in plate tectonic history of Madagascar. a, Position of Madagascar before rifting between West Gondwana (South America and Africa) and East Gondwana (Madagascar,Seychelles,Indian subcontinent, Sri Lanka,Antarctica and Australia) at 183 Myr ago (Early Jurassic epoch). b, Separation of Indo-Madagascar from Antarctica and Australia at 124 Myr ago (mid-Early Cretaceous epoch).c, Separation of Indian subcontinent from Madagascar at 88 Myr ago (mid-Late Cretaceous epoch).d, Approximate time of deposition of Maevarano Formation at 66 Myr ago (latest Cretaceous period).Solid black lines indicate current coastlines of Madagascar and east Africa; brown represents Precambrian terranes;and yellow indicates sedimentary basins along west coast of Madagascar.The discovery site of UA 9030 is indicated by red star in d. Scale bars,500 km.Maps adapted from Earthworks (www.reeves.nl/gond.com).
Extended Data Fig. 3 | Cranium of A. hui holotype (UA 9030). a–e, Photographs of external surface... more Extended Data Fig. 3 | Cranium of A. hui holotype (UA 9030). a–e, Photographs of external surfaces of cranium in right lateral (a), left lateral (b), dorsal (c), ventral (d) and anterior (e) views.a'–e', Labelled ΜCT images of cranium in the same views as in a–e, respectively.f, Labelled ΜCT image of medial view of right side of nasal cavity.aC,alveolus for upper canine; as, alisphenoid;eo, exoccipital; fr,frontal;ID,distal upper incisor;IM,mesial upper incisor; ju, jugal; la, lacrimal;mx, maxilla; na, nasal;os/ps, orbitosphenoid/presphenoid complex;PC,upper postcanine tooth;pe, petrosal;pmx,premaxilla;pt,pterygoid;smx,septomaxilla;sq, squamosal; v,vomer.
Extended Data Fig. 4 | Inner ear of A. hui holotype (UA 9030). a, Ventral view of reconstructed c... more Extended Data Fig. 4 | Inner ear of A. hui holotype (UA 9030). a, Ventral view of reconstructed cranium, with petrosal fragment bounded by red line enlarged in a'. b–e, Reconstructed cochlear canal in dorsomedial (b), ventrolateral (c) and posteroventromedial (d, e) views,with the view in d being slightly more posterior and the view in e slightly more medial.In e, only the medial aspect of cochlear canal in grey is shown, to reveal primary bony lamina and cochlear nerve foramina.Semi-transparent grey,cochlear canal;yellow, cochlear nerve;blue, secondary canal.
Extended Data Fig. 5 | Lower jaw of A. hui holotype (UA 9030). Photographs of left dentary in lef... more Extended Data Fig. 5 | Lower jaw of A. hui holotype (UA 9030). Photographs of left dentary in left column; photographs of right dentary in right column. a, b, Lateral views.c, d, Dorsal (occlusal) views.e, f, Medial views.i, lower incisor;pc, lower postcanine tooth.
Extended Data Fig. 2 | Bivariate plots of body mass estimates for A. hui. a, Relationship between... more Extended Data Fig. 2 | Bivariate plots of body mass estimates for A. hui. a, Relationship between cranial length and body mass in 423 extant mammals, plus estimated body mass in the gondwanatherians A.hui and Vintana sertichi. b, Relationship between cranial width and body mass in 423 extant mammals, plus the estimated body mass in A. hui and V.sertichi. c, Relationship between cranial size and body mass in 423 extant mammals,plus the estimated body mass in A.hui and V.sertichi. d, Relationship between humeral length and body mass in 187 extant therian mammals,plus the estimated body mass in A.hui. e, Relationship between femoral length and body mass in 184 extant species of therian mammal,plus the estimated body mass in A.hui. f, Relationship between stylopodial diaphyseal circumference and body mass as calculated for a sample of 245 tetrapod species45 (data points shown for mammals only, n = 200),plus the estimated body mass in A.hui. Regression lines in a–e are from ordinary leas...
Fig. 3 | Skeleton of A. hui holotype (UA 9030). a–g, Digitally reconstructed skeleton in left lat... more Fig. 3 | Skeleton of A. hui holotype (UA 9030). a–g, Digitally reconstructed skeleton in left lateral view,highlighting the left scapulocoracoid in lateral view (a), thoracic vertebra 6 and lumbar vertebra 7 in anterior and dorsal views (missing parts mirrored and rendered as semi-transparent) (b), the left femur in distal and anterior views (c), the left humerus in anterior and distal views (d), the left astragalus and navicular in anterior view,and left calcaneus in medial and dorsal views (e), left hind foot in dorsal view (f), and the left tibia in lateral and anterior views (g). L,lumbar vertebra; T,thoracic vertebra.Scale bars,5 cm (main skeleton),1 cm (a–d, f, g), 5 mm (e).
Proceedings of the National Academy of Sciences, 2019
Significance Almost nothing is known about the origin and evolution of Old World monkeys (cercopi... more Significance Almost nothing is known about the origin and evolution of Old World monkeys (cercopithecoids) because the first ∼12 million years of their fossil record is documented by only two isolated teeth. We describe a new primitive monkey from Kenya that dates from ∼22 million years ago and reveals a previously unknown stage of evolution. Comparisons between this monkey and other cercopithecoids offer detailed insights into the development of the novelties associated with the evolution of the cercopithecoid dentition, and particularly bilophodonty. Results suggest that this fossil monkey exhibited dental adaptations for frugivory and perhaps hard object feeding. Bilophodonty, the dental trait that unites all living cercopithecoids, evolved later, likely in response to the inclusion of leaves in the diet.
ABSTRACT—The cranium of Vintana sertichi preserves the first associated upper dentition of a gond... more ABSTRACT—The cranium of Vintana sertichi preserves the first associated upper dentition of a gondwanatherian mammal. Gondwanatherians are known almost exclusively from isolated teeth, particularly molariforms. As such, referral of V. sertichi to the Gondwanatheria, differentiation of V. sertichi from other gondwanatherians, and determination of the relationships of V. sertichi to other gondwanatherians must rely heavily on dental morphology. The hypsodont nature, gross morphology, enamel microstructure, and wear pattern of its molariform teeth serve to unequivocally identify the cranium of V. sertichi as that of a sudamericid gondwanatherian. Based on available morphology, V. sertichi appears to have had an upper dental formula of 2.0.1.4. There are two long, curved alveoli in each premaxilla for enlarged, buccolingually compressed, procumbent incisors that were well separated from the cheek teeth by a long diastema. There is no evidence of a canine. The single premolariform tooth appears to have been small and two-rooted, but neither the left nor the right crowns are preserved. Of the eight upper molariform alveoli, four are preserved with teeth in situ, three in the left maxilla (antepenultimate, penultimate, and ultimate) and one in the right (penultimate). The molariform cheek teeth have several salient characteristics: large size, hypsodont crowns, roughly quadrangular outlines, occlusal surfaces worn essentially flat, numerous cementum-filled infundibula, cementum-filled furrows that invaginate from the buccal side but do not extend to the base of the crown, and multiple, short root apices. The relative amounts of wear on the molariform cheek teeth of V. sertichi indicate a mesial-to-distal eruption sequence. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP
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