The origin of birds from theropod dinosaurs,by any measures,is the most eye-catching evolutionary transition in the history of life,which encompasses numerous extensive morphological and biological changes.Compared to...The origin of birds from theropod dinosaurs,by any measures,is the most eye-catching evolutionary transition in the history of life,which encompasses numerous extensive morphological and biological changes.Compared to postcranium,little progress has been made regarding the evolutionary assemblage of the birds’skull,because of few detailed early records of cranial materials of stem lineages.Anchiornis is the oldest known record of the Paraves(~160 Ma),the most inclusive clade that contains all living birds but not Caudipteryx or Epidexipteryx.With hundreds of known specimens,Anchiornis constitutes an ideal taxon for investigating morphological modifications across the theropod-bird transition,but its cranial morphology remains enigmatic.Here we present in-depth description of the cranial morphology of Anchiornis based on three-dimensional reconstruction of a well-preserved specimen,including elements from the temporal and palatal regions that are poorly recognized previously.Our study shows that Anchiornis retains the plesiomorphic dinosaurian condition in having a diapsid akinetic skull.The mixture of cranial characters,shared with dromaeosaurids,troodontids,and stemward avialans,present in Anchiornis demonstrates the complex history of early avialan cranial evolution.展开更多
It has recently become clear that several human lineages coexisted with Homo sapiens during the late Middle and Late Pleistocene.Here,we report an archaic human fossil that throws new light on debates concerning the d...It has recently become clear that several human lineages coexisted with Homo sapiens during the late Middle and Late Pleistocene.Here,we report an archaic human fossil that throws new light on debates concerning the diversification of the Homo genus and the origin of H.sapiens.The fossil was recovered in Harbin city in northeastern China,with a minimum uranium-series age of 146 ka.This cranium is one of the best preserved Middle Pleistocene human fossils.Its massive size,with a large cranial capacity(1,420 mL)falling in the range of modern humans,is combined with a mosaic of primitive and derived characters.It differs from all the other named Homo species by presenting a combination of features,such as long and low cranial vault,a wide and low face,large and almost square orbits,gently curved but massively developed supraorbital torus,flat and low cheekbones with a shallow canine fossa,and a shallow palate with thick alveolar bone supporting very large molars.The excellent preservation of the Harbin cranium advances our understanding of several less-complete late Middle Pleistocene fossils from China,which have been interpreted as local evolutionary intermediates between the earlier species Homo erectus and later H.sapiens.Phylogenetic analyses based on parsimony criteria and Bayesian tip-dating suggest that the Harbin cranium and some other Middle Pleistocene human fossils from China,such as those from Dali and Xiahe,form a third East Asian lineage,which is a part of the sister group of the H.sapiens lineage.Our analyses of such morphologically distinctive archaic human lineages from Asia,Europe,and Africa suggest that the diversification of the Homo genus may have had a much deeper timescale than previously presumed.Sympatric isolation of small populations combined with stochastic long-distance dispersals is the best fitting biogeographical model for interpreting the evolution of the Homo genus.展开更多
文摘The origin of birds from theropod dinosaurs,by any measures,is the most eye-catching evolutionary transition in the history of life,which encompasses numerous extensive morphological and biological changes.Compared to postcranium,little progress has been made regarding the evolutionary assemblage of the birds’skull,because of few detailed early records of cranial materials of stem lineages.Anchiornis is the oldest known record of the Paraves(~160 Ma),the most inclusive clade that contains all living birds but not Caudipteryx or Epidexipteryx.With hundreds of known specimens,Anchiornis constitutes an ideal taxon for investigating morphological modifications across the theropod-bird transition,but its cranial morphology remains enigmatic.Here we present in-depth description of the cranial morphology of Anchiornis based on three-dimensional reconstruction of a well-preserved specimen,including elements from the temporal and palatal regions that are poorly recognized previously.Our study shows that Anchiornis retains the plesiomorphic dinosaurian condition in having a diapsid akinetic skull.The mixture of cranial characters,shared with dromaeosaurids,troodontids,and stemward avialans,present in Anchiornis demonstrates the complex history of early avialan cranial evolution.
基金This project has been supported by the National Natural Science Foundation of China(41842039,41625005,41888101,41988101,41877430,41977380)the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)(XDB26030300,XDA20070203,XDA19050100)+3 种基金the People’s Government of Hebei Province(Z20177187)the China Geological Survey(DD20190601)the Science Foundation of Hebei GEO University(TS2017-001)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0705).
文摘It has recently become clear that several human lineages coexisted with Homo sapiens during the late Middle and Late Pleistocene.Here,we report an archaic human fossil that throws new light on debates concerning the diversification of the Homo genus and the origin of H.sapiens.The fossil was recovered in Harbin city in northeastern China,with a minimum uranium-series age of 146 ka.This cranium is one of the best preserved Middle Pleistocene human fossils.Its massive size,with a large cranial capacity(1,420 mL)falling in the range of modern humans,is combined with a mosaic of primitive and derived characters.It differs from all the other named Homo species by presenting a combination of features,such as long and low cranial vault,a wide and low face,large and almost square orbits,gently curved but massively developed supraorbital torus,flat and low cheekbones with a shallow canine fossa,and a shallow palate with thick alveolar bone supporting very large molars.The excellent preservation of the Harbin cranium advances our understanding of several less-complete late Middle Pleistocene fossils from China,which have been interpreted as local evolutionary intermediates between the earlier species Homo erectus and later H.sapiens.Phylogenetic analyses based on parsimony criteria and Bayesian tip-dating suggest that the Harbin cranium and some other Middle Pleistocene human fossils from China,such as those from Dali and Xiahe,form a third East Asian lineage,which is a part of the sister group of the H.sapiens lineage.Our analyses of such morphologically distinctive archaic human lineages from Asia,Europe,and Africa suggest that the diversification of the Homo genus may have had a much deeper timescale than previously presumed.Sympatric isolation of small populations combined with stochastic long-distance dispersals is the best fitting biogeographical model for interpreting the evolution of the Homo genus.
