New material of Strenulagus solaris, a stem lagomorph, from the lower part of the Middle Eocene Irdin Manha Formation at the Irdin Manha and Huheboerhe localities, Erlian Basin, Nei Mongol, China includes remains of i...New material of Strenulagus solaris, a stem lagomorph, from the lower part of the Middle Eocene Irdin Manha Formation at the Irdin Manha and Huheboerhe localities, Erlian Basin, Nei Mongol, China includes remains of isolated cheek teeth, fragmentary upper incisors （dI2） and postcranial elements, reported from the species for the first time. The tarsal bones display advanced features, such as a wide calcaneofibular articulation surface and, along with an increase in hypsodonty, the new data document the early stage of lagomorph evolution in the Middle Eocene of the Erlian Basin. This finding is stratigraphically well constrained and probably predates that of the type material of S. solaris from the Khaychin Formation, Bugin-Tsav Basin, Mongolia.展开更多
The typical mammalian neck consisting of seven cervical vertebrae(C1–C7)was established by the Late Permian in the cynodont forerunners of modern mammals.This structure is precisely adapted to facilitate movements of...The typical mammalian neck consisting of seven cervical vertebrae(C1–C7)was established by the Late Permian in the cynodont forerunners of modern mammals.This structure is precisely adapted to facilitate movements of the head during feeding,locomotion,predator evasion,and social interactions.Eutheria,the clade including crown placentals,has a fossil record extending back more than 125 million years revealing significant morphological diversification in the Mesozoic.Yet very little is known concerning the early evolution of eutherian cervical morphology and its functional adaptations.A specimen of Zalambdalestes lechei from the Late Cretaceous of Mongolia boasts exceptional preservation of an almost complete series of cervical vertebrae(C2–C7)revealing a highly modified axis(C2).The significance of this cervical morphology is explored utilizing an integrated approach combining comparative anatomical examination across mammals,muscle reconstruction,geometric morphometrics and virtual range of motion analysis.We compared the shape of the axis in Zalambdalestes to a dataset of 88 mammalian species(monotremes,marsupials,and placentals)using three-dimensional landmark analysis.The results indicate that the unique axis morphology of Zalambdalestes has no close analog among living mammals.Virtual range of motion analysis of the neck strongly implies Zalambdalestes was capable of exerting very forceful head movements and had a high degree of ventral flexion for an animal its size.These findings reveal unexpected complexity in the early evolution of the eutherian cervical morphology and suggest a feeding behavior similar to insectivores specialized in vermivory and defensive behaviors in Zalambdalestes akin to modern spiniferous mammals.展开更多
基金the Chinese Academy of Sciences (Grant No.KZCX2-EW-106),Special Fund for Fossil Excavation and Preparation of Chinese Academy of Sciencesthe National Basic Research Program of China(Grant No.2012CB821900)the Nationa lNatural Science Foundation of China(GrantNo.40532010)~~
基金supported by the Young International Scientist Grant of the Chinese Academy of Sciences (No. 2013Y1ZA0006) to LFFthe Major Basic Research Projects of MST of China (Nos. 2012CB821900 and 2006CB806400)+1 种基金the Chinese Academy of Sciences (No. KZCX2-EW-106)the Special Fund for Fossil Excavation and Preparation of the Chinese Academy of Sciences, and the China Geological Survey (Nos. 1212011120115 and 1212011120142)
文摘New material of Strenulagus solaris, a stem lagomorph, from the lower part of the Middle Eocene Irdin Manha Formation at the Irdin Manha and Huheboerhe localities, Erlian Basin, Nei Mongol, China includes remains of isolated cheek teeth, fragmentary upper incisors （dI2） and postcranial elements, reported from the species for the first time. The tarsal bones display advanced features, such as a wide calcaneofibular articulation surface and, along with an increase in hypsodonty, the new data document the early stage of lagomorph evolution in the Middle Eocene of the Erlian Basin. This finding is stratigraphically well constrained and probably predates that of the type material of S. solaris from the Khaychin Formation, Bugin-Tsav Basin, Mongolia.
基金supported by the National Science Centre(NCN,Kraków,Poland)(2015/18/E/NZ8/00637)the Polish National Agency for Academic Exchange(NAWA,Warszawa,Poland)(BPN/BEK/2021/1/00357/U/00001)to LFF。
文摘The typical mammalian neck consisting of seven cervical vertebrae(C1–C7)was established by the Late Permian in the cynodont forerunners of modern mammals.This structure is precisely adapted to facilitate movements of the head during feeding,locomotion,predator evasion,and social interactions.Eutheria,the clade including crown placentals,has a fossil record extending back more than 125 million years revealing significant morphological diversification in the Mesozoic.Yet very little is known concerning the early evolution of eutherian cervical morphology and its functional adaptations.A specimen of Zalambdalestes lechei from the Late Cretaceous of Mongolia boasts exceptional preservation of an almost complete series of cervical vertebrae(C2–C7)revealing a highly modified axis(C2).The significance of this cervical morphology is explored utilizing an integrated approach combining comparative anatomical examination across mammals,muscle reconstruction,geometric morphometrics and virtual range of motion analysis.We compared the shape of the axis in Zalambdalestes to a dataset of 88 mammalian species(monotremes,marsupials,and placentals)using three-dimensional landmark analysis.The results indicate that the unique axis morphology of Zalambdalestes has no close analog among living mammals.Virtual range of motion analysis of the neck strongly implies Zalambdalestes was capable of exerting very forceful head movements and had a high degree of ventral flexion for an animal its size.These findings reveal unexpected complexity in the early evolution of the eutherian cervical morphology and suggest a feeding behavior similar to insectivores specialized in vermivory and defensive behaviors in Zalambdalestes akin to modern spiniferous mammals.
