Birch mice(family Sicistidae)are small dipodoid rodents distributed in regions surrounding the Qinghai-Xizang Plateau and extending across the Palearctic.In China,members of the genus Sicista are rarely recorded,and t...Birch mice(family Sicistidae)are small dipodoid rodents distributed in regions surrounding the Qinghai-Xizang Plateau and extending across the Palearctic.In China,members of the genus Sicista are rarely recorded,and their systematics remain poorly resolved.As part of the Second Xizang Plateau Expedition by the Kunming Institute of Zoology,Chinese Academy of Sciences,systematic surveys conducted in southern Xizang and the western Tianshan Mountains yielded two previously unrecognized species.Two specimens from southern Xizang were found to occupy a deeply divergent phylogenetic position within Sicistidae.Morphological assessments and molecular phylogenetic analyses of both extant and fossil Sicistidae,along with total-evidence dating and ancestral distribution reconstruction,identified these specimens as representatives of an ancient extant lineage that diverged from Sicista approximately 20.38 million years ago.This lineage is designated as a new genus,defined by the new species Breviforamen shannanensis gen.et sp.nov.Furthermore,11 specimens from the Tianshan Mountains are described as a second new species,Sicista brevicauda sp.nov.,based on diagnostic morphological and genetic features.Ancestral distribution reconstructions,combined with fossil records,indicate an early Miocene origin for Sicistidae across a broad region spanning the“Gobi”Desert to parts of North America.Climatic deterioration and increasing desertification during the mid-Miocene likely drove southward dispersal of Breviforamen gen.nov.into southern Xizang prior to the complete formation of the Yarlung Zangbo River.Overall,these findings broaden current understanding of Sicistidae diversity,elucidate the origin and dispersal patterns of the family,and highlight the presence of an ancient relict lineage in China.展开更多
A strange Papilio female specimen with a prominent yellow wing band type very much like P. brevicauda （and also seen in P. machaon, and P. zelicaon） was captured in the forested mountains of southwest Vermont, USA. ...A strange Papilio female specimen with a prominent yellow wing band type very much like P. brevicauda （and also seen in P. machaon, and P. zelicaon） was captured in the forested mountains of southwest Vermont, USA. Despite its brevicauda-like appearance, it had mt-DNA of P. polyxenes. In eastern North America the P. brevicauda （Maritime Provinces of Canada） is currently believed to reflect previous （ancient） hybridization between ancestral P. machaon and P. polyxenes. It is uncertain whether the brevicauda-like wing trait features in the odd Vermont female may be a result of some introgression of P. machaon or P. brevicauda with P. polyxenes in eastern North America as seen also in the Ozark Mountains with P. joanae. Nonetheless, the significance of wing trait analyses in relation to hybrid zones with P. polyxenes remains relevant. The segregation of wing color patterns and hostplant use abilities （efficiencies and growth rates） were examined for laboratory hand-paired F-2 hybrids of P. zelicaon ~ Papilio polyxenes relative to the parental species and primary hybrids. The black adult color pattern characterizing P. polyxenes is presumed to be inherited as a simple autosomal dominant. These hybrids were examined to determine： （i） how F-1 primary hybrid offspring perform relative to the parental types in survival, growth rates, and growth efficiencies; and （ii） whether these larval traits and the adult color patterns might be linked with wing morphology in the F-2 hybrids. While the F-1 hybrids grew as well as the P. polyxenes parent （P. zelicaon was significantly less efficient and slower in growth than either of these）, we could not convincingly determine whether the growth performances of the F-2 segregants were linked with the parental wing patterns.展开更多
基金supported by the Second Qinghai-Xizang Plateau Scientific Expedition and Research Program(2024QZKK0200,2019QZKK05010100)Survey of Wildlife Resources in Key Areas of Xizang(ZL202203601,ZL202303601)。
文摘Birch mice(family Sicistidae)are small dipodoid rodents distributed in regions surrounding the Qinghai-Xizang Plateau and extending across the Palearctic.In China,members of the genus Sicista are rarely recorded,and their systematics remain poorly resolved.As part of the Second Xizang Plateau Expedition by the Kunming Institute of Zoology,Chinese Academy of Sciences,systematic surveys conducted in southern Xizang and the western Tianshan Mountains yielded two previously unrecognized species.Two specimens from southern Xizang were found to occupy a deeply divergent phylogenetic position within Sicistidae.Morphological assessments and molecular phylogenetic analyses of both extant and fossil Sicistidae,along with total-evidence dating and ancestral distribution reconstruction,identified these specimens as representatives of an ancient extant lineage that diverged from Sicista approximately 20.38 million years ago.This lineage is designated as a new genus,defined by the new species Breviforamen shannanensis gen.et sp.nov.Furthermore,11 specimens from the Tianshan Mountains are described as a second new species,Sicista brevicauda sp.nov.,based on diagnostic morphological and genetic features.Ancestral distribution reconstructions,combined with fossil records,indicate an early Miocene origin for Sicistidae across a broad region spanning the“Gobi”Desert to parts of North America.Climatic deterioration and increasing desertification during the mid-Miocene likely drove southward dispersal of Breviforamen gen.nov.into southern Xizang prior to the complete formation of the Yarlung Zangbo River.Overall,these findings broaden current understanding of Sicistidae diversity,elucidate the origin and dispersal patterns of the family,and highlight the presence of an ancient relict lineage in China.
基金Acknowledgments This research was supported in part by the National Science Foundation Population Biology Program （DEB 99- 81608） and the Michigan Agricultural Experiment Station （MAES Project # MICL 01644）. Thanks are extended to Dr. Felix Sperling and Evgueny Zakharov for the mitochrondrial analyses. The scientific and editorial assistance of Rodrigo Mercader and Matthew Aardema are also appreciated. Thanks to Ted Herig for supplying the P. brevicauda and to Robert Lederhouse for photography and assistance with the P. zelicaon.
文摘A strange Papilio female specimen with a prominent yellow wing band type very much like P. brevicauda （and also seen in P. machaon, and P. zelicaon） was captured in the forested mountains of southwest Vermont, USA. Despite its brevicauda-like appearance, it had mt-DNA of P. polyxenes. In eastern North America the P. brevicauda （Maritime Provinces of Canada） is currently believed to reflect previous （ancient） hybridization between ancestral P. machaon and P. polyxenes. It is uncertain whether the brevicauda-like wing trait features in the odd Vermont female may be a result of some introgression of P. machaon or P. brevicauda with P. polyxenes in eastern North America as seen also in the Ozark Mountains with P. joanae. Nonetheless, the significance of wing trait analyses in relation to hybrid zones with P. polyxenes remains relevant. The segregation of wing color patterns and hostplant use abilities （efficiencies and growth rates） were examined for laboratory hand-paired F-2 hybrids of P. zelicaon ~ Papilio polyxenes relative to the parental species and primary hybrids. The black adult color pattern characterizing P. polyxenes is presumed to be inherited as a simple autosomal dominant. These hybrids were examined to determine： （i） how F-1 primary hybrid offspring perform relative to the parental types in survival, growth rates, and growth efficiencies; and （ii） whether these larval traits and the adult color patterns might be linked with wing morphology in the F-2 hybrids. While the F-1 hybrids grew as well as the P. polyxenes parent （P. zelicaon was significantly less efficient and slower in growth than either of these）, we could not convincingly determine whether the growth performances of the F-2 segregants were linked with the parental wing patterns.
