More than 100 Hemeroscopid larva fossils were discovered from the Lower Cretaceous in Southwest Beijing, which effectively ends the discussion of morphology and makes it more complete. It is assigned within the Libell...More than 100 Hemeroscopid larva fossils were discovered from the Lower Cretaceous in Southwest Beijing, which effectively ends the discussion of morphology and makes it more complete. It is assigned within the Libellu-loidea, and shows close evolutionary correlations with modern Libellulidae. Although the wing characters of adult Hemeroscopus from the same formation indicates the close relationship to Aeschnoidea, we suggest that the larvae and the adults were the same species. Therefore, it probably shows the evolutionary ancestors of Libellulidae. Being the fundamental species discriminating Jehol Entomofauna and Lushangfen Entomofauna, Hemeroscopus bears great significance in the study of stratigraphy.展开更多
Core 255 from the southern Okinawa Trough was selected to monitor the shift of the Kuroshio axis over the last 20 000 years. During the last glacial maximum the Kuroshio axis had ever shifted outside the Okinawa Troug...Core 255 from the southern Okinawa Trough was selected to monitor the shift of the Kuroshio axis over the last 20 000 years. During the last glacial maximum the Kuroshio axis had ever shifted outside the Okinawa Trough. It entered the Okinawa Trough again at about 6 500 a BP, leading to abrupt increase of sedimentation rate, distinctly coarser sediment and remarkably increased abundance of foraminiferal indicators of the Kuroshio in the core. But, during about 4 000-3 000 a BP the abundance of the Kuroshio indicator Pulleniatina obliquiloculata sharply decreased again, indicating that the Kuroshio axis had ever shifted easterly for a short period or the Kuroshio was weakened and that moment.展开更多
Dear Editor, The origin of vertebrate-specific characters and functional systems is one of the most important questions in the evo- lutionary biology （Holland and Chen, 2001）. Amphioxus, the most basal chordate, is ...Dear Editor, The origin of vertebrate-specific characters and functional systems is one of the most important questions in the evo- lutionary biology （Holland and Chen, 2001）. Amphioxus, the most basal chordate, is considered as the sister of verte- brates based on the recent molecular phylogenetic evi- dences, and it is used as an ideal model organism to study the origin and evolution of vertebrate organ systems including immune system （Yu and Holland, 2009）. Three digestive organs, gill slits, hepatic caecum and intestine in amphioxus were also considered as primitive immune organs of amphioxus （Schmitz et al., 2000）. In addition to the respiratory and digestive function,展开更多
基金the National Natural Science Foundation of China.
文摘More than 100 Hemeroscopid larva fossils were discovered from the Lower Cretaceous in Southwest Beijing, which effectively ends the discussion of morphology and makes it more complete. It is assigned within the Libellu-loidea, and shows close evolutionary correlations with modern Libellulidae. Although the wing characters of adult Hemeroscopus from the same formation indicates the close relationship to Aeschnoidea, we suggest that the larvae and the adults were the same species. Therefore, it probably shows the evolutionary ancestors of Libellulidae. Being the fundamental species discriminating Jehol Entomofauna and Lushangfen Entomofauna, Hemeroscopus bears great significance in the study of stratigraphy.
文摘Core 255 from the southern Okinawa Trough was selected to monitor the shift of the Kuroshio axis over the last 20 000 years. During the last glacial maximum the Kuroshio axis had ever shifted outside the Okinawa Trough. It entered the Okinawa Trough again at about 6 500 a BP, leading to abrupt increase of sedimentation rate, distinctly coarser sediment and remarkably increased abundance of foraminiferal indicators of the Kuroshio in the core. But, during about 4 000-3 000 a BP the abundance of the Kuroshio indicator Pulleniatina obliquiloculata sharply decreased again, indicating that the Kuroshio axis had ever shifted easterly for a short period or the Kuroshio was weakened and that moment.
文摘Dear Editor, The origin of vertebrate-specific characters and functional systems is one of the most important questions in the evo- lutionary biology （Holland and Chen, 2001）. Amphioxus, the most basal chordate, is considered as the sister of verte- brates based on the recent molecular phylogenetic evi- dences, and it is used as an ideal model organism to study the origin and evolution of vertebrate organ systems including immune system （Yu and Holland, 2009）. Three digestive organs, gill slits, hepatic caecum and intestine in amphioxus were also considered as primitive immune organs of amphioxus （Schmitz et al., 2000）. In addition to the respiratory and digestive function,
