神秘化石为昆虫进化提供新线索

German scientists at the Stuttgart Natural History Museum were leading in the discovery of a new insect order from the Lower Cretaceous of South America. The spectacular fossils were named Coxoplectoptera by their discoverers and their findings were published in a special issue on Cretaceous Insects in the scientific journal Insect Systematics & Evolution. The work group led by Dr. Arnold H. Staniczek and Dr. Günter Bechly, both experts on basal insects, determined¹ that these fossils represent extinct relatives of modern mayflies（蜉蝣） . Coxoplectoptera however significantly differ from both mayflies and all other known insects in anatomy²（解剖） and mode of life. Due to the discovery of adult winged specimens³ and excellently preserved larvae⁴, the scientists were able to clarify the phylogenetic（系统发生的） position of these animals and presented a new hypothesis regarding the relationships of basal winged insects. Equipped with wing venation（脉络） of a mayfly, breast and wing shape of a dragonfly, and legs of a praying mantis⁵, these winged insects look like a patchwork⁶ of various animals. The peculiar⁷ larvae, however, are reminiscent of freshwater shrimps⁸. Their lifestyle turned out to be a major enigma⁹: Mode of embedding¹⁰ and some of their characters clearly suggest a fluvial habitat. Their unique anatomy indicates that these animals were ambush¹¹ predators¹² living partly dug in the river bed. These animals furthermore provided clues to the long-standing controversial debate of the evolutionary¹³ origin of the insect wing: The scientists presume that wings originated from thoracic（胸的） backplates, while leg genes¹⁴ were recruited for their developmental control.

Overall, the exciting discovery of Coxoplectoptera contributes to a better understanding of insect evolution.