Research On New Enantiornithes Materials From Fengning,Heibei Provience

As the sister group of Ornithuromorpha in the evolution,Enantiornithes once flourished in the Cretaceous Period and were widely distributed all over the world.Based on abundant fossil discoveries,the skeleton characteristics,feather characteristics and other organizational characteristics of Enantiornithes have been fully studied.Its genealogy development is also expanding.The research on Enantiornithes is helpful to reveal the evolution of birds' flight,reproduction and living habits.In this paper,the study of specimen 1611803 N,including the description of the morphology of its skeleton and feather,and the analysis of its function.Then,according to the characteristic matrix established by predecessors,the evolutionary position of the Enantiornithes is analyzed by TNT software.The specimen 1611803 N is from the early Cretaceous Yixian Formation in Fengning,Hebei Province.The skeleton is not well preserved,but the feathers are well preserved.Through observation and comparison,it is found that the skeleton characteristics of specimen1611803 N accord with the basic characteristics of Enantiornithes,but it also has its unique characteristic combination,so it is a new species of Enantiornithes,and it is closest to the genus Cathayornis.Based on the characteristics of the Pectoral Girdle,Forelimb and feather of the specimen 1611803 N,it is speculated that it can fly at low speed,move freely among branches and fly directly to branches from the ground.In this paper,melanosomes of 1611803 N were sampled and analyzed.The results showed that the melanosomes of the crown feathers were oval with low ratio of length to width,while the melanosomes of flying feathers were long rods with high ratio of length to width.Combined with the relationship between the color of feathers and the morphology of melanosomes of living birds,it was inferred that the color of crown feather of specimen 1611803 N was close to reddish brown,the color of flying feather was close to gray black,and the color of crown feather was different from that of flying feather It plays a decorative role,used to show off and courtship,but also to intimidate predators.In this paper,the compound bones fusion of specimen 1611803 Nis discussed.It is found that the compound bone fusion mode is different from that proposed by predecessors.This provides a new basis for the study of the ontogeny of Enantiornithes,and also indicates that it should be a sub adult close to adult.In this paper,the phylogenetic analysis of specimen 1611803 N has not been done,but the similar sternal morphology of Shangyang,Pterygornis and cathayornis are also located in comb like structure.According to the position of these three genera in other phylogenetic analysis and combined with the characteristics of specimen 1611803 N,it is speculated that specimen 1611803 N should be located in Middle position of Enantiornithes evolution.