current position:Home>China has discovered the most complete duckbill embryo in scientific records so far

China has discovered the most complete duckbill embryo in scientific records so far

2022-05-15 05:29:49Chinese industry information station

 Embryonic fossils and restoration of platypus

Embryonic fossils and restoration of platypus

The specimens are collected in Fujian Yingliang stone natural history museum , The museum nicknamed this group of specimens “ Yingbeibei Ying Baby”, We can use them to answer some important questions about dinosaur development and reproduction . This paper was published in the academic journal recently BMC Ecology and Evolution(《BMC Ecology and evolution 》) On .

“ Yingbeibei ” Hadrosaur embryo

“ Yingbeibei ” Hadrosaur embryo

2000 About years ago , The chairman of Yingliang group collected a batch of suspected egg fossils .2015 In the beginning , During the preparation of Fujian Yingliang stone natural history museum , With the support and organization of Fujian Provincial Bureau of cultural relics , Niu Kecheng, curator of the museum, comprehensively combed the existing specimens in the warehouse , And began to clean up some specimen tissues with potential research value , In the process , A batch of embryos and specially preserved egg fossils were found .

“ Yingbeibei ” Hadrosaur embryo

“ Yingbeibei ” Hadrosaur embryo

2019 year , China university of geosciences ( Beijing ) Xing Lida research group cooperates with Fujian Yingliang stone natural history museum , Start a detailed study of this batch of specimens , With the help of synchrotron radiation ,MCT Scanning and other technical means to examine specimens , And achieved a series of results , Such as 2021 year 12 Published in “ The most complete dinosaur embryo ever recorded in Science ” etc. .

 Close up of embryos in eggs

Close up of embryos in eggs

The duckbill embryos published this time “ Yingbeibei ” It is native to the strata of Late Cretaceous in southern Jiangxi , About 7200 Wan to 6600 In ten thousand, . The egg in which the embryo is located is about 9 Centimeter ellipsoid , The volume is about 660 ml , The embryonic part accounts for about... Of the whole egg 40%, The embryonic egg has a thin about 0.4 Mm thick eggshell , Its microstructure shows that it belongs to round egg family (Spheroolithidae).

 Embryonic fossils

Embryonic fossils

According to the skull of a dinosaur embryo 、 The unique shape of the spine and limb bones , It can be inferred that the fossil embryos contained in the egg “ Yingbeibei ” It belongs to hadrosaurs . This is a kind of large herbivorous dinosaurs that lived at the end of the dinosaur era , They all have very recognizable duck like flat mouths . The famous Edmonton Dragon 、 Shantungosaurus , Qingdao Dragon , Helmet Dragon , Mother dragons belong to this group . Hadrosaur embryos are not the first to be found worldwide , But these new platypus embryos are by far the best preserved of their kind .

however , It is difficult for scholars to know exactly which genus or species of hadrosaurs this group of embryos represents ; The identification characteristics of a specific species often show up later in life . however , The unique shape of the in situ scaly bone preserved at the posterior edge of the upper part of the embryonic skull : The posterior process is high and blunt , Reminiscent of some hadrosaur superfamilies (hadrosauroids) The dinosaur , For example, all of them are also from Asia (Levnesovia)、 Tan Shilong (Tanius) And Nanning Dragon (Nanningosaurus), It shows that the new specimen may be related to these species .

The size of the egg and embryo fossils found this time is similar to that of the more special hadrosaurs of the upper Cretaceous in North America (hadrosaurids) Is comparable . These hadrosaurs are traditionally divided into two categories : Ryanoidea subfamily with a delicate hollow ridge crown on its skull (lambeosaurines), And the subclass Chlamydomonas without this ridge crown (saurolophinae) Or platypus (hadrosaurines).

Generally speaking , Duck billed dragons produce much smaller eggs than ryanoidea ( The volumes are 900 Ml and 4000 ml ), So the hatchlings are also smaller . More Than This , Hatchlings of the duckbill subfamily are considered to be less developed than those of the ryosaurus subfamily , Especially in the formation of limb bones . in other words , The hatchlings of hadrosauridae are late maturing , After a long time after hatching , The bones of the limbs are fully grown .

by comparison , The larger hatchlings of the subfamily ryosaurus are early adults , You can join the dragon group soon after birth . This interesting difference for evolutionary biologists , Naturally, a question arises about the ancestral traits of hadrosaurs : The ancestors of hadrosaurs were in the process of hatching , Its young dragon is late or early ? Among the embryonic eggs found this time , Eggs and embryos are small , Similar to hadrosauridae , This shows that small eggs and late maturing young dragons are the original traits of hadrosaurs , The larger eggs of the ryanoidea subfamily are derived from the early hatchlings , This is it. “ Yingbeibei ” The most important new scientific knowledge that dinosaur embryos tell us .

 Restoration map mapping Guard the forest

Restoration map mapping Guard the forest

Knowledge development : Dinosaur eggs and dinosaur embryos

Like other reptiles , Dinosaurs are also egg laying animals . When dinosaurs ruled the earth 1.6 In a hundred million years of history , Left a lot of dinosaur eggs , A small number of fossils formed through long-term geological processes , Preserved in Mesozoic strata . from 1859 Since then , There are many Mesozoic strata all over the world and in China , In particular, a large number of dinosaur egg fossils have been found in the strata of the late Cretaceous . Generally speaking , Dinosaur egg fossils only retain the Eggshell Structure , The egg white and yolk inside have long been lost , Instead, the mineral solution penetrates through the eggshell and fills the cavity . Dinosaur egg fossils have a round shape 、 ellipse 、 Oval 、 Olive shape and other shapes , Sizes range from quail egg size , To larger than 50 centimeter , At present, only a few of these dinosaur eggs can be determined which kind of dinosaur produced them .

Very few dinosaur eggs still contain embryonic fossils , Is one of the rarest fossils , These fossils are used to study the reproductive development of dinosaurs 、 Behavior 、 Evolution and paleoecology provide valuable information . However , Under the influence of many factors , Dinosaur embryos can stop at any stage of development , The ossification of its early embryos is very low , Fossils are hard to distinguish , Only when the embryo in the dinosaur egg reaches a certain stage of development , Only then can we find a well preserved 、 Easily distinguishable embryonic fossils .

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