Artists impression of Kylinxia zhangi in life
X. Wang
A team from the University of Leicester, Yunnan Key Laboratory for Palaeobiology and the Institute of Palaeontology at Yunnan University, Chengjiang Fossil Museum, and the Natural History Museum in London, have redescribed a unique fossil animal from rocks nearly 520 million years old that fills in a gap in our understanding of the evolution of animals known as arthropods.
The animal, Kylinxia zhangi, simply shouldn’t be there if creationists claims were true. It is from almost 520 million years before Earth and the life on it was created and its one of those 'transitional' species showing characteristics of not just two different species, but two entire classes of the arthropod phylum. As such, of course, they are evidence of the evolutionary common origin of those two classes within the major taxon.
They're the sort of species that would have any creationist scratching their heads and declaring, "But they're still er... insects.... er... crustaceans"! before hurriedly redefining 'kind' as a major taxonomic class that includes hundreds of thousands of disparate species with different appendages and body plans of the sort that the same creationist will assure you can't have evolved because 'macro-evolution', i.e., evolving new appendages, body plans, etc., is impossible, while 'micro-evolution, i.e., evolution within the same 'kind' is now perfectly possible. 25 years ago, it was impossible until they realised no Ark could be big enough to contain 2 (or 7)of each known and extinct species.
So, the standard knee-jerk response will be necessary: the scientists lied; the scientists got the dates wrong; the dating techniques are flawed; the scientists are part of a world-wide satanic conspiracy to turn people away from Jesus - even the Chines scientists for whom Jesus and Satan are as mythical as are the Chinese Taoist gods to an American Christian fundamentalist.
But, leaving aside the arrogant cultural chauvinism in assuming the locally popular god in America is the only real one, I wonder how many creationists can explain why the dating methods used were wrong by many orders of magnitude, returning dates in the hundreds of millions of years when the real date should have been about 4,000 years.
The find and its significance is explained in a University of Leicester news release:
The animal, which has the scientific name Kylinxia, was imaged using a CT scanner which revealed its soft anatomy buried in the rock. The size of a large shrimp, its surprising features include three eyes on the head and a pair of fearsome limbs presumably used to catch prey. The study is published this week in the high impact journal Current Biology. Fossils of many kinds of marine animals first appear in rocks from about half a billion years ago and signal a time when complex ecosystems were developing in the world’s oceans. One of the key localities for such fossils is the area around the town of Chengjiang in southern China, where the fossils in this study were collected by the Chinese team. The fossils were recovered from the Cambrian Chengjiang biota of China’s Yunnan Province, from which over 250 species of exceptionally preserved fossil organisms have been described.
The new find is important for deciphering the history of arthropods. These are animals whose bodies are divided into segments, most of which bear a paired of jointed limbs, like crabs, lobsters, insects, and spiders.Professor Yu Liu
Yunnan Key Laboratory for Palaeobiology
Although there are plenty of arthropods in the fossil record – most famously the trilobites - the vast majority only preserve their hard skeletons. Because the new Chinese material is preserved nearly complete, the team were able to image the head of Kylinxia, identifying six segments: the front one bearing eyes, the second with a pair of large grasping limbs, and the other four each bearing a pair of jointed limbs.
The preservation of the fossil animal is amazing. After CT-scanning we can digitally turn it around and literally stare into the face of something that was alive over 500 million years ago. As we spun the animal around, we could see that its head possesses six segments, just as in many living arthropods.
Robert O’Flynn, lead author PhD student School of Geography, Geology and the Environment University of Leicester.Kylinxia, and the Chengjiang biota whence it came, are instrumental to building our understanding of early euarthropod evolution. I like to think that similar discoveries will continue to be made by Robert.
Professor Mark Williams, co-author
School of Geography, Geology and the Environment
University of Leicester, Leicester, UKRobert and I were examining the micro-CT data as part of his doctoral thesis in the hope of refining and correcting previous interpretation of head structures in this genus, Kylinxia. Amazingly, we found that its head is composed of six segments, as in, e.g., insects.
Professor Yu Liu, corresponding author.
Yunnan Key Laboratory for Palaeobiology
Yunnan University, Kunming, ChinaMost of our theories on how the head of arthropods evolved were based on these early-branching species having fewer segments than living species. Discovering two previously undetected pairs of legs in Kylinxia suggests that living arthropods inherited a six-segmented head from an ancestor at least 518 million years ago.
Dr Greg Edgecombe, co-corresponding author
The Natural History Museum, London, UKArtists impression of Kylinxia zhangi in lifeX. Wang
Highlights
- CT imaging clarifies head structure in the Cambrian stem-group euarthropod Kylinxia
- Kylinxia has three eyes and four pairs of biramous head limbs
- The six-segmented head of living arthropods dates to shared ancestry with Kylinixia
- Phylogeny supports homology of frontal appendages across stem-group arthropods
Summary
The early Cambrian Kylinxia zhangi occupies a pivotal position in arthropod evolution, branching from the euarthropod stem lineage between radiodonts (Anomalocaris and relatives) and “great-appendage” arthropods. 1 ,2 Its combination of appendage and exoskeletal features is viewed as uniquely bridging the morphologies of so-called “lower” and “upper” stem-group euarthropods. 3 ,4 Microtomographic study of new specimens of Kylinxia refines and corrects previous interpretation of head structures in this species. Phylogenetic analyses incorporating new data reinforce the placement of Kylinxia in the euarthropod stem group but support new hypotheses of head evolution. The head of Kylinxia is composed of six segments, as in extant mandibulates, e.g., insects. 5 In Kylinxia, these are an anterior sclerite associated with an unpaired median eye and paired lateral eyes (thus three rather than five eyes as was previously described 1 ), deutocerebral frontal-most appendages, and four pairs of biramous appendages (rather than two pairs of uniramous appendages). Phylogenetic trees suggest that a six-segmented head in the euarthropod crown group was already acquired by a common ancestor with Kylinxia. The segmental alignment and homology of spinose frontal-most appendages between radiodonts and upper stem-group euarthropods 6 ,7 ,8 ,9 ,10 is bolstered by morphological similarities and inferred phylogenetic continuity between Kylinxia and other stem-group euarthropods.
O’Flynn, Robert J.; Liu, Yu; Hou, Xianguang; Mai, Huijuan; Yu, Mengxiao; Zhuang, Songling; Williams, Mark; Guo, Jin; Edgecombe, Gregory D.
The early Cambrian Kylinxia zhangi and evolution of the arthropod head
Current Biology (2023) DOI: 10.1016/j.cub.2023.08.022
© 2023 Elsevier Inc.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.
The only flood of any relevance to creationists and their money-making scam cults is the deluge of scientific evidence that shows the childish stupidity of a cult that insists it's evidence-free superstitions are literal truth, in the face of irrefutable evidence that they are simply Bronze Age creation myths from the fearful infancy of our species, as the late, great Christopher Hitchens put it.
No wonder they are reduced to telling themselves that mainstream biologists are coming over to their infantile superstition and abandoning the theory that perfectly explains the evidence in favour of one which doesn't. Such delusional thinking can only believed by children who also believe in magic and find it impossible to believe their mummy and daddy could be wrong.
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