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A strange ancient shrimp changed scientists’ understanding of evolution



During the Cambrian period, the world’s oceans are full of exotic creatures, can swim, segments.

Over millions of years, these milipede-like long-bodied animals will eventually evolve to become modern arthropods: crustaceans like crabs, spiders like scorpions, and insects like bees. and ants.

But about 500 million years ago, these aquatic Cambrian organisms were more experimental when it came to their physical features and body plan than their more familiar descendants. 3 feet in length Opinion, with five balanced eyes on a tree trunk and an elephant-like mouth, and predator Radiodonta species, is fully equipped with two spiky, curved and segmental appendages designed to catch prey.

But there is another creature swimming around Earth̵

7;s oceans, displaying both of these strange features, and more and more. Import Kylinxia zhangi.

This newly discovered breed of shrimp is described in an article published Wednesday in the journal nature.

In the article, the researchers reveal that instead of having just one peculiarity, this small fossilized arthropod possesses a wide range of body features, including five eyes on the stalk and curved hooks, which have spikes extending up from the front of the body like claws. It also seems to have been armored. The fossil has a fused head shield, an armored body, segments and other claw-like appendages located under its sheath.

This discovery helped scientists understand how Cambrian arthropods may be related and how their legacy exists for crabs and insects today.

Diying Huang is a co-author of the article and a professor at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences. He say Inverse that while modern arthropods appear to resemble a diverse group, they have nothing of their ancient ancestors.

“Modern arthropods are very rich and diverse. They are everywhere and familiar [to] “he said.” The arthropods of the Cambrian period were also very complex, not just diversity, [but] also morphology, anatomy, and functional morphology. “

Hologram image of the strange new fossil, Kylinxia zhangi.D.-Y. Huang & H. Zeng

In response to its bizarre physiology, the researchers named the new shrimp Kylinxia zhangi, named after Kylin, a mythological Chinese chimera. And while its mismatched body is curious, it’s also a rare indication of a pivotal moment in ancient animal evolution. Kylinxia possibly a “transitional” species that could shed light on evolutionary relationships between other animals living at the same time.

“[These] the group will [have] Huang said he lived in the Cambri Sea at the same time or so. “They might have [the] same ancestor for a while earlier. “

The researchers use a process called phylogenetic analysis to try and recreate, based on its strange physiology, Kylinxia‘S Evolutionary pathway among arthropods. Analytical techniques pay attention to details such as how many segments the organism has, the shape of the head, or how sharp their appendages are. It assumes that the similarities between animals are more likely based on evolutionary relationships than by chance.

In fact Kylinxia has a spiky, shaped-like hunting appendage Radiodonta, combined with the fact that they are upturned, like another arthropod, Megacheira, and a Megacheira-like body, leading researchers to believe Radiodonta and Megacheira inherit their appendages from a common ancestor, rather than evolve independently in each organism.

In other words, it’s the same creepy appendage, just flipped over.

Curiously, this patchy creature sheds light on how antennas or pliers evolved in modern arthropods.D.-Y. Huang & H. Zeng

More Kylinxia to the old tree also shed light on the evolution of modern arthropods. Previous work has suggested that Megacheira, with their spiked appendages, are closely related ChelicerataThe group includes modern scorpions and spiders, as well as a group of ancient animals with antennas, which may have evolved into insects, such as bees and ants.

The appendages have upper spines Megacheira, the mouth pinched on scorpions and spiders, and the antennas on the bees all lie similarly on these animals, leading researchers to believe they could all have evolved from one organism or organism. has a similar structure.

But researchers don’t know what comes first. Do spiky appendages develop into antennas, develop into pins? Or is it the first speaker? The discovery Kylinxia aggravates spiny appendages, indicating that they give rise both puckers and antennae along separate lineages, rather than the mouth arising from the beard or vice versa.

Little baby’s undersea world Kylinxia, vortex with many segmented sub-beasts, very unlike the modern ocean. However, the researchers say that the morphological and ecological diversity experiments of such arthropods “probably laid the foundation for their later evolutionary success”.

Abstract: Solving the early evolution of arthropods was one of the most difficult problems in metazoan evolution1,2. Specially preserved fossils from the Cambrian period contributed important paleontological data to decoding this evolution3,4. Phylogenetic studies have identified Radiodonta (also known as anomalocaridids) as the closest group to all arthropod species with anterior appendage on the second head segment (Deuteropoda) 5-9. However, the reciprocal relationship between large Cambrian groups of arthropods remains controversial 1,2,4,7, which hinders our understanding of the evolutionary gap between Radiodonta and Deuteropoda. . Here we describe the gene Kylinxia zhangi. et. sp. nov., a species of arthropod from the early Cambrian Chengjiang biome of China. Kylinxia not only possesses the features of arthropods such as a fused head shield, complete vertebral body and articulated intracellular parts, but also an eyeball (as in Opabinia) as well as appendages. in front of head like radioactive scabies. Our phylogenetic regeneration restores Kylinxia as a transitional taxon that serves as a bridge between Radiodonta and Deuteropoda. The most basic species of deuteropods are considered to be a paraphyletic line that has a variety of rapids-shaped anterior appendages and includes Kylinxia, ​​megacheirans, panchelicerates, bivalve arthropods and ‘large appendages’ isoxyid. This phylogenetic topology supports the idea that the outermost anterior appendages of radiation and megacheiran are homologous, that the chelicerae of the Chelicerata are derived from the megacheiran large appendages and that the antennae Mandibulata responses are derived from ancestral rapids. Therefore, Kylinxia provided important insights into the phylogenetic relationship between the original arthropods, evolutionary variation and differences of anterior appendages, and the origin of these changes. important new evolution in this branch.


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