505-Million Year Old Jellyfish Fossils

• 07 Aug 2023

Source: TOI 

Why in News?  

Recently, researchers have unveiled a collection of jellyfish fossils from the Cambrian period, providing a unique glimpse into their distant past. 

• These preserved fossils, found in the Burgess Shale- a renowned fossil-rich site in the Canadian Rockies, offer an improbable pathway to preservation. 

What are the Major Findings of the Research?  

• Special Features of the Fossils: 
  • The newly discovered jellyfish fossils retained remarkable features, such as over 90 fingerlike tentacles protruding from their bell-shaped bodies. 
  • Some specimens even contained stomach contents and gonads, providing invaluable insights into their anatomy and behavior. 
  • These things help scientists learn about how the jellyfish looked and acted. 
• Link with Old Fossils from a Quarry:  
  • In the 1990s, scientists dug up over 170 jellyfish fossils in a place called Raymond Quarry in British Columbia. These fossils were kept for a long time. 
  • Researchers re-examined the specimens from the excavation and identified that the fossils actually belonged to a previously unknown species. 
    • This newly discovered species was named Burgessomedusa phasmiformis. The species falls under the medusozoans category. 

What are Jellyfish?  

• About:  
  • Jellyfish are members of the phylum Cnidaria, a group of animals that includes corals, sea anemones, hydroids, and siphonophores.  
    • Cnidarians are characterized by having radial symmetry, a central mouth surrounded by tentacles, and specialized stinging cells called cnidocytes that can inject venom into their prey or predators. 
  • Jellyfish tend to just follow the currents of the ocean, they can be found around the world in every type of ocean water. 
    • They are considered to be one of the earliest branches of the animal tree of life. 
• Characteristics:  
  • Despite their name, jellyfish do not have much characteristics of a fish, they are invertebrates, or animals with no backbones. 
    • Jellyfish are also among the simplest animals in terms of body organization and nervous system, lacking a brain, a heart, or a skeleton.  
  • However, some jellyfish have evolved remarkable adaptations, such as eyes, bioluminescence, and complex behaviors. 
• Prey: 
  • They dine on fish, shrimp, crabs and tiny plants. They have tiny stinging cells in their tentacles to stun or paralyze their prey before they eat them. 
• Challenge of Jellyfish Fossilization:  
  • Jellyfish, composed of 95% water, pose a considerable challenge when it comes to fossilization. Their delicate structure makes them prone to rapid deterioration, leaving behind minimal traces in the fossil record.