The penis worm Eximipriapulus occupying a hyolith shell. Credit: Prof Zhang Xiguang, Yunnan University
A new study by researchers from Durham University and Yunnan University exposes that penis worms (Priapulida) developed the hermit lifestyle, some 500 million years back, at the rise of the earliest animal environments in the Cambrian period.
Hermit crabs are popular for using snail shells as shelters versus predators, however researchers have actually now found that penis worms invented the hermit lifestyle hundreds of million years before hermit crabs initially evolved.
Researchers studied collections of the Guanshan fossil deposits– popular due to the fact that they preserve soft tissue (such as the bodies of worms) along with the shelly product that makes up the traditional fossil record.
Credit: Prof Zhang Xiguang, Yunnan University
Credit: Prof Zhang Xiguang, Yunnan University
Four specimens of the penis worm Eximipriapulus were discovered inside cone-shaped shells of hyoliths, a long-extinct fossil group.
” The worms are always sitting snugly within these same kinds of shells, in the exact same position and orientation,” discusses Dr. Martin Smith, co-author of the study.
The researchers established that Cambrian predators were aggressive and numerous, requiring the penis worms to take irreversible shelter in empty shells.
Dr. Smith broadens: “The only description that made good sense was that these shells were their homes– something that came as a genuine surprise. Not long prior to these organisms existed, there was absolutely nothing alive more complicated than seaweeds or jellyfish: so its mind-boggling that we start to see the complex and hazardous ecologies usually associated with much more youthful geological periods so right after the very first complex animals show up on the scene.”
Credit: Prof Zhang Xiguang, Yunnan University
The research shows the crucial role of predators in forming ecology and habits in the really early phases of animal development.
The study findings will be published in the journal Current Biology.
A “hermiting” lifestyle has never ever been documented or observed in living or fossil penis worms; nor has it been straight observed in any organism living earlier than the Mesozoic Marine Revolution in the age of dinosaurs.
The fact that it developed independently in the immediate consequences of the “Cambrian explosion,” which marked the rapid increase of contemporary animal body plans, highlights the amazing speed and versatility of the evolutionary procedure.
Reference: “A hermit shell-dwelling way of life in a Cambrian priapulan worm” by Yang, Xiao-yu, Smith, Martin R., Yang, Jie Guo, Qing-hao, Li, Chun-li, Wang, Yu and Zhang, Xi-guang, 8 November 2021, Current Biology.DOI: 10.1016/ j.cub.2021.10.003.