Paleontologists have unearthed the 20-million-year-old fossil skeleton of a species of sirenian mammal from the dugong family. Cleavage Shark and crocodile bite marks have been found in northwestern Venezuela. The most prominent bite marks are from deep, dragging tooth impacts concentrated on the snout of the animals. Researchers interpret this as the result of active predation, as they are similar to bite marks made by crocodiles when they grab and roll their prey. Moreover, shark bite marks can be observed throughout Venezuela. CleavageThe skeleton of Tiger shark (Galeocerdo Aduncus) The teeth associated with this skeleton.
Tiger sharks are congregating to make easy catches of larger prey as crocodiles attack ancient dugong-like siren mammals. CleavageImage courtesy of Jaime Bran Sarmiento.
“Our discovery adds to the growing evidence that food chains millions of years ago worked in a similar way to how they do today,” said Dr Aldo Benitez Palomino, a paleontologist at the institute. University of Zurich.
“Today, when we observe predators in the wild, we often find dead prey, indicating that the animal also served as a food source for other animals. However, the fossil record of this is rare.”
“It was unclear which animals would serve this purpose as a food source for multiple predators.”
“Our previous research has confirmed that several shark species scavenge sperm whale carcasses, and this new study highlights the importance of sea cows in the food chain.”
Evidence for food web interactions is abundant in the fossil record, but most of it is represented by fragmentary fossils that provide ambiguous meaning.
Therefore, it is often difficult to distinguish between active feeding and signs of saprophytic activity.
“Our results are one of the few to document multiple predators on a single prey and provide a glimpse into food webs in the region during the Miocene,” Dr Benitez-Palomino said.
The dugong specimen studied by the team was collected from an outcrop of the Agua Clara Formation, south of the city of Coro, Venezuela.
The fossil is closely related to a species of sirenian in the dugong family. Cleavage.
“We first heard about the site through word of mouth from local farmers who noticed some unusual 'rocks'. We were intrigued and decided to investigate,” said Professor Marcelo Sánchez-Vilagra from the University of Zurich.
“Initially, we weren't familiar with the geology of the site, and the first fossil we unearthed was just part of a skull.”
“It took us a while to identify what it was – very strange looking remains of a sea cow.”
“By studying geological maps and examining the sediments at the new site, we were able to determine the age of the rocks in which the fossils were found.”
“One of the factors that allowed us to observe evidence of aquatic mammal predation, which is known to exist in this region, is the extremely well-preserved cortical layer of the fossil, which is likely due to the fine sediment in which the fossil was embedded.”
“After locating the fossils, our team organized a paleontological rescue operation, employing extraction techniques with full case protection.”
“A team of five people was involved in working on the fossil, and the job took about seven hours.”
“The subsequent preparations, particularly the meticulous task of preparing and repairing the skull, took several months.”
Team Survey results Published in Journal of Vertebrate Paleontology.
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Aldo Benitez Palomino othersTrophic interactions between sharks and crocodiles and Sirenia in the Miocene of Venezuela. Journal of Vertebrate Paleontologyy, published online August 28, 2024, doi: 10.1080/02724634.2024.2381505
Source: www.sci.news
