An ancient fish fossil tells a new story about laminiform shark evolution

An international, multi-university research team, including scientists from Columbus State University, has uncovered an important new piece of the puzzle in shark evolution.

A recent study published in Communication biology“Early giant laminiform marks the beginning of mega-body size in modern shark evolution,” identifies a new, extinct laminiform shark. This is a group that includes modern day great white and mako sharks. This marks the earliest known example of a very large shark, suggesting that the mega-body size trend began earlier in modern shark evolution than previously thought.

Led by Stanford University’s Dr. Muhammad Bazzi, the team included Dr. Mike Newbury of Columbus State’s Department of Biology and 2020 alumni Tatiana Black. They drew their conclusions after studying samples from the Darwin Formation, which occurs in Darwin, Australia. The specimens, which had been collected by other researchers in the 1980s, were stored in a museum collection and only recently were they examined in detail by the team.

By analyzing newly discovered fossil evidence, the group’s findings rewrite the evolution timeline of mega-body-sized sharks as apex predators, pushing it back by 15 million years. The 115-million-year-old fossil vertebrate was used to estimate a body length of 6 meters to 8 meters (19.5 ft to 26.3 ft), and a weight of more than 3 tons. The earliest limniform fossils were small and uncertain at about 135 million years old.

“As a field, we are interested in the environmental and ecological conditions required to evolve megabody sizes.” “As researchers, we need a rigorous method of estimating body size to answer the question of the conditions required to evolve large body sizes in lymphoid sharks.”

The size estimates used in this study were derived from a dataset of body lengths from 10 species of living laminiform sharks collected and analyzed ethnographically, Newbry explained. Prior to this study, there was no way to evaluate the effects of different species on body length estimates from fossil material, nor was there an informed interpretation of body length estimates from the incomplete fossil material of lymphoid sharks.

Previous interpretations suggested that giant laminiform sharks evolved in the Late Cretaceous period (100.5 to 66 million years ago) with a specialization in a pelagic lifestyle. However, Newbury said the team’s investigation supports the first evolution of a very large limniform shark in the Early Cretaceous period (145.1 to 100.5 million years ago) when it was relatively cooler than in the Late Cretaceous period. As a result of this research, the field has a new set of questions to consider in the evolution of giant limniform sharks.

From student to published researcher

In addition to the team’s discovery, the project revealed the research interests of another—Columbus State undergrad Tatiana Black. Newbury mentored Blake as part of her undergraduate research project, which she completed as a biology student. Her involvement in New Bray’s research continued after she graduated, earning her a co-authorship credit in communication biology.

“[T]Hat chance [to work with Newbrey] “It had a lasting effect on my academic trajectory,” Blake recalled. The mentor I received [from Newbrey] And the nature of the project itself provided the foundation I needed to appreciate and pursue further research. “

Continuing scientific research was not necessary when she graduated with her biology degree and concentration in veterinary medicine. Instead he served as a logistics officer in the U.S. Army and Advanced Leadership, and later, taught high school aquatic science and astronomy. Blake is now focused on getting accepted into a doctoral program and conducting research in marine science.

“[Dr. Newbrey’s] About his experience as an undergraduate researcher he said, “The passion for ichthyology inspired me to explore fish research myself. It was exciting to work with actual fossil specimens and contribute original data to a field I hadn’t considered before. This experience instilled a deep appreciation for research and its broader implications.”

New Bray said that not every project leads to publication in such a prestigious scientific journal, but faculty-led research is a priority for her and her faculty colleagues, including students.

“Students perform best academically, and later professionally, when they have opportunities to apply what they learn,” he said.

“We strive to engage our students in research opportunities early in their education, so they can realize the power and potential of how what they learn in the classroom contributes to the fields of science and education, while also improving the communities in which we live.”

Future research applications

Newbury said the new analysis will be useful for many future studies of limniform sharks. The new large limniform predicts other large sharks, and this study provides a protocol for estimating body size for studying the effects of ecological and environmental factors that allow sharks to reach such proportions.

“For example, the team notes that large cardiobiodont IDs existed during relatively cold times, and they hypothesize that the large body size may have enabled these particular sharks to survive in colder waters, thereby exploiting the niches filled today by other large lymphoid sharks,” he said.

“Being able to estimate body size from isolated vertebrate material will enable us to answer big questions about shark evolution while considering the effects of climate change.”