New fossil evidence shifts the timeline of lamniform giant sharks
A collaborative international study, highlighted in Communications Biology, reveals a pivotal new fossil that suggests giant lamniform sharks emerged much earlier than previously thought. The research, led by Dr. Mohamad Bazzi of Stanford University and involving Dr. Mike Newbrey of Columbus State University, centers on specimens from the Darwin Formation in Australia and points to an Early Cretaceous origin for mega-sized lamniform sharks. This discovery reframes how scientists understand the evolution of apex predators in the ocean.
What the fossil tells us
The team identified an 115‑million-year‑old fossil vertebrae that enabled researchers to estimate a body length of 6 to 8 meters (19.5 to 26.3 feet) and a body mass exceeding 3 tons. These measurements place the lineage of gigantic lamniform sharks well before the Late Cretaceous, challenging previous timelines that reserved megamorphs for the later parts of the Cretaceous period.
By comparing the fossil material with a new dataset drawn from ten living lamniform species, the researchers established a robust method for translating vertebral dimensions into overall body length. This approach provided a way to infer the size of incomplete fossils with greater confidence and helps clarify how environmental conditions may have influenced the evolution of extreme body size.
Early giant lamniforms and the cooler oceans
Contrary to earlier assumptions that gigantic lamniforms arose in a warmer climate, the study argues that early giants appeared during a relatively cooler Early Cretaceous. This finding implies that mega-body size could have offered advantages in cooler waters, possibly aiding these apex predators in exploiting vacant ecological niches. The new analysis also creates a framework for testing how climate fluctuations and ocean productivity shaped the evolution of large, pelagic sharks.
The role of mentorship and student involvement
The project also spotlighted the pathway from student to published researcher. Columbus State University undergraduate Tatianna Blake contributed to the study under the mentorship of Dr. Newbrey, earning co-authorship in Communications Biology after completing her biology degree. Blake’s journey—from undergraduate research to a continued role in the project—highlights the impact of faculty-led research experiences on students’ scientific careers and aspirations.
Blake’s experiences illustrate how rigorous fieldwork, specimen study, and data analysis can catalyze a student’s transition to professional science. Her story underscores the value of integrating undergraduate research into biology curricula and the broader importance of mentorship in academic science.
Implications for future shark research
The study not only shifts the timeline for when mega-bodied lamniform sharks first appeared but also provides a practical protocol for estimating body size from isolated vertebral material. This framework enables researchers to tackle larger questions about shark evolution in the context of climatic change, ocean temperatures, and available ecological niches. As researchers refine these methods, we can expect new insights into how early giants navigated ancient oceans and what their existence reveals about modern apex predators such as the great white and mako.
Looking ahead
Future work will likely apply this body-size estimation approach to additional fossil lamniforms, expanding our understanding of the pace and drivers of gigantism in shark evolution. The findings invite paleontologists to revisit other widely cited timelines and to explore how shifting marine environments influenced the emergence of megafauna in the seas.
