A recent study suggests that one of the warmest eras in Earth’s history may have caused a genetic divide among lampreys. This research could provide insights into how aquatic species might adapt to the changes prompted by today’s climate change.
A recent study suggests that one of the warmest eras in Earth’s history may have caused a genetic divide among lampreys. This research could provide insights into how aquatic species might adapt to the changes prompted by today’s climate change.
“Lampreys are strange yet fascinating creatures; people often view them merely as elongated tubes with an unsettling ring of teeth,” shares Lily Hughes, the lead author of the study. Hughes is a research assistant professor at North Carolina State University and the ichthyology curator at the North Carolina Museum of Natural Sciences.
“These ancient and remarkable organisms play a crucial role in filtering nutrients and preserving water quality in stream habitats,” she mentions. “However, our understanding of their evolutionary connections and lineage remains limited.”
Currently, there are 48 recognized lamprey species, categorized into three families: one family inhabits the Northern Hemisphere, while the other two are found in the Southern Hemisphere. Notably, lamprey species do not exist in the tropical regions near the equator.
Hughes, along with co-first author Devin Bloom and the research team, aimed to pinpoint when these populations separated from their ancestral lineage. Bloom is an associate professor at Western Michigan University.
The team utilized DNA samples from extant lampreys in conjunction with fossil data to create phylogenomic trees, which illustrated a division between the Northern and Southern Hemisphere lampreys approximately 93 million years ago during the Cretaceous period.
“During this time frame, global average temperatures hovered around 82°F (28.1°C), with average tropical temperatures reaching 93.5°F (34.2°C),” Hughes explains. “Lamprey larvae prefer cooler conditions, which is why they burrow into stream beds. The temperatures in the tropics at that time were likely too extreme for them to endure.”
“Several scenarios could account for this separation due to elevated temperatures: perhaps tropical lampreys became extinct, leading to a loss of a shared genetic lineage, or they could have migrated away from the equator towards more temperate regions. Although we cannot ascertain how lampreys were distributed then, we know that their split occurred during this period.”
The results introduce a new theory regarding the distribution of lampreys.
“A common explanation for the randomly distributed lampreys has been the existence of the ancient supercontinent Pangea, which might have kept these groups apart,” Bloom notes. “However, our research, integrating fossil and genomic data, indicates that the separation between Northern and Southern Hemisphere lampreys took place long after Pangea had broken apart.”
The findings are published in Proceedings of the Royal Society B: Biological Sciences and have received support from the National Science Foundation under grant DEB-1754627. Contributing researchers include Kyle Piller from Southeastern Louisiana University, Nicholas Lang from Lane Tech College Prep High School, and Richard Mayden from St. Louis University.
