New Research Reveals Frogs Have Preserved Their Ecology for 45 Million Years
Frog melanosome geometry study shows similarities between ancient and modern frog eyes. Image credit: Falk et al., doi: 10.1016/j.isci.2025.114220.
This groundbreaking study led by University College Cork investigates 45 million-year-old frog fossils from Geiseltal, a notable paleontological site in central Germany.
These remarkable fossils preserve not only skin remnants but also microscopic fossilized cell structures known as melanosomes.
Melanosomes are essential for synthesizing, storing, and transporting melanin, the pigment responsible for the coloration of skin, hair, and eyes.
Like contemporary frogs, these ancient melanosomes are found in various body areas, including the eyes, skin, and internal organs.
While melanosome shapes differ between fossilized and modern soft tissues, the shapes in the eyes and internal organs remain consistent.
Dr. Valentina Rossi, a researcher at University College Cork, stated, “The shape of melanosomes may correspond to different functions across tissues, including photoprotection and homeostasis.”
Dr. Daniel Falk, also from University College Cork, noted, “The unchanged shape of eye melanosomes over millions of years suggests their function has remained constant, indicating that no evolutionary changes were necessary.”
Some frog species appear to maintain ancestral traits rather than evolving new characteristics.
This research confirms that frogs have preserved their ecological niche for at least 45 million years, adapting to activities such as hunting and mating during dawn and night.
This study is the first to analyze a large dataset of both extant and fossil melanosomes from frogs.
Utilizing advanced electron microscopy and synchrotron X-ray fluorescence analysis, researchers gained insights that were unavailable in the early 20th century when the fossils were first discovered.
Professor Maria McNamara emphasized, “Integrating fossil and living species data in paleontological research can illuminate our understanding of evolutionary processes.”
“We are just beginning to recognize that melanin may serve as a significant evolutionary signal.”
Read the full study published in this month’s iScience magazine here.
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Daniel Falk et al. “Evolutionary Constraints on Melanin over 45 Million Years.” iScience, published online December 17, 2025. doi: 10.1016/j.isci.2025.114220
Source: www.sci.news
