Four camera-type eyes in the earliest vertebrates from the Cambrian Period
Article Date: 21 January 2026
Article URL: https://www.nature.com/articles/s41586-025-09966-0
Article Image: https://www.nature.com/articles/s41586-025-09966-0/figures/5
Summary
Researchers report direct fossil evidence that some of the earliest vertebrates from the Cambrian (including Haikouichthys and myllokunmingids) preserved camera-type eyes with lenses and retinal pigments. Using a combination of microscopy (SEM, FIB, TEM), Raman spectroscopy, XPS and ToF–SIMS, the team identified carbonaceous remains and melanosome-like microbodies in the eye regions, plus structures identifiable as lenses. These data indicate that complex, camera-style vision — including additional photosensory organs beyond the paired lateral eyes — existed far earlier in vertebrate history than previously demonstrated.
Key Points
- Fossils (notably Haikouichthys ercaicunensis and a myllokunmingid species) show preserved eye structures consistent with camera-type eyes and lenses.
- Microscopy (SEM/FIB/TEM) reveals melanosome-like microbodies in the eye tissues; elemental maps and ultrastructure support their biological origin.
- Spectroscopic analyses (Raman, XPS, ToF–SIMS) distinguish organic, melanin-like signals in eyes from surrounding sediment, supporting genuine preservation of retinal pigments.
- Quantitative measurements (melanosome shape distributions, PCA of ToF–SIMS spectra) back the interpretation that these are photoreceptive structures, not taphonomic artefacts.
- The presence of multiple camera-type eyes (including dorsal/pineal-region photosensors alongside lateral eyes) pushes the origin of complex vertebrate vision into the Cambrian and has implications for early behaviour and ecology.
Content summary
The study combines exceptionally preserved Chengjiang fossils with multiple imaging and chemical techniques to demonstrate that early vertebrates had camera-style eyes. Lenses are visible in several specimens; melanosome-like bodies occur in consistent distributions within the eye regions. Raman and ToF–SIMS spectra match signals expected of melanin-related compounds and differ from sediment controls, while XPS supports the presence of carbonaceous organic material in the eyes. The authors also provide comparative imagery from other fossil fishes and modern references to frame the interpretation.
Beyond anatomical description, the paper quantifies melanosome morphology and performs statistical analyses to show the fossil signals cluster with known melanin samples (including experimentally matured melanin). Extended data document preservation states, element maps, and imaging that together make a compelling case for genuine preservation of eye tissues and lenses in Cambrian vertebrates.
Context and relevance
This work matters because it moves the origin of complex, camera-type vision deeper into the vertebrate tree and earlier in geological time. It bears on major questions in evolution — how quickly sophisticated sensory systems evolved during the Cambrian radiation, the developmental origins of eyes and retinal tissues, and how vision shaped early vertebrate behaviour (for example, swarming, predator–prey interactions and navigation).
The study also demonstrates the power of combining ultrastructural imaging with modern chemical mapping (ToF–SIMS, Raman, XPS) to distinguish biological pigments from diagenetic residues — an approach increasingly important in palaeobiology and macroevolutionary studies.
Why should I read this?
Short answer: because it’s a proper eyes-on fossil story that rewrites when vertebrates first had camera-style vision. If you’re into evolution, fossils, or how sensory systems first got good enough to matter ecologically, this is the paper that saves you digging through the technical stuff — the team did the heavy lifting with imaging and chemistry so you can get the headline: complex eyes were already around in the Cambrian. Pretty neat, and important for anyone following vertebrate origins.