.jpg)
Two pearlside species that have hybrid photoreceptors in their eyes as larvae and adults, Maurolicus muelleri and Maurolicus mucronatus.
Photo credit: Dr Wen-Sung Chung
Scientific Frontline: Extended "At a Glance" Summary
The Core Concept: A newly discovered type of visual cell found in deep-sea fish larvae that challenges the traditional biological dichotomy of rod and cone photoreceptors. These cells are specifically adapted to optimize vision in "twilight" or gloom-light conditions found at intermediate ocean depths.
Key Distinction/Mechanism: While vertebrate vision is historically categorized into cones (for bright light) and rods (for dim light), this hybrid cell functions as a bridge between the two. It uniquely combines the molecular machinery and genetic profile of cones with the physical shape and form of rods to maximize efficiency in half-light environments.
Origin/History: The discovery was announced in February 2026 by researchers at The University of Queensland, following marine exploration voyages in the Red Sea. The findings overturn approximately 150 years of established scientific consensus regarding vertebrate visual systems.
Major Frameworks/Components:
- Hybrid Morphology: Cells exhibiting the structural rod shape for sensitivity but utilizing cone-specific genes for processing.
- Developmental Adaptation: Found in larvae inhabiting depths of 20 to 200 meters, serving as a transitional visual system before the fish descend to deep-sea habitats (up to 1km) as adults.
- Twilight Optimization: A specialized biological design for low-light environments that balances sensitivity and detection better than standard rods or cones alone.
Branch of Science: Marine Biology, Visual Neuroscience, and Evolutionary Biology.
Future Application:
- Optical Technology: Development of advanced sensors for cameras and night-vision goggles that offer high efficiency in low light without sacrificing image sharpness.
- Medical Research: Investigation of cellular resilience in high-pressure environments to identify new biological pathways for treating human eye conditions such as glaucoma.
Why It Matters: This discovery rewrites a fundamental rule of vertebrate biology and provides a blueprint for next-generation imaging technologies inspired by deep-sea evolutionary adaptations.
.jpg) |
| Photo Credit: The University of Queensland with fish illustration by Julie Johnson |
Researchers have identified a new type of visual cell in deep-sea fish larvae that challenges a century of knowledge about vertebrate visual systems.
Dr Fabio Cortesi from The University of Queensland’s School of the Environment said the finding could lead to new camera technology and medical treatments.
“For more than 150 years, textbooks have taught that vision in most vertebrates is made of cones and rods – cones which work in bright light and rods for dark situations,” Dr Cortesi said.
“But our study of deep-sea fish larvae revealed a new cell type – a photoreceptor that optimizes vision in gloomy or twilight conditions.
“It combines the molecular machinery and genes of cones with the shape and form of rods.
“This hybrid cell has the best bits of both the bright light and dark light systems to be something new that's really efficient for twilight vision.”
The research team, which also included Dr. Lily Fogg and Dr. Fanny de Busserolles, examined the retinas of fish larvae caught at depths between 20 and 200 meters in the Red Sea during a series of marine exploration voyages.
“It was very tricky because the larvae are only half a centimeter long, and their eyes are smaller than a millimeter,” Dr. Fogg said.
“We know in adulthood some of these fish descend to live up to 1 kilometer below the surface where they optimize their vision to see in the dark.
“We wanted to investigate how their early vision develops in half-light closer to the surface, where they feed and grow before descending into one of the dimmest and largest habitats on Earth.”
Dr. Cortesi says the team hoped the discovery would serve as inspiration for several fields of applied science.
“This finding is fascinating because it builds on the little we know about the deep sea, but there are also practical applications for this knowledge,” he said.
“In technology, creating sensors based on this unique cell structure could lead to more efficient cameras or goggles for low-light situations without sacrificing image sharpness.
"In medicine, learning how these fish build this type of visual cell in the high-pressure environment of the deep ocean could unlock new biological pathways relevant to human eye conditions such as glaucoma."
Published in journal: Science Advances
Title: Deep-sea fish reveal an alternative developmental trajectory for vertebrate vision
Authors: Lily G. Fogg, Stamatina Isari, Jonathan E. Barnes, Jagdish Suresh Patel, N. Justin Marshall, Walter Salzburger, Fanny De Busserolles, and Fabio Cortesi
Source/Credit: University of Queensland
Reference Number: ebio021126_02