A neck-like vertebral motion in fish. Credit: Dr Ariel L Camp
One University of Liverpool researcher discovered that fish can bend their heads and spines upwards, despite being different from humans and other land-dwelling vertebrates.
Today's publication in Proceedings of the Royal Society B: Biological Sciences, reveals the results of the study.
Dr. Ariel L Camp, the author of this study, measured the spine motion in rainbow trouts and frogfish using digital animation and X-ray video.
She stated that the fish used two-thirds of the spine instead of the vertebral joints behind their heads like humans. This allows us to see how fish move their spines three-dimensionally while swimming and eating.
Tetrapods, four limbed animals, use their necks to move the head three-dimensionally relative to the body. This neck is not present in fish, but many species raise the head relative to their bodies during feeding. Cranial elevation may be caused by the craniovertebral or cranialmost intravertebral joints acting like a neck and dorsally rotating (extending). This has not been proven due to difficulties in visualizing and measuring vertebral movement in vivo. To measure the three-dimensional vertebral kinematics of rainbow trout and Commerson frogfish during their feeding, I used Xray reconstruction of moving morphology.
"Despite having drastically different morphologies, dorsoventral rotates in both species extended beyond the craniovertebral or cranial intervertebral joint. To elevate the neurocranium, trout combine small dorsal rotations (mostly less than 3), over up to a quarter of their intervertebral joint. Frogfish rotate extremely large amounts of the first intervertebral and craniovertebral joints, often exceedingly many times 2030. However, smaller rotations were made across the two-thirds vertebral columns during cranial elevation. Fish rotate large areas of the vertebral column to rotate their heads, unlike tetrapods. To understand the mechanism by which non-tetrapods control headbody motion, it is important to consider both the cranial vertebrae and the more caudal ones.
Dr. Ariel L Camp, a BBSRC Discovery Fellow at University of Liverpool, is Dr. Her research focuses on how animals move. How their muscles and bones interact to create motions that are as amazing as flying, or as common as breathing. She focuses specifically on the interface between head and body, the neck. This is where she examines the shape of the neck and records how it moves in 3-D using digital animations, X-ray images, slow-motion video and X-rays. These results can be used to identify patterns in animal evolution and provide inspiration for human designers looking to create moving machines or improve the movement of our bodies.
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