Danielle’s braina translucent fish species only 12 mm long, produces a high-amplitude sound exceeding 140 dB (re. 1 µPa, at a distance of one body length) — comparable to a jet engine during takeoff -off at 100 m distance.
Danielle’s brain has a pair of extrinsic, indirect sonic muscles containing drumming cartilage. When a sonic muscle contracts, the fifth rib is pulled forward and develops tension as it pulls on the cartilage. The sudden release of the cartilage causes it to quickly hit the swim bladder, producing a short, strong pulse. A burst of pulses is generated with either bilaterally alternating or unilateral muscle contractions. Altogether, this mechanism allows strong and stereotyped sounds to be captured in structured sequences, making it a unique solution for acoustic communication and ultrafast skeletal motion in vertebrates that exceed the limit of speed of muscle contraction. Photo credit: Ralf Britz, Senckenberg Natural History Collections.
“The snapping shrimp can produce a popping sound of up to 250 dB with its claws,” said Dr. Ralf Britz, an ichthyologist at the Senckenberg Natural History Collections.
“The flightless kakapo’s mating calls reach 130 dB, and elephants can make a noise of up to 125 dB with their trunks.
“Fish, on the other hand, are generally considered relatively quiet members of the animal kingdom.”
“However, there are some fish species that can be surprisingly loud. For example, the male plainfin midshipman fish attracts its females with an audible vibrato of about 100 Hz and 130 dB.
In the new study, Dr. Britz and his colleagues Danielle’s braina miniature teleost fish with the smallest known vertebrate brain.
“These small fish can make sounds of more than 140 dB at a distance of 10 to 12 mm – this is comparable to the noise that a person sees in an airplane while flying at a distance of 100 m and is quite unusual for an animal like this. small size,” said Dr. Britz.
“We tried to understand how the fish manage this and what mechanisms are responsible for this success.”
Using a combination of high-speed video, micro-computed tomography, gene expression analysis, and finite difference methods, the researchers found that Danielle’s brain males possess a unique sound-producing apparatus that includes drumming cartilage, a specialized rib, and a muscle that resists fatigue.
“This apparatus accelerates the drumming cartilage with a force of more than 2,000g and fires it against the swim bladder to produce a fast, powerful pulse,” said Dr. Britz.
“These pulses are combined to produce calls with either bilaterally alternating or unilateral muscle contractions.”
Due to its small size and lifetime optical transparency, Danielle’s brain is an emerging model organism in biomedical research.
The species is native to the shallow and murky waters of Myanmar.
“We hypothesize that competition between males in this visually restrictive environment contributed to the development of a specialized mechanism for acoustic communication,” said Dr. Britz.
The results of the study challenge the conventional notion that the speed of skeletal movement in vertebrates is limited by muscle movement.
“Understanding the extraordinary adaptation of Danielle’s brain expands our knowledge of animal locomotion and highlights the remarkable diversity of propulsion mechanisms in different animal species,” the authors said.
“It contributes to a broader understanding of evolutionary biology and biomechanics.”
“The sounds made by others Daniella the species has not been studied in detail; it will be interesting to know how their sound production mechanism differs and how these differences relate to evolutionary adaptation.”
“Along with its lifelong transparency, the genus Daniella offers a unique opportunity to compare the neural mechanisms underlying sound production between different species.”
The study was published in Proceedings of the National Academy of Sciences.
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Verity WHAT Cook et al. 2024. Ultrafast sound production mechanism in one of the smallest vertebrates. PNAS 121 (10): e2314017121; doi: 10.1073/pnas.2314017121
