Explained by Franz Steindachner in 1876, Bothragonus swanii is a types in the household Agonidae.

This fish is discovered in the eastern Pacific Ocean from Alaska to Carmel Bay, California to depths of 18 m.

Marine biologists have actually long disputed numerous hypotheses for why Bothragonus swanii has a spacious cranial pit– a cavity about the size of the fish’s brain.

Some believed it assisted camouflage the animal amongst rocks, others hypothesized that it may help hearing or sensory understanding.

Now, thanks to advanced imaging innovation, Louisiana State University trainee Daniel Geldof recommends a completely various description– one that stimulates the rhythms of a rock show instead of the silence of a reef.

“The objective of my whole thesis task was to find out why,” Geldof described.

Utilizing a high-resolution micro-CT scanner, he developed in-depth 3D designs of the rockhead poacher’s anatomy.

These scans exposed that the fish’s very first set of ribs are uncommonly big, free-moving and flattened, sitting near the cranial pit without direct accessory.

At the bases of these ribs are effective muscles and tendons– like drumsticks.

When vibrated versus the mineralized cavity in the skull, these ribs can develop below ground pulses of noise.

Geldof argues that this percussion-like system most likely developed to assist the fish interact through the ground in its acoustically disorderly intertidal environment.

In this rocky, shallow zone where crashing waves and ecological sound make standard waterborne interaction hard, vibrations sent through the substrate might take a trip better– a method much better matched to this fish’s special way of life.

Geldof likewise integrated contrast-agent improved soft-tissue scans with bone structure information to trace nerves, muscles and microstructures within the rockhead poacher’s head, discovering proof that the cranial pit might likewise play a sensory function.

A branch of the posterior lateral line nerve, part of the fish’s motion-sensing system, goes into the pit, and the plan of surface area microstructures might support mechanoreception– the capability to identify motion or pressure.

Geldof argues that the function might be multifunctional, serving both interaction and sensory functions in the loud intertidal community.

“What does this small thing appear like up-close isn’t simply a clinical concern– it’s a fundamental human interest,” he stated.

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Daniel L. Geldof. 2025. The hole reality: morphology of the cranial pit in the rockhead poacher, Bothragonus swanii (Agonidae). LSU Master’s Theses 6270