420 Dive Log Australasia OCTOBER 2026

occupy a niche in the same area. This means that both Parrotfish can survive because they may have differing diets and so do not compete with each other for a limited food supply. The huge Bump Headed Parrotfish had far more powerful teeth. They actually bite chunks of coral and grind them up in the Deep Throat jaws known as the pharyngeal jaws, a second set of teeth in the throat. They don’t scrape coral. Their teeth are fused and are strong enough to bite the coral rocks. Incidentally, many references on Parrotfish state that they do not eat coral but rather eat the algae. In my opinion, this is confusing. The coral scrapings are filled with living tissue from coral polyps that contain symbiotic algae. They eat both. Eating coral polyps, i.e. animal tissue is carnivorous. Eating both is omnivorous. A very small number of a third type is vegetarian which has differing teeth structure suited to eating algae. Napoleon Wrasse have different teeth. They have eat large shells, crabs and sea urchins They can break open hard shells with their powerful teeth. They also eat Crown of Thorns sea stars and other toxic animals. Napoleon wrasse help to maintain the health of the reef. ADAPTIVE RADIATION Similar species have similar anatomical features. A great example are the Syngnathids, the Pipefish and Sea Horse families. They share the feeding techniques and similar mouth parts as well as the bony rings that help to protect them from predators. This Comparative anatomy. Logically, they can be traced back to some

distant common ancestor many millions of years ago. These variations on a theme are examples of Adaptive Radiation. Darwin used the example of the Finches of the Galapagos Islands. He assumed that some ancestral Finches arrived from mainland South America and settled on differing islands in the Galapagos with differing

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Dive Log Australasia #420 October ’26

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