Coral reefs are home to a magnificent selection of fish. A fresh study by biologists at the University of California, Davis implies that a lot of this diversity is driven by way of a relatively recent innovation among bony fishfeeding by biting prey from surfaces. The task is published the week of July 25 in Proceedings of the National Academy of Sciences.
Although jawed fish come in the fossil record almost 500 million years back, feeding by grazing, nibbling or gnawing food off rocks and corals didn’t appear on the list of teleosts (the group which includes most bony fish) until following the dinosaur-killing mass extinction by the end of the Cretaceous period, about 60 million years back, based on the new study.
“There might have been some biting done by teleosts prior to the end-Cretaceous, but our reconstructions claim that it had been very uncommon,” said Katherine Corn, graduate student in the UC Davis Department of Evolution and Ecology and Center for Population Biology, and lead author on the paper.
Suction, ramming and biting
Modern reef fish feed in many ways. Many suck floating food to their mouths by rapidly expanding their heads. This suction feeding is regarded as ancestral in teleosts. An inferior number are “ram biters,” which catch food by essentially swimming about it making use of their mouths open.
Many reef fish, including iconic species such as for example parrotfish, butterflyfish and triggerfish, bite their food off hard surfaces. Thus giving them usage of prey such as for example snails and shellfish, echinoderms, anemones, algae along with other animals and plants which may be quite firmly stuck to the substrate.
Corn, dealing with Professor Peter Wainwright along with other colleagues in the UC Davis Department of Evolution and Ecology classified 1,530 living species of reef fish by feeding method, then mapped them onto an evolutionary tree of the teleosts. In addition they studied the rate of physique evolution in every of the fish.
They discovered that by the end of the Cretaceous, almost all of the fish in these lineages were suction feeders. Today, four in 10 reef species are “benthic biters” that browse on the substrate. The biting species are evolving in physique at almost twice the rate of suction feeders, they discovered.
What tripped these changes? The finish of the Cretaceous saw changes in coral reefs, with an increase of complex and branching structures that made grazing more productive. Simultaneously, teleosts evolved shorter jaws which were better for biting.
“Both of these changes together really exposed biting being an effective mode for fishes,” Corn said. Biting allowed reef fish to gain access to diverse new prey, promoting the evolution of a wide selection of body shapes, she said.
“So once biting evolved, it had been really in a position to take off, which may explain the high rates of physique evolution and diversity of biters that people see,” Corn said.
Additional authors on the paper are: at UC Davis, Sarah Friedman, Edward Burress and Christopher Martinez; Olivier Larouche and Samantha Price, Clemson University, SC.
More info: Katherine A. Corn et al, The rise of biting through the Cenozoic fueled reef fish physique diversification, Proceedings of the National Academy of Sciences (2022). DOI: 10.1073/pnas.2119828119
Citation: Reef fish evolution driven by biting (2022, July 27) retrieved 27 July 2022 from https://phys.org/news/2022-07-reef-fish-evolution-driven.html
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