New research on ancient tides during the Late Silurian-Devonian (420 million to 380 million years ago), published in Proceedings of the Royal Society A, suggests that high tides may have been a key ecological factor in the evolution of bony fish and early tetrapods, the first terrestrial vertebrates.
The study is a detailed development of a theory previously published in the same journal. The theory assumed that a certain mass of the Moon and its orbital position were suitable for creating large tidal ranges and isolating tidal basins. And this, in turn, could be a biological stimulus for the development of limbs in fish stranded between very high tides.
Scientists at Bangor and Oxford Universities in the UK and Uppsala University in Sweden were the first to perform detailed numerical simulations to find out for sure whether there were large tides during this critical period of evolution. Incidentally, these are the first calculations linking tidal hydrodynamics with an evolutionary biological event.
Numerical modeling was carried out using paleogeographic reconstructions of the Earth’s continents in the established modern numerical model of ebb and flow. Modeling results show that tidal fluctuations exceed four meters in the South China block. It is he who is the place of origin of the earliest group of teleost fish, judging by the fossils found.
The researchers are confident that the method used in this study can be used in other paleogeographic reconstructions, finding out what happened to living species at other times. Among other things, it will help to study the influence of tides on the origin and diversity of other early vertebrates.