The earliest and most primitive fish date all the way back to around half a billion years ago, however, around this time and for many millions of years after this they were usually at the bottom of the food chain and most, if not all of the large predatory niches were occupied by giant ancient invertebrates. However this changed around 400 million years ago in the devonian peridod when there was a major shift that largely persists to this day, with fish becoming the most dominant animals in the ocean.
To support me on Patreon (thank you): https://www.patreon.com/MothLightMedia
To donate to my PayPal (thank you): https://www.paypal.me/mothlightmedia
To buy merchandise: teespring.com/en-GB/stores/moth-light...
Email: [email protected]
If I have used artwork that belongs to you but have neglected to credit it this will just be because I was unable to find one. If this has happened please contact me and I will add a credit. Some Art work has been altered for the purposes of bettering them for video format; these alterations were done independent from the artists who created the original work, so they are not responsible for any inaccuracies that could have occurred with the changes being made.
Sources:
https://royalsocietypublishing.org/doi/10.1098/rsos.200272
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2373817/
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2865068/
https://academic.oup.com/zoolinnean/article/176/4/806/2449910?login=false
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5723140/
https://www.bristol.ac.uk/news/2009/6596.html
https://ucmp.berkeley.edu/vertebrates/basalfish/placodermi.html