When Fish Wore Armor

PBS Member Stations rely on viewers like you. To support your local station, go to http://to.pbs.org/DonateEons ↓ More info below ↓ Check out Hot Mess:    / @hotmesspbs   420 million years ago, some fish were more medieval. They wore armor, sometimes made of big plates, and sometimes made of interlocking scales. But that armor may actually have served a totally different purpose, one that many animals still use today. Produced for PBS Digital Studios. Super special thanks to the following Patreon patrons for helping make Eons possible: Aldo Espinosa Zúñiga, Betsy Radley, Svetlana Pylaeva, Colin Sylvester, Philip Slingerland, John Vanek, Jose Garcia, Noah offitzer, Eric Vonk, Tony Wamsley, Henrik Peteri, Jonathan Wright, Wilco Verweij, Jon Monteiro, James Bording, Brad Nicholls, Miles Chaston, Michael McClellan, Elysha Nygård, Jeff Graham, Maria Humphrey, Nathan Paskett, Connor Jensen, Ehit Dinesh Agarwal, Sapjes, Dave, Daisuke Goto, Zachary Winkler, Hubert Rady, Yuntao Zhou, Gregory Kintz, Tyson Cleary, Chandler Bass, Maly Lor, Joao Ascensao, Tsee Lee, Sarah Fritts, phil parker, Ruben Winter, Ron Harvey Jr, Joshua Mitchell, Johnny Li, Katie Fichtner, Budjarn Lambeth, Jacob Gerke, Katie M Vasilescu, Brandon Burke, Alex Yan, Jordon Sokoll If you'd like to support the channel, head over to   / eons   and pledge for some cool rewards! Want to follow Eons elsewhere? Twitter -   / eonsshow   Instagram -   / eonsshow   References: Sim, Min Sub, Shuhei Ono, and Matthew T. Hurtgen. "Sulfur isotope evidence for low and fluctuating sulfate levels in the Late Devonian ocean and the potential link with the mass extinction event." Earth and Planetary Science Letters 419 (2015): 52-62. Sallan, Lauren, and Andrew K. Galimberti. "Body-size reduction in vertebrates following the end-Devonian mass extinction." Science 350.6262 (2015): 812-815. Afanassieva, O. B. "On the growth and regeneration of the exoskeleton in early jawless vertebrates (Osteostraci, Agnatha)." Doklady Biological Sciences. Vol. 466. No. 1. Pleiades Publishing, 2016. Anderson, Philip SL, and Mark W. Westneat. "Feeding mechanics and bite force modelling of the skull of Dunkleosteus terrelli, an ancient apex predator." Biology Letters 3.1 (2007): 77-80. http://rsbl.royalsocietypublishing.or... Arsenault, Marius, et al. "New data on the soft tissues and external morphology of the antiarch Bothriolepis canadensis (Whiteaves, 1880), from the Upper Devonian of Miguasha, Quebec." Recent Advances in the Origin and Early Radiation of Vertebrates: Verlag Dr. Friedrich Pfeil, München (2004): 439-454. http://www.pfeil-verlag.de/wp-content... Brazeau, Martin D., and Matt Friedman. "The origin and early phylogenetic history of jawed vertebrates." Nature 520.7548 (2015): 490. Brett, Carlton E., and Sally E. Walker. "Predators and predation in Paleozoic marine environments." The Paleontological Society Papers 8 (2002): 93-118. https://www.cambridge.org/core/journa... Carr, ROBERT K. "Paleoecology of Dunkleosteus terrelli (Placodermi: Arthrodira)." KirtlandIa, the Cleveland Museum of Natural History 57 (2010): 36-55. Carr, Robert, K. "Placoderm diversity and evolution." Bulletin du Muséum national d'histoire naturelle: Sciences de la terre, paléontologie, géologie, minéralogie. Section C 17 (1995): 85. https://www.researchgate.net/profile/... Chevrinais, Marion, Claire Jacquet, and Richard Cloutier. "Early establishment of vertebrate trophic interactions: Food web structure in Middle to Late Devonian fish assemblages with exceptional fossilization." Bulletin of Geosciences 92.4 (2017): 491-510. De Vleeschouwer, David, et al. "Timing and pacing of the Late Devonian mass extinction event regulated by eccentricity and obliquity." Nature communications 8.1 (2017): 2268. https://www.nature.com/articles/s4146... Denison, Robert H. "The soft anatomy of Bothriolepis." Journal of Paleontology (1941): 553-561. http://www.jstor.org/stable/1298812 Doherty, Alison H., Cameron K. Ghalambor, and Seth W. Donahue. "Evolutionary physiology of bone: bone metabolism in changing environments." Physiology 30.1 (2015): 17-29. Donoghue, Philip CJ, and Ivan J. Sansom. "Origin and early evolution of vertebrate skeletonization." Microscopy research and technique 59.5 (2002): 352-372. Giles, Sam, Matt Friedman, and Martin D. Brazeau. "Osteichthyan-like cranial conditions in an Early Devonian stem gnathostome." Nature 520.7545 (2015): 82. https://www.nature.com/articles/natur... We've hit YouTube's description character limit so you can find all references we used in this video here: https://pastebin.com/raw/XkhEwmyU