Tanis: 'First dinosaur fossil linked to asteroid strike'
The sturgeon and paddlefish in this fossil tangle are key. They have small particles stuck in their gills. These are the spherules of molten rock kicked out from the impact that then fell back across the planet. The fish would have breathed in the particles as they entered the river.
The spherules have been linked chemically and by radiometric dating to the Mexican impact location, and in two of the particles recovered from preserved tree resin there are also tiny inclusions that imply an extra-terrestrial origin.
https://www.bbc.com/news/science-environment-61013740
Grrr, BBC and their "we don't know how to do paragraphs, so we separate all sentences." Also, it's a misleading headline. The jury is still out on the dino leg, except it was tipped off the animal and not by a predator. There are a couple of vids with the story that are worth watching.
Still, the fish prove what a bad day it was for everyone.