Hydrogen ions are edible, although usually dissolved in water. Hydrogen ions existed before oxygen or water

That's because when something becomes a new species is a surprisingly difficult and contentious debate in biology.

That's simply due to the nature of evolution. It's nearly impossible to look at one past generation of chicken to the next to figure out when the ancestor was no longer a chicken. Yet, go back far enough and you'll find T-Rexes in the mix.

Every generation is a new missing link. It's an extremely fuzzy process.

> I'm finding it surprisingly hard to find sources for known age of species - is that information collected somewhere? Or is it something we often just don't know because of how sparse the fossil record is?

It depends on what you mean by the age of the species. You can find the oldest known fossil occurrence at the Paleobiology Database [1] and the divergence time from molecular phylogenies via TimeTree [2].

[1] https://paleobiodb.org/

[2] https://timetree.org/

It's pretty tricky to find out, yeah. And new evidence is coming in all the time. All the methods are either floors (a fossil at X date proves a species existed then, but lack of fossils found yet might be inconclusive) or estimates (like molecular clock techniques). Dating fossils themselves (or rather the rocks they're buried in) isn't always easy or possible. For more out-of-the-way species, if anyone has bothered trying to figure out the age it's likely buried in scientific sources that are tricky for novices to find or search, and maybe under debate.

I think this might say more about your geographic location than you think :)

People from other continents always surprise me with various fruits they taken for granted their entire life, but I've never heard about, and vice-versa.

Lotus root is pretty common in Chinese and Japanese cuisine. I've had it pickled and in a Sichuan dry pot. It's crunchy and takes on flavors pretty well.

my wife and I regularly eat lotus root, it's quite delicious and common in chinese cooking. the others not so much.

On a side note there are 1000s even 10s of thousand of edible plant based species that grow on the earth. i don't know how old they are though.

Whoever smelled a ginkgo fruit and said "let's eat this" !

Water caltrop nuts are common in Taiwan, very nutty and good for meat soups.

Fiddleheads from ferns are available at farmer's markets in the spring in my area, though not from the cinnamon fern specifically.

I'm having trouble finding sources for other specific fern species, though many ferns have been around for hundreds of millions of years.

Fern fiddleheads aren't bad if you get them at the right time, but I wouldn't go out of my way to eat them.

Lotus root is pretty common. A crunchy tuber that keeps its texture after cooking, bland taste, unique visual appeal. I threw some in the last pot of bean chili my family made, and the kids liked it.

Funnily enough they're toxic to all remaining dinosaurs.

> Avocado. I heard it was dinosaur food.

Nope, and this is trivial to check. Source: https://en.wikipedia.org/wiki/Avocado#Taxonomy_and_evolution

The proposed dispersers are now-extinct mammalian megafauna. Much more recent - 10k to 100k years ago.

'eaten as a delicacy in some parts of Asia' according to Wikipedia, but to be fair OP is only asserting possibilities anyway (the criteria are 1) old enough to have been around for dinosaurs to eat; 2) edible by humans).

Technically they eat the roe. Horseshoe crabs have very little meat and it’s so tough as to be practically inedible.

A lot of vegetables are toxic when raw, but safe after cooking. My favorite among these is mandioca, when it’s cooked and then fried. Goes well with churrasco.

It's a staple food in some cultures. It needs preprocessing, but people have been doing that for a while

Evolution rarely escape local maxima.

It was once thought that giant ground sloths were important for spreading avocados, but that seems to have been a mistake. Anyway, that was long after the dinosaurs. Flowering plants in general were still pretty new by the time the dinosaurs died out. I bet an actual dinosaur never saw an avocado. :)

Edit: transcript of a video about the sloth/avocado thing: https://nerdfighteria.info/v/jpcBgYYFS8o

Which one?

In university, one year, our building started smelling like there had been a sewage overflow. Pretty soon, everything around started smelling like this - the stores, restaurants, cinema, etc. in central campus was stinking. It was soon found out that the decorative Ginko trees planted in the central part of campus were fruiting (probably for the first time since planting) and the fruit was getting crushed underfoot and carried everywhere. The smell took a few weeks to go away.

> contact dermatitis

Lots of food is like this, for example mangoes.

I eat foods with long history of co-evolution and domestication.

Barley and Yogurt, they are the dogs we domesticated from wolves that changed us too.

Daily barley water is a life changer, I don't think our digestive systems really function without a smidgen of daily barley.