As far as I've been able to gather, mosasaurus wasn't a dinosaur, nor were any its superfamily mosasauroidae. They're simply marine reptiles.

http://www.fossilguy.com/gallery/vert/reptile/mosasaur/#about

Tag: https://e621.net/wiki/show?title=mosasaurus

[...]they were reptiles that returned to the sea during the Cretaceous Period.

In other words, they're still Dinosaurs.

Furrin_Gok said:
In other words, they're still Dinosaurs.

That makes no sense. Not all land reptiles that lived during that period were automatically dinosaurs, if I'm not very mistaken.

I'm not clear on the origin of the term "Dinosaur," but it includes animals from both the Reptilian and the Avian families. We'd have to bring in somebody with more knowledge on it, because the articles I'm finding are conflicting.

Furrin_Gok said:
I'm not clear on the origin of the term "Dinosaur," but it includes animals from both the Reptilian and the Avian families. We'd have to bring in somebody with more knowledge on it, because the articles I'm finding are conflicting.

Hello then.

Not all extinct reptiles are dinosaurs. Mosasaurs are an example of an extinct reptile that is not a dinosaur. Likewise, Pterosaurs were not dinosaurs either.

Yes, the clade dinosauria includes aves, so you are technically correct, but by analogy it would be like saying "the term canine includes animals from both the mammal and dog families".

To make that a little more clear - of course dinosauria includes members from reptilia, because reptilia includes the entirety of both dinosauria and aves.

With all that said, e621 does not try to go by "correct" taxonomy. We do not imply "avian" to "dinosaur", for instance, even though that would be correct, because it is more effective for searching for it not to be implied. Same reason we don't imply human to ape.

Turtles are not true reptiles, for instance, and so to be taxonomically accurate we should not imply turtle to reptile. But most people who are searching for "reptile" are probably also looking for turtles.

So the question here isn't whether mosasaurs are dinosaurs (because they're not), but whether people searching for "dinosaur" would be happy or unhappy to see pictures of mosasaurs.

Neither is pteranodon, but we still stick them in dinosaur. We've never really been completely accurate with taxonomy since the technicalities are usually less important to us than being able to group tags into simple categories.

That being said, I wouldn't be against unimplicating it.

Edit: Clawdragons put it way better than I could have :P

Indeed, and he makes a decent point too, I suppose most people searching for dinosaurs wouldn't be that bothered by getting the (very) occasional mosasaur among the results. Guess I forgot about how we don't always follow taxonomy strictly to the utmost degree, because there have been other examples of that.

Well, alright, I've no real objections to the implication then. ;)

Thanks, Clawdragons. Between your post and Parasprite's comment, I think it should remain implicated. It "Looks like" a dinosaur, afterall.

Furrin_Gok said:
Thanks, Clawdragons. Between your post and Parasprite's comment, I think it should remain implicated. It "Looks like" a dinosaur, afterall.

Glad to be of assistance!

people searching for dinosaurs wouldn't be that bothered by getting the (very) occasional mosasaur among the results.

https://e621.net/post/show/845184#2434391

We were wroooong! >w<

Jugofthat said:
https://e621.net/post/show/845184#2434391

We were wroooong! >w<

Also https://e621.net/post_tag_history/index?post_id=845184

Jugofthat said:
https://e621.net/post/show/845184#2434391

We were wroooong! >w<

We can never have a perfect tagging system. There will always be those who complain that there is an implication, or that there isn't one.