Saurus is Greek (not Latin) for lizard so that’s where a lot of prehistoric reptiles (even non lizards like dinosaurs) get it from. Also Eurhinosaurus isn’t a fish it’s another reptile.
We now know that dinosaurs are birds, not lizards, but back when we were naming all those things, we weren’t as good as classifying them, so the incorrect names stuck
The suffix “-saur” is used for many animals that fall under the sauropsid clade including dinosaurs and their other archosaur cousins, lizards, snakes, turtles, and other reptiles. Non-reptile animals with -saur in their name like basilosaurus (a whale) got their names because their remains were originally thought to be those of reptiles. Eurhinosaurus is actually an icthyosaur and not a fish, so the name is appropriate in that case.
There’s one more piece I didn’t see mentioned here. Once a species or other taxon is given a formal scientific name, that name generally does not change unless it is later discovered that another name was previously assigned to it, or sometimes if it is reclassified out of its original category. So, when a prehistoric non-lizard like Basilosaurus is initially given the “saurus” word root, and eventually discovered not to be a lizard or even a sauropsid at all, we are stuck with the original name.
People didn’t always know what they were looking at when they named things.
For example Basilosaurus isn’t even a reptlie but a whale, but they named it before the realized that and the name stuck.
The slapped that label on all sorts of large extinct creatures for while.
Saurus just means lizard and very few of the creatures with saurus in the name are actually lizard. Dinosaurs aren’t technically really lizards either.
Some non Dinosaur creatures with -saurus in the name like Mosasaurus, a giant extinct marine reptile, are actually much close to being lizards than dinosaurs are.
This is why we have scientific names and common names. Scientific names. The scientific names get periodically corrected as new knowledge and theories change our understanding/belief of how a species evolved and what it’s related to:
Common names is what lay people call something which can change over time or parts of the world. For example the fish with the scientific name of Coryphaena hippurus is found in tropic waters almost world wide. Depending on where you are you might call it mahi mahi, dorado, dolphin fish and a few other names in the South Pacific and Asia and Mediterranean.
In the case of dinosaurs. Sometimes it’s because the scientific community reorganized the categories and species in that category. It it was a lay name that just stuck
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The word “saurus” comes from the Greek word sauros (σαῦρος), which just means “lizard” or “reptile.” So it’s not exclusive to dinosaurs at all.
Saurus is Greek (not Latin) for lizard so that’s where a lot of prehistoric reptiles (even non lizards like dinosaurs) get it from. Also Eurhinosaurus isn’t a fish it’s another reptile.
Let me try again.
The saurus suffix means’lizard’.
The ‘fish’ you listed? Belongs to the class ‘reptilia’.
It’s a suffix attached to reptiles, basically. Take a look at the scientific classification on the Eurhinosaurus wiki article
Dinosaur means “terrible lizard”
We now know that dinosaurs are birds, not lizards, but back when we were naming all those things, we weren’t as good as classifying them, so the incorrect names stuck
I agree with what others have said but just need to point out that Eurhinosaurus is an aquatic reptile not a fish similar to Elasmosaurus.
The suffix “-saur” is used for many animals that fall under the sauropsid clade including dinosaurs and their other archosaur cousins, lizards, snakes, turtles, and other reptiles. Non-reptile animals with -saur in their name like basilosaurus (a whale) got their names because their remains were originally thought to be those of reptiles. Eurhinosaurus is actually an icthyosaur and not a fish, so the name is appropriate in that case.
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There’s one more piece I didn’t see mentioned here. Once a species or other taxon is given a formal scientific name, that name generally does not change unless it is later discovered that another name was previously assigned to it, or sometimes if it is reclassified out of its original category. So, when a prehistoric non-lizard like Basilosaurus is initially given the “saurus” word root, and eventually discovered not to be a lizard or even a sauropsid at all, we are stuck with the original name.
Fun fact: there’s a prehistoric whale called “basilosaurus”
They gave it this name because they originally thought it was some sort of aquatic reptile, before more research showed that it was actually a mammal
People didn’t always know what they were looking at when they named things.
For example Basilosaurus isn’t even a reptlie but a whale, but they named it before the realized that and the name stuck.
The slapped that label on all sorts of large extinct creatures for while.
Saurus just means lizard and very few of the creatures with saurus in the name are actually lizard. Dinosaurs aren’t technically really lizards either.
Some non Dinosaur creatures with -saurus in the name like Mosasaurus, a giant extinct marine reptile, are actually much close to being lizards than dinosaurs are.
My mind is blown right now. I turned 37 a few days ago and now I find out all these creatures like Elasmosaurus weren’t dinos? 😅
This is why we have scientific names and common names. Scientific names. The scientific names get periodically corrected as new knowledge and theories change our understanding/belief of how a species evolved and what it’s related to:
Common names is what lay people call something which can change over time or parts of the world. For example the fish with the scientific name of Coryphaena hippurus is found in tropic waters almost world wide. Depending on where you are you might call it mahi mahi, dorado, dolphin fish and a few other names in the South Pacific and Asia and Mediterranean.
In the case of dinosaurs. Sometimes it’s because the scientific community reorganized the categories and species in that category. It it was a lay name that just stuck
Well, no. An elasmo-saur is not a dino-saur. Just like a key-board is not a surf-board, but they’re both types of boards.
Eurhinosaurus isn’t a fish. It’s a reptile that looks like a fish. Like a dolphin is a mammal that looks like a fish.