
Why a Pterosaur Is Not a Dinosaur - nonbel
https://www.smithsonianmag.com/science-nature/why-a-pterosaur-is-not-a-dinosaur-87082921/?no-ist
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xref
_“Dinosaur” is a word for a specific group of creatures united by shared
characteristics and which had their own evolutionary history—it is not a
catch-all term for anything reptilian and prehistoric "_

Fascinating, didn't know Pterosauria split off from Dinosauria so far prior to
either's evolution.

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quotemstr
> Calling a pterosaur a dinosaur is an error of the same order of magnitude as
> saying that our species is a marsupial

I'd say it's more like the error of calling a tomato a vegetable. While it's
true that from a phylogenetic perspective that pterosauria aren't dinosaurs,
they still have many basal characteristics (relative to today's flying
dinosaurs, the aves) that give them a certain dinosaur-like quality in the
imagination. Besides, they're contemporaneous with the true dinosaurs.
Grouping them with the dinosaurs is understandable. The grouping is incorrect
under one classification scheme, but correct under another.

BTW: this site screws up copy and paste, appending marketing junk to any text
copied to the clipboard. I wish it were possible to prohibit these clipboard
shenanigans.

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black6
> I wish it were possible to prohibit these clipboard shenanigans.

It is in Firefox, at least:

    
    
      about:config 
    
      dom.event.contextmenu.enabled = false
    
      dom.event.clipboardevents.enabled = false

~~~
tomrod
Great tip!

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lostmsu
When they were building their taxonomy, why did not they name its level, that
includes both what they now call "dinosaur" and pterosaurs "dinosaur", and
come up with a different name for their "dinosaur", if it is a common
conception?

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nonbel
I think the "common conception" comes from Land Before Time and Jurassic Park,
it seems almost everything we learned about dinosaurs from those movies is
wrong.

Edit:

I just looked it up and discovered both were made by Steven Speilberg...

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monocasa
Nah, pterodactyls and such were commonly taught to children to be dinosaurs
before Jurassic Park and Land Before Time came out.

Source: was child before 1988.

~~~
nonbel
Where do you think it originated then?

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Izkata
Ehh, they're using the name "Dinosauria" as evidence that people use
"dinosaur" wrong. I'd say they're misunderstanding the word "dinosaur".

It's a bit like (though in reverse) how "canine" is often used for the Canis
genus (dogs), but is easily confused for "canid" (the Canidae family) which
includes foxes and tanukis.

~~~
p1necone
This reminds me of the "fun fact" that people throw around about tomatoes
being a fruit.

Really there are two sets of terms - culinary and botanical. Botanically
tomatoes are a fruit yes, but they are also a vegetable. And in the culinary
context you would never use a tomato like a fruit.

The English language is defined by it's usage, and the same word can mean
different things in different contexts. Dinosaur is used commonly to refer to
Pterosaurs in the "general" context, so a Pterosaur _is_ a Dinosaur in that
context. If you were instead a biologist talking in the context of academia
then a Pterosaur would not be a Dinosaur.

~~~
Rexxar
I'm nitpicking but tomatoes are (sometimes) use as a fruit in culinary
context:
[https://en.wikipedia.org/wiki/Tomato_jam](https://en.wikipedia.org/wiki/Tomato_jam)

~~~
desdiv
To be pedantic, the first Wiki link in that article goes to the Fruit
preserves article[0], which begins with: "Fruit preserves are preparations of
fruits, vegetables and sugar, often stored in glass jam jars."

So while tomato jam is a type of fruit preserve, not all fruit preserves are
made of fruits (despite the name).

[0]
[https://en.wikipedia.org/wiki/Fruit_preserves](https://en.wikipedia.org/wiki/Fruit_preserves)

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curtis
On a tangential note, I'm still trying to wrap my head around the notion that
a flying reptile the size of Quetzalcoatlus (believed to have wingspan on the
order of 10 meters) could ever get airborne.

This has made me wonder if it's possible that juvenile Quetzalcoatlus could
fly but adult Quetzalcoatlus could not. Natural selection would presumably
select towards smaller and smaller wings on adults, but maybe this could be
offset by a serious evolutionary advantage bestowed on juveniles from being
able to fly.

I don't know of any bird existing or extinct with this kind of lifecycle, but
maybe you can find something similar in insects?

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btilly
No, pterosaurs had wings built out of hand bones, and hands develop their size
early in vertebrates. Therefore if you've got the right proportions to fly as
a grownup, you should be able to as a kid. Whether that was right to birth is
still debated, but certainly they could fly from being young.

By contrast birds and bats use arm bones in their wings, and so cannot fly
until nearly an adult. That imposes child care needs on the parents that are
pretty severe if you are large.

Now when species compete, they usually don't do it head on. Instead each
specializes on what it does better. Pterosaurs couldn't do much about the fact
that feathers are more efficient flight surfaces than their hair. But they had
one advantage - it was easier for them to grow big. And that is why at the end
of their time, the last niche that they held was a freakishly big carrion
eater. (And dinosaurs could make for some freakishly big carrion for them to
eat!)

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DuskStar
> No, pterosaurs had wings built out of hand bones, and hands develop their
> size early in vertebrates. Therefore if you've got the right proportions to
> fly as a grownup, you should be able to as a kid. Whether that was right to
> birth is still debated, but certainly they could fly from being young.

You've got the GP's question exactly backwards - they aren't questioning
whether the juveniles could fly, only the adults. If you develop the full hand
size early in life, and that supports flying with 20kg of mass, a 15kg
juvenile is going to have a much better time of things than a 50kg adult.
(Numbers pulled out of my ass, I'm not sure what the actual ones would be)

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aequitas
Useless fact but since where talking about naming things. The word helicopter
is a combination of helix and pteron (spiral wing).
[https://en.m.wiktionary.org/wiki/helicopter](https://en.m.wiktionary.org/wiki/helicopter)

~~~
yesenadam
Greek _helix_ (genitive _helikos_ ) + _pteron_ "wing" (from PIE root _pet-_
"to rush, to fly").

[https://www.etymonline.com/word/helicopter](https://www.etymonline.com/word/helicopter)

That page says ' _helix_ : "a spiral thing", a word used of anything in a
spiral shape (an armlet, a curl of hair, the tendril of a vine, a serpent's
coil)' \- though all these examples are helices, not spirals; I suspect the
author(s) didn't know the difference.

~~~
pbhjpbhj
Well you piqued my interest, what's the difference?

I note that Wiktionary, and the Oxford Pocket Dictionary (which I believe is
what Google use), consider them to be synonyms.

For example this from the latter's definition of "spiral" -

"winding in a continuous curve of constant diameter about a central axis, as
though along a cylinder; helical. synonyms: coiled, helical, helix-shaped,
corkscrew, curling, winding, twisting, whorled"

~~~
yesenadam
A spiral is 2D, like the Archimedean spiral. A helix is 3D, like a spring, or
DNA's double helix. Calling them _Archimedean helix_ or _DNA 's double spiral_
would make no sense.

Dictionaries aren't a great place to find the actual meaning of words. :-)
..mathematical terms, anyway.

~~~
taejo
Mathematics isn't a great place to find the actual meaning of words, either,
if by actual meaning you mean the meaning understood by the general native-
speaking population.

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dzdt
Related : a ladybug is not a bug. [1] Scientific nomenclature and common
language often disagree!

[1] [https://theamericanscholar.org/a-bug-is-not-a-
beetle/#.W5-t5...](https://theamericanscholar.org/a-bug-is-not-a-
beetle/#.W5-t5p8pA0M)

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jondubois
This article is incorrect, a pterosaur may not be a dinosauria but it
definitely is a dinosaur.

Dinosaur has become a generic term. You can even refer to humans who have old-
school ideas as dinosaurs.

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pvg
Metaphorical use doesn't count as turning something into a generic term. You
can call obstinate humans buttheads, and yet, etc.

This is more in the 'a gorilla is not a monkey' or 'a dolphin is not a fish'
category. Getting this sort of thing wrong is going to get you torn apart by
gangs of roaming five-year-olds on your next natural history museum visit.

~~~
perl4ever
Even though mammals are a subset of the descendants of things that are
unquestionably fish, we don't call mammals fish, and we do call things fish
that are of separate ancestry, so I feel there is kind of an arbitrary double
standard here if we get pedantic about dinosaurs. There's no question that in
general, categories of living creatures don't have to be monophyletic.

~~~
gus_massa
"Fish" is a bad category, or to be more precise from
[https://en.wikipedia.org/wiki/Fish#Taxonomy](https://en.wikipedia.org/wiki/Fish#Taxonomy)

> _Fish are a paraphyletic group: that is, any clade containing all fish also
> contains the tetrapods, which are not fish. For this reason, groups such as
> the "Class Pisces" seen in older reference works are no longer used in
> formal classifications._

I think we mostly agree, because you wrote

> _There 's no question that in general, categories of living creatures don't
> have to be monophyletic._

But I think that the main effort is to make all the categories monophyletic,
and drop/replace the other one when possible. Some non monophyletic categories
are very useful in practice and they are keep to make communication easier.

The problem is that if you try to make "fish" a monophyletic category you must
put "dolphins" inside them, because the dolphins are distant descendants of
some fish (as you and me and all mammals).

But Pterosaur and Dinosaur are sibling categories, neither of them descend of
the other. Using much smaller categories, it is like comparing penguins and
orcas (both are black and white, both swim, both have to breath air, both eat
fish), but neither of them descend of the other.

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andrewflnr
The article linked at the top of this one is quite readable, a few technical
terms aside. I recommend it. The referenced part about how pterosaurs launched
is very near the end.

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ggm
because pluto isn't a planet? I mean sure, inside the discipline knowing the
distinction between an integer and an ordinal number matters, but outside?
Less sure.

I'm going to keep mentally filing pterosaurs in dinosoar memory. I think 99%
of the non-obsessives older than 12 will do likewise. Pluto came back from the
dead, after all...

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comesee
Pelicans seem to evolve from pterosaurs but ostriches seem to have come from
theropods. Since those are both birds, I would guess pterosaurs and theropods
are just as closely related as pelicans and ostriches.

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quotemstr
I'm really curious about where you learned that.

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comesee
Natural history museum in LA. They have a big exhibit on theropods and
pterosaurs and show the birds that possibly evolved from them. Birds are
dinosaurs under all the usual biological classification schemes. Similar
phenotypes, similar genotypes.

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nickserv
Are you sure it was "evolved from" and not "looks like"?

Because pterosaurs have no living descents, and all birds descended from
therapod dinosaurs (even if birds were already widespread before the end of
the Cretaceous).

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comesee
Yeah it might seem that way but pelicans don't come from pterosaurs.

