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Re: BAD vs. BADD (was: Re: Most popular/common dinosaur misconceptions)
Apologies for making another digest form of a post.
It's hard for me to find free time for this at the
moment, and even harder to condense 50 separate
e-mails into one giant one. Apologies ahead of time
for any spelling mistakes, misquotes, or missed
"David Marjanovic" <firstname.lastname@example.org> wrote:
>> My complaint is with the use of cladistics in
>> classification (i.e. phylogenetic nomenclature, as
>> HP Marjanovic pointed out in a prior post).
> To the contrary, I pointed out that phylogenetic
> nomenclature has_nothing_to do with cladistics.
> Phylogenetic nomenclature is a method to apply
> names to a tree, cladistics is the method to find
> such a tree. You can easily have one without the
> other (and of course examples of cladistics without
> PN are numerous in the literature, not least
> everything by Hennig himself).
I've read you say this a few times in this thread now.
While I am well aware of the fact that PN can be
removed in favour of a more rank based system in a
cladistic analysis, I know of no case where the roles
were reversed. That is to say, when has PN ever been
used without cladistics (i.e. naming a traditional
Linnean tree using PN)?
>> That snakes are members of Lacertilia, yes
> Fortunately this is not necessary, because the name
> Squamata is already available. We haven't been this
> lucky for the dinosaurs.
A couple others on the list gave mention to this too.
I feel that this is more of a cop out than it is an
answer. Both lizards and snakes are members of the
group (order) Squamata, but it's referring to the
names of the subgroup (the suborder) that I'm
questioning. No one says non-ophidian lacertilian
(non-serpentean saurian, or any mix inbetween). Yes
one could say non-ophidian squamate, but it's much
easier to just say saurian, or lacertilian. In both
such cases, the exact meaning is made apparent without
the loss of the knowledge that snakes evolved from
If anything, you and others raise an interesting
point. Why not use/create a higher "level" grouping
that is understood to contain dinosaurs and birds?
Something like "Dinoaves," but preferably more
original (besides I think GSP already used that term).
Maybe something like "rigidectus" for the rigid erect
stance of dinosaurs and birds (please pardon any
butchering of the language there. I don't have time to
properly formulate the word).
This would seem to allow for a more accurate
representation of specified groups. Just like how
squamate is still divided into saurian/lacertilians
and serpents/ophidians (and amphisbaenians now and
again) to allow for a greater specification of the
One could even coopt a term that is already in place
(ornithodira). It would just include pterosaurs as
well (assuming they are still ornithodirans at the
>> Cetacea never evolved from Mammalia. It evolved
>> within Mammalia. I don't think there was ever any
>> real doubt that whales were mammals. Well, at least
>> after it was found that they really weren't fish.
>> They still fall in as mammals on morphological
>> grounds, even if they have evolved back to a water
>> bound life. The same goes for bats (the
>> morphological thing, not the water bound thing).
> Then how can you possibly argue that the same does
> not go for birds?
Well, for one, birds locomote in a manner completely
different from those of dinosaurs (classic dinosaurs).
I'm not talking about flying either. No dinosaur has
been shown to be a tibia based walker. There was an
argument in favour of _Caudipteryx_ doing that (at
least a little bit), but this seems to have been based
on bad data. Dinosaurs probably didn't see like birds
either; with relatively fixed eyes that require head
bobbing in order to walk effectively.
In all honesty the only grey area that I've ever seen
with birds and dinosaurs involves a small set of
maniraptors and very early, (archaeopterigiformes and
> Ah, no, we're not back to the days of Lamarck and
> Jussieu. Life is not a continuum (points on a
> one-dimensional line), it is a tree; almost all
> imaginable lines between any two organisms cross a
> very real gap.
If this is true, then why do I see Jaime and others
arguing that there is no gap?
Quick aside: it should be pointed out that Lamarck did
view the evolution of life as a tree, and not a
straight line ladder arrangement. This occurred later
in his life, but was still published. He really wasn't
as backwater as he is so often portrayed.
>> Even cladistically minded herpetologists like Eric
>> Pianka and Laurie Vitt, still use classic ranks
>> classification (families, subfamilies and the
> Do they stop above the family or superfamily, like
> Frost et al. do in their recent humongous phylogeny
> and classification of extant amphibians? If
> so, an important reason could be the desire to have
> nomenclature regulated -- and the PhyloCode isn't
> implemented yet, so there is no other choice
> than the ICZN, which stops above the superfamily.
I've only seen them go up to superfamily (Iguania,
Scleroglossa), but I'm not sure if they've ever gone
further. I know they still accept order Squamatas, if
"T. Michael Keesey" <email@example.com> wrote:
>> I'm afraid I don't quite get what you are saying
>> here. Why is it okay to call a bird a dinosaur,
but >> it's not okay to call a snake a lizard?
> "Lizard" is a purely vernacular term, while
> "dinosaur" is a vernacular form of a formal taxon
> (_Dinosauria_). Snakes are squamates, but not
> lizards. "Lizard", like any vernacular term, is
> governed by popular usage.
I've seen you get pretty heated over this in later
posts. You seem very insistent on stating that words
like "lizard" and "fish" hold no sway in this debate
(and that they basically mean what they were
historically assumed to mean).
Yet, and this part bugs me, everytime a person on this
list says that birds are dinosaurs (or just invokes
the acronym BAD), I see quiet. "Bird" is just as
vernacular as "lizard" and "fish" (though better
defined than the latter). If calling a snake a lizard
is considered bad form (as you and Jaime seem to
suggest), then I'm forced to repost my original
Why is it okay to call "birds" dinosaurs, but it's not
okay to call snakes "lizards?" It just seems like a
double standard to me.
>> From Archie (presumably), birds went off in a
>> completely different direction from dinosaurs, and
>> became wildly successful at it.
> By this you are saying that all non-avian dinosaurs
> were evolving in the same direction. The fact is
that > *every* lineage evolves in its own direction;
> ceratopsids and tyrannosauroids and titanosaurs
> ankylosaurs and dryosaurids are all hugely different
> from each other.
I'd say that dinosaurs, for the most part, were
generaling adapting to various niches as large
terrestrial animals. A couple did go the small route
and go for a more volant lifestyle (though even crow
size is still not considered small by today's
standards). Birds not only became a completely aerial
group (with later moves to the ocean and land again),
but they also show a much smaller size range. Again,
they were also wildly successful at it. We know of
some 10,000 species of birds. Even if the fossil
record was perfect, I find it hard to believe that
dinosaurs surpassed this number at any one point in
time (the limitations of being big).
> (And if you point out that those are all
terrestrial, > then you have to acknowledge Classes
Chiroptera, > Cetacea, Sirenia, Pinnipedia....)
I admit that cetaceans have done some serious
morphological upheavals to get to where they are. They
are also the only mammal group to be comprised solely
of giants (even dolphins are big). I'd hesitate from
separating them as a class just because they still
retain many of the key features that unite mammals
(the inner ear bones, suckling, etc). They also hold
relatively limited niches, and diversity. Admittedly
though, the latter is probably that limitation of
being big, thing again.
The others don't appear to be as derived away from
Mammalia in general, as cetaceans (even bats still
retain fur, the inner ear bones, and still suckle
>> This is like how
>> snakes went in a separate direction from lizards,
>> and became highly successful at it.
> It seems to me that many lizard lineages did go in a
> similar direction: glass lizards, worm lizards, etc.
> Snakes happen to have been the best at it (so far),
> but why would that separate them from other
It doesn't separate them from other squamates, it
separates them from other saurians (they're still
considered squamates). I think HP Tim Williams
mentioned something similar to this in another post.
Snakes don't warrant a separate status just because
they are limbless. It's the huge changes to their
skull that matters more. Most limbless lizards all
retain relatively fixed skulls. This limits the type
of prey they can subdue, and thus their overall size.
Snakes evolved the most maleable skull ever seen in
tetrapods (as far as we know). This allowed for
greater prey choice, and far greater niche
expandability. The only lizards that ever came close
to following snakes were pygopodids. Though they are
interesting, they still lag far behind in terms of
diversity and size range.
> "Prokaryota" is not a clade--"non-eukaryote biote"
is > probably what you want, but there's already a
handy > informal phrase or three for that group
> ("prokaryote", "bacterium", "moneran"). There
isn't > one for "non-avian dinosaur", once birds are
included > as dinosaurs.
You keep arguing the semantics, but seem to be missing
my point. No one goes around using these "non-"
monikers anywhere but in vertebrate paleontology
(mostly dinosaurs, but I admit that there are cases of
it in mammal paleo as well). In the example you gave,
no one goes around saying "non-eukaryotic biote."
You say it's because we have these handy informal
phrases like "bacteria," but we don't have one for
"non-avian dinosaur." I beg to differ. We had dinosaur
before it was hijacked.
Besides, Prokaryota is an acknowledged group, even if
it was never included as a clade.
> I have argued before that "non-avian dinosaurs"
> aren't really that interesting as a paraphyletic
> group, anyway, and the term is only popular because
> of historical reasons. If you're talking about
> flight, talk about "terrestrial dinosaurs" or
> "non-avialan dinosaurs". If talking about feathers,
> just talk about "unfeathered dinosaurs". If talking
> about the extinction, talk about "Mesozoic
dinosaurs" > and perhaps "non-neornithean dinosaurs"
(or > "non-avian" if you use the crown clade
definition). > Think about the context before you
decide that > "non-avian dinosaur" is what you
want, because 9 > times out of 10 there's a more
Perhaps if there was a more varied vocabulary in the
terms, this "non-" stuff wouldn't be so bothersome.
Still, after seeing all the examples given, I'd still
think it would be easier to say "dinosaur,"
"theropod," "maniraptor." etc.
Incidentally, we cal also talk about non-avian
maniraptors, non-avian theropods, non-avian
archosaurs, non-avian diapsids ... it goes on and
I don't doubt that. I've seen non-avian theropod
before, and I know of one case where I saw non-avian
archosaur. Short of that, the "non-" terms really seem
to disappear once one heads out of Dinosauria.
>> For instance, I do see a
>> problem with the term: "non-mammalian pelycosaur."
> Me too, since "Pelycosauria" is not a clade, and all
> "pelycosaurs" (non-therapsid synapsids) are not
> mammalian, anyway.
I don't see why not having all pelycosaurs being
mammalian has anything to do with the forgoing of the
Not all dinosaurs were avian either, yet "non-avian
[in response to HP Don Ohmes' statement about removing
> And "dinosaur" isn't a term that was borrowed by
> science from the lay public, either. It was coined
as > a biological taxon, and the term entered public
usage > from science, not the other way around. Should
> bend over backwards to appease a public who
considers > pterosaurs, plesiosaurs, mastodons,
crocodiles, and > even trilobites more "dinosaurian"
than birds? What > is there to benefit from this? How
is such a grouping > scientifically useful at all?
I think it's pertinent to point out that the lay
public doesn't even realize that there is a debate
over the use of the term "non-avian" dinosaur, or of
including birds within Dinosauria. These arguments are
not coming from the average Joe. They are coming from
scientists and interested amateurs. So this debate
isn't about appeasing the masses. If we were talking
about feathering _Velociraptor_ for JP4, then that
would be more about mass appeal.
Furthermore, just because a term had its base in
science, doesn't mean it can't be abolished when it
becomes cumbersome. Just look what happened to
"thecodontia." Better yet, look what happened to
"rhynchocephalia." That name wasn't dumped because
re-evaluation of it's members wound up emptying the
proverbial wastebin (as what happened with
"thecodontia"). "Rhynchocephalia" was dumped because
it contained too much nomenclatural baggage. This was
a term that practically never saw the public eye, yet
it was abolished for many of the same reasons that Don
Tim Williams" <firstname.lastname@example.org> wrote:
>> So these papers you mention, do they refer to
>> annelids now as non-pogonophoran annelids??
> Yes. They sure do. Or they use similar PN terms
> (e.g., non-vestimentiferan pogonophorans,
> non-clitellate polychaetes, non-siboglinid annelids,
> For some relevant references, check out:
Interesting, the papers you mention only very quickly
use the "non-" moniker, before replacing it with an
E.g.: "The phylogenetic systematics of the
polychaetes, i.e. the nonclitellate annelids..."
"To avoid assigning rank to taxonomic names throughout
this manuscript, we use the terms "vestimentiferan"
and "perviate pogonophoran" (i.e., the traditional
I'd say that the invert guys are on the right track by
assigning new names to keep the traditional (and
obviously still useful) boundaries in check.
Jaime A. Headden" <email@example.com>
> It is similarity, rather than dissimilarity, that
> Linnaeus himself might object to, since it was less
> understood than typological differentiation was to
> people making discrete "units" of life. At what
point > is the rank system logical, since it provides
no > actual means of adhering itself
sceintifically? It is > a system of "taste," and
neither logical nor > scientific in the least.
Science would do itself an > honor and service to
abandon the rank and file, as
> it were.
There is logic in the old rank system. It provides a
nice, relative, guage of how far apart different
animals are. That there is no rigorous and
standardized definition of what constitutes a family,
order, or class, is a problem. I do think it could be
fixed if there were enough people willing to devote
the time to it. That said, having a relative guage of
separation is helpful. For instance if one told me
that _Spinosaurus_ was an offshore of some
crocodyliforme lineage, than I could be able to test
that simply by looking at the ranks. _Spinosaurus_ is
in the family Spinosauridae, which is in the order
Saurischia, which is in the class (for all intents and
purposes) Dinosauria. Crocodyliformes are in the
"class" Crurotarsi (again, for all intents and
purposes). So right off the bat, I know that
_Spinosaurus_ is probably not an offshoot of the
crocodyliformes because it differs all the way at the
"class level." To do the same thing using PN is
harder. In order to test the validity of _Spinosaurus_
is a crocodyliforme offshoot, I have to see where
clade Spinosauridae is, and how many clades away from
clade Crurotarsi that is. So right off the bat I need
a cladogram to answer my question (which is done in
cartoonish example so as to get the point across).
Clade names might remain static, but clade membership,
and relationship with other clades does not. For
instance, if some paleontologist somewhere discovered
that _Spinosaurus_ and its kin actually had
crurotarsal ankles, and a few dozen other features
that would link it with Crurotarsi (which were
"remodeled" during evolution towards a theropod mimic
lifestyle), then Spinosauridae would still contain all
its current members, but the clade would have hopped
all the way into Crurotarsi. So no cladogram, means no
way of answering the question.
Long story short, as a disparity guage, the Linnean
rank system tends to work very well. Much like how
relative dating, or Newtonian Physics all remain
useful, even after more accurate mechanics are
Speaking of, I completely missed another useful
example of an arbitrary system. This one was right
under my nose, in the other half of our field. How
about lithostratigraphic classification. The dividing
line between one member and another is not always (not
often?) distinct. So too is the classification of a
specified formation. It might be a group in one state,
but a member in another and so on. In turn, one
geologist might see a formation with 3 members, while
another geologist sees one with 1 member. Yet despite
the arbitrariness of it all, lithostratigraphy is
still widely used in geology.
> There are MORE differences between bats
> morphologically (and apparently genetically as well)
> and any given ancestral stock than between
> *Archaeopteryx* and any maniraptoran that is also
not > an avian. Indeed, between *Archaeopteryx* AND,
say, > *Confuciusornis*. That there is no metric for
> difference, yet one is easier to claim because the
> separate is more obvious and more entrenched
> in the human awareness than the other. Bats have
been > mammals for over 200 years, birds have not been
> reptiles (or recognized by most of the
> scientific community as dino-descendants) for hardly
> two decades.
I have a problem with separating bats partly because
bats make up the majority of mammal species alive
today (and probably in the past as well). It would
almost seem easier to call bats mammals, and other
mammals something else.
That aside, the standard definition of a mammal was
based on fur, suckling and the three inner ear bones.
Bats are different from other mammals, but they still
retained all these features. While I normally wouldn't
include fur do to its rareness of fossilization, given
the rash of "fuzzy" dinosaurs coming out of China, I'm
not so sure it is as rare as was once thought. I
suppose the suckling aspect would be hard to prove
paleontologically too, though this seems to be an
argument based on living creatures rather than extinct
> Now, as for birds: Exactly what IS the cutoff
> determination for "Bird"? What does one qualify as
> the break between "Dinosaur" and "Bird"? For
> "Snake" and "Lizard" this seems easy, until you find
> legged-snakes and mosasaurs, but for birds, people
> usually start with two familiarities:
> *Archaeopteryx*, or living birds. Why the former,
but > not, say *Rahonavis*? Or why the latter, but not
> *Ichthyornis*? These differentiations are
illogical, > and again, as I said above, are suited to
taste > alone.
Since Darwin, the traditional cutoff has been
_Archaeopteryx_. Personally I'd have gone closer to
the split between Enantiornithines and Neornithines
(where substantial differences between "classic"
dinosaurs occurs), but it seemed to have been decided
long ago that a single character was more important
than a suite. So for better or for worse,
_Archaeopteryx_ seems to be it. For snakes, the cut
lies in the skull and when it reached a specific
degree of kinesis. Yes, regardless the cut will be
arbitrary, but as I and others on this list have tried
to point out, it still remains useful. I do think a
standard measure of differences would make this form
of classification more rigorous, and helpful.
> And the question is, WHAT hypothetical cut-off
point? > Certainly one everyone can agree on? Define
"Bird" > and then define "Dinosaur", and tell me why
> one can't be another.
I'm running out of time for this post, but for bird
I'd say it would be defined as a bipedal animal with
feathers (pennaceous & down), forearm wings,
relatively fixed eyes, and tibia based walking (i.e.
they "sit" on their femora). I'd also add in a lack of
teeth and a tail, but like I said. Someone decided
long ago that Aves should start with Archie, so oh
I'd take an all, or nothing approach to the
hypothetical cutoff too. That is, a dinosaur would
have to have all the above to be called avian. An
avian would probably have to lose all of the above to
be called something else, but that gets a little too
forward thinking and dangerous.
Basically, it would be something like that, but more
rigorous and osteological (since that's what would
probably fossilize anyway).
>>None of those are comparable examples. All are
>>sub-members of the groups you mentioned.
> But this is PRECISELY my point. Birds ARE submembers
> of dinosaurs (in the vernacular), just as gharials
> are subgroups of crocs. That some people quibble
> about the specified use of "croc" ONLY for
> crocodylids while others (many others) use it for
the > entirety of croc-like animals, and many
> croc-researchers for the crurotarsans and
> crocodylomorphans (or just plain Crocodylia).
My argument was that "croc" would be a term best
served if limited to eusuchia (where it has
traditional stayed until relatively recently).
If you don't think calling other crurotarsans "crocs"
is a problem, then I'd direct you to review the old
e-mails related to the discovery of _Effigia
okeeffeae_ and see the complaints about the fact
that: "it wasn't a croc. It was a poposaur."
> Science is about what again? Arbitrarily, I could
> ignore everything you said and say you were wrong,
> and never have to prove a thing. One can say the sky
> is green, arbitrarily delcaring this to be so, and I
> could say purple -- and why would we do so? No
> reason, but it's easy to communicate, no?
Er, no. I've already given you plenty of examples
where arbitrary definitions are in effect today, and
are still useful. Obviously I don't mean subjectively
arbitrary things. I'm referring to things that are
generally agreed upon in the field (e.g. group,
formation, member, etc). Another prime example is that
of the IAU and how that group has gotten together to
agree on the arbitrary criteria that make up a planet.
I don't remember seeing you complain too much about
that (deciding that Pluto should be the cutoff point,
yes, but not the actual criteria itself).
Where ARE these invisible boundary points? How does
one find them? When can one recognize one if he finds
it? Why can't I change the boundary as I see fit
(arbitrarily)? What defines this boundary, even: Whay
does it represent? Do you see what I mean by
unscientific systems? This is what led to people
trying to make concrete the metric system (using the
rather solid rule of exponents by tens, rather than
the Imperial system America is still using).
Youc can change the boundary, but you'd have to
publish your findings and see if they are agreed upon.
This has been occurring in science for decades. How
many taxonomic revisions are out there that were done,
but never took hold. How many new genus, or species
names were coined, that were ignored by the others.
All this was still done scientifically. The scientists
in question had to prove the validity behind their
thinking. But, since this is strictly a case of what
to call something, and not any actual physical
relationship, the end result still depended on the
will of the scientific masses to accept the new terms.
This does occur with actual phylogenetic relationships
too, as is amply shown by the dearth of people who
accept Feduccia's phylogeny of dinosaurs.
Finally firstname.lastname@example.org wrote:
> Again, in what way were Microraptor and Caudipteryx
> going in the "same direction" as Brachiosaurus and
> Triceratops rather than in the "same direction" as
> Archaeopteryx and Jehlornis?
I'm not sure what those two taxa were doing exactly. I
haven't heard any real talks about _Microraptor_ being
an active flapper (vs. gliding), and _Caudipteryx_ was
showy, but earthbound. At least, that what it seems.
In some ways there were definitely following the
direction that birds took, but at a couple dozen
million years late, they obviously weren't going the
exact same way.
For this case, I would consider the radiation that
occurred among birds once they did "officially" become
Aves. So I'd say diversity should matter as a
criterion for a name change. I know that will probably
gain some scour, since we only have the fossilized
remains of dinosaurs to compare with it. Though I
would say that saying dinosaurs probably didn't hit
the sheer number of species that birds did (for any
given time period) would probably hold true. As I
mentioned above (somewhere), it seems to be a
limitation of being a big creature.
"I am impressed by the fact that we know less about many modern [reptile] types
than we do of many fossil groups." - Alfred S. Romer
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