Did We Have "Reptilian" Ancestors?

Did we have reptillian ancestors? Or is that an abuse of terminology.

I’m happy to hear from anyone, but I think this one is right up @John_Harshman’s alley. @NLENTS, I hope you follow this too.

“Reptile” is an ambiguous term. It used to apply to a paraphyletic group, essentially Amniota minus Mammalia and Aves. More often, these days, it applies to anything more closely related to birds than to mammals, or sometimes something within that group. So the answer is "it depends on what you mean by ‘reptilian’ ".

Then again, if the question is whether we had ancestors that looked a little bit like lizards, then yes.


Pretty sure this is covered in Dawkins’ The Ancestor’s Tale.

Will read later, but I thought “reptile” had long since fallen out of fashion since it is paraphyletic, but we have synapsid ancestors for sure.


@John_Harshman at what point in the tree are the mammalian inner ear bones co-opted from ancestral jaw bones?

Neil Shubin surely thinks so.


I don’t have a dog in this fight, but I want to get my language as precise as possible, so I don’t get critiqued on something simultaneously debatable and peripheral.

Be specific. What do you want to say? Who do you want to say it to?

Imagine a room full of nit-picky scientists. That is our audience. How would you rewrite this sentence, so that it becomes (without debate) taxonomically correct?

Two bones in our middle ear were co-opted from the jaws of our reptilian ancestors, leaving mammals with unique ossicles and a single-hinged jaw.

Yes the term reptilian has become old school. it doesn’t work. this because it was a invention in the first place by folks counting traits.
Mr harshman said here BIRDS has changed what reptiles means. Really? surely classification is in trouble!
I think for creationists the whole concept of reptiles should be seen as not a God invented group but a human one. In other words the few traits they use to group reptiles are masking the greater number of traits that would put them into general other groups. Turtles are not more related to snakes because of certains traits.
There are no reptiles. likewise birds are not reptiles in any way. This is only said now because they found theropod dinosaurs to be so bird like. it actually just meamns they are birds and not reptiles or dinosaurs.
Classification is wrong and is holding up wrong ideas on biological relationships.
There are KINDS. Possib;y a bigger Bird group. i’m not sure.
Yet only KINDS really and likeness in traits between creatures is due to a common blueprint and limited options.
We were never anything but what we are. We are not reptiles but nether are lizards.

And don’t forget a room more filled by an omni present more nit picky God who wrote a text that describes His act of creation quite different than the expectations from a group of nit picky scientists. Sorry for this interjection, but the evolutionary “science” you speak of that gives such certainty of reptile, human relationship is just too loaded with speculation and philosophy to just sit still and not reply even as it seems unrelated to topic

What about the well documented evolutionary transition from earlier reptile jaws to mammalian ear bones do you think is “loaded with speculation and philosophy”?


Sorry, I didn’t know where this was coming from in my earlier response. So after some poking around, I think “reptilian” is fine to say because the sentence is not attempting to identify any specific organism or even a taxon. Reptile is no longer used scientifically, but it is used casually, even by scientists, and herpetology, the study of reptiles, is still a thing. Museums and nature shows still talk about reptiles because, while not a valid clade, the group still means something to us. It is defined group of organisms, even if the borders of that definition poorly captures phylogeny. Anyway, my point is, while calling a specific organism a reptile should probably be avoided (because more accurate terms are available), referring to a group of generic, unspecified ancestors as “reptilian” is perfectly fine because the intention is not to communicate something about classification. That’s just my opinion, and I do think we lose something something if we drop the word reptilian because we’re calling in the research on the “reptile-mammal” transition, a real and important field of study.


Can you decisively conclude that these fossil fragments are not being wrongly interpreted in a way to prove what you already believe? -that one evolved from the other via mutation? Are you interested in the long term philosophical implications of choosing to interpret fossils through a neo darwinian lense as opposed to one supported by creationists? Creationist believe that God creating kinds is not only far more rational than animal groups arriving by accidental natural causes but, for many is more in line with what those Creationists have most reverence towards: the God who clearly reveals His character, works, love and expectations in the Bible. It seems that many are more interested to make their appeals in these subjects in the fear of what man may think, forgetting that there is surely Another also in the room. Perhaps guys like me are just going to remain the few who care more about and revere the Other more.

Two of our three middle ear bones once formed the jaw joints of our non-mammalian ancestors.

Incidentally, this happens developmentally too. Those bones begin as cartilages in your embryonic jaws before migrating to your ear. And the transition is unusually well documented in the fossil record. Here’s a recent review.

Also incidentally, there was a short period during which there was a double jaw joint, but it began with a single joint, articular to quadrate, and ended with a single joint, dentary to squamosal.


Yes. Have you ever looked at any of the fossils? There’s a beautiful series showing the transition. They’re not as fragmentary as you suppose, either.

Now that was certainly arrogant, not to mention insulting to all the Christians in the room. You have chosen to ignore all empirical evidence in favor of your interpretation of Genesis. Others may not be so hasty.


The conclusion is not based on just these fossils. Evolution is a conclusion based on 150+ years of consilient positive evidence from dozens of different scientific disciplines. There are literally millions of independent pieces of evidence which taken as a whole indicate evolution over deep time has happened.

We get that you don’t like the science which threatens your weak religious beliefs but that is not scence’s problem, is it?


Perhaps you could show how us how these fossils are being misinterpreted. More to the point, perhaps you could describe the features a real transitional fossil would have and how these known fossils lack these features.

Again, what features does a fossil need in order to be transitional according to the methods used by creationists? What criteria are they using?

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So, Mr Horton…where do u stand today? Do u believe in universal common decent or more of a sort of common decent of created kinds that adapt and speciated the planet? If universal, do you think it is statistically honest to suggest that mutations got us here? Does science back this up legitimately or is this just more of something one has just believed over a lifetime, so it is in their dna sort of thing?

So I believe in the latter option (and that God more than likely interacts directly and miraculously in the adaptation process) as it is fitting of science, scripture, is statisticallly honest, provides soil that lessens propensity for racism.

Where i will have a bone to pick w man’s science is where it wants to flex its muscles before the living God whom I know created the universe to declare that His Word needs to conform to sciences “objective” conclusions. Jacob thought he could manhandle God in a wrestling match, and God played along for a bit…then He decided to touch Jacobs hip and popped it out of joint. God rewards us for persevering towards Him for blessing. But ulitmately, God laughs at any arrogant disposition in man that thinks he has the upper hand on Him such as in the case that we demand that sacred scipture conform to our evolutionary guesswork.

Scientists on the history of our beginnings need to get a handle on reality and realize that even if they think that there is possibly a living Creator, to not be so quick to pay allegiance to naturalism let alone the nerve to suggest that this is objective where theism or intelligence is not.

I believe it takes far more blind faith to believe that a populations random selection of genetic mistakes concluded with the majesty, complexity, and beauty of life systems on earth, than to simply believe that God said that He did it!

All the scientific evidence we have indicates all life is related by common descent. The concept of Biblical “kinds” was scientifically disproven over a century ago.

Evolution doesn’t posit only mutations. There are also HGT, feedback from selection, and neutral drift.

Yes, many many times over. The evidence for evolution can be found thousands of places online. But first you have to be honest enough to look.

Willful ignorance is still ignorance no matter how good it makes you feel.