How do we know these teeth came from Cretaceous birds?

[ThePhysicist]

I've seen several teeth that are purportedly from Cretaceous avian dinosaurs/birds, specifically Avisaurus sp. I've done some light digging, but I don't yet know how these teeth can be assigned to a bird. My thinking was that you need an identifiable jaw with these teeth, but I couldn't find any such literature on Avisaurus at least. My other guess is that they closely match the morphology of other Enantiornithine bird teeth? In any case, I'd be much obliged if someone could pass along some relevant paper(s).

 

These are examples of Avisaurus archibaldi posted by @Auspex:

[jpc]

As I undertand it, that one with the scale bar next to it shows the diagnostic pinching at the base. To me, that is what makes it a bird tooth.  

[fossilsonwheels]

I don’t think you’ll find any papers dealing specifically with the teeth identified as Avisaurus. The holotype did not include any cranial material, just a single bone. 

I spoke to Jingmai O’ Connor about the subject of Cretaceous bird teeth early last year. According to her, there is a grad student at USC that is working on Cretaceous bird teeth, including teeth labeled Avisaurus. Hopefully a paper gets published soon to shed some light on the subject 

There are Enantiornithine birds known from complete skeletons including one, maybe more I don’t know for sure, that is related to Avisaurus according to the literature I have read. I think the ID as Avisaurus is based on morphological similarities to known Enantiornithine skulls. 

[ThePhysicist]

13 hours ago, jpc said:

As I undertand it, that one with the scale bar next to it shows the diagnostic pinching at the base. To me, that is what makes it a bird tooth.  

Thank you. Maybe to rephrase my question, why do you associate basal constriction with bird teeth?

 

12 hours ago, fossilsonwheels said:

I don’t think you’ll find any papers dealing specifically with the teeth identified as Avisaurus. The holotype did not include any cranial material, just a single bone. 

I spoke to Jingmai O’ Connor about the subject of Cretaceous bird teeth early last year. According to her, there is a grad student at USC that is working on Cretaceous bird teeth, including teeth labeled Avisaurus. Hopefully a paper gets published soon to shed some light on the subject 

There are Enantiornithine birds known from complete skeletons including one, maybe more I don’t know for sure, that is related to Avisaurus according to the literature I have read. I think the ID as Avisaurus is based on morphological similarities to known Enantiornithine skulls.

Thank you, will look out for that paper. 

[Auspex]

14 hours ago, ThePhysicist said:

they closely match the morphology of other Enantiornithine bird teeth

That's pretty much the story, but as studied, described, and reviewed by some of the best in the field.

[Troodon]

Just to support the discussion J. Sankey, Currie et al. 2002 paper on Theropod  & Bird teeth identifies them as bird teeth and are identified as pertaining to birds because of their similarity with those of Hesperornis.

 

[TNCollector]

I don't have any scientific value to add to this conversation, but here are the two in my collection, both from the Hell Creek Formation. The larger one is 7.2mm in length, which is the largest one I have heard of as of yet.