It is a Richard’s Pipit and the chick on the left looks like it has a buzz-saw of teeth on the roof of its mouth. The article doesn’t mention what it could be.
What is that? Is that the throat, or is the throat behind the tongue?
I believe what you are seeing, on the roof of the mouth of the left hand chick, are papillae (soft “fingers”) on the edge of the internal nares (nostrils), where the nasal cavity enters the mouth. They are not teeth.
I think what you are looking at are the three black dots on the tongue, rather than what HubZilla mentions. That is their probable function.
No living birds have teeth. Chicks upon hatching have a structure called the “egg tooth” on the beak that helps them cut open the shell, but this is soon shed.
Although birds lost their teeth more than 65 million years ago, surprisingly researchers found some years ago that chickens still possess the gene for dentin, a component of teeth.
In a word, nope. Beaks is not teeth; beaks is jaws.
On the other hands, some chicks come with egg teeth to break out of the shell.(Or is that just reptiles?)
Someone or another has found a way to grow bird teeth by activating the long-forgotten “Tooth-making” part of bird DNA and growing the resultant tooth in a non-bird host. I have no cite, but presume there must be a site that a photo, what a sight! These of course would not be the teeth of a bird, but of a bird’s ancestor.
I will second that. The slit that the papillae surround is called the choana. The size, shape, and overall appearance of the papillae is one way to assess health in psittacines. For example, parrots with blunted papillae are often vitamin A deficient.
I gather expression of teeth as actual functional (or vestigial) body parts was selected against, although clearly at least some birds retain the genes for them.
And I presume this was because they were heavy, complex structures not needed for the average early-avian diet, and for which beaks would substitute quite effectively as needed. (Confirm, please?)
I’d be curious when teeth vanished from bird-dom. I know not only Archaeopteryx but Hesperornis, Ichthyornis, and the Iberomesornithidae still had them. And I gather from Colibri’s comment in post #3 that they were gone by the time of the K-T transition. (Nothing in the line of a dentate bird survived?) What about Enantiornithidae? Did any early forms in modern families display them?
Note that a possible mechanism for the loss of teeth in birds is given in thepaper that I linked above. As for the reason teeth were lost, some ideas are presented in this excerpt from a paper (which, unfortunately, does not include the names or title of the paper, nor where it is to be found!)
The loss appears to have occurred around 70-80 million years ago, so by the time of the K-T event(s), birds seem to have fully lost their teeth. Enantiornithes did have at least some members with teeth: Sinornis, Boluochia, * Eoenantiornis*, Longipteryx. Another bird classified as an enantiornith, Gobipteryx, did not have them. The shape of the teeth, when present, in this group is conical and unserrated. Gobipteryx is (or was…) considered the earliest known “beaked” bird. It dates from the Campanian of the late Cretaceous (~83 - 70 MYA).
Confuciusornis is an even earlier (dating to around 153MYA) critter that had lost its teeth, but it appears that this was independent from the rest of its lineage.
EDIT: To answer another question of Polycarp’s: no, it does not appear that any dentate bird survived the K-T boundary. They seemed to be in decline in the late Cretaceous, but went extinct at the end.
Were teeth lost once in the avian lineage (i.e., one avian clade lost its teeth and all modern birds descend from it)? Or, were they lost independently in different branches of the bird tree?
From Paul in Saudi: “beaks is jaws”. Is that correct? I thought a beak was horny growth over the bone, rather than bone itself.
The clade Neornithes is that which contains all modern, living birds; one of the diagnostic characters of this group is the lack of teeth – that is, no member of the clade has teeth (although, as discussed above, at least some groups do still retain the genetic means to produce them). At the very least, then, the common ancestor of Neornithes would have been toothless. Others have lost teeth independently (e.g., the aforementioned Gobipteryx, which is classified as an Enantiornith, while other enantiornith birds did have teeth).
So, a little from column a, and a little from column b.
[You can see roughly how Enantiornithes and Neornithes relate to each other from the cladogram here.]