Wednesday, 26 May 2021

Transitional Evolution News - Ancient Baleen Whales with Teeth!

Aetiocetus weltoni
Ancient Baleen Whales Had a Mouthful | NewsCenter | SDSU|

You can quite understand why Creationists never read scientific papers and have had to devise all sorts of mental exercises for dismissing them out of hand as the work of liars and conspirators out to fool people, when there is a veritable tsunami of papers like this one that refute their dogmas with simple facts.

Here again we have another example of one of those transitions that Creationists need to believe never happened, because some Bronze Age hill farmers didn't know how life came to be the way it was then, and still is today, and guessed it must have all been the result of magic. This time it is evidence of the transition between the toothed whales (the common ancestors of all the whales had teeth) and the baleen whales.

The research also resolves another piece of embarrassment for Creationists - the fact that baleen whales like blue whales, humpback whales and grey whales, all start to develop teeth as embryos, then lose them again before birth. This an atavistic remnant of the fact that they all once had teeth. There is no reason at all for an intelligent designer to give embryo baleen whales teeth, especially since they are never going to need them as adults.

This evidence was discovered by biologist, Eric Ekdale, of San Diego State University and palaeontologist, Thomas Deméré, of the San Diego Natural History Museum, when they examined a 25 million year-old fossil whale skull of Aetiocetus weltoni, an evolutionary “cousin” of today’s baleen whales (Mysticeti), loaned to them by the University of California, Berkeley. They examined the skull using high-resolution computed tomography (CT) and discovered that it had teeth as well as baleen.

Since baleen is composed of keratin, like hair and fingernails, it does not normally preserve long enough to become fossilized, so the team used the CT scans to find evidence of grooves and holes on the roof of the mouth that connect internally to a vascular canal, consistent with the same structures in living baleen whales.
We have found evidence that supports a co-occurrence of teeth and baleen, indicating the tooth-to-baleen transition occurred in a stepwise manner from just teeth, to teeth and baleen, to only baleen.

Our study provides tangible fossil evidence of a major shift in feeding behavior from a raptorial carnivorous feeding mode to a bulk filter-feeding mode for obtaining food, among the largest animals that have ever lived in earth’s oceans. Krill are around 1/600th the size of blue whales. That’s like us humans eating nothing larger than sesame seeds floating in a pool.

Eric G. Ekdale, Lead author.
Department of Biology
San Diego State University,
San Diego, CA, USA
This also showed that the blood vessels that supply the baleen in modern whales is a modification of the blood supply to teeth.

The research was published two days ago in the Zoological Journal of the Linnean Society of London:
Abstract

Extant baleen whales (Mysticeti) have a deciduous foetal dentition, but are edentulous at birth. Fossils reveal that the earliest mysticetes possessed an adult dentition. Aetiocetids, a diverse clade of Oligocene toothed mysticetes, have a series of small palatal foramina and associated sulci medial to the postcanine dentition. The openings have been homologized with lateral palatal foramina that transmit neurovascular structures to baleen in extant mysticetes, thereby implying a co-occurrence of teeth and baleen in aetiocetids. However, homology of the foramina and sulci have been questioned. Using CT-imaging, we report that the lateral palatal foramina of Aetiocetus weltoni are connected internally to the superior alveolar canal, which transmits neurovascular structures to baleen in extant mysticetes and to teeth in extant odontocetes. Furthermore, the lateral palatal foramina of Aetiocetus are separate from the more medially positioned canals for the greater palatine arterial system. These results provide critical evidence to support the hypothesis that the superior alveolar neurovasculature was co-opted in aetiocetids and later diverging mysticetes to serve a new function associated with baleen. We evaluate competing hypotheses for the transition from teeth to baleen, and explore the transition from raptorial feeding in early mysticetes to filter-feeding in extant species.

And so another transitional form is added to Creationism's list of fossils they have to pretend don't exist. It must be so tiresome for Creationists having to remember which fossils to ignore, what scientific evidence should never be looked at and which questions you don't want answers too in case an imaginary magic, mind-reading sky thug notices and adds your name to his list of people to burn alive, but such is the power of parental child abuse and brainwashing.


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