Adding Homo sapiens to the large reptile tree

Not sure why I didn’t think to do this earlier.
I added Homo sapiens to the large reptile tree (still not updated) and ran a phylogenetic analysis to see where we nest. To no one’s surprise Homo (Fig. 1) nested with the cynodont Procynosuchus among the Therapsida (no other mammals are yet entered).

Figure 1. Homo sapiens alongside sister taxa Australopithecus and Ardipithecus (both in gray).

Figure 1. Homo sapiens alongside sister taxa Australopithecus and Ardipithecus (both in gray). Click to learn more.

Entering characters for Homo and Procynosuchus
was more than enlightening as so many traits were shared between the two. You should try it sometime!

Figure 2. Procynosuchus, a basal cynodont therapsid synapsid sister to humans in the large reptile tree (prior to the addition of advanced cynodonts including mammals).

Figure 2. Procynosuchus, a basal cynodont therapsid synapsid sister to humans in the large reptile tree (prior to the addition of advanced cynodonts including mammals). Click to learn more.

What happens when taxa are excluded? (How deep can we go?)
The contribution of cynodont traits to the story of human evolution was more powerful than I thought. I was surprised at one happened when I took one step further.

Deleting only Procynosuchus
results in Homo nesting results in Homo nesting between Dibamus and Tamaulipasaurus (Fig. 2) two burrowing skinkomorph squamates. My guess is the fusion/loss of so many skull bones, the brevity of the rostrum, the great depth of the coronoid process of the dentary and the complete lack of postcranial characters for the two burrowing taxa are attracting the taxon Homo with similar skull traits.

With the present character and taxon list, these skinkomorphs nest closer to humans than Biarmosuchus and more basal synapsids, like Dimetrodon. They’re just not human enough.

Biarmosuchus, the most basal therapsid.

Figure 3. Biarmosuchus, the most basal therapsid and not a cynodont. Despite nesting as a basal therapsid, its traits do not attract the taxon Homo more than others do. 

You think THAT’S ridiculous. Let’s take the next step…

Figure 2. Tamaulipasaurus nests with Homo sapiens when the basal cynodont, Procynosuchus, is excluded.

Figure 2. Tamaulipasaurus nests with Homo sapiens when the basal cynodont, Procynosuchus, is excluded. The fusion of skull bones, the short rostrum, and the large coronoid process of the dentary are traits shared with humans.

Deleting all the skinkomorph squamates
results in Homo nesting as a turtle/pareiasaur ancestor. Here the short face, anterior nares, tall pelvis and loss of manual and pedal phalanges appear to attract Homo to turtles like Proganochelys.

Proganochelys. Formerly the most primitive turtle.

Figure 2. Proganochelys. Formerly the most primitive turtle. Click to learn more. 

See what happens with taxon exclusion?
Strange bedfellows can result. So many current problems and enigmas in paleontology can be readily settled with a large enough family tree.

In the same light, I challenge paleontologists
to add thalattosaurs to Vancleavea studies… to add fenestrasaurs to pterosaur studies… to add mesosaurs to ichthyosaur studies… and to add millerettids to caseasaur studies. There’s no harm in doing so, and we all might learn something.

 

From the Beginning – The Story of Human Evolution – Now in PDF

Figure 1. From the Beginning - The Story of Human Evolution was published by Little Brown in 1991 and is now available as a FREE online PDF from DavidPetersStudio.com

Figure 1. From the Beginning – The Story of Human Evolution was published by Little Brown in 1991 and is now available as a FREE online PDF from DavidPetersStudio.com. Click image to download it.

With Giants and A Gallery of Dinosaurs already vacating late-1980s bookstore shelves, “From the Beginning – The Story of Human Evolution” became my third book in 1991. Publishers are always looking for novelty. I thought this might fill the bill and answer a few Creationist objections. It would also answer the age-old questions, “how did we get here?” and “when did I lose my tail?”

Unfortunately,
the people most interested in human evolution are against it (about 44% of today’s Americans).

The evolution of humans from primates and anthropoids had been well covered by others, notably Jay Matternes and Louis Leakey in National Geographic! But what animals came before the hominids, anthropoids and primates?

Mark Hallett’s illustrated therapsid family tree actually turned me on to the whole subject of paleontology a few years earlier.

Family trees are bushy
and I wanted to focus precisely on ‘the ladder’ of succeeding organisms closest to the actual lineage of humans, ignoring, as much as possible, birds, turtles, etc. etc. It seemed to me that nothing complete from this specific genre had been illustrated since, well, basically since the time of Haeckel,  Darwin and Huxley.

From The Beginning, The Story of Human Evolution (Peters 1991, 128 pp.) appeared without much fanfare, other than a whirlwind media tour around St. Louis, my hometown. Now the book can only and occasionally be found at Amazon.com. Some nice comments are posted there.

From ‘little acorns,’ like this, 
ReptileEvolution.com arose. And that website has been vastly more popular and accessible than the book ever was…until now.

Now From the Beginning is available as a PDF file (11Mb). If you missed it earlier or can’t find it on your library shelves, you can read it here. I own the copyright. Feel free to use images if you’re a teacher. Commercial use must be negotiated.

In 1991 From The Beginning was cutting edge.
Today FTB still tells the correct basic story, but some taxa are no longer up to date. The tree is better represented by the large reptile tree and the subsequent discoveries and insights it covers ((since 1991, like Stenocybus and Cutleria). Here ReptileEvolution.com provides the latest guidance.

Human evolution.

Figure 2. Human evolution back to the cynodonts — and beyond to fish, worms and raw chemicals.

Even with its 1991 dating…
FTB is not without merit. It takes the reader from the origin of the universe and raw chemicals, then shows how modern cells evolved, adding and subtracting traits through the worms, fish, reptiles and mammals that make up the heritage of all humans. You’ll learn when we started coughing, when our tail disappeared and when the Achilles tendon first appeared, among hundreds of other traits, like chins, belly buttons, sex organs, teeth and that strange “third eye.” It also reports on the continuing evolution of humans as some of us are evolving a little different from others.

You can also see pdfs of Giants and A Gallery of Dinosaurs on the same web page.

Your comments are always welcome. And please tell your interested friends.