Anteosaurus: a killing machine? No.

Benoit et al. 2021
“reconstruct Anteosaurus [Figs. 1-4] as an agile terrestrial predator based on the enlarged fossa for the floccular lobe of the cerebellum and semicircular canals of the inner ear.” 

Yes, that’s what they wrote. Not the teeth. Not the limbs. The inner ear.

Figure 6. Anteosaurus scale model.

Figure 1. Anteosaurus scale model.

From the Material and Methods section:
“The disarticulated skull (BP/1/7074) of a juvenile Anteosaurus magnificus from the middle Permian of the South African Karoo…”

The BP/1/7074 specimen (Figs. 2–4) does not nest with Anteosaurus (Figs. 1–4) in the Therapsid Skull Tree (TST; Fig. 3) as we learned earlier here after testing (Fig. 3).

Figure 2. Kruger et al. 2017 figure 21. provided "Ontogenetic changes in the skull of Anteosaurus; A. juvenile; B, intermediate sized; C, adult sized, redrawn from Kammerer 2011. Their figure 20 labeled the intermediate sized skull as Titanophoneus. So this is a phylogenetic series, not an ontogenetic one.

Figure 2. Kruger et al. 2017 figure 21. provided “Ontogenetic changes in the skull of Anteosaurus; A. juvenile; B, intermediate sized; C, adult sized, redrawn from Kammerer 2011. Their figure 20 labeled the intermediate sized skull as Titanophoneus. So this is a phylogenetic series, not an ontogenetic one.

 

Figure 3. Therapsid Skull Tree with herbivorous clades colored.

Figure 3. Therapsid Skull Tree with herbivorous clades colored.

Figure 1. Anteosaurus magnifies compared to the smaller and coeval BP/1/7074 specimen others considered a juvenile. Other more closely related specimens in the TT are also shown alongside BP/1/7074 specimen.

Figure 4. Anteosaurus magnifies compared to the smaller and coeval BP/1/7074 specimen others considered a juvenile. Other more closely related specimens in the TT are also shown alongside BP/1/7074 specimen.

Phylogenetic context is paramount and required.
There are several problems with the conclusions of Benoit et al. 2021.

  1. The specimen is not Anteosaurus.
  2. Dinocephalians were all herbivores.
  3. Those huge teeth were as sharp as bananas, like hippo teeth.
  4. The bones of the inner ear do not determine whether you are predator or prey.

What is going on
at the universities nowadays?? Is phylogenetic analysis old-fashioned? Let’s get back to basics.


References
Benoit J, Kruger A, Jirah S, Fernandez V and Rubidge BS 2021. Palaeoneurology and palaeobiology of the dinocephalian therapsid Anteosaurus magnificus. Acta Palaeontolgocia Polonica 66(X):xxx-xxx. https://doi.org/10.4202/app.00800.2020

https://phys.org/news/2021-03-prehistoric-machine-exposed.html?fbclid=IwAR0ZhQ_5_Qgn4LscUgK0rUVcUv8XmwDAdtKdDXJJ6pHNG3M3UAjvRpw9d-s

8 thoughts on “Anteosaurus: a killing machine? No.

  1. Elements of the inner ear can actually be a lot more reliable than some other elements when determining an animal’s nature. Depending on what area of the ear we’re talking about, it could be involved in predator or prey detection (Webster, 1980; “Morphological Adaptations of the Ear in the Rodent Family Heteromyidae” – among others) or maintaining balance while moving at high speeds (Frýdlová et al, 2019 “A gyroscopic advantage: phylogenetic patterns of compensatory movements in frogs” – among others). I’m not quite knowledgeable enough about the matter to point out anything else, but since you only glossed over the inner ear I thought I should elaborate.

    • Thank you. It would have been more informative if the inner ear was from the eagle, cheetah or great white shark, all apex predators. Rodents and frogs are likely both prey and predator. We have to be careful with assessments. Simbakubwa was considered an apex predator, but analysis shows it was a hippo relative. Phylogenetic bracketing within an herbivorous clade is usually a good clue, but then Thylacoleo, the giant sugar glider (and an omnivore), comes along.

      • No problem. Unfortunately, papers on these matters were extremely hard to find, so I had to make do with what I could find.

    • Well, after looking for more than five seconds, I found a cheetah paper:

      Camille Grohé, Beatrice Lee & John J. Flynn; 2018 “Recent inner ear specialization for high-speed hunting in cheetahs”

      Also, cheetahs aren’t technically apex predators. They’re preyed upon by leopards, spotted hyenas, and lions, not to mention how they’re easily displaced from ecosystems by more powerful animals, or the extinction of their main prey (hence the extinction of the original Indian population of cheetahs).

      • Possibly. It depends on if the animal has any adaptations (even reduced ones) to a cursorial lifestyle. Like I said, I’m not knowledgeable enough on the subject, but for smaller, longer-limbed animals, I say go for it.

    • There was no ‘modern view’ applied to the limbs of Anteosaurus. They were mechanically no different than those of cynodonts (known predators). Rather the phylogenetic nesting of Anteosaurus apart from cynodonts and surrounded by hippo-like herbivores with large blunt teeth is the key critique of the authors’ hypothesis.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.