The koala (genus: Phascolarctos) joins the LRT

Something cute and fuzzy today.
As the koala (genus: Phascolarctos) is added to the large reptile tree (LRT, 1187 taxa, subset Fig. 1). And, based on phylogenetic bracketing, the case for carnivory in Thylacoleo (Fig. 4) fades.

Figure 1. The koala, Phascolarctos cinereus, nests between Thylacoleo + Vombatus and the interatheres and toxondontids in the herbivorous clade of the Marsupialia.

Figure 1. The koala, Phascolarctos cinereus, nests between Thylacoleo + Vombatus and the interatheres and toxondontids in the herbivorous clade of the Marsupialia. Thylacoleo is the exceptional carnivore.

Everyone loves the koala.
It’s a cute climbing wombat.

Figure 2. Skeleton of the koala (genus: Phascolarctos)

Figure 2. Skeleton of the koala (genus: Phascolarctos)

Two ‘thumbs’
one big toe and two skinny central toes distinguish the auto podia of Phasolarctos.

Figure 3. Koala (Phascolarctos) skull

Figure 3. Koala (Phascolarctos) skull. Note the differences between the photo and drawing.

The Thylacoleo problem
Smack dab in the middle of a long list of marsupial herbivores nests the marsupial lion, Thylacoleo (Figs. 4, 5) nesting here (Fig. 1) as a sister to the wombat, Vombatus. Said to be carnivorous due to its shearing post-canine teeth, it would be the exception in this clade of plant-eaters. Wait! Doesn’t Triceratops also have scissor-like shearing teeth? Maybe it’s the cat-like retractable claws found on Thylacoleo? Another tree-climber, Phasolarctos doesn’t have claw sheaths like Thylacoleo. This problem has surrounded Thylacoleo for decades and it won’t be solved here. More data below.

BTW,
the Arctocyon to Vincelestes clade (Fig. 1) are all carnivores, except Ernanodon, a likely ant/termite eater with blunt post-canine teeth.

Figure 4. Thylacoleo skeleton. This is another wombat with unusual hands and and feet... and teeth. Said to be carnivorous, it would be the exception in this clade of herbivores.

Figure 4. Thylacoleo skeleton. This is another wombat with unusual hands and and feet… and teeth. Said to be carnivorous, it would be the exception in this clade of herbivores. The bony manus claws resemble those of cats, with a small bony core and large keratinous claws.  Look at the size of that calcaneum. This was not a speedy predator, if it was a predator at all.

This YouTube video
describes the finding of a complete and unburied Thylacoleo skeleton. About 45 minutes long, as I recall…

References

wiki/Thylacoleo
wiki/Koala

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