A koala bear cousin in the Eocene: tiny Apatemys
Recent housekeeping
in the large reptile tree (LRT, 2338 taxa) brought two marsupial taxa closer together, Apatemys, the extinct apatemyid, and Phascolarctos, the much larger extant marsupial koala bear (Figs 1, 2).
Figure 1. Several views of the koala (Phascolarctos) skull to scale with that of Apatemys (see figure 2 for a larger view).
” data-image-caption=”
Figure 1. Several views of the koala (Phascolarctos) skull to scale with that of Apatemys (see figure 2 for a larger view).
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg?w=584″ class=”size-full wp-image-92819″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg” alt=”Figure 1. Several views of the koala (Phascolarctos) skull to scale with that of Apatemys (see figure 2 for a larger view).” width=”584″ height=”535″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg?w=584&h=535 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg?w=150&h=138 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg?w=300&h=275 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/koala-skull-lateral588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 1. Several views of the koala (Phascolarctos) skull to scale with that of Apatemys (see figure 2 for a larger view).All the elements in these two taxa are quite similar,
allowing for proportions to change along with the size change.
Notably Apatemys had a long tail that is lost in Phascolarctos.
Notably the orbit is very high on the skull, close to the dorsal margin in both taxa.
Notably the tooth patterns are similar.
Figure 1. The skull of Apatemys in situ and reconstructed.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg?w=584″ class=”size-full wp-image-92822″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg” alt=”Figure 1. The skull of Apatemys in situ and reconstructed. ” width=”584″ height=”559″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg?w=584&h=559 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg?w=150&h=144 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg?w=300&h=287 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/apatemys_skull_insitu588-1.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 2. The skull of Apatemys in situ and reconstructed.
These two taxa nest with arboreal
Thylacoleo and Wakaleo,which no longer nest with Phalanger in the LRT. Terrestrial wombats are widely acknowledged to be close to arboreal koalas and that is also reflected in the LRT.
Figure 2. Skeleton of the koala (genus: Phascolarctos)
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg?w=584″ class=”size-full wp-image-29981″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg” alt=”Figure 2. Skeleton of the koala (genus: Phascolarctos)” width=”584″ height=”404″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg?w=584&h=404 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg?w=150&h=104 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg?w=300&h=208 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2018/03/koala-phascolarctos-cinereus-588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 3. Skeleton of the koala (genus: Phascolarctos)
This interrelationship has been traditionally overlooked
and for good reason. Nevertheless, when taxa are tested together, as in the LRT, sometime they nest together.
Figure 1. Apatemys, only complete fossil skeleton of an apatemyid, turns out to be a basal shrew. So this clade is not extinct.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg?w=104″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg?w=356″ class=”size-full wp-image-24320″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg” alt=”Figure 1. Apatemys, only complete fossil skeleton of an apatemyid, turns out to be a basal shrew. So this clade is not extinct.” width=”584″ height=”1678″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg?w=584&h=1678 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg?w=52&h=150 52w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg?w=104&h=300 104w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2016/09/apatemys-insitu588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 4. Apatemys, only complete fossil skeleton of an apatemyid, turns out to be a basal shrew. So this clade is not extinct.
The odd manus of koalas
with two ‘thumbs’ (like a chameleon, Fig 5) is not quite reflected in the manus of Apatemys, which is odd in its own way (Fig 5) and MIGHT have been used similarly… or not.
Figure 4. The odd manus of Apatemys compared to the odder manus of the koala, Phascolarctos, which has two ‘thumbs’.
” data-medium-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg?w=300″ data-large-file=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg?w=584″ class=”size-full wp-image-92925″ src=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg” alt=”Figure 4. The odd manus of Apatemys compared to the odder manus of the koala, Phascolarctos, which has two ‘thumbs’. ” width=”584″ height=”453″ srcset=”https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg?w=584&h=453 584w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg?w=150&h=116 150w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg?w=300&h=233 300w, https://pterosaurheresies.wordpress.com/wp-content/uploads/2025/05/phascolarctos_manus_compared588.jpg 588w” sizes=”(max-width: 584px) 100vw, 584px” />
Figure 5. The odd manus of Apatemys compared to the odder manus of the koala, Phascolarctos, which has two ‘thumbs’.
This appears to be a novel hypothesis of interrelationships.
If not, please provide a citation so I can promote it here.
References
de Blainville H 1816. Prodrome d’une nouvelle distribution systématique du règne animal. Bulletin de la Société Philomáthique, Paris (in French). 8: 113–124.
Marsh OC 1872. Preliminary description of new Tertiary Mammals. Parts I– IV: American Journal of Science 4: 122–128, 202–224.
wiki/Phascolarctos
/wiki/Koala
wiki/Apatemys
Source: https://pterosaurheresies.wordpress.com/2025/05/20/a-koala-bear-cousin-in-the-eocene-tiny-apatemys/
Anyone can join.
Anyone can contribute.
Anyone can become informed about their world.
"United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
Before It’s News® is a community of individuals who report on what’s going on around them, from all around the world. Anyone can join. Anyone can contribute. Anyone can become informed about their world. "United We Stand" Click Here To Create Your Personal Citizen Journalist Account Today, Be Sure To Invite Your Friends.
LION'S MANE PRODUCT
Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules
Mushrooms are having a moment. One fabulous fungus in particular, lion’s mane, may help improve memory, depression and anxiety symptoms. They are also an excellent source of nutrients that show promise as a therapy for dementia, and other neurodegenerative diseases. If you’re living with anxiety or depression, you may be curious about all the therapy options out there — including the natural ones.Our Lion’s Mane WHOLE MIND Nootropic Blend has been formulated to utilize the potency of Lion’s mane but also include the benefits of four other Highly Beneficial Mushrooms. Synergistically, they work together to Build your health through improving cognitive function and immunity regardless of your age. Our Nootropic not only improves your Cognitive Function and Activates your Immune System, but it benefits growth of Essential Gut Flora, further enhancing your Vitality.
Our Formula includes: Lion’s Mane Mushrooms which Increase Brain Power through nerve growth, lessen anxiety, reduce depression, and improve concentration. Its an excellent adaptogen, promotes sleep and improves immunity. Shiitake Mushrooms which Fight cancer cells and infectious disease, boost the immune system, promotes brain function, and serves as a source of B vitamins. Maitake Mushrooms which regulate blood sugar levels of diabetics, reduce hypertension and boosts the immune system. Reishi Mushrooms which Fight inflammation, liver disease, fatigue, tumor growth and cancer. They Improve skin disorders and soothes digestive problems, stomach ulcers and leaky gut syndrome. Chaga Mushrooms which have anti-aging effects, boost immune function, improve stamina and athletic performance, even act as a natural aphrodisiac, fighting diabetes and improving liver function. Try Our Lion’s Mane WHOLE MIND Nootropic Blend 60 Capsules Today. Be 100% Satisfied or Receive a Full Money Back Guarantee. Order Yours Today by Following This Link.
| Online: | |
| Visits: | 1,696,534,093 |
| Stories: | 8,417,507 |
Whistler Blowers, Insiders
