#euarchontoglires

[alphynix]

Apatemyids were a group of unique early placental mammals that lived during the first half of the Cenozoic, known from North America, Europe, and Asia. Due to their specialized anatomy their evolutionary relationships are rather murky (they were traditionally part of the convoluted mess that was "Insectivora"), but currently they're thought to be a very early offshoot of the Euarchontoglires, the branch of placentals that includes modern rodents, lagomorphs, treeshrews, colugos, and primates.

Living in what is now western Europe during the mid-Eocene, around 47 million years ago, Heterohyus nanus was a small apatemyid about 30cm long (~12") – although just over half of that length was made up of its tail.

Like other apatemyids it had a proportionally big boxy head, with large forward-pointing rodent-like incisors in its lower jaw and hooked "can-opener-shaped" incisors in its upper jaw.

Example of an apatemyid skull from the closely related American genus Sinclairella. From Samuels, Joshua X. "The first records of Sinclairella (Apatemyidae) from the Pacific Northwest, USA." PaleoBios 38.1 (2021). https://doi.org/10.5070/P9381053299

The rest of its body was rather slender, and fossils with soft tissue preservation from the Messel Pit in Germany show that it had a bushy tuft of longer fur at the end of its long tail.

But the most distinctive feature of apatemyids like Heterohyus were their fingers, with highly elongated second and third digits resembling those of modern striped possums and aye-ayes. This suggests they had a similar sort of woodpecker-like ecological role, climbing around in trees using their teeth to tear into bark and expose wood-boring insect holes, then probing around with their long fingers to extract their prey.

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References:

Kalthoff, D. C., W. Von Koenigswald, and C. Kurz. "A new specimen of Heterohyus nanus (Apatemyidae, Mammalia) from the Eocene of Messel (Germany) with unusual soft part preservation." Courier Forschungsinstitut Senckenberg 252 (2004): 1-12. https://www.researchgate.net/publication/263714512_A_new_specimen_of_Heterohyus_nanus_Apatemyidae_Mammalia_from_the_Eocene_of_Messel_Germany_with_unusual_soft-part_preservation

Koenigswald, W. V., and H-P. Schierning. "The ecological niche of an extinct group of mammals, the early Tertiary apatemyids." Nature 326.6113 (1987): 595-597. https://www.researchgate.net/publication/232761846_The_ecological_niche_of_early_Tertiary_apatemyids_-_extinct_group_of_mammals

Samuels, Joshua X. "The first records of Sinclairella (Apatemyidae) from the Pacific Northwest, USA." PaleoBios 38.1 (2021). https://doi.org/10.5070/P9381053299

Silcox, Mary T., et al. "Cranial anatomy of Paleocene and Eocene Labidolemur kayi (Mammalia: Apatotheria), and the relationships of the Apatemyidae to other mammals." Zoological Journal of the Linnean Society 160.4 (2010): 773-825. https://doi.org/10.1111/j.1096-3642.2009.00614.x

[dystopianroach]

portrait of a common treeshrew (tupaia glis). check out the process and some cool NOT-shrew facts on my Instagram and TikTok page!

[biol525-mammalogy]

primates -> haplorrhini -> hylobatidae (gibbons etc)

[jackson-imbecille]

Pacarana

Dinomys branickii

Family Dinomyidae, pavorder Caviomorpha, suborder Hystricomorpha, order Rodentia

This animal is called the pacarana because it looks a bit like a paca, another South American rodent.

They are the only living member of their taxonomic family. Some other members of this family grew to incredible sizes, like the bison sized Josephoartigasia, which is the largest known rodent. Pacaranas themselves are pretty large, weighing as much as 15 kg, or 33lbs.

Pacaranas are very slow moving and peaceful animals. They eat fruits, leaves, and stems of plants and eat sitting down while holding their food like they have hands. It’s very cute.

The males also stand on their hind legs when approaching females during courtship and there was a viral video of one of these guys standing on their hind legs a while back trying to remove soap from their fur. It has been confirmed by an expert that no, you should not put soap on a pacarana.

They’re mainly nocturnal and terrestrial, but they do a bit of climbing.

These animals are vulnerable to becoming endangered.

@jackalspine @fifiibibii

How do we feel about pacarana

I love pacarana

I hate pacarana

I feel indifferent about pacarana

Voting ended onOct 4, 2023

[yellowballoonx]

[indagold-orchid]

I think about how cute monkeys are and forget I have pet rats which are basically monkey adjacent.

[animalids]

Capybara (Hydrochoerus hydrochaeris)

Photo by Sergio Ali

[penurie-de-tops-a-qc]

I think most people are aware of the fact that humans are related to other primates such as chimps, gorillas, mandrills and probably even Curious George. As a matter of fact, humans ARE primates, which means we share a common ancestor with all other primates. The order Primate includes many species other than just humans and animals that we usually call "monkeys", it also includes lemurs and some other minor families.

However, what I was curious to know was what animals are the most closely related to humans after the primates. To find out, we need to go up the ranks in our phylogenetic tree. As seen on the image on top, primates are part of the mirorder (like an order, but bigger) Primatomorpha, which includes the order Dermoptera (yes, Greek nerds, this means something along the lines of "wing skin"). The order Dermoptera consists entirely of colugos, which are also known as flying lemurs. Despite their name, they are not lemurs and despite their appearance, they are not flying squirrels. They just happen to also be equipped with a patagium (the skin membrane they use to glide) due to convergent evolution. While this is surely interesting, colugos are quite obscure animals and I was looking for a group of animals that would be more "commonly known", even if a bit less related to humans.

We can go even higher up in our phylogenetic tree and see that Primatomorpha are part of the grandorder (like a mirorder, but even bigger) Euarchonta and have a sister order, Scandentia. Animals in the order Scandentia are referred to as "tree shrews", but again, the name is misleading because while they are indeed arboreal, they are not shrews. The image above has one example of these creatures, a tupaia, and while they are cute and all, they are still not what I would call a "commonly known animal". Also, note that the position of the order Scandentia in the evolutionary tree is actually debatable as some researchers place them as a sister clade* to the Glires.

Going one more rank up in our phylogenetic tree, we see that Euarchonta are part of the superorder (like a grandorder, but bigger, you get the idea) Euarchontoglires, which includes the clade Glires. Within this clade are found the orders Lagomorpha and Rodentia, which are both comprised of very well known animals, such as rabbits and rats. I think it's pretty cool to think that those animals are quite closely related to primates, and therefore, to humans. Probably this is why they are (sadly) used for animal testing of medicine and cosmetics, although they are also probably used because of economical reasons.

* I will one day make a post about this word, it's actually pretty interesting.