Therocephalians Were A Group Of Synapsids Very Closely Related To – Or Possibly Even Ancestral To –

A colored line drawing of Tetracynodon, an extinct relative of early mammals, in a sitting pose. It has a somewhat badger-like body covered in short fur, with fairly slender limbs ending in paws with long claws. Its head resembles a long-snouted lizard with large eyes. It's depicted with brown-and-tan coloration.

Therocephalians were a group of synapsids very closely related to – or possibly even ancestral to – the lineage leading to modern mammals. They were a diverse and successful group of carnivores during the latter half of the Permian, but suffered massively during the "Great Dying" mass extinction, with only a handful of representatives making it a few million years into the Triassic.

Tetracynodon darti was one of these rare Triassic therocephalian survivors, living in what is now South Africa around 251 million years ago. Only about 25cm long (~10"), it had slender limbs and strong claws that suggest it was a scratch-digger. Its long snout was lined with pointed teeth, and it was probably an active predator hunting by snapping its jaws at fast-moving prey like insects and smaller vertebrates.

Its combination of small size, burrow-digging habits, and unspecialized diet may be the reason it scraped through the Great Dying when most of its relatives didn't – but unfortunately it seems to have been a "dead clade walking", disappearing only a short way into early Triassic deposits.

———

NixIllustration.com | Tumblr | Patreon

References:

Fontanarrosa, Gabriela, et al. "The manus of Tetracynodon (Therapsida: Therocephalia) provides evidence for survival strategies following the Permo-Triassic extinction." Journal of Vertebrate Paleontology 38.4 (2018): 1-13. https://doi.org/10.1080/02724634.2018.1491404

Sigurdsen, Trond, et al. "Reassessment of the morphology and paleobiology of the therocephalian Tetracynodon darti (Therapsida), and the phylogenetic relationships of Baurioidea." Journal of Vertebrate Paleontology 32.5 (2012): 1113-1134. https://www.researchgate.net/publication/254315180_Reassessment_of_the_Morphology_and_Paleobiology_of_the_Therocephalian_Tetracynodon_Darti_Therapsida_And_The_Phylogenetic_Relationships_of_Baurioidea

Wikipedia contributors. “Tetracynodon” Wikipedia, 21 Aug. 2024, https://en.wikipedia.org/wiki/Tetracynodon

Wikipedia contributors. “Therocephalia” Wikipedia, 01 Oct. 2024, https://en.wikipedia.org/wiki/Therocephalia

The public paid for "Moderna's" vaccine, and now we're going to pay again (and again and again)

Moderna is quadrupling the cost of covid vaccines, from $26/dose to $110–130. Moderna CEO Stephane Bancel calls the price hike “consistent with the value” of the mRNA vaccines. Moderna’s manufacturing costs are $2.85/dose, for a 4,460% markup on every dose:

https://arstechnica.com/science/2023/01/moderna-may-match-pfizers-400-price-hike-on-covid-vaccines-report-says/

If you’d like an essay-formatted version of this thread to read or share, here’s a link to it on pluralistic.net, my surveillance-free, ad-free, tracker-free blog:

https://pluralistic.net/2023/01/24/nationalize-moderna/#herd-immunity

Keep reading

176 notes View Post

we-are-all-paranoid

3 years ago

Stop the ban on blood donation of gay men

51K notes View Post

we-are-all-paranoid

3 years ago

vitamin sea, if you will

331 notes View Post

we-are-all-paranoid

1 year ago

i got to work with some HeLa cells today!

as cool of an experience as this was and as interesting as these things are, it’s always important to acknowledge the bad along with the good. Henrietta Lacks’ cells revolutionized so many areas of research, but she deserved so much better.

working with these cells today just really reminded me of the duality of many scientific developments. many things have come with great cost and harm and i think that’s something important to keep in mind.

if you aren’t familiar with the story of Henrietta Lacks, i highly recommend looking her up. there’s a book about her live (the immortal life of henrietta lacks) that’s very illuminating.

59 notes View Post

we-are-all-paranoid

3 years ago

biologists will be like this is a very simplified diagram of a mammalian cell

chemists will be like this is a molecule

256K notes View Post