Discover Top Posts Tagged with #stem mammals

I’m trying to get back into drawing paleo art. Here’s a happy estemmenosuchus

#my art #estemmenosuchus #paleoart #paleontology #paleobr #permian #synapsids #therapsid #stem mammals #digital aritst

2022 Reading Log pt. 21

101. The Rise and Reign of the Mammals by Steve Brusatte. This book covers mammalian evolution throughout synapsid history, starting in the Carboniferous and ending in the present day. There’s a lot of good information in here, both about the species themselves and the history of their discovery and discoverers. But I found the authorial voice consistently off-putting. Brusatte writes about evolution alternately like a war or a poker game, and there are constant references to dominating, beating or tricking other lineages, particularly dinosaurs. After crowing about how mammals survived and thrived in the Mesozoic by exploiting small body sizes and niches like eating seeds and insects, he dismisses all of bird evolution (which in the Cenozoic did the same thing) in a paragraph, and never talks about Cenozoic animals other than mammals at all. What’s weird is I don’t remember his previous book, The Rise and Fall of Dinosaurs, being so mercilessly jingoistic about its focus clade. Maybe the publisher told him to write more enthusiastically about a “less exciting” group; maybe it’s the zeal of the newly converted (Brusatte was primarily a dinosaur paleontologist until relatively recently); maybe the first book was this annoyingly written and I have forgotten.

102. The Accidental Ecosystem by Peter S. Alagona. This book is a short overview about how wild animals have moved into American cities, why American cities developed into places where animals can thrive, how humans are reacting to these and how we should in the future. The tone is generally optimistic but realistic—that cities can serve as oases of biodiversity during climate change and extinction events, but a world with only rats, crows and sparrows would be a depauperate one. Most of the book is organized around an incident of some charismatic megafauna making the news (like Pedals the bipedal bear of New Jersey, or a nesting pair of bald eagles blithely feeding their chicks fresh kitten), and then talking about that species in greater context. I’ve read several other books recently about human/animal interactions, and this one did the best job at being inclusive, talking about how parks can and have been used as agents of gentrification, the impact of economic decisions on the fate of cities and animals alike, and existing biases within ecology and evolutionary studies. Highly recommended.

103. Travels to the Otherworld and other Fantastic Realms, edited by Claude and Corinne Lecouteux, translated by Jon E. Graham. This is a collection of medieval European fantastic literature, although not all of it is necessarily fantasy in the modern sense. Some are religious visions, others historical fantasies, others excerpts from novels and folk tales. All of them are wild. Both as a look into the medieval mindset and for their various bizarre creatures and occurrences. Some highlights include multiple versions of the adventures of Alexander the Great, the Vision of Tundale, a German journey through Hell that’s much gnarlier than anything in Dante, and the adventures of Marcolf, the Sherlock Holmes to King Solomon’s Watson (!). Also highly recommended; this might be the most fun I’ve had with a book this year.

104. Empire of the Scalpel: The History of Surgery by Ira Rutkow. Just what it says on the cover. The book starts with trepanations of cavemen and progresses to the modern era. Rutkow follows the Great Man school of history, and many of the chapters are biographical sketches of a surgeon who was important in developing the field. It feels somewhat incomplete—not only are non-surgical advances in medicine basically ignored, the development of the modern American insurance state is glossed over, even as the book discusses how hospitals became prestigious institutions and surgeons very wealthy. The book also uses weird kennings, as if it were written by an Icelandic skald—surgeons are “scalpel wielders” or “students of the knife”, etc, as often as they’re just surgeons. I definitely learned stuff from this book (like the quack “orifical surgery”, which posed that all diseases could be cured by cutting out irregular shapes from the mouth, nose, anus and genital openings!), but found the book rather less than the sum of its parts.

105. Monster Anthropology, edited by Yasmine Musharbash and GH Presterudstuen. This is a collection of academic essays about monsters as cultural signifiers and participants. After a very good introduction (the Works Cited of which will keep me busy a long while), the bulk of the book looks at particular cultures and particular monsters. The book was published in Australia, and several of the essays are on the same group of Indigenous Australians, the Warlpiri, and their monsters (most of which have not penetrated Western consciousness, but the pankarlangu is starting to make some inroads). One minor note I found interesting—there’s an actual folkloric monster that fits the D&D concept of a rakshasa! The tepun of the Eastern Penan people in Borneo is a shapeshifting hedonist that has aspects of humans and tigers.

106. Scent: A Natural History of Fragrance by Elise Vernon Pearlstine. Gave up on 50 pages in. The book purports to be a natural history—what molecules are made by what plants, why, and how those plants live. The actual contents contain some of that, but much more cultural histories. I’ve read and enjoyed several books about the cultural history of plants recently, so I’m not inherently opposed to the concept. But the book is incredibly poorly organized. The narrative skips back and forth through time and space and species, words are used and then defined several pages later as if it’s the first time we’re seeing them, concepts will be repeated multiple times to the point of redundancy, and the preface and introduction contain the exact same sentences, twice! The fact that this book was published in this state is frankly embarrassing.

#reading log #bad books #botany #cultural history #paleontology #stem mammals #prehistoric mammals #anthropology #monster books #surgery #medical history #european folklore #medieval folklore #ecology #urban ecology

Say hello to your great great great great great great... great grandmother!

💜

Work in progress underpainting for Estemmenosuchus mirabilis, a genus of therapsid that lived during the Middle Permian (267 million years ago). Found in what is now the Perm region of Russia in the 1960s, both of the currently recognized species: E. uralensis and E. mirabilis are most recognizable from their distinctive knobby, antler-like facial structures; these structures are in face where they get their name which means "crowned crocodile."

Larger specimens of Estemmenosuchus have been estimated to reach over 10 feet in length, they possessed a varied dentition and were most likely omnivorous which was more mammal-like when compared to most modern reptiles, fossil skin impressions also suggest that they had a texture that was more glandular than scaly, often compared to that of hippopotamus or other less hairy modern day mammals.

When the Synapsids Struck Back

Synapsids were the world’s first-ever terrestrial megafauna but the vast majority of these giants were doomed to extinction. However some lived on, keeping a low profile among the dinosaurs. And now our world is the way it is because of the time when the synapsids struck back.

Thanks to Ceri Thomas for the excellent Synapsid illustration (including Bulbasaurus!)!

Check out more of Ceri's paleoart at http://alphynix.tumblr.com and http://nixillustration.com

And thanks as always to Studio 252mya for their wonderful illustrations. You can find more of their work here: https://252mya.com/

via: PBS Eons

#evolution #synapsid #mammal like reptile #animals #nature #stem mammals #video #prehistoric #extinction #end permian #permian #great dying #cynodont #thrinaxodon #therapsid

Juramaia – Late Jurassic (160 Ma)

Just who is this beautiful boy? This chubby, shrew-looking fellow? He’s only a few inches long, and he has a sharp little nose. His name is Juramaia, and if you went back about 120 million generations, your ancestor would look something like him.

Juramaia was discovered in Liaoning, China, in 2011. Recent enough that if you’ve been following paleontology for a while, you may have heard of him. China has, since the beginning of this century, been a treasure trove of important fossils. We first found feathers on a Chinese dinosaur named Sinosauropteryx. We also found Juramaia, who is absurdly important to our understanding of mammal history.

Juramaia is a basal Eutherian. Eutherians are, simply put, living mammals who aren’t marsupials or monotremes. In fact, this is the oldest known Eutherian to date. We can’t say for sure that Juramaia is our direct ancestor. In fact, he’s probably not, statistically speaking. But he’s close enough to give us tons of insight into our origins.

When the first true mammals evolved depends on how you define a mammal. The late Paleozoic was ruled by a group of animals known as synapsids. These were our earliest ancestors and cousins, sometimes called proto-mammals. Originally considered a subclass of reptiles, we now know that they diverged from basal amniotes around the same time as reptiles, and have much more in common with mammals, anyway. They’re still popularly referred to as mammal-like reptiles, though that term is outdated. The terminology is a bit confusing, since synapsids also include true mammals, but I’ll use ‘synapsid’ here to mean the same thing as ‘proto-mammal.’

So, even when synapsids first appear in the fossil record in the late Caboniferous, they look distinctly mammalian on the inside. Their skulls have holes behind the eye socket, a trait shared by all their ancestors (fun fact, we lost this trait; our skull temples are the recently-closed secondary holes of the skull). They don’t have scales, either, so if you see a scaly Dimetrodon or Gorgonops, the portrayal is either outdated or incorrect. Synapsids also developed a semi-erect gait, something halfway between that of an alligator and a deer, for reference. Synapsids also immediately show the variety of teeth mammals eventually came to be most known for in paleontology. Towards the end of the Permian, they even develop bristles and fur.

By the Triassic period, we have the Cynodonts, a group so close to mammals that they’re easily mistaken for them. We aren’t quite at mammals yet, though. Cynodonts are pretty uncontroversially considered proto-mammals, but they’re definitely considered transitional. It’s when you move a few million years up that things get dicey. Animals like Megazostrodon and Morganucodon appear in the late Triassic, and they’re almost indistinguishable from a shrew or mouse. Plenty of people consider Megazostrodon and company to be the most basal mammals. This gets into what I talked about in Westlothiana’s writeup. These animals are so close together, and so close to the symbolic gulf between proto-mammal and true mammal that it’s almost impossible to come to agreement on which it is. In The Ancestor’s Tale, Richard Dawkins has a policy of not getting too hung-up on labels when dealing with these animals, and I think that’s a good rule of thumb.

Juramaia, though, is unambiguously a mammal. It has every trait we associate with the class today, and was a card-carrying member of the group that would eventually become the majority of mammals we know today. Most mammals looked a lot like Juramaia during the Mesozoic, with a few glorious exceptions. Most of our 100+ greats grandparents were relegated to exploiting the lower niches of nocturnal insectivores. Make no mistake, though, we flourished under the footfalls of dinosaurs, and spread all over the world. We made the most of that strategy for 100 million years, until there was room to diversify. If you can believe it, we—that is, mammals as a whole—retain a lot of holdovers from our stint as tiny nocturnals. Juramaia is an animal with just about all of those traits.

Think about some defining features of mammals. I don’t necessarily mean technical stuff, like bone structure and all that. That’s irrelevant to this particular point. You’d be surprised by how many of those traits are the result of 100 million years as pseudo-shrews:

Most mammals have dull coloration. Most of us are brown or tan or gray or black. Being the same color as the dirt or decaying leaves is very advantageous to a tiny animal that sleeps all day and spends all night worrying about being eaten by other animals. And remember that dinosaurs probably hunted primarily with eyesight, considering how good birds are at it. The color of our fur is a relic from when we needed camouflage to survive.

Your typical mammal has scent as their strongest sense, with hearing close behind. On top of that, they have terrible eyesight. It can be hard to remember that since we’re an exception, but it’s true for almost all non-primate mammals. Nocturnal animals tend to have poor color vision, trading off detail for the ability to see in as little light possible. Scent and hearing are really good traits for an animal that can’t and doesn’t need to see that well, too. It’s also worth mentioning that mammals on the whole have a well-developed sense of touch. It’s weird to think that other animals aren’t as good at feeling things as us, but it seems to be true.

Even fur and warm-bloodedness might be holdovers from Mammals: Nights. They might have served to keep us warm in dry places, where it would get much colder at night. Since we weren’t sleeping at night, it was important to have a mechanism to stay warm.

All of these points, are bundled together in a theory called the “Nocturnal Bottleneck.” There isn’t much evidence of nocturnality in other groups of animals back in the day, which suggests mammals pretty much had that niche on lockdown. Juramaia displays all of these traits, and it’s easy to see how an animal like this eventually diversified into the mammals we have today, who, despite having all kinds of shapes and roles, still retain some traits that betray their nocturnal heritage.

So, like an evolutionist in a Jack Chick comic, it wouldn’t be unreasonable for you to frame a picture of one of this guy and label it “Daddy.” Or maybe something like “Great Grandpa,’ because, I mean, “Daddy” has some implications in this age when nothing is sacred.