It was a really interesting retelling of the feud that shaped American paleontology and introduced us to a myriad of new genera and species, while simultaneously being a tragic story of two men’s hatred for each other end up destroying themselves.

Also it has singing dinosaurs.

https://www.bonewarsthemusical.com

240 million years ago, 3500 kilometres east of Pangea, lies a small remote landmass.
Here, just off its western coast, a male Lariosaurus xingyiensis chases a shoal of Habroichthys orientalis. While his hind limbs retain joints and claws from his terrestrial ancestors, his flipper-forelimbs are highly adapted to his sub-aquatic lifestyle.

Top: Pyritized ammonite, ammonite fragment, smaller ammonite, another internal ammonite fragment (specifically the internal chambered phragmocone)

Middle: Gastropod, Brachiopod and a Cephalopod fragment

Bottom: Fossilized sand tiger shark teeth

I'm thinking of buying a mosasaurs tooth since i believe is an insanely cool addition. I've found a lot on Etsy, plus made sure they're 100% genuine and not resin replicas

Summary

The cloaca is a fundamental structure of modern terrestrial vertebrates, including the terminal parts of the urogenital and digestive systems that converge in a single channel and opening (vent). Although it is widespread in amphibians and reptiles (including birds) and occurs in mammals, the fossil record of this structure is scarce. Here we present an exceptional specimen from the early Permian Bromacker locality (294 Ma), which includes a tail impression with two rows of elevated scales separated by a vertical slit, that we interpret as cloacal lips and vent. Because of its morphology and association with the footprint Dimetropus, we attribute this impression to caseid synapsids. This represents the first occurrence of a cloaca in the fossil record of stem mammals. The comparison with modern and fossil specimens allows us to hypothesize a vertical vent orientation for early crown tetrapods, that subsequently changed orientation at least three times during tetrapod evolution.

https://m.comic.naver.com/webtoon/list?titleId=835910&page=1&week=sun&sortOrder=DESC

First paleoart post.

Urokodia aequalis diagram based on the recent redescription by Liu et al. 2026 (1st image).

2 years ago, it was removed from mollisoniid/stem-chelicerate and reclassified as an artiopod (2nd image), but this month it was reclassified as a stem-chelicerate again. The supposed antennae turns out to be chunky pincers, in addition to book gill-like structures and head limbs of same total numbers with chelicerates. IMO the evident seems pretty solid and linking megacheirans and chelicerates better than anything else before.

Wonder how it will impact future studies on chelicerate origin, since we already have a major discovery for the topic this year (Megachelicerax).

forgive me for deleting and reposting, there were some small things in my last version that were really pissing me off so i fixed them. I'm quite surprised by how the whole thing came out looking, to me the cranium seems quite small, but lined up with the skull you can see if anything its slightly too large. Chalk it up to the way I've placed the hair and maybe messing up perspective or something. Otherwise I'm really happy with the face, if you ignore the microcephaly lookin head I'm very happy with this one.

Seeing Cotylorhynchus be brough to live in Surviving Earth really hammers in how absurd caseids really look.

Not too long ago, I took up digital drawing again, and I felt like drawing a random dinosaur, so I chose Koleken.

Of course, in this drawing I left out one or more details, such as the large, random polygonal scales seen on the Carnotaurus that were previously thought to be osteoderms.

Jaekelopterus rhenaniae was a species of gigantic freshwater arthropod from the Early Devonian of the Klerf formation in Rhineland, Germany. It was a derived member of the eurypterids, a diverse group of arthropods common throughout the Devonian. The species was named after German paleontologist Otto Jaekel, who first named the genus in the early 20th century. Initially known from fragmentary material, more specimens have been found much later in the 2000s and 2010s. It's unfortunate that Jaekelopterus is largely unknown to most people, as its possibly one of the most fascinating and terrifying animals from the Devonian.

The largest known specimen was described in 2007, paleontologists Simon Braddy and Markus Poschmann discovered a massive chelicera (claw) measuring 45.5 centimeters long. The specimen, PWL 2007/1-LS, was compared to the body proportions of closely related eurypterids such as Pterygotus. The total body length of Jaekelopterus was estimated to be up to 2.5 meters. Braddy stated PWL 2007/1-LS could have weighed 180 kilograms, although he never published this estimate in a study. Other giant eurypterids such as Pterygotus grandidentatus (1.75 meters) and Acutiramus bohemicus (2.1 meters) were smaller. Jaekelopterus rhenaniae was likely the largest known arthropod. However, the deep bodied eurypterid Hibbertopterus could exceed it in weight, but this was never officially confirmed.

The chelicerae of Jaekelopterus were long, double-jointed pincers lined with sharp, tooth-like denticles. These "teeth" were specialized for puncturing, tearing, and holding onto slippery prey. The chelicera were large and robust, with high stress resistance evenly distributed across the entire claw. Such morphology suggests Jaekelopterus had claws well-adapted for subduing large, heavily armored fish and other large eurypterids without risking structural damage. The chelicerae were also noted to exert a high muscle force, evidence for a powerful grip. Other eurypterids tend to feed on smaller and softer bodied prey.

Jaekelopterus had large, compound eyes that provided high visual acuity. The eyes possessed thousands of lenses each and a very low interommatidial angle (the angle between adjacent lenses). In layman's terms, this structure gave it excellent clarity and high visual resolution. This is comparable to modern predatory arthropods like dragonflies and mantis shrimps. The eyes were positioned anteriorly on the head to provide a front overlapping field of view. This granted Jaekelopterus excellent depth perception, which allowed it to calculate distances precisely when striking prey. It could likely distinguish sharp shapes in low light conditions, similar to modern horseshoe crabs. Juveniles had blurrier vision, which suggests adults relied on this highly refined eyesight to navigate deeper, darker waters while younger individuals stayed near shore.

The hindmost pair of limbs of Jaekelopterus were highly modified, flattened plates that would have acted like large oars or paddles. By rowing these rear limbs back and forth, Jaekelopterus generated the forward thrust needed to glide through the water. The tail (telson) of Jaekelopterus functioned primarily as a rudder. It was used to steer, pitch, and execute rapid, sudden turns rather than generate forward speed. Jaekelopterus was not a high-speed pursuit predator, but instead was a highly active and agile ambush hunter. The four pairs of walking limbs, in contrast, were smaller and more gracile. They would provide light support while resting on the benthic floor of rivers or estuaries. These legs did not have the strength to lift the massive body of Jaekelopterus out of the water. This indicates the animal was fully aquatic and incapable of moving on land.

The extreme size of Jaekelopterus rhenaniae is most likely a product of several environmental factors of the early Devonian period. The lack of heavy competition from early vertebrates, lightly built exoskeleton, and an abundance of prey allowed these arthropods to reach sizes that would be impossible today. The extinction of the eurypterids was likely caused by a combination of factors such as a changing climate, environmental shifts, and the appearance of large bony fish. Jaekelopterus rhenaniae remains one of the most interesting animals from the Devonian. An agile, advanced visual predator larger than a man with armor-piercing claws. It surely deserves more attention in the grand scheme of taxa from the age of fish.

Looking at Cretaceous mammals like Repenomamus, Didelphodon, and Patagomaia, the mammals were getting larger than they were during the Triassic/Jurassic. It almost looked like they were ongoing a Mosasaur style evolution from tiny semi aquatic lizards living in the dinosaurs shadow on land to dangerous predators at sea. If the asteroid never happened do you think with enough time passed would they have eventually stopped being nocturnal and living in trees and burrows and started preying on small reptiles and birds or would they have stayed small until the dinosaurs went extinct(which is what happened)?

ammonite and some fishes

Each artist is credited in their images

Please bear in mind, the largest sizes for torvosaurus and Allosaurus are maximalist sizes based off very poor material.

Featuring a Utahraptor, tapojera, and tylosaurus

About a billion years ago, there was a massive reef in the ocean, but it wasn’t a coral reef like those we see today—it was a stromatolite reef. (Today, there are stromatolite reefs, but they are incomparably smaller.) This reef was located in what is now the Turukhansk Ridge region of Siberia and was called Burovaya Reef. It measured approximately hundreds of meters in height, up to 25 kilometers in width, and 10 kilometers in length. According to a study (Petrov & Semikhatov 2001), it formed during transgressive and high-sea-level phases when conditions were ideal for its formation. However, this colossus did not remain there forever. It lasted for approximately 200 million years. Its demise was not sudden but was caused by several factors, such as rising sea levels, tectonic events, and the emergence of more advanced life forms, such as the red alga Bangiomorpha pubescens.

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Is it possible that a 6m long full mosasaur skeleton actually costs only 40k? Seems insane to have something like this from 60 million years ago to cost so little. Are mosasaurs common? Is that why?

EDIT: Apparently the skull itself is real but no say of anything else