#dorudon

[mesozoicmarket]

A fossilized tooth of an indeterminate basilosaurid, possibly Basilosaurus isis from the Samlat Formation in Dakhla, Morocco. It is unclear if the larger teeth from these ancient whales can be attributed to Basilosaurus.

[bulkhead08]

Dorudon, an early species of whale.

[dimorphodon-x]

Was messing a bit with my sketch pens and ended up doodling some ancient whales.

Except that big one in the top right, I don’t know what it is but it kinda reminds me of a thylacine🤷

[dumbfaec]

Some prehistoric whale girls I did for Mermay.

[videogamewhales]

[ID: An image of Dorudon, a prehistoric whale character from the SpongeBob franchise, as he appears in The Cosmic Shake. End ID.]

Dorudon from The Cosmic Shake (2023)

[catboy-cyrus]

SPEAR TOOTH

Water/Dark -- The Paradox Pokémon

This Pokémon resembles a sea monster of legend, said to eat ships. An old book describes it as Spear Tooth.

--

Tried my hand at designing a Paradox Pokemon! I'm fascinated by ancient animals and whales were the perfect thing to create a Paradox pokemon based on. This one is based heavily on Dorudon, hence the name. It'd be the only Scarlet pokemon smaller than its modern form, but whales have literally only gotten bigger so it works. I was going to base this on Kutchicetus but it was much harder to make it read as a Wailord relative, and I struggled even here.

[entelodontidae]

Daeodon was such a strange animal. Literally a terrestrial, (probably) carnivorous hippopotamus. Never ceases to be my favorite thing this earth has grown.

Daeodon (heavily stylized), dorudon and hippopotamus

[bluewhaleking]

History of the Blue Whale King, Part III: Tethys Sea, 48,000,000 - 33,900,000 BC

Ambulocetus quickly lost the ability to support their weight on land. But though the world of land was locked behind them, the much larger world of the sea had opened in front.

For a while, they were confined to shallow seas. But even then, they made progress. Led by their King and Queen, they spread beyond the Tethys Sea and the Indian Subcontinent to shallow seas around the world. During that time, many smaller groups broke off and became their own species, led by other rulers. But sadly, those groups all became extinct as evolutionary dead ends.

Over millions of years and thousands of reincarnations, the King and Queen honed their his people into nearly perfect swimmers. All fur gone except a few sensory hairs, hind limbs reduced, forelimbs streamlined into flippers, a dorsal fin on top, the tail strengthened and added a propulsive fin, a fluke, on the end.

They were no longer recognizable as land animals. They had broken off of Order Artiodactyla to become Order Cetacea.

Until one day, an ambitious Cetacean decided to leave the species Dorudon with his own group, and create something new.

"I'll improve on your design, Dorudon King," said the rogue Cetacean. "I'll make a new species, of the longest creatures to ever roam the seas!"

"I wish you luck," said the Dorudon King. "But I will win this race in the end."

"And I as well," said the Dorudon Queen. "You cannot hope to defeat a partnership such as ours." (removed from current timeline)

And so the group split. Those that followed the rogue Cetacean added more and more vertebrae, until they were over 50 feet (15 meters) long.

They became Basilosaurus, "King Lizard," so named by humans millions of years later who mistook their fossils for reptiles. They grew 50-65 feet (15-20 meters) long, with the largest of them 75 feet (22.8 meters) long, dwarfing the 15 foot (4.6) meter long Dorudon.

Then another group broke off of Basilosaurus, and betrayed the Dorudon King who had created the Order Cetacea and its now many species. Basilosaurus Isis began to hunt and kill Dorudon.

"We must do something!" said a Dorudon at a meeting of their High Council. "Basilosauris Isis is killing our calves! This cannot be tolerated!"

"Hear hear!" said another, and the rest joined in earnest.

"We are well aware of the threat and are working on a solution," said the Queen. "Basilosaurus Isis will be defeated."

"Despite our much smaller size, we have a distinct advantage," said the King. "They cannot dive nearly as well as we can. If you are attacked, dive. Those of us who can dive better will survive better, and our species will improve. Basilosaurus Isis will be left behind."

And so it was. Dorudon and its descendants outdove their predators as they continued to hone their fishing skills and grow larger. By 33,900,000 BC, Basilosaurus Isis was extinct. Unfortunately, the harmless Basilosaurus Cetoides died out as well, having the same weakness.

"We did it," said the King. "Our people are safe again. For now. What should we do next?"

"I have an idea," said the Queen. "Plankton are a larger and more stable food supply than fish. If we could switch, or at least add them to our diet, our survival would be more secure, and we could grow larger. Perhaps, eventually, even larger than Basilosaurus."

"That does sound like a good idea," said the King. "But how will we implement it? Our teeth cannot catch plankton."

"We will strain them out," said the Queen. "The keratinous ridges in our upper jaws will grow longer for that purpose. Someday, one of our people will have a mutation that makes them grow as bristles. It will spread like wildfire in future generations. It will be perfect for filter feeding. I call it, *Baleen.*"

"Very well," said the King. "You are truly a genius, it's one reason why I love you so much. We shall be the Baleen Whales!"

[fluttering-by]

Look at these little old ancient babies and tell me they don't make you feel something.

Whale evolution by Rainbowleo

[arminreindl]

Pachycetinae: The Thick Whales

Oh look I'm way behind not only on my work with wikipedia but also in regards to summarizing it on tumblr. Good thing, three of the pages I've worked on these past few months can just be summed up in one post because they are all one family.

So Pachycetinae, at the most basic level, are basilosaurid archaeocetes, the group that famously includes Basilosaurus and Dorudon. Reason I've picked up the articles in addition to my usual croc work, basically a friend and I noticed how lacklustre many pages are and stupidly decided to start revising all of Cetacea (pray for me).

Currently theres two genera within the group. Pachycetus aka Platyosphys aka Basilotritus, which is a whole mess I will get into at the end for those interested, and Antaecetus, which I'll just call "the good one" for now. Among those are three species. Pachycetus paulsonii (or Basilotritus uheni) from continental Europe (Germany and Ukraine mostly), Pachycetus wardii (Eastern United Staates) and Antaecetus aithai (Morocco and Egypt)

Picture: Pachycetus and Antaecetus by Connor Ashbridge

So the hallmark of Pachycetines, as the name would suggest, is the fact that their skeletons are notably denser than that of other basilosaurids. The vertebrae, the most abundant material of these whales, are described as pachyostatic and osteosclerotic. The former effecitvely means that the dense cortical bone forms thickened layers, while the latter means that the cortical bone, already forming thickened layers, is furthermore denser than in other basilosaurids with less porosities. The densitiy is increased further by how the ribs attack to the vertebrae not through sinovial articulation but through cartilage, so adding even more weight to them. Overall this is at times compared to manatees, famous for their dense skeletons.

Pictured below, the currently best preserved pachycetine fossil, an individual of the genus Antaecetus from Morocco.

Now there are some interesting anatomical features to mention that either differ between species or just can't be compared. For example the American species of Pachycetus, P. wardii, shows a well developed innominate bone, basically the fused pelvic bones. This is curious as one would think of it as a more basal feature, with derived whales gradually reducing them. The skull is best preserved in Antaecetus and has a very narrow snout. One way to differentiate the two is by the teeth. Pachycetus has larger, more robust teeth while that of Antaecetus are way more gracile and is thought to have had a proportionally smaller skull (in addition to being smaller than Pachycetus in general).

All of this has some interesting implications for their ecology. For instance, why the hell are they so dense? Well its possible that they were shallow water animals using their weight as ballast, staying close to the ocean floor. This would definitely find some support in the types of environments they show up in, which tend to be shallow coastal waters. There are some Ukrainian localities that suggest deeper waters, but that has been interpreted as being the result of migration taking them out of their prefered habitat.

Now while pachycetines were probably powerful swimmers, their dense bones mean that they were pretty slow regardless. And to add insult to injury, they were anything but maneuverable. Remember those long transverse processes? Turns out having them extend over the majority of the vertebral body means theres very little space for muscles in between, which limits sideways movements.

From this one can guess that they weren't pursuit predators and needed to ambush their prey. What exactly that was has been inferred based on tooth wear. Basically, the teeth of Pachycetus show a lot of abrasion and wear, not dissimlar to what is seen in modern orcas that feed on sharks and rays. And low and behold, sharks are really common in the same strata that Pachycetus shows up in. Now since Antaecetus had way more gracile teeth, its thought that it probably fed on less well protected animals like squids and fish.

Below: Pachycetus/Basilotritus catching a fish by @knuppitalism-with-ue

The relationship between pachycetines and other basilosaurids is wonky, again no thanks due to Pachycetus itself being very poorly known. Some studies have suggested that they were a very early branching off-shoot, in part due to their prominent hip bones, but in the most recent study to include them, the description of Tutcetus, they surprisingly came out as not just the most derived basilosaurids but as the immediate sister group to Neoceti, which includes all modern whales. Regardless, in both instances they seem to clade closely with Supayacetus, a small basilosaurid from Peru.

And now for the part that is the most tedious. Taxonomy and history.

Remains of pachycetines have been known for a while and were first described as early as 1873 by Russian scientists. To put into perspective how old that is. The material's history in science predates both World Wars, the collapse of the Russian Empire and even the reign of Tsar Nicholas II. Now initially the idea was to name the animal Zeuglodon rossicum, but the person doing the actual describing changed that to Zeuglodon paulsonii reasoning that it would eventually be found outside of Russia (something that aged beautifully given that Ukraine would eventually become independent).

And this is where the confusion starts to unfold. Because at the same time people unearthed pachycetine fossils in Germany too, which would come be given the name Pachycetus (thick whale) and be established as two species. Pachycetus robustus and Pachycetus humilis, both thought to be baleen whales.

Pictured below: Pierre-Joseph van Beneden who coined Pachycetus and Johann Friedrich Brandt who described Zeuglodon paulsonii. Beneden easily has the better beard.

These latter two names however were later rejected in 1935 by Kuhn and lumped into other species, whereas Zeuglodon paulsonii was elevated to a full on new genus by Remington Kellogg in 1936. For those curious, Platyosphys means "broad loin", in combination with the species "Paulson's broad loin" to the amusement of some friends of mine.

And then people stopped caring and we have a nearly 70 year research gap. Eventually Mark D. Uhen found fossil material in the United States, but interpreted those fossils as being part of the genus Eocetus, naming them Eocetus wardii, a move that many following researchers disagreed with.

Then in 2001 a new species of Platyosphys, P. einori, was named. It's bad, moving on. More importantly, we got the works of Gol'din and Zvonok, who attempted to bring some clarity into the whole thing. To do so they rejected the name Platyosphys on account of the holotype having been lost sometime in WW2 and picked out much better fossil material to coin the genus Basilotritus ("the third king" in allusion to Basilosaurus "king lizard" and Basiloterus "the other king", isn't etymology fun?). They erected the type species Basilotritus uheni and then proclaimed Eocetus wardii to also belong into this genus, making it Basilotritus wardii.

This move was however not followed by other researchers. Gingerich and Zhouri maintained that regardless of being lost, Platyosphys is still valid and can be sufficiently diagnosed by the original drawings from the 19th and early 20th century. And to take a step further they added a new species, Platyosphys aithai (weird, why does that name sound familiar).

Then Van Vliet came and connected all these dots I've set up so far, noting that the fossils of Platyosphys are nearly identical to those of Pachycetus. This lead to the fun little thing were "paulsonii", applied first to Zeuglodon in the 1870s, takes priority over "robustus", coined just a few years later, BUT, the genus name Pachycetus easily predates Platyosphys by a good 60 years. Subsequently, the two were combined. Platyosphys paulsonii and Pachycetus robustus became Pachycetus paulsonii (simplified*). Van Vliet then deemed humilis to be some other whale and carried over Basilotritus uheni, Basilotritus wardii and Platyosphys aithai into the genus Pachycetus. *Technically Pachycetus robustus was tentatively kept as distinct only because of how poorly preserved it was, making comparisson not really possible.

Then finally in the most recent paper explicitly dealing with this group, Gingerich and Zhouri came back, killed off P. robustus for good, sunk Pachycetus uheni into Pachycetus paulsonii for good measure and decided to elevate Pachycetus aithai to genus status after finding a much better second skeleton, coining Antaecetus (after the giant of Greek myth).

And that's were we are right now. Three species in two genera, but only one of them is actually any good. So perhaps at some point in the future we might see some further revisions on that whole mess and who knows, perhaps Basilotritus makes a glorious comeback.

To conclude, sorry about the lack of images, despite the ample history theres just not much good material aside from that one Antaecetus fossil and I didn't want to include 5 different drawings in lateral view. Obligatory Wikipedia links: Pachycetinae - Wikipedia Antaecetus - Wikipedia Pachycetus - Wikipedia

Ideally Supayacetus will be the next whale I tackle, distractions and other projects not withstanding (who knows maybe I'll finally finish Quinkana)

[leaping-laelaps-art]

I do not usually post WIPs, but I am happy with this one. The newly described basilosaurid Perucetus colossus (i.e., Chonkocetus the Large), contender for the title of heaviest known animal.

Missing parts (i.e., most of the animal, as customary for fossil vertebrates) based on Basilosaurus spp., Dorudon atrox, modern whales (Neoceti), and sirenians.

[conkreetmonkey]

One of my favorite crack theories is that the Loch Ness monster is a dinosaur ghost, and that's why no hard evidence can be found of it's physical presence within the lake and cameras tend to "conveniently" go staticky/blurry or malfunction altogether when it appears.

We could apply this to most cryptids if we were crazy enough, really.

Sasquatches are the ghosts of early humans that lived before we had lost our fur.

All lake monsters and sea serpents are the ghosts of long-extinct aquatic animals such as plesiosaurs and dorudons.

The mokele-mbembe is a ghost sauropod, and the legend about it cursing those who eat its flesh is true because it's a vengeful type of ghost, perhaps angry that it was eaten by carnivores in life, or that mammals inherited an earth it feels robbed of.

All cryptids that are mundane animals but of extraordinary size are the ghosts of ice age megafauna.

idk what Chupacabras could be but they're probably ghosts idk.

You get it. We can stretch this as far as we want, and get as ridiculous as we want with it. It's prime pseudoscience; easy to rationalize evidence for, impossible to disprove, and as annoying a theory as you want it to be.

[tired-inyxe]

Ok so

uhh

i didnt plan to do any more tonight

…

I did 3 more

Cass: jaekelopterus rhenaniae

ref 1 ref 2

Steph: Dorudon atrox

ref 1 ref 2

Tim: Velociraptor mongoliensis

ref 1 ref 2 (go check out more of Fred Wierums work! Ofc check out all the other artists but he’s my favorite and I absolutely love his stuff)

Prompt:

The Bat Family as shifters.

But they’re all some extinct animal.

[makairodonx]

Unleash the Beasts: Part One

A collection of animals from the Paleocene to Eocene, lasting from 56-33 million years ago, from bottom to top: Arctocyon primaevus, Barylambda feberi, Gastornis geiselensis, Propaleotherium hassiacum, Uintatherium anceps, Ambulocetus natans, Godinotia neglecta, Leptictidium auderiense, Andrewsarchus mongoliensis, Moeritherium andrewsi, Arsinoitherium zitteli, Basilosaurus isis, Dorudon atrox, Embolotherium andrewsi, Megacerops coloradensis, and Apidium phiomense

[luxudus]

Merfolk in the Trail of Cryptids (for @jennywolfgal)

woah hey i wasnt expecting to have participated in mermay bet here i am now. This is for @jennywolfgal and her project the Trail of Cryptids which i talked about awhile ago with her dragons. enjoy!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Another group of species endemic to this alternate earth are the legendary Merfolk. Trident wielding Half-man half-fish people of the sea of the myths in our world. The merfolk here aren’t humans or hominids, nor are they even great apes. But instead they are a sister-clade of the family Cebidae. They are related to the Capuchin monkeys of central and south America.

They split off 10 million years ago with a similar evolutionary history to the cetaceans. Allowing an evolution of similar extremeness akin to the time between Pakicetus and Dorudon.

Icthypithicids contain a variety of aquatic monkey species. True merfolk belong in the genus Meralosapiens. With some species inhabiting the mediteranean, coast of east Europe, and their ancestral ground the Caribbean with a leaner build adorned in less fat.

To start off physically, They are like Cetaceans, kind of. their tail extended to an extreme degree to swim. Unlike cetaceans and like some ancient artwork of mermaids of our earth. Their legs still remain useful to swim and hold onto partners. Their arms freed up, remain as manipulators. They remain folded to reduce drag. Which lets them hold onto large objects and young merfolk when breastfeeding.

Uniquely they have a full head of hair like humans in spite of the drag created. This hair is maintained and kept healthy through grooming with the aid of two serrated claws on the lower half of their hand. Their teeth are tipped with canines and slowly become more trident shaped further back. Which they use to flush water out of their mouth. And Lastly their nostrils can completely close like a seal, and are at the very front of the face to ensure they breach the water first.

Ecologically, they are mostly carnivorous. They eat a wide array of fish, squid, and other small marine life. They take a particular liking to seaweeds and copepods, which they use their trident teeth to filter them out of the water. They take so much of a liking to copepods they will even follow their vertical migration.

They are quite social and live in family pods. Like mentioned earlier they will groom each other to strengthen social bonds. While most Icthypithicids are comparable in intelligence to their capuchin cousins. Meralaosapiens are fully sophont organisms that have the capacity for understanding and creating art and complex language. Technologically they are comparable to neolithic humans. Most populations use stone tools or other organisms slightly bred for more cooperation, living tools if you will. While other populations scavenge for more advanced tools left behind by humans.

Overall they are neutral to humans. Often keeping their distance or outright hiding from humans. Some more aggressive merfolk will attack or even hunt humans as a source of preyluring them in with their locks of hair. Which is believed to have arisen from a few merfolk cultures going through famine and growing desperate for food, eventually looking to their cousins beyond the water.

And of course there are others naturally curious of their terrestrial relatives and will frequently come up to human divers, even attempting to communicate with them. The future is uncertain, but hopefully the humanity of this earth will treat these people with respect and maybe even lend them a hand.

[cambriancutie]

new dorudon friend ??