A new plesiosaur from the early Jurassic of Germany and a important missing link in plesiosaur evolution! Congratulations to the three authors, here the paper for those who haven't seen it
I have a rather personal connection to this specimen because me and Sven were on a road trip to the EAVP meeting in Munich when we came across this fossil in Bayreuth. It was quite the surprise walking into the collection and finding this, already largely out of the matrix.
It was quite funny to see Sven dive right in and after roughly 15 min of looking at it proclaiming, "pretty sure that's a new genus", I think we had a name for it already on the drive back
Franconiasaurus wasn't an apex predator, that time hadn't come yet for plesiosaurs, but it fills an important evolutionary gap between basal and more derived plesiosaur clades of the Jurassic. Here a little overview of animals that lived with it. This formation, the Jurensismergel, isn't as productive as the underlying Posidonia shale, but it's also a thinner, and less studied formation. Quite a few fossils still await a proper description or a name. These Temnodontosaurus for example.
A little background for my illustration. The Jurensismergel appears to preserve largely a deep water environment but I wanted to show the animal not in a blue void or with some dark sludge near the bottom so I gave it a patch reef to rest on, sourced from some locally available Muschelkalk. The whole presentation is very much inspired by the collection of the Museum in Bayreuth. down to the Temnodontosaurus rostrum jutting out of the ground here. Saurichthys is known from the Jurensismergel but the Dapedium and other fish were burrowed from Posidonia.
when you zoom in you can see crustaceans climbing over and cleaning the Franconiasaurs.
wanted to share two posters i made with prehistoric animals found exclusively in mexico (for now) the first one has colors based on endemic animals and the second on alebrijes
Most mosasaurs all had very similar body plans: they were streamlined scaly monitor-lizard-like marine reptiles with four rounded paddle-shaped flippers, and many of them also had large shark-like tail fins.
But Megapterygius wakayamaensis here seems to have been doing something a bit different.
Living towards the end of the Cretaceous, about 72 million years ago, in the waters covering what is now western Japan, this mosasaur was around the size of a modern orca, roughly 6m long (~20').
Unlike other known mosasaurs its flippers were huge, bigger than its own head and distinctively wing-shaped, with the back pair being larger than the front. This is an arrangement oddly reminiscent of the unrelated plesiosaurs, and may suggest a convergent sort of highly maneuverable "underwater flight" swimming ability – but unlike plesiosaurs Megapterygius also still had a powerful fluked tail, so how exactly all of its fins worked together is still unknown.
It's also the first mosasaur known to preserve potential evidence of a dorsal fin. Some of its back vertebrae show a change in orientation at the point where a fin base would be expected to be, closely resembling the vertebrae shape of cetaceans like the modern harbor porpoise.
The recently described mosasaur Jormungandr walhallaensis (what a name!) surfaces to observe an unfortunate young tyrannosaur adrift on a vegetation raft
Hupehsuchians were small marine reptiles closely related to ichthyosaurs, known only from the Early Triassic of southwestern China about 249-247 million years ago. They had toothless snouts, streamlined bodies, paddle-like limbs, and long flattened tails, along with a unique pattern of armor along their backs made up of overlapping layers of bony osteoderms.
Hupehsuchus nanchangensis was a mid-sized member of the group, about 1m long (3'3"). Newly-discovered fossils of its skull show that its long flattened snout had a distinctive gap between the bones (similar to the platypus-like snout seen in its relative Eretmorhipis) with an overall shape surprisingly convergent with that of modern baleen whales – suggesting that this hupehsuchian may have been a similar sort of filter-feeder.
Hupehsuchus skull compared to a modern minke whale
[From fig 2 & fig 3 of Fang et al (2023). First filter feeding in the Early Triassic: cranial morphological convergence between Hupehsuchus and baleen whales. BMC Ecol Evo 23, 36. https://doi.org/10.1186/s12862-023-02143-9]
Grooves in the bones along the outer edges of its upper jaws may be evidence of filtering structures similar to baleen, although with no soft-tissue preservation we don't know exactly what this would have looked like. Its slender flexible lower jaws probably also supported a large expandable throat pouch, allowing it to filter plankton out of larger volumes of water.