#gondwana

[derived-centrosaur]

Spec-Dinovember Day 1: Short King, an apex predator of an ecosystem composed of only small creatures

Somewhere in the Southern Ocean, between Australia, Antarctica and Zealandia, islands formed from the latter's rifting play host to a diminutive island fauna. On this archipelago titanosaurs have diminished greatly in size due to lesser amount of available forage. Megaraptorans have shrunk as well, and the resident top order carnivore of these islands is about as large as a coyote or jackal. While the titansoaurs have changed in proportions and armor in response to their new role in the ecosystem, the megaraptorans have needed to change very little. Their short, fuzzy coating of feathers has become a bit shaggier and fluffier to insulate them from the chilly Antarctic winds blowing in from the south, and they are more sprightly in their movements. Their bauplan works well across size ranges!

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My initial thought of this prompt was "where would you get an ecosystem of little guys?" and obviously that would be islands. So then who's the top-order carnivore? On Hațeg Island that was Hatzegopteryx, so I wanted to do something other than a pterosaur, though an an ornithocheirid in that role here would be interesting.

I wanted to put more creatures in the pic but that would've eaten up a lot more time, though I did put them in the silhouettes. Parankylosaurs were pretty small even on the mainland so I don't think they'd shrink much in this scenario. Elasmarians on the other hand I think could experience some Island-gigantism, which would be cool to see one outsizing the local sauropods.

[rebeccathenaturalist]

A 108-Million-Year-Old Bone Just Rewrote Our Understanding of the World’s Strangest Mammal

New fossil evidence suggests echidnas evolved from a water-dwelling ancestor, not a land-based one. The bone structure closely resembles tha

Our existing monotremes, the four species of echnidna and the platypus, don't seem like they have all that much in common besides their basic monotreme traits like egg-laying and milk production. Echidnas are spiny and relatively slow-moving as they trundle across the land, while platypodes (platypuses? platypi?) are semi-aquatic and quite adept at swimming.

Scientists have long assumed that the last common ancestor of these species was a terrestrial mammal, since semi-aquatic and aquatic mammals tend to stay in the water once they've evolved the proper adaptations. So when this little fossil monotreme humerus discovered in southeastern Australia was examined in further detail, it suggested a much more unusual evolutionary path.

The bone was much more robust than expected, more resembling the heavy bones of the platypus than the comparatively gracile bones of the echidnas. Denser bones help the semi-aquatic platypodes to stay submerged in water with less effort, but they would be a detriment to a relatively small land animal.

What this suggests is that the last common ancestor of today's monotremes may have been semi-aquatic. The platypus's origins wouldn't be surprising, but it is exceedingly rare for a mammal lineage that headed into the water to then return to a fully terrestrial existence later on.

Of course, there are a lot of ifs involved. We don't know for sure that the newly found stem-monotreme humerus represents the direct ancestors of modern monotremes. Even as much as paleontologists have learned about the living beings of the past and the ecosystems they inhabited, it is likely that less than one tenth of one percent of all species that have ever lived ended up fossilized. We can only guess at the biodiversity we don't have direct evidence for, and it may be that another species living at the same time as the stem-monotreme was the actual last common ancestor of today's monotremes.

Still, every species we do manage to uncover represents another line in the grand story of life on Earth, and this finding may have given us a view into an evolutionary track that is a little less uncommon than we thought.

[diemelusine]

Art created by the Gondi people of central India. https://commons.wikimedia.org/wiki/User:Sumita_Roy_Dutta

[mon-nid]

[hasellia]

Qantassaurus intrepidus Body Study Based on the skeletal model from the Australian Museum / Wikipedia image for Quantassaurus.

Oops, dino hyperfixation! I didn't check for the correct musculature, so don't take this as super accurate. The background was also just thrown together quickly.

[nathan-e-rogers]

Spinophorosaurus Middle Jurassic, 167 Ma, Africa

The discovery and study of this sauropod illustrate the scientific process; this dinosaur was first thought to have spikes on its tail, and the low posture often seen in traditional depictions of sauropods. After innovative research in 2020 involving 3D models of the skeleton, the new Spinophorosaurus reconstruction may have implications for understanding the life posture of other dinosaurs as well.

Read the paper here: https://www.nature.com/articles/s41598-020-63439-0.pdf

I made this using Blender, my own photos, and Photoshop digital painting. Not for use in AI training datasets. Thanks!

[pesura]

album stream: Hania Rani - Sentimental Value (Gondwana, 2026)

[stavrosskundromichalis]

Oldest sea-going reptile from the Southern Hemisphere!

New paper by Benjamin Kear et al. (with artwork by yours truly, first time for a scientific find🤩) that documents a nothosaur that swam along the shores of an ancient polar super-ocean covering what is now the South Island of Aotearoa New Zealand 246 million years ago. This discovery reveals the early global radiation of marine reptiles, which as the authors show probably dispersed across both the southern and northern high-latitudes to dominate the world’s oceans at the dawn of the Age of Dinosaurs. The paper is open access and can be read in the scientific journal Current Biology.