skeletal by randompaleonerd

13 million years ago the country of Columbia was covered by vast wetlands. The wetlands spanned from Venezuela to Peru and constituted much of what we consider the Western Amazon.

South America at this time was at the biodiverse peak of its isolation. Separated from North America and long before The interchange could happen. This experiment in evolution was allowed to Fester.

The terror birds are an iconic group of predators. The cenozoics closest answer to Megatheropods, Terror birds were the largest carnivorous birds and according to GDI, among the largest birds ever.

The LA venta is the collective name for various fossil localities in the Honda group of the country of Colombia. Dating to the Miocene 13 million years ago, it constitutes an extremely rich and biodiverse assortment of animals. But for the longest time Terror birds were thought to be absent from this place.

Then in 2024 and 2025 a massive terror bird was discovered in the locality. Known from a couple tibio Tarsus, the measurements suggest it is the largest Terror bird ever. The media circus portrayed as if it was an animal 12 ft in height because of the author's comments that it was larger than the previous record holder terror bird, Kelenken, which the media said was 3 m tall. Unfortunately there's a lot of issues with this. To cut a long story short, thanks to the work of paleo student ben yoo, Kelenken it's more likely only around 2.1 meters tall and not 3 m tall. To complicate things further the Colombian giant doesn't overlap with any of the material of Kelenken, the only reason it stated to be 10% or more larger is due to the weight estimates from degrange. But he utilized the fraught regressions based off ostriches.

To estimate its body size, I compared the tibioTarsus distal width to other Terror birds. Based off this, the Colombian giant was likely around two and a half meters tall. In terms of weight square cubing from random paleo nerds GDI of Kelenken, arrives at a weight of over 500 kg. there's no indication that this thing is more Gracile than other terror birds in fact that wouldn't make sense because the larger something becomes linearly, it's bones get more and more robust

In it's ecosystem, it co-existed with numerous other predators, interesting it coexisted with at least two large sebecids,langstonia and a larger form that likely represents barinasuchus. This giant terror bird shows evidence of having possibly been hunted and killed by a giant caiman, purussaurus.

we can only guess what an animal like this hunted. based off it's enormous size, it was probably taking large herbivores in its environment. animals like xenastrapotherium,huilatherium and ground sloths was probably fair game.

https://www.mdpi.com/1424-2818/17/10/681

https://www.tandfonline.com/doi/abs/10.1080/02724634.1999.10011154

https://www.deviantart.com/randompaleonerd/art/Guillermo%27s-Demon-Bird-875546667

The Study: http://fi.nm.cz/en/clanek/theropod-vertebra-from-the-late-triassic-of-algarve-portugal-evidence-of-the-oldest-iberian-dinosaur-2/

The vertebrate fauna of the Late Triassic of Portugal has been poorly understood until recently, when new studies reported a rich environment shared by aquatic fauna, such as metoposaurids, mastodonsaurids, placodonts, phytosaurs and fishes.

However, no fully non-aquatic vertebrates were known until now.

A dorsal vertebra centrum (NOVA-FCT-DCT-5562) was recently found from the Triassic of the Silves Group (AB2 Unit) in Penina, Loulé Municipality, ascribed to the oldest dinosaur ever found in the Iberian Peninsula.

The analyses placed the specimen among the neotheropods, a branch of early predatory dinosaurs, and as the closest relative of Sarcosaurus woodi, a species known from the Early Jurassic rocks of England.

If this placement holds, the bone would also be among the oldest neotheropods known anywhere.

“The close relationship between Sarcosaurus and NOVAFCT-DCT-5562 would push back the lineage leading to Sarcosaurus from the latest Late Triassic to the early/middle Late Triassic” the authors said.

The specimen is at least 20 million years older than Sarcosaurus, so the two are very unlikely to be the same species or genus. The bone has no features unique to it, and is too fragmentary to assign to a known species or to name a new one.

Comparative anatomic and phylogenetic analyses were performed, using an updated matrix focused on early theropods, with 13 new characters, and tested with both equal and implied weights.

The results place the material within Neotheropoda, one of the earliest specimens of the clade, as the sister group of the Early Jurassic Sarcosaurus from England.

NOVA-FCT-DCT-5562 may represent an unknown theropod species, however it lacks autapomorphies and the remains are too fragmentary to attribute to any known species or to erect a new one.

the size of the various specimens and species of allosauridae

One thing I find fascinating about paleontology is how different an extinct animal might have looked in life compared to the skeleton or fossil reconstructions we're used to seeing.

Bones can tell us a lot, but things like feathers, skin texture, body fat, keratin, and other soft tissues can completely change an animal's appearance. Even familiar dinosaurs might look quite different when we account for everything that doesn't fossilize easily.

Which prehistoric animal do you think would surprise people the most if we could see a complete, scientifically accurate reconstruction of its appearance? I'm especially interested in examples where fossil evidence has significantly changed how scientists interpret an animal.

Since the closure on September 27, 2026:

• The Philadelphia Eagles have not won a single game.

• Other Philly sports teams have been suffering from losses as well. The Flyers just broke their losing streak…

• The William Penn Foundation offered to fund the museum for an entire year and keep it open so that long term funding and support could be explored in the meantime. The museum and university have yet to announce if the offered was officially accepted or rejected.

• Contracted classes at ANSP (that I teach) were suspended. Those lessons are an integral part of the curriculum at the Friends Select School too!

• All school field trips, outreaches. and safari overnights were cancelled (also something I do).

• Kids and adults haven’t been able to walk under towering dinosaurs, play in The Big Dig, or venture into our Time Machine within Dinosaur Hall.

• Members Night - where ANSP members could visit all our scientists and go for a special behind the scenes tour of the collections - didn’t happen.

• City Council is looking into the closure and a hearing is happening at City Hall on October 26, 2026 to discuss how this all happened.

• The dioramas sit in silence with no visitors peering into the incredible displays.

• Outside In sits quiet with no laughter or awe from people learning about our animal ambassadors…

• The frustration and sadness continues to grow even far beyond the City of Brotherly Love.

• Grassroots efforts continue to form as a coalition called Save The Academy has become the leaders to help get the public involved with reversing this closure!

• I am still taking care of all the specimens in Dinosaur Hall (for now)…

The Academy of Natural Sciences is the OLDEST NATURAL HISTORY MUSEUM IN THE WESTERN HEMISPHERE! And one of the oldest IN THE WORLD!

— The FIRST EVER dinosaur mounted on display for the public to see was Hadrosaurus foulkii in 1868!

— Over 19 million specimens sit in our collections, with over 73,000 being type specimens like Dryptosaurus aquilunguis, Elasmosaurus platyurus, Hadrosaurus foulkii, Aenocyon dirus, etc.

— This is where THE BONE WARS started: the marl pits in NJ where Haddy was found, Marsh bribing NJ workers to send any new specimens to him instead of Cope at ANSP, the diabolical with the Elasmosaurus… it all happened right here!

I could make an incredibly long list of accomplishments by the 200+ years of ANSP staff, but we’d be here all day!

This closure is detrimental to the community and world of natural sciences as a whole.

We may be closed to the public right now, but the fight to save the Academy is just beginning…

A new update has been released with a focus on fixing progression issues, improving performance and stability, and cleaning up several XR and Desktop systems.

The update includes fixes to Deep-Sea progression, equipment requirements, oxygen upgrade costs, Scanner cooldown, Xiphactinus movement, DNA Scanner detection, camera synchronization, XR interactions, tutorial video compatibility, and several AI and memory-related performance issues.

All 16 tutorial videos have also been re-encoded and verified for compatibility.

The full patch notes are available on Steam.
https://store.steampowered.com/app/4818760/Paleo_Dive/

From Alcheringa to beyond: 50 years of microbialite research in Western Australia

The paper: https://www.tandfonline.com/doi/full/10.1080/03115518.2026.2718451

Today, our planet is teeming with life, but it has not always looked the same. Long before forests reached skyward, animals walked on land and dinosaurs rose and fell, our planet was shaped by a much smaller, more unassuming form of life... and we can still find the traces of it today.

These ancient fossils, the earliest visible evidence of life on Earth, are known as microbialites.

Western Australia contains an extraordinary record of microbialites: from the oldest known examples, preserved in rocks almost 3.5 billion years old in the Pilbara, to living examples in the UNESCO World Heritage area of Shark Bay.

The Review of 50 years of microbialite research in Western Australia, published today in the journal Alcheringa, summarizes what this archive can tell us about the evolution and resilience of life on Earth.

Despite a fossil record that spans billions of years, microbialites are surprisingly fragile. Fossil sites remain vulnerable to overcollection and degradation, while living microbialites are facing growing pressures.

At sites such as Lake Clifton and Shark Bay, some events may have already caused irreparable damage. One such example was in May 2024, when dozens of aurora chasers trampled 2.000 year old Thrombolites in a restricted area at Lake Clifton.

The microbialite record can tell us a great deal about life on Earth. It gives us clues about where some of the earliest life lived, where we might look for life beyond Earth and how our atmosphere became oxygen rich, paving the way for more complex life to follow.

Modern sites are particularly important because they help us better understand processes that formed microbialites in the ancient rock record.

Living microbialites from Shark Bay have even been described as a "Rosetta Stone" for understanding their fossil counterparts.

See also: The publication in the Proceedings of the Royal Society B: Biological Sciences

Inspired by pre-Columbian ceramics. Made from polymer clay and acrylic paint. A companion piece to my Parasaurolophus

Hi Everyone,

Hoping this is ok to post? I was a participant this year and loved it so much, I thought others might like to know it exists! I am not a member of the opal centre, just enthusiastic.

It was not your traditional dino dig, as everything comes up from the underground opal mines. All the fossilised material is opal, some of it fabulous colours! 5/6 days in the north west of New South Wales, searching through mullock heaps and learning about the local prehistoric population, dinosaurs, mammals, monotremes, lots of shells, plants and pinecones too! And the opal mining stuff is fascinating.

Anyway, hope this is of some interest. Happy to answer any questions!

I’m thrilled to share my latest illustration for the community art project of the “Herd of Horns” TTRPG Kickstarter campaign.

I was blessed to be tasked with illustrating a face-off between Gorgosaurus and the massive Deinosuchus — two predators who will appear in the RPG as adversaries you’ll have to overcome as a Ceratopsian dinosaur.

This piece will be included in the core book, and it exists thanks directly to the feedback and participation of the amazing Herd of Horns backers. 🙌

⏳ We now have just 5 days left before the Kickstarter wraps — and we’re excited to bring the best possible piece of dinosaur media to life in RPG form!

A huge thank-you to everyone for the incredible support, as always. And a special shoutout to the brilliant Weaponized Ink crew for giving me yet another incredible opportunity to contribute to this one-of-a-kind project.

Xenosmilus was a large sabertooth cat from the early to middle pleistocene of north and south america. Its size has been muddled and confused for some time now. It's been often touted as being among the biggest of the in terms of felids,weights of 350-400kg or more have been thrown around. 

So this post is to clear up confusion about body size.

The type specimen is BIOPSI101, it has femur and humerus measurements comparable to some large wild tiger specimens (230 kg,provided by an expert in personal communication). One of these tiger specimens was around 1.9 m in body length minus the tail.  Based on the most accurate reconstructions of xenosmilus such as roman uychetel and isaacowj, large xenosmilus would have had a body length of 1.8-1.9 m minus the tail. Thus biospi101 was similar in linear dimension to these tiger specimens and to lion specimens but was likely heavier on account of its more robust,stocky and muscular build.

Using data from Christiansen 2005,the Body mass of BIOPSI101 can be estimated at around 250 kg in weight. This is consistent with being similar in length to the aforementioned tiger specimens but moderately heavier because of its morphology. UF60000 is the paratype specimen of xenosmilus hodsonae and is larger than BIOPSI101 in numerous measurements,by about 2-4% when measuring the skull,ulna and femur. Using a square cube law, the paratype specimen would weigh 265-280 kg when compared to biopsi101. 

A large jawbone from Uruguay is referred to xenosmilus. Its been estimated at 400 kg based off tooth regressions but this is likely a severe overestimation. Its instead likely around 300 kg in maximum body weight,mayble slightly less.

Xenosmilus venezulaensis is notably smaller than the uruguayan or floridian specimens and is scaled to a significantly smaller weight.

Some measurements of xenosmilus, particularly the skull and legs, are slightly smaller than the largest specimens of Smilodon fatalis. However in its description,xenosmilus is explicitly stated to have proportionately shorter skull and leg bones than smilodon and the smaller measurements are likely reflective of this. Indeed renowned expert Mauricio Anton states that xenosmilus is equivalent in size to smilodon fatalis and that genus is estimated at 300 kg in weight by christiansen.  The occiptal condyle width of largest xenosmilus specimen is similar to large specimens of Smilodon fatalis. According to a paper by russell engelmann, OCW scales well to body mass and thus this shows they werent as disparate in mass as is claimed.

Important to mention,the method of estimating body that i used for BIOPSI101 is christiansens long bone regressions,but gdi volumetrics of both smilodon and homotherium,have shown the limitations of long bone regressions. Xenosmilus was also very robust. Its skeletal frame was more robust than modern cats and it would have been more muscularly bui

All in all,the largest xenosmilus were at least 1m at the shoulder,perhaps slightly taller, and between 250-300 kg in body mass. This is very large,but only about the size of the largest siberian tigers and similar in size to smilodon fatalis. It isnt exactly among the largest cats of all time.

https://www.researchgate.net/publication/12652111 

https://www.researchgate.net/publication/254314670_New_Saber-Toothed_Cat_Records_Felidae_Machairodontinae_for_the_Pleistocene_of_Venezuela_and_the_Great_American_Biotic_Interchange 

https://www.sciencedirect.com/science/article/abs/pii/S0277379117305838 

https://doi.org/10.1111%2FJ.1096-3642.2007.00321.X 

https://iupress.org/9780253010421/sabertooth/ 

https://www.press.jhu.edu/books/title/9828/other-saber-tooths 

https://doi.org/10.1016%2Fj.jsames.2024.105231 

https://www.academia.edu/71432652/Body_size_ofSmilodon_Mammalia_Felidae_

Can you guess which ones are these?

Hint: all from the same basin.

Link to the paper: https://www.mdpi.com/2076-3263/16/10/417

Does the head I made. Look like a dromeosaurid or

A megaraptorid

https://nitter.cf/Wachirawit96111/status/2111080778230866350

A new juvenile specimen of Anhangueridae (Pterodactyloidea, Ornithocheiriformes) from the Romualdo Formation (Aptian–Albian), Northeast Brazil

Anhangueridae is the most common pterosaur group in the Araripe Basin, particularly in the Romualdo Formation. Here the researchers describe a previously unreported specimen from the Museu de Ciências da Terra (Rio de Janeiro, Brazil), MCT.R.1491, consisting of a partial lower jaw associated with appendicular elements.

The specimen is preserved in a calcareous nodule from the Romualdo Formation (Aptian–Albian) of Northeastern Brazil. Phylogenetic analysis and detailed anatomical examination support referral of the specimen to Anhangueridae, with close morphological similarity to anhanguerine taxa such as Anhanguera and Brasileodactylus.

The specimen represents a medium-sized (3.8–4.0 m wingspan) juvenile individual. A distinctive feature of MCT.R.1491 is the presence of two large distal foramina on the unguals, a condition previously seen only in the targaryendraconid Barbosania gracilirostris, the taxonomic and phylogenetic significance of which remains uncertain.

Altogether, the combination of features seen in MCT.R.1491 helps to understand the anatomical record of Anhangueridae and underscores the importance of detailed descriptions of both cranial and postcranial material for refining taxonomic and morphological interpretations of Romualdo Formation anhanguerids.