Luis Collantes

Archaeocyatha were sessile, filter-feeding, calcareous, sponge-like organisms, characterized by a conical, vase-shaped, or cylindrical skeleton. Their structure consisted of two porous, nested calcite cones (inner and outer walls) separated by a space called the intervallum, which contained vertical plates (septa, taeniae) or horizontal plates (tabulae). Root-like structures at the bottom (holdfast) secured them in place. https://alchetron.com/Archaeocyatha

Primary reef builders during the Neoproterozoic (Ediacaran) and early Paleozoic (Cambrian, Ordovician, and Silurian). The Neoproterozoic is primarily dominated by microbial organisms including the stromatolites (see Geology Bites episode with Martin Van Kranendonk). The Cambrian is dominated by a variety of sponge organisms including the archaeocyaths. In the Ordovician and Silurian, coral and stromatoporoid species became the dominant reef builders. The red star denotes the approximate interval of the Mongolian reefs where some of the best-preserved archaeocyath reefs are found. Cordie, D. R. et al. (2019), Palaeogeography, Palaeoclimatology, Palaeoecology 514, 206

Phosphatized internal molds of archaeocyaths from the upper Salaagol Formation in southwestern Mongolia. Pruss, S. B. et al. (2019), Palaeogeography, Palaeoclimatology, Palaeoecology 513, 166

Modern calcareous sponges provide the closest analog to the archaeocyaths. https://www.inaturalist.org/taxa/60583-Calcarea

🧪⚒️ I just posted an episode on the first reef builders with Sara Pruss of Smith College. These were sponges with skeletons. Their reefs fostered biodiversity, contributing to the Cambrian explosion. Listen, and give me feedback. #paleontology #earthscience

This is figure 2, which shows non-bilaterian metazoans, deuterostomes and problematic taxa from the Huayuan biota.

A paper in Nature describes a collection of soft‑bodied fossils discovered in a quarry in China, dating to around 512 million years ago. The Huayuan biota contains 153 animal species from 16 major groups, of which 59% are previously undiscovered species. go.nature.com/49KUOdw #Paleosky 🧪

🚨New paper🚨

A new article in Swiss Journal of Palaeontology, led by Dr. Lorenzo Lustri (Yunnan University), in which we discuss the affinities of two enigmatic Ordovician arthropods from the Czech Republic by means of elliptical Fourier analysis.

Link: sjp.pensoft.net/article/1791...

The flounder effect: disparities in taxonomic and ecological study intensity across extant and fossil marine organisms hamper conservation - npj Biodiversity npj Biodiversity - The flounder effect: disparities in taxonomic and ecological study intensity across extant and fossil marine organisms hamper conservation

Excited to present the flounder effect - how our biases in sampling and worker effort impact our view of organisms.

A long term collaboration with @fossilsndcoffee.bsky.social, @bigfacecats.bsky.social, Jon Hendricks, and Curtis Congreve!

#FossilFriday ⚒️🧪

www.nature.com/articles/s44...

Four camera-type eyes in the earliest vertebrates from the Cambrian Period Nature - Early vertebrates, particularly myllokunmingids, possessed four camera-type eyes (a pair of lateral eyes and pineal and parapineal organs), which indicates that these structures functioned...

A Chengjiang fossil that made it to Nature! 🧪

Four camera-type eyes in the earliest vertebrates from the Cambrian Period,
by Lei et al.

Our paper on the mysterious Devonian organism Prototaxites has now finally been published! See the paper here (www.science.org/doi/10.1126/...) and our explainer thread below!
Prototaxites reconstruction by Matt Humpage

#TrilobiteTuesday. Deiphon barrandei from the Silurian Wenlock Limestone of Dudley, showing the dome-shaped glabella particularly well. Specimen 3 cm across.

#MolluscMonday Neither nautiloid nor ammonite, this is an early ammonoid, Timanites keyserlingi (Order Agoniatitida) of Devonian age. The large body chamber in this specimen is sediment-filled, whereas the chambers forming the phragmocone are infilled with calcite.

Jimbacrinus is a really strange, alien looking crinoid. Permian aged crinoids are uncommon. These are from Australia.

Keep creating and sharing your art.

#FossilFriday #SciArt

#FossilFriday Graptolites are extremely useful as zonal fossils in the Ordovician and Silurian. Some look like pencil marks but better preserved examples, like this Monograptus priodon from the Wenlock of Scotland, resemble miniature saw blades.

Photograph of a buff-coloured limestone with many archaeocyathid fossils as circular features.

#FossilFriday: archaeocyathid reef mound in the Lower Cambrian Labrador Group Forteau Formation on the Great Northern Peninsula, Western Newfoundland.

OU Undergraduate Publishes New Research on Ancient Fossils Housed in the Oklahoma Museum of Natural History In a rare achievement for an undergraduate student, Colby Higdon, a geology major on the paleontology track with the University of Oklahoma has published original paleontological research conducted at...

"OU undergraduate publishes new research on ancient fossils housed in the Oklahoma Museum of Natural History" @oupaleobiology.bsky.social 🧪

When the Levee Breaks - Taphonomy in Action YouTube video by Earth Encompassed

The first chapter of my PhD is published! If you're interested in how bones can be buried in floods, check it out in Paleobiology! (doi:10.1017/pab.2025.10087) And if you want to see the full scale experiments we ran, I did a summary video featuring a cover of When the Levee Breaks! #Taphonomy

On the left is the positive split: A brown trilobite fossil is protruding from the surface of a beige stone. The trilobite has an oval-shaped body with a ribbed carapace; its head is smooth and rounded; its hind-end has a sharp point. On the right is the negative split. An indentation of the trilobite fossil can be seen in the stone; there's also a sea shell on the upper-half of the stone.

Happy Trilobite Tuesday! Pictured is a 430 million-year-old Silurian Dalmanites caudatus from England. This 2.5-in- (6.4-cm-) long specimen was preserved in rock that, when carefully opened, revealed positive and negative splits! 🌗

Mass extinction triggered the early radiations of jawed vertebrates and their jawless relatives (gnathostomes) A mass extinction 445 million years ago triggered the rapid rise of armored and jawed vertebrates.

Mass extinction triggered the early radiations of jawed vertebrates and their jawless relatives (gnathostomes) | Science Advances www.science.org/doi/10.1126/...

15. Una revista por y para aficionados a los artrópodos. Con Sandra Ruzafa Pérez - Cascando de Ciencia - Podcast en iVoox Escucha este episodio de Cascando de Ciencia gratis en iVoox. Vivimos rodeados de divulgación científica, charlas, podcast, programas de radio como éste, revistas, etc. Mucha de ella está especializad...

Es triste volver a la rutina y enero puede parecer muy largo, por eso os traemos un nuevo episodio de Cascando de Ciencia para que paséis un buen rato descubriendo una revista gratuita dedicada a artrópodos y arácnidos. Entrevistamos a Sandra Ruzafa, la directora de Mundo Artrópodo

Fuck it.

It's not Friday, but I'm going to share fossils.

This is Porocrinus, an echinoderm from the Ordovician Maquoketa formation near Eldorado, Iowa.

The arms are missing, but the calyx is very unique.

It looks like some ammonites made through K/Pg extinction!

Ammonite survival across the
Cretaceous–Paleogene boundary
confirmed by new data from
Denmark

www.nature.com/articles/s41...

Fossil worm traces in a floor slab

The floor of the gift shop in Birr castle. It is made up of slabs covered in fossil traces.

Amazing trace fossils in the floor slabs of the Birr Castle's gift shop, Ireland.

In addition to spectacular volcanic structures, this territory also features intense hydrothermal activity, such as that which can be observed in Rèhǎi (熱海).

I’ve spent this week traveling through Baoshan county, in Yunnan province, and I’ve had the opportunity to enjoy the Tengchong Volcanic and Geothermal National Park, on the border with Myanmar; a Cenozoic volcanic area formed by the Indo-Asian continental collision.

Multiple fossil crinoids displayed.

Plate of 3 crinoid fossils.

On the 12th day of fossils, my true love gave to me...

12 Crawfordsville echinoderms!

Crawfordsville, Indiana is home to the Mississippian aged Edwardsville formation, famous for an amazing diversity and density of crinoids. 95+ different crinoids are found here.

1/x

#12DaysofFossils

A large collection of Cambrian aged fossils

On the 11th day of fossils, my true love gave to me...

11 Cambrian fossils from the Great Basin.

The Great Basin is a large area of Utah and Nevada that was under water 500 million years ago. Life was experimenting and there's lots of strange creatures found here.

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#12DaysofFossils

Welcome back to #TrilobiteTuesday

Here is a pygidium (tail section) from a large Dalmanitid trilobite. This specimen comes from the Lower Devonian Birdsong Shale in eastern Tennessee.

Multiple examples of trilobite and arthropod gut tracts preserved from Cambrian Weeks Fm.

Some special locations preserve trilobite and arthropod soft tissue digestive systems. The gut tract is highlighted with the element phosphorus.

@cambrianlife.bsky.social described the process in this open access paper: pmc.ncbi.nlm.nih.gov/articles/PMC...

#12DaysofFossils

Fossil arthropod from the Weeks Fm of Utah.

X-ray fluorescence image of an arthropod showing the gut tract in green and body in pink

On the 2nd day of fossils, my true love gave to me...

An arthropod with 2 elements preserved.

A heavily pyritized arthropod, possibly Emeraldella brutoni, from the 500 million year old Weeks Fm. of Utah with a phosphatized gut tract. Green is phosphorus. Pink is iron.

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#12DaysofFossils

After the Greeks colonized Cyrenaica—now part of Lybia—and established settlements in the lower Nile Delta, they came to associate Zeus with the Egyptian supreme god Amun-Ra, who was often depicted with the head of a ram. The features of both deities are combined in this sculpture. Worship of Amun, called Ammon by the Greeks, also spread north to the Greek peninsula, with statues and temples erected at Delphi, Sparta, Thebes, Aphytis, and Megalopoli. The poet Pindar wrote a hymn to Ammon, which was inscribed on a triangular pillar at Thebes, where Ammon came to become the principal local deity

Zeus-Ammon. #Roman copy of a #Greek original from the late 5th century BC. The Greeks of the lower Nile Delta and Cyrenaica combined features of supreme #god Zeus with features of the #Egyptian god Amun-Ra.
Königsplatz collections. #Art

#AncientBlueSky🏺 #History

This #FossilFriday I am delighted to say that I have been awarded a @erc.europa.eu Consolidator Grant looking at selection in #Ediacaran animals. If interested in Ediacaran life, do come and chat at #palass2025 @thepalass.bsky.social

We love to fetishize "top" researchers and give them special big pots of money. But we get far more science by spreading money among all researchers (closer to the NSERC DG model). This old post is magically relevant again... scientistseessquirrel.wordpress.com/2015/05/12/w...

Thanks Harrie! I definitely wish we have the opportunity to meet soon :)