Tag Archives: Fossil Friday

Fossil Friday: new armless dinosaur species unearthed in Argentina

Researchers in Argentina have discovered a new — and pretty armless — species of dinosaur.

Carnotaurus sastrei, an abelisaurid relative of the new species, and probable look-alike dinosaur. Image credits Fred Wierum / Wikimedia.

Christened Guemesia ochoai, it was a species of abelisaurid, a clade of dinosaurs that roamed today’s Africa, South America, and India, and lived around 70 million years ago. Based on its age, researchers believe that this species was a close relative of the ancestors of all abelisaurids.

The animal’s partially-complete fossil skull was unearthed in Argentina and points to a unique ecosystem that developed in the area during the Late Cretaceous. The discovery is quite exciting as the area where it was found has yielded very few abelisaurid fossils, so it fills in an important piece of its historical puzzle.

Armless in Argentina

“This new dinosaur is quite unusual for its kind. It has several key characteristics that suggest that is a new species, providing important new information about an area of the world which we don’t know a lot about,” says Professor Anjali Goswami, co-author of the study describing the species and a Research Leader at the Natural History Museum of London.

“It shows that the dinosaurs that live in this region were quite different from those in other parts of Argentina, supporting the idea of distinct provinces in the Cretaceous of South America. It also shows us that there is lot more to be discovered in these areas that get less attention than some of the more famous fossil sites.”

By the time this species emerged, the ancient supercontinent of Pangaea had already begun to break apart forming Gondwana and Laurasia. The former would, in turn, split into the major continents in the Southern Hemisphere today and India.

Despite these landmasses slowly drifting apart, species could still move between them, so researchers assume that the fauna of these landmasses remained quite similar, as animals migrated between them. Abelisaurids were among these species.

Abelisaurids were top predators in their ecosystems, preying even on the mighty Titanosaurus. One of their most defining features was the front limbs; even shorter than those of the T. rex, these were virtually useless. In other words, the species did their hunting without being able to grasp, relying instead on their powerful jaws and necks to capture and subdue prey. They seem to have been quite successful at it, too: fossils of these dinosaurs have been found in rocks across Africa, South America, India, and Europe, dated all the way to the extinction of the dinosaurs 66 million years ago.

Although Argentina is well-known for abelisaur fossils (35 species have been discovered here so far), the overwhelming majority of these were discovered in Patagonia, in the country’s south. The north-western stretches of the country have yielded precious few. The newly-discovered skull joins this exclusive list.

The fossil, consisting of the braincase with the upper and back parts of the skull, was unearthed in the Los Blanquitos Formation near Amblayo, in the north of Argentina. The rocks it was encased in have been dated to between 75 and 65 million years ago. In other words, this specimen lived very close to the end-Cretaceous mass extinction, the event that wiped out the dinosaurs.

Like other abelisaurids, the skull contains a “remarkably small” braincase, according to its discoverers; its cranium is around 70% smaller than that of any of its relatives. This could suggest that the animal was a juvenile, but this is yet unconfirmed. One distinguishing feature of the dinosaur is a series of small holes at the front of its skull, arranged in rows, known as foramina. Researchers believe these holes helped the animal cool down, by allowing blood pumped into them (and covered by the thin skin at the front of the head) to release the heat it contained.

In contrast to other species of abelisaurids, the skull completely lacks any horns. This suggests that the species is among the first to emerge in the abelisaurid clade before these dinosaurs evolved horns.

Given that there is enough evidence to distinguish it as a new species, the team christened it after General Martin Miguel de Güemes, a hero of the Argentine War of Independence, and Javier Ochoa, a museum technician who discovered the specimen.

“Understanding huge global events like a mass extinction requires global datasets, but there are lots of parts of the world that have not been studied in detail, and tons of fossils remaining to be discovered,” Professor Anjali says.

“We left some exciting fossils in the ground on our last trip, not knowing that it would be years before we could get back to our field sites. Now we are hoping that it won’t be too much longer before we can finish digging them up and discovering many more species from this unique fauna.”

The paper “First definitive abelisaurid theropod from the Late Cretaceous of Northwestern Argentina” has been published in the Journal of Vertebrate Paleontology.

Fossil Friday: giant ammonites were involved in a size battle with their predators

Ammonites, the infamous coil-shaped mollusks of Earth’s ancient seas, could grow to incredible sizes. New research found that their predators were the likeliest driver of the ammonites’ growth.

One of the specimens used in this study. Scale bar is 100 mm (10 cm, around 4 inches). Image credits Christina Ifrim et al, (2021), PLOS One.

An international team of researchers with members from Germany, Mexico, and the U.K is peering into the evolutionary history of ammonites. They focused their efforts on two related, but visually distinct species: The approach by the team was to first learn more about ammonites in general—to that end they collected 154 specimens from various institutions, all of which were of two species: Parapuzosia leptophylla and Parapuzosia seppenradensis.

Although closely related, there is a huge size difference between the members of these two species. According to the research, the root cause of this difference was pressure applied by predators.

Growing into it

Ammonites are a group of extinct mollusks that are well known for their distinctive coil-shaped shells with frilled suture lines. In general, they were quite small animals, averaging around half a meter (around 1.5 ft) in diameter.

However, one species definitely stands out, size-wise, among this group — Parapuzosia seppenradensis. Individuals of this species could grow very large for an ammonite, up to 1.5 or even 1.8 meters (5 to 6 ft) in diameter.

Up to know, their huge size remained more of a curiosity, one whose causes were poorly understood. In order to get to the bottom of things, however, the team compared a large sample of P. seppenradensis fossils to those of a closely-related species, P. leptophylla.

They report that although the former evolved from the latter after a group of P. leptophylla moved away from their traditional range — the coastlines of today’s western Europe — to new waters, corresponding to today’s Americas.

P. seppenradensis individuals became progressively larger after this shift in location, the team explains. While there are no immediately-obvious causes for this change, no climactic shifts or ecological upheavals, the authors note that mososaurs also began getting bigger at around the same time.

Mosasaurs were giant marine reptiles that lived around the same time as ammonites and were believed to be their main predators.

The researchers’ theory is that P. seppenradensis evolved to grow to larger sizes as smaller individuals were more readily captured by mososaurs. Over time, this would naturally select the group in favor of larger body sizes. However, this shift also started applying pressure on the mososaurs; larger individuals would be better able to hunt the larger ammonites. In turn, this selected the species in favor of larger size.

In other words, it’s possible that we’re seeing a curious case of predator and prey involved in an evolutionary arms race with each other, each driving the other to achieve ever-greater body sizes.

One element that the team admits they cannot explain is that prior research has shown that mososaurs continued growing even after P. seppenradensis reached their maximum size. Furthermore, P. seppenradensis eventually started to revert back to smaller proportions for reasons unknown.

The paper “Ontogeny, evolution and palaeogeographic distribution of the world’s largest ammonite Parapuzosia (P.) seppenradensis (Landois, 1895)” has been published in the journal PLOS One.

Fossil Friday: the story of how tusks evolved from teeth

What, exactly, makes a tusk a tusk? And how did they come to be? New research by U.S. paleontologists sheds light on both of these questions.

Left side of the skull of a dicynodont Dolichuranus fossil used in the study. The tusk is visible at the lower left. Image credits: Ken Angielczyk.

Multiple animal species today have tusks. From elephants to walruses, however, one thing they all have in common is that they’re mammals. This wasn’t always the case, new research reveals. The history of tusks, according to a team of paleontologists at Harvard University, the Field Museum, the University of Washington, and Idaho State University started with an ancient relative of mammals that lived before the age of the dinosaurs.

Those relatives were dicynodont (meaning “two canine teeth), a species that shared some of the characteristics of mammals but also reptiles — including sporting a turtle-like beak.

Tooth or tusk?

“For this paper, we had to define a tusk, because it’s a surprisingly ambiguous term,” said lead author Megan Whitney, a postdoctoral researcher at Harvard University and a UW doctoral alum, in a press release. “Enamel-coated teeth are a different evolutionary strategy than dentine-coated tusks. It’s a trade-off.”

For this study, the team defined tusks as being teeth not covered in enamel (i.e. they’re entirely made of dentine), that extend out past an animal’s mouth, and keep growing throughout the individual’s lifetime. Using this definition, the authors set out to determine the evolutionary history of such appendages. They worked with thin slices cut out from the teeth of several fossil species in order to determine when tusks first appeared. They investigated these using micro-CT scans, to determine how the teeth were attached to the skulls of the animals, and to check for signs of continuous growth around their roots.

Dicynodonts lived from 270 to 201 million years ago, roughly, so they’re quite ancient animals. As a group, they were very diverse, ranging in size from a rat to a modern elephant. They got their name from the two distinctive teeth in their upper jaws, teeth which were the focus of this study.

According to the findings, some dicynodont teeth were indeed tusks. One important finding is that there wasn’t a clear-cut transition between the two. The team analyzed 19 different dicynodont specimens comprising 10 species, finding that tusks evolved independently several times in this extinct clade. Another important hint that we’re looking at the first evolution of tusks was that the earlier dicynodont species only showed teeth, whereas tusks started making an appearance among the later species to arise in this clade.

The enamel layer on this Diictodon caniform (the colorful ring on the cross-section) makes it resemble teeth more than tusks. Image credits Megan Whitney.

“We were able to show that the first tusks belonged to animals that came before modern mammals, called dicynodonts,” said co-author Ken Angielczyk, a curator at the Field Museum in Chicago. “Despite being extremely weird animals, there are some things about dicynodonts — like the evolution of tusks — that inform us about the mammals around us today.”

The authors further report on some adaptations dicynodonts had to go through to enable the evolution of true tusks. These include flexible ligaments connecting the tusks to their jaws, and a reduced overall rate of tooth replacement. The roots of their tusks were hollow, as well, to allow for fresh dentine to be continuously added over time.

Apart from the findings of this study, the team’s classification of what exactly constitutes a tusk and how they’re different from regular teeth is more broadly applicable to other species. In particular, it gives us insight into the different tasks these structures are meant to serve.

The enamel layer on the surface of our teeth is harder than dentine, making it more resilient to wear and tear. But it’s also much harder to heal damaged enamel than it is to heal dentine. Its presence also prevents teeth from growing continuously, as tusks do. Animals with tusks use them for fighting or rooting through the ground, so they’re much more exposed to damage than teeth. A complete enamel covering would be impractical in this situation, as it would present a liability. Since tusks regrow, damaging or losing a tusk isn’t a death sentence. If they had the same structure as teeth, however, they couldn’t be replaced, and any damage would constitute a direct and significant threat to an individual’s survival.

An example of a true tusk in the dicynodont Lystrosaurus, with a hollow pulp cavity in its root where fresh dentine would have been created. Image credits Megan Whitney.

“Tusks have evolved a number of times, which makes you wonder how — and why? We now have good data on the anatomical changes that needed to happen for dicynodonts to evolve tusks,” said co-author Christian Sidor, a UW professor of biology and a curator at the UW’s Burke Museum of Natural History & Culture. “For other groups, like warthogs or walruses, the jury is still out.”

Most of the dicynodont fossils analyzed in this study were unearthed in Tanzania and Zambia. They’re currently stored in a range of museums in the U.S., and are scheduled to be returned to the National Museum of Tanzania and the Livingstone Museum in Zambia after the conclusion of the research project.

The study “The evolution of the synapsid tusk: insights from dicynodont therapsid tusk histology” has been published in the journal Proceedings of the Royal Society B.

Fossil(ish) Friday: Minnesotans want the Giant Beaver to be their new state fossil

The people of Minnesota have just elected their new state fossil: it’s going to be a Giant Beaver (Castoroides ohioensis). Hopefully.

The specimen that the Museum enrolled in the voting competition.

Don’t you just love democracy at work? The Minnesota Science Museum certainly does. They’ve asked the people “what should our state fossil be?” using the magic of the Internet, and the people have answered. A Wednesday post on the Museum’s page together with a live broadcast revealed that the vote went to a Giant Beaver specimen in their collection.

All that’s left now is to make it official.

Big Beaver

“Thank you for voting for our state fossil! What comes next, you ask? We’ll bring your massive mammal candidate to the legislature!”

The Science Museum of Minnesota offered the public a chance to vote which among nine specimens (we’ll see them in a bit) in its collection should come to represent the state as its state fossil. The Giant Beaver received 11,000 votes. It outdid other iconic species such as the crow shark, trilobite, and scimitar-toothed cat. Overall, a landslide win — it gained around 25% of all the votes cast in the competition.

So what exactly were Giant Beavers? Unsurprisingly, they were giant relatives of today’s beavers. Outwardly and in behavior, they resembled the dam-building mammals we all know and love; they had buck teeth and an aquatic lifestyle.

But there were some differences as well: Giant Beavers grew to around 200 pounds and could reach between 1.9 m and 2.2 m (6.2 ft to 7.2 ft) in length. They lived between 2.58 million years and 10,150 years ago, during a geological Epoch known as the Pleistocene.

In many ways, they looked like oversized versions of the beavers that inhabit Minnesota to this day, although their hind legs were much shorter with bigger feet relative to their body proportions. Their teeth were much larger, although proportional to their bigger bodies, but with a rough, striated enamel texture; modern beavers have smooth-textured enamel protecting their teeth. Judging from their skulls, however, we’re pretty confident that Giant Beavers had a smaller brain volume relative to their body, meaning they were probably not quite as smart as modern beavers and had less sophisticated interactions with their environment.

The genus Castoroides was first described from a specimen found in the USA in Ohio (hence its scientific name ‘ohioensis’). All known specimens have been unearthed from the USA and Canada. They’re generally clustered around the midwestern United States in states near the Great Lakes, particularly Illinois and Indiana. However, their habitat certainly ranged between today’s Alaska, Canada, and Florida, as Castoroides specimens have been found at these sites.

“Pretty impressive right? There’s beavers still throughout Minnesota today, they’re an important part of the ecosystems here. A lot of people have seen them, and learned to love these little toothy critters, so why wouldn’t you love an even larger version of that?” said Alex Hastings, the museum’s chair of paleontology, during the livestream on Wednesday.

The specimen that won this competition was found at a site near St. Paul, Minnesota. The museum will present the fossil alongside the results of the vote to lawmakers, who will get to decide if the Giant Beaver should become the state’s first official fossil. Minnesota is one of only seven states that have yet to designate an official fossil; the others are Arkansas, Hawaii, Indiana, Iowa, New Hampshire, and Rhode Island. The Giant Beaver almost became Minnesota’s official fossil back in 1988, but the measure failed in the legislature. Fingers crossed it makes it this time!

The museum also put up some cool and actually damn funny YouTube videos for each of the contenders, which you can see on their individual voting pages; they’re still up, even if the voting is closed. I will put up links to the individual pages or directly to their YouTube shorts for your convenience (the ones here are for the Giant Beaver).

Go give them a subscribe and some likes if you’re on YouTube, it really helps them out, and they really deserve it. I wish Netflix had content as good as this.

But we’re all here for fossils, and every runner-up in this competition is definitely deserving of some of our love.

Endoceras.

These squid-like creatures were among the largest animals alive during their time (during the Ordovician Period around 450 million years ago) and sported 10 arms. This specimen at the Science Museum of Minnesota was found by a local collector. Individual page and YouTube link.

Stromatolite.

Stromatolites have the honor of being the oldest fossils in Minnesota. They do look unassuming, but that comes down to their history. These clumpy fossils were formed almost 2 billion years ago by photosynthesizing bacteria. What you’re seeing here are the fossils of the first oxygen-producing organisms on Earth. They started the trend that led all the way to us breathing oxygen today. Individual page and YouTube link.

Squalicorax (Crow Shark).

An extinct species that lived during the Cretaceous Period, 90 to 100 million years ago, the Crow Shark prowled the seas as dinosaurs roamed the Earth. Judging by the serrations on its teeth, this shark used to punch high above its weight — and tooth marks found on the bones of fish, dinosaurs, marine reptiles, and even some flying reptiles tell us that it did so with frightening enthusiasm. Individual page and YouTube link.

Dikelocephalus minnesotensis (Trilobite).

Trilobites… were sea bugs. A great, very diverse family of sea bugs who lived during the Cambrian Period, between 492 and 487 million years ago. This particular species got its name for being discovered near Stillwater, Minnesota, and that specimen is now housed at the Smithsonian National Museum of Natural History. Individual page and YouTube link.

Bison antiquus.

A relatively young contender, this bison native to Minnesota lived between 60,000 and 4,270 years ago, making the transition from the Late Pleistocene to the Holocene Epoch (the one we’re currently in right now). This species eventually gave rise to the bison we all know. They were probably larger than modern bison, however. Individual page and YouTube link.

Homotherium serum (Scimitar Toothed Cat).

A large predator that stalked the tundras of Minnesota some 27,000 years ago during the Pleistocene Epoch. It had somewhat smaller canines than the infamous saber toothed cat, but more muscular shoulders and arms. Individual page and YouTube link.

Terminonaris robusta.

An extinct (and much bigger) relative of the modern crocodile that lived between 90 and 100 million years ago during the Cretaceous Period. Like modern crocs, it was very toothy and not afraid to bite. Individual page and YouTube link.

Mammuthus columbi.

The Columbian Mammoths lived during the Pleistocene Epoch, between 2 million and 12,000 years ago. They’re one species that are well represented in the state of Minnesota, as the tundra landscapes present here at that time were an ideal stomping ground for these huge beasts. This particular tusk belongs to the Lyle Mammoth which was discovered in the state and is now on display at the Science Museum of Minnesota. Individual page and YouTube link.

All images in this post are courtesy of the Science Museum of Minnesota.

Fossil Friday: ancient whale that walked on all fours found deep in the Egyptian desert

Roughly one decade ago, Egyptian environmentalists uncovered the bones of an ancient whale — in the sands of the Western Desert. Now, a new paper details this strange finding, describing a brand new species of ‘semi-aquatic’ whale ancestor.

The holotype (the specimen from which the species was described and named) of Phiomicetus anubis. Image credits Abdullah S. Gohan et al., (2021), Proc. R. Soc. B.

This four-legged whale ancestor lived around 43 million years ago, and was, by all indications, an accomplished hunter.

Grandma whale

“We chose the name Anubis because it had a strong and deadly bite,” said paleontologist Hesham Sallam, professor of paleontology at Mansoura University in Egypt, who led the research effort. “It could kill any creature it crossed paths with.”

Phiomicetus anubis is a key new whale species, and a critical discovery for Egyptian and African palaeontology,” the study’s lead author, Abdullah Gohar, told Reuters news agency.

The whale is part of the extinct Phiomicetus genus of protocetidae whales — essentially, the family from which modern whales emerged. It was given the name Anubis in honor of the ancient Egyptian god of death, as judging from its fossils, the animal was quite an accomplished killer.

The animal’s elongated snout and skull point to it being a capable carnivore both in regards to grasping prey and chewing through tough hides and bones.

Perhaps its most unusual features, for most people, would be that P. anubis was semi-aquatic, and possessed four stout legs instead of flippers. The area that makes up the Western Desert today used to be a sea 43 million years ago. P. anubis hunted in its waters and, likely, walked around its shores.

The fossil was first found in 2008, but Sallam put off investigating it until 2017, as he worked to assemble a team of paleontologists that would do the fossil justice. Their work culminated last month when they officially confirmed that the fossil belongs to a completely new species.

From a paleontological standpoint, the discovery is particularly exciting as P. Anubis is one of the last known members of the whale family that retained functional, land-going limbs. Whales as a family have evolved from land mammals that returned to the sea, also transitioning from a herbivorous to a carnivorous diet in the process. Today, all members of the whale family (cetaceans) live exclusively in the seas and oceans. Thus, they have quite an interesting story to tell.

P. anubis was a species that emerged during that transition period, making it a valuable source of information on how it took place and when. Fossils from this window of the whales’ evolutionary history are particularly valuable for helping us understand when they finally made the full transition to ocean life, and where. Currently, our best indication is that it took place around 50 million years ago in today’s India or Pakistan, but this is by no means a settled topic. The new species will undoubtedly help flesh out our understanding of this timeline.

Surprisingly for a desert, Egypt’s Western Desert is quite famous for its prehistoric whale fossils. One area in particular, the White Valley of Wadi al-Hitan, has been declared a natural World Heritage site and attracts a lot of tourist attention due to its prehistoric whale fossils.

The paper “A new protocetid whale offers clues to biogeography and feeding ecology in early cetacean evolution” has been published in the journal Proceedings of the Royal Society B: Biological Sciences.

Fossil Friday: the oldest kind-of-bat species seen so far, described from set of teeth found in China

Asian bats — I think we’ve all heard more about them than we’d like, these past two years. But new research comes with a twist on that subject. Researchers from the US and China have identified the oldest known bat fossil from the Asian record.

The upper molars of Altaynycteris aurora, from which the species was described. Image credits Matthew F. Jones et al., (2021), Biology Letters.

The discovery helps us better understand the evolutionary history of the only true mammalian flyers, pushing their story back to the Eocene — as far as we know. It also raises the possibility that the bat family originates in Asia entirely, although it’s too soon to say for sure.

Whence bats come from

“Bats show up in the fossil record out of the blue about 55-ish million years ago — and they’re already scattered on different parts of the globe,” said lead author Matthew Jones, a doctoral student at the KU Biodiversity Institute and Department of Ecology & Evolutionary Biology. “Before this, the earliest bats are known from a couple of places in Europe — Portugal and southern France — and Australia. So, when they show up early in the fossil record as these fragmentary fossils they’re already effectively worldwide.”

“By the time we get their earliest known full skeletons, they look modern — they can fly, and most of them are able to echolocate. But we don’t really know anything about this transitional period from non-bats to bats. We don’t even really know what their closest living relatives are among mammals. It’s a really big evolutionary mystery where bats came from and how they evolved and became so specialized.”

The team comprised members from the University of Kansas and the Chinese Academy of Sciences. The fossil they describe was unearthed at a remote field site in the Junggar Basin, China, after quite a long digging effort. Although they suspected that the sites would be rich in Paleocene and Eocene fossils, Jones explained, various members of the team worked here for several years, sifting the sediment, before finding any actual fossils.

“We’ve been fortunate enough to be able to host our Chinese colleagues here in Lawrence for extended research visits, and they’ve more than reciprocated by hosting us for research and fieldwork in China. This work in the Junggar Basin is really trailblazing work because the fossil record in this part of China is only just barely beginning to emerge, and this area is very removed and isolated. It’s just a giant empty place. There are some camels, some snakes and lizards, but you don’t see many people there. That remoteness makes the logistics to do fieldwork there quite difficult and expensive because you’ve got to bring in all your food and water from far outside — all of that hindered research in this area previously.”

Residues from the sieving were sent to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing for sorting. Back in 2017, they got the first sign that their work would pay off: a possible fragment of a fossilized bat — a tooth. One year later, a second tooth was found amid the sieved dirt. Their structure was distinctive enough to suggest they belonged to a yet-undescribed species; the team christened it Altaynycteris aurora.

Residue from the sifting was sent to the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing for sorting. Back in 2017, they got the first sign that their work would pay off: a possible fragment of a fossilized bat — a tooth. One year later, a second tooth was found in the dirt. Their structure was distinctive enough to suggest they belonged to a yet-undescribed species; the team christened it Altaynycteris aurora.

Still, the teeth leave us with more questions than answers. The morphological details of the species remain unknown; we can’t even say for sure whether it was able to fly, or echolocate, like bats today do. According to Jones, they look to be “in between what we would expect a bat ancestor to look like […] and what true bat looks like”.

“So, they have some features that are characteristic of bats that we can point to and say, ‘These are bats.’ But then they have some features that we can call for simplicity’s sake ‘primitive,'” he adds.

The paper “The earliest Asian bats (Mammalia: Chiroptera) address major gaps in bat evolution” has been published in the journal Biology Letters.

Researchers discover a new species of ancient beetle inside fossilized poop

Researchers at the Uppsala University have reported on an exciting find: the world’s first species identified from a piece of fossilized dinosaur poop.

Image credits Martin Qvarnström et al., (2021), Current Biology.

The 230-million-year old insect was found in excellent condition inside a dinosaur coprolite, a piece of fossilized feces. It was christened Triamyxa coprolithica in honor of this.

In-dung beetle

Coprolites are quite common in museum collections around the world, but aren’t generally examined to see if they contain any fossils. This is due to the fact that the consensus among paleontologists is that small insects (the only animals small enough to fit inside coprolites) wouldn’t have been able to survive through the digestive tract of a dinosaur intact.

Because of this, most of our knowledge regarding insect evolution in the past comes from specimens that were trapped in amber, fossilized tree resin. The downside with this is that such specimens aren’t that common, so we can miss bits of the original picture, and they’re also not very old, geologically speaking. The oldest such fossils we’ve ever found are around 140 million years old — which isn’t that old.

For the study, Uppsala University paleontologist Martin Qvarnström and his colleagues examined coprolites from Poland that were previously dated to the Triassic period (230 million years ago). They selected a particular fragment based on its external features. It was 2 centimeters long with broken ends, and their shape suggested it was once part of a larger specimen which the team believed would make it more likely to contain insect remnants.

This fragment was then examined with X-rays inside a synchrotron, which allowed the team to rotate the coprolite in the beam in order to create a 3D model of its inside structure. There, they found excellently preserved, almost complete insect bodies measuring 1.4 millimeters in length, alongside fragments including heads, legs, and antennae.

Based on the wealth and quality of the specimens found in the coprolite, the authors were able to determine that they are a new species belonging to the group Myxophaga, small beetles that live in wet habitats and feed on algae. Although this species — coprolithica — is now extinct, four lineages in the Myxophaga group are alive to this day. This is the first time we’ve found enough fossilized material of good enough quality to “describe a new species, genus, and family,” says lead author Martin Qvarnström.

The classification was made based on characteristics like the number of abdomen segments or the position of the antennae which were compared to those of modern Myxophaga.

The coprolite was most likely dropped by a Silesaurus opolensis, a beaked dinosaur ancestor that grew to about 2.3 meters in length. It’s very likely what kept the insects in such good condition, as the material creates a microenvironment that preserves organic material such as soft tissues without flattening them, like typical fossilization processes do.

All in all, this research gives us fresh information about the evolution of beetles, as well as a glimpse into the dietary habits of certain dinosaurs and the structure of food webs during the Triassic.

For T. coprolithica itself, we still can’t know for sure how or why it went extinct while some of its relatives survived into the modern period. Many factors, which can often seem unrelated, contribute to a species surviving or dying off — so its causes are never easy to understand.

The paper “Exceptionally preserved beetles in a Triassic coprolite of putative dinosauriform origin” has been published in the journal Current Biology.

Fossil Friday: 1,000-year-old egg found whole in a cesspit in Israel

Researchers at the Israel Antiquities Authority (IAA) report finding an unusual and exciting fossil: a 1000-year-old, unbroken chicken egg preserved in an unfortunate place.

The ancient egg. Image credits: Dafna Gazit, Yoli Schwartz, Gilad Stern, Israel Antiquities Authority.

It might be hard to imagine this today, but for the majority of human history, poultry was a rather exotic meat. Sacrificing a laying bird for its meat meant giving up all the eggs it would potentially lay in the future — an extravagant waste. Male birds, or those too old to lay eggs, were an exception to this rule. Still, chicken farming was quite common all around the world, as the birds themselves are easy to care for and provide a constant source of food.

Finding evidence of that farming as an archeologist, however, is no easy feat. Which makes the IAA’s discovery all that more exciting.

Unbroken

“Eggshell fragments are known from earlier periods, for example in the City of David and at Caesarea and Apollonia, but due to the eggs’ fragile shells, hardly any whole chicken eggs have been preserved,” said IAA archaeologist Dr. Lee Perry Gal.

“Even at the global level, this is an extremely rare find.”

The fossilized, unbroken egg was discovered at the site of Yavne, on Israel’s southern Mediterranean coast, in an Islamic-era cesspit. The “soft human waste” material it found itself in helped keep it intact over the centuries, the team explains, an example of “unique preservation”.

Poultry farming in Israel has its roots in the Hellenistic and Early Roman periods, starting roughly 2,300 or so years ago. Later, during the Islamic period (from around the 7th century CE), poultry farming became even more popular. This coincides with a noticeable decrease in the quantities of pig bones found at various archeological sites in the region.

Although faith definitely played a part in this shift (the consumption of pork is completely forbidden in the Islamic faith), sheer practicality also played a part. People living in the region around this time needed a reliable source of protein that wouldn’t need to be preserved or kept cool to prevent spoiling over short periods. Eggs, and to a lesser extent, chicken meat, served that purpose, Gal explains.

“How did the egg end up in the cesspit? We will never know,” the archaeologists said.

“Unfortunately, the egg had a small crack in the bottom so most of the contents had leaked out of it. Only some of the yolk remained, which was preserved for future DNA analysis.”

Several other items were retrieved from the same cesspit, including bone dolls typical of the Islamic period, dating back probably around 1,000 years or so.

Fossil Friday: ancient poop offers insight into what the ancient, giant Moa birds ate

Sometimes, archeology is about finding a whole T. rex and being showered with fame and glory. Other times, it’s about analyzing fossilized bird dung. Today’s story involves the latter.

The coprolite specimen, in all of its glory. Image credits Wood et al., (2021), QSR.

Researchers at the Manaaki Whenua—Landcare Research Institute have recently discovered a deposit of moa coprolites (fossilized feces) in the Fiordland National Park, New Zealand. DNA sequencing and microscope analysis performed on the fossil, as well as our previous knowledge of where individual moa species lived, are helping us better understand what the little bush moa (Anomalopteryx didiformis) ate.

Taken at feces value

Virtually everything we know of the moa’s diets comes from coprolites and fossilized gizzard contents. These are usually run through DNA sequencing (to identify exactly which species they originate from), then dissected and examined under a microscope so scientists can get an idea of what the birds ate.

So far, most of what we know of the moa is concentrated around only three species from the South Island — the South Island giant moa, upland moa, and heavy-footed moa. Around 90% of all the material of this type we’ve found so far is related to one of these three species. The remaining six moa species, in contrast, are quite poorly understood. The new coprolite will help fill in missing parts of this picture — it belongs to one of the six latter species, the little bush moa.

This bird used to live in lowland, closed-canopy forests throughout New Zealand, growing to between 50 and 90 cm (1.64 to 2.95 ft) tall, and weighing around 26 to 64 kg (57 to 141 lbs). It’s a particularly important discovery, explains lead researcher Dr. Jamie Wood, because it comes from the southernmost site at which moa coprolites were ever discovered. The site is also the one with the longest documented timespan of coprolite accumulation, totalling around 2200 years.

“Until now, only five little bush moa coprolites have previously been identified, all from central Otago,” he adds.

“Pollen and plant DNA from the coprolites, as well as associated plant macrofossils, show that the deposit spans a period when the forest canopy was transitioning from conifers (dominated by miro, matai, totara, and mountain toatoa from the Podocarpaceae family) to silver beech (Lophozonia menziesii) dominance about 6800 to 4600 years ago.”

Evidence of red mistletoe (Peraxilla tetrapetala) was also found in the newly-discovered coprolites.

One interesting tidbit, however, is that very few seeds were found in this specimen compared to coprolites from other moa species. These birds often served to disperse tiny seeds around their habitats in their droppings, which is a very important ecological function. Regardless, the little bush moa seems instead to have been eating large conifer seeds, which get completely ground down in their gizzards, and not dispersed.

These findings seem to indicate that the little bush moa dined primarily on trees and shrubs in the forest understory, and offer reliable evidence that ground ferns made up an important part of their diet.

“While little bush moa may not have been great seed dispersers, based on our finding of ground fern DNA, frond cuticle remains and high spore counts, they may have played a previously unrecognized role as dispersers of ground fern spores throughout New Zealand forests,” according to Dr. Wood.

The paper “Mid-Holocene coprolites from southern New Zealand provide new insights into the diet and ecology of the extinct little bush moa (Anomalopteryx didiformis)” has been published in the journal Quaternary Science Reviews.

Fossil Friday: a 6-year-old UK boy finds ancient fossil in his backyard with a toy archeology kit

A six-year-old boy in Walsall, England, is probably the youngest individual to ever make it into a Fossil Friday story. His discovery: a fossilized horn coral, several hundred million years old, that he uncovered in his family’s back yard with a fossil-hunting kit he received for Christmas.

The fossil. Image via standard.co.uk.

Sid, or Siddak Singh Jhamat in full, said he was “excited” to make the discovery, and that he was just looking for worms. His father helped him identify what the fossil actually was through a fossils’ enthusiasts group on Facebook. Estimates place the specimen’s age between 251 and 488 million years old according to Vish Singh, said the boy’s father, and it is most likely a Rugosa coral.

Beginner’s luck

“I was just digging for worms and things like pottery and bricks and I just came across this rock which looked a bit like a horn and thought it could be a tooth or a claw or a horn, but it was actually a piece of coral which is called horn coral,” the schoolboy said.

“I was really excited about what it really was.”

Mr. Singh explains that his son found the “odd-shaped” horn coral in the soil in their back yard, next to “some smaller pieces”. Encouraged by his success, Sid went digging again the next day, finding a congealed block of sand. Locked inside this block were several little molluscs, seashells, and even a partial crinoid specimen.

During the time this coral fossil was still a living coral, the area that is the UK today was just one tiny part of the supercontinent Pangea, and it was also virtually all underwater — an inland lake.

Sid and his coral fossil. Image via standard.co.uk.

The finding is quite surprising because Walsall, the area where the Singh family lives, isn’t really known for its fossils. Other areas of the UK, such as its suggestively named Jurassic Coast, are hotbeds for fossil hunters. Still, Mr. Singh says their garden has lots of natural clay outcroppings, and his son found the coral in one of these.

If anything, this unlikely event showcases that it’s never too early to start looking for fossils. It’s also a good reminder that fossils can, really, be anywhere. That being said, a large specimen such as the one unearthed by Sid and his trusty toy kit is quite a rare discovery even for hardened paleontologists.

Fossil Friday: private collector wanted a dinosaur skull, but got a huge, fossilized bony fish lung

Researchers at the University of Portsmouth have run into the fossilized remains of an ancient bony fish — the coelacanth — out of sheer luck. Or bad luck, depending on who you’re asking.

The original slab as purchased. The coelacanth ossified lung in close proximity to a series of associated, but disarticulated wing elements of a large, but indeterminate pterosaur. Image credits University of Portsmouth.

In a break from our traditional story path for Fossil Friday, there won’t be much talk about anything being ‘unearthed’ today. That’s because the fossil in question is part of a private collection from a London aficionado. It was identified as having belonged to a species of coelacanth by Professor David Martill, a paleontologist from the University’s School of the Environment, Geography and Geosciences, after he was asked to take a look at the specimen and determine its origin.

Although the discovery is quite exciting from an academic point of view, the collector was (reportedly) less than thrilled: they wanted a pterosaur skull, but got a bony fish.

Old fish

“The collector was mightily disappointed he didn’t have a pterosaur skull, but my colleagues and I were thrilled as no coelacanth has ever been found in the phosphate deposits of Morocco, and this example was absolutely massive!” explains Professor Martill.

“The thin bony plates were arranged like a barrel, but with the staves going round instead of from top to bottom. Only one animal has such a structure and that is the coelacanth — we’d found a bony lung of this remarkable and bizarre-looking fish.”

The fossil corresponds to a fish that’s similar in size to a great white shark of today and is the largest fossil of its kind to ever be discovered by accident. Although they’ve been swimming around since the dinosaurs were still roaming the Earth, coelacanths are still alive to this day, although they are quite rare and rarely seen. They’re also quite endangered.

The collector bought this fossil thinking it could have been part of a pterodactyls’ skull. Professor Martill instead found that the specimen was composed of numerous, thin bone plates, not a single piece, as you’d see in a skull. Prof. Martill worked together with Dr. Paulo Brito of the State University of Rio de Janeiro, a leading Brazilian paleontologist, to study the fossil. Brito, an expert on coelacanths and their lungs, admitted to being ‘astonished’ at how large this specimen was.

It has been embedded in a block of phosphate with a plaster backing, and everything was then coated in lacquer — this, the two explain, caused the fossils to take a brown hue. It was found next to a pterodactyl specimen (which is probably why the collector thought it was part of that animal). Although they turned out to be completely different species, this does help give us a rough estimate of when the fish lived: around 66 million years ago, in the Cretaceous era.

The lung specimen and its likely position in a mawsoniid coelacanth.
Image credits University of Portsmouth.

Following an initial investigation of the specimen, its owner offered to give the researchers the remains of the bony lung off the slab, which they accepted. Later, they removed the lacquer using specialized equipment (mostly dental tools and fine brushes) to enable more thorough research on the fossils.

The very large size of the lung belonging to this animal suggests that it was a very, very big individual during its day — around five meters in length, the team reports. This is much larger than the coelacanths of today, which grow to around two meters in length, at most.

“We only had a single, albeit massive lung so our conclusions required some quite complex calculations,” Professor Martill explains. “It was astonishing to deduce that this particular fish was enormous — quite a bit longer than the length of a stand-up paddleboard and likely the largest coelacanth ever discovered.” 

The fossil will be given back to the Moroccan government, the owner explains, and will most likely be added to the collections in the Department of Geology at Hassan II University of Casablanca.

The paper “A marine Late Cretaceous (Maastrichtian) coelacanth from North Africa” has been published in the journal Cretaceous Research.

Fossil Friday: surprise teen Plesiosaurus found in ammonite mine in Alberta, Canada

Sometimes, even professional fossil-seekers can be surprised to find a fossil. That’s exactly what happened recently at the Enchanted Designs Ammonite Mine, south of Lethbridge, Canada, when workers (who mine for ammonite fossils) ran into a Plesiosaur fossil estimated to be around 75 million years old.

Image capture from a CTV coverage of the discovery.

This particular specimen was likely an adolescent at the time of its death judging from its size, local news outlets report.

Suddenly, Plesiosaurus

“The guys started scraping and noticed there were some vertebrae that appeared below the concretion line, and right away we knew we had a new fossil,” said Michael Shideler, manager of the Enchanted Designs Ammonite Mine.

Plesiosaurs were highly specialized marine dinosaurs. They had a small head on a very long neck, long tear-shaped bodies, a stumpy tail, and four wide flippers. They were pretty similar in shape to what you’d imagine the Loch Ness monster to be.

And just like with the Loch Ness monster, none of the workers at the mine expected to run into this fossil. The Enchanted Designs Ammonite Mine has been shut down during winter, so activity at the site is still picking up as the mining season is still fresh. One of the crews digging for ammonites there ran into a large and compact mass of material (a ‘concretion’) that stood out from the mine’s rock walls.

Based on the fossilized fragments recovered so far, the specimen was likely 7 meters (~23 ft) long when it died; almost half of that length is just neck. This would mean that the animal was still pretty young, likely an adolescent, when it met its end. Other plesiosaur specimens that we’ve recovered reach up to 14 m (46 ft) in length, with a similar neck-to-not-neck ratio.

What made the discovery particularly surprising is that marine reptile fossils are very rare in the Bearpaw Formation, which stretches through Alberta, Saskatchewan, and Montana, and into which the mine delves. Around 75 million years ago, when this formation was still on the surface, the area was the bottom of a shallow tropical sea. A large number of ammonites, fish and marine reptiles lived here, which is why the formation is such a rich source of fossils. However, this is the first time a specimen of this kind has been recovered from the mine.

The plesiosaur and other undetermined fossils have been collected and taken to the Royal Tyrrell Museum, where they will be removed from their rocky prisons for research.

Fossil Friday: we might have found the earliest known cephalopod, extending the family’s history by 30 million years

Cephalopods, a family including animals like the octopus and cuttlefish, are definitely some of the most interesting animals on Earth today. According to new research, they could also be one of the oldest lineages on the planet as well.

 Thin section of the specimen. Red arrows point to the septa, blue to a possible other specimen. Image credits Anne Hildenbrand et al., (2021), NatCom.

The discovery of 522 million-year-old (possibly cephalopod) fossils in the Avalon Peninsula, Newfoundland, Canada, could push this lineage’s history back by roughly 30 million years, a new paper reports. This would mean that cephalopods first evolved during the early Cambrian period, making them one of the earliest multicellular organisms on Earth.

Old Squid

“If they should actually be cephalopods, we would have to backdate the origin of cephalopods into the early Cambrian period,” says Dr Anne Hildenbrand from the Institute of Earth Sciences, co-lead author of the study.

“That would mean that cephalopods emerged at the very beginning of the evolution of multicellular organisms during the Cambrian explosion.”

The fossils were unearthed by earth scientists from the Heidelberg University in Germany on the eastern stretches of the Avalon Peninsula. They’re pretty chalky shells, resembling elongated cones. Individual chambers are present inside the shells, each defined by a pair of walls. A tube called the siphuncle runs along the length of the shell linking all of these rooms together.

If this fossil belonged to a cephalopod — and we’re not yet sure that it did — it could have quite a dramatic effect on our understanding of this lineage’s evolutionary history. For starters, the segmented-yet-connected structure of the shell suggests that it had a part to play in controlling the animal’s buoyancy. This is the earliest example we’ve ever seen of such a mechanism, meaning that cephalopods could have been the first lineage to be able to settle the open ocean (as opposed to the sea bed or reefs) as their habitat.

For now, we have reason to believe that the shell belonged to a cephalopod. Its structure is reminiscent of the spiral-shaped nautilus, suggesting a certain level of relatedness, but they also differ in shape from known representatives of that class. In other words it’s probably a cephalopod, but we can’t tell for sure due to some differences in shape.

“This find is extraordinary,” says Dr. Austermann. “In scientific circles, it was long suspected that the evolution of these highly developed organisms had begun much earlier than hitherto assumed. But there was a lack of fossil evidence to back up this theory.”

This discovery, however, might finally allow researchers to gain some insight into the topic, the team argues. On the one hand, it has structural similarities to other known early cephalopods. On the other, there are enough differences between it and other known cephalopod specimens to give us some information about the evolutionary process of the lineage as a whole.

The paper “A potential cephalopod from the early Cambrian of eastern Newfoundland, Canada” has been published in the journal Communications Biology.

Fossil Friday: ancient predatory worm leaves behind no trace, except its burrows

Fossil hunters in Taiwan have found the undersea lair of an ancient, predatory giant worm. The 20-million-year-old animal grew to be 2 meters (6.6 ft) long and ambushed unsuspecting prey and dragged them down to its burrow.

Vertical section of the upper part of Pennichnus formosae with funnel top (yellow line), disturbed zone (dashed red lines), and feather-like collapse structures (dashed white lines). Image credits Yu-Yen Pan et al., (2021), Scientific Reports.

The worm might have been similar to Eunice aphroditois, modern ambush predator worms that hunt using a similar approach. Although it’s not possible to tell if these two species were related by the fossil alone, it’s still a spectacular find.

Ancient murder macaroni

“After 20m years, it’s not possible to say whether this was made by an ancestor of the bobbit worm [Eunice aphroditois] or another predatory worm that worked in more or less the same way,” said Prof Ludvig Löwemark, a sedimentologist at National Taiwan University and co-author of the paper.

“There’s huge variation in bobbit worm behaviour, but this seems very similar to the shallow water worms that reach out, grab fish and pull them down.”

Although they’re soft-bodied like other worms, these predatory worms have sharp, powerful jaws that can pack quite a punch. The fossil worm likely hunted in a similar fashion, but for now we can only hypothesize.

What the team found isn’t a fossil of the worm itself (soft tissues don’t fossilize and worms are basically entirely soft tissue), rather, they found the fossil of its burrow. Löwemark and his colleagues discovered it while studying sedimentary rocks on the north-eastern coast of Taiwan that hail from around the same time as the worm. If they’re anything like today’s worm burrows, these were reinforced with mucus produced by the worm to make them more resilient.

Today, the fossil burrows sometimes simply protrude from the sandstone they formed in, suggesting that they’re harder than the rock and supporting the mucus-reinforcement hypothesis.

Although the team was initially confused as to what these were, they noticed a distinctive pattern at the top of the 3 cm-wide structures. This looked like several inverted funnels that got stacked on top of one another, they explain, giving the opening of the structures a feathered look in cross-section.

Schematic of E. aphroditois hunting from burrows, likely a similar behavior to that of the fossil species. Image credits Yu-Yen Pan et al., (2021), Scientific Reports.

These marks allowed the team to rule out burrowing creatures such as shrimp or stingrays as the builders. Finally, the only remaining possibility was that of an animal behaving like today’s predatory worms. The structures at the top, the team notes, is produced by repeated rebuilding of the lair as it collapses every time the worms pull prey in.

“This results in the stack of cone-in-cone structures that form the ‘feathers’ around the uppermost part of the tube,” said Löwemark.

The team reports they’ve found 319 such burrows in sandstone formations from the Yehliu Geopark and on the nearby Badouzi promontory, suggesting that the area was heavily populated with these worms in the past. They’ve named the trace fossil burrows Pennichnus formosae.

Although they hoped to find fossilized remains of the worms themselves or their prey, the team hasn’t been so lucky yet.

The paper “The 20-million-year old lair of an ambush-predatory worm preserved in northeast Taiwan” has been published in the journal Scientific Reports.

Fossil Friday: Adalatherium, the largest mammal to run with the dinosaurs

New research sheds light on a 66-million-year-old mammal that lived alongside the dinosaurs. The findings help us better understand the evolutionary history of mammals from the southern supercontinent Gondwana — today’s Africa, South America, Australia, Antarctica, India, and Arabian Peninsula.

Adalatherium huiA, photograph of skull and skeleton with BC, skeletal reconstructions in left lateral and dorsal views. Image credits David W. Krause et al., (2020), Journal of Vertebrate Paleontology.

Christened Adalatherium hui, which is a combination of Malagasy and Greek meaning “crazy beast,” the paper describes this new species based on an almost complete, excellently-preserved fossil skeleton. The authors explain that this specimen is the most complete for any mammal yet discovered in the southern hemisphere from the time of the dinosaurs.

Oldboy

Research on the fossil specimen was carried out over a period of 20 years or so. In its day, the opossum-sized animal was a giant of its family, as most mammals at the time were mouse-sized. It lived on Madagascar near the end of the Cretaceous period (145-66 million years ago). At first glance, it looks quite like a badger, but that similarity is only skin-deep, the team explains.

Adalatherium is simply odd. Trying to figure out how it moved, for instance, was challenging because its front end is telling us a completely different story than its back end” says Dr David Krause of the Denver Museum of Nature & Science, co-lead author of the paper.

“Knowing what we know about the skeletal anatomy of all living and extinct mammals, it is difficult to imagine that a mammal like Adalatherium could have evolved; it bends and even breaks a lot of rules”.

The bizarre features Dr Krause makes mention of include a greater number of vertebrae in the animal’s torso than in other mammals, a strange limb arrangement — crocodile-like hind legs with sprinting front legs that could be tucked underneath the animal as in modern mammals — front teeth like those of rabbits but back teeth that are completely unique. It was all topped off with a strange gap in the bones at the top of the animal’s snout.

Adalatherium belongs to an extinct group of mammals known as gondwanatherians, known since around the 1980s. We’ve only known the group from small fragments such as teeth and bits of jawbone, but even these showed that the gondwanatherians were strikingly different from today’s mammals. But we didn’t know where they fit in the larger tree of life due to this lack of material.

The discovery of Adalatherium thus represents a massive break for our understanding of gondwanatherians. It is the first reliable evidence of the shape and structure of this family of mammals, and will help us piece together how they went about their lives. For example, its hind legs seem tailored to digging, but its front legs are indicative of an animal that evolved to run at great speeds.

Its teeth are indicative of a herbivore lifestyle, computer micro-tomography imaging revealed, but the structure of its back teeth is unlike that of any mammal, fossil or alive, ever seen. The authors admit that they have no clue why they’re shaped the way they are, or for what purpose.

All in all, the animal likely grew to about 3.1kgs in its adult years. While it lived, Madagascar had already been separated from Africa for over 150 million years and from the Indian subcontinent for over 20 million years.

“Islands are the stuff of weirdness,” says Krause, “and there was therefore ample time for Adalatherium to develop its many extraordinarily peculiar features in isolation.

Adalatherium is an important piece in a very large puzzle on early mammalian evolution in the southern hemisphere, one in which most of the other pieces are still missing,” adds Hoffmann.

The paper “Introduction to Adalatherium hui (Gondwanatheria, Mammalia) from the Late Cretaceous of Madagascar” has been published in the Journal of Vertebrate Paleontology.

Fossil Friday: this ancient bottom feeder could have ‘invented’ modern sight

A new paper examines how life first developed advanced eyes and sight, and how this led to an “evolutionary arms race” around 500 million years ago. The findings rely on radiodont fossils, a group of arthropods that were abundant in the ocean at the time.

Artist’s reconstruction of ‘Anomalocaris’ briggsi.

The radiodont order, meaning “radiating teeth”, is comprised of many species with a similar body layout — a head and a pair of segmented limbs that would capture prey. They had circular mouths with sharp, serrated teeth, and were roughly squid-shaped. They likely inhabited the deeper layers of the ocean, at around 1000 meters in depth. Due to the low light levels there, they evolved large, sophisticated eyes in order to catch prey. But this ‘sensor’ upgrade would send ripples throughout life on the planet, the authors explain, making vision a driving force in evolution as it pitted predator against prey.

See food, eat food

“Our study provides critical new information about the evolution of the earliest marine animal ecosystems,” said Professor John Paterson from the University of New England’s Palaeoscience Research Centre, lead author on the study.

“In particular, it supports the idea that vision played a crucial role during the Cambrian Explosion, a pivotal phase in history when most major animal groups first appeared during a rapid burst of evolution over half a billion years ago.”

The development of complex eyes allowed animals to perceive their surroundings better than ever before, which also helped predators spot prey more easily. But sight can also warn the hunted of the hunter, so it became a very powerful driver of evolution — after all, the one with poorer sight might not make it through the day. It has retained its importance up to today when virtually every ecosystem and ecological interaction on the planet is shaped by sight.

Acute zone–type eye of ‘A.’ briggsi. Image credits John R. Paterson, Gregory D. Edgecombe, and Diego C. García-Bellido, (2020), Science Advances.

The fossils used in this study were first unearthed around a century ago at Emu Bay Shale on South Australia’s Kangaroo Island and were comprised of isolated body parts. However, initial attempts to reconstruct the animals based on their fossils were quite unsuccessful and resulted in several “Frankenstein’s monsters”, the authors note. Over the decades, as more radiodont material was discovered, including whole bodies, we’ve gained a better understanding of these animals, their body structure, diversity, even possible lifestyles. Still, the specimens from Emu Bay Shale had some unique properties.

“The Emu Bay Shale is the only place in the world that preserves eyes with lenses of Cambrian radiodonts. The more than thirty specimens of eyes we now have, have shed new light on the ecology, behavior, and evolution of these, the largest animals alive half-a-billion years ago,” says Associate Professor Diego García-Bellido from the University of Adelaide and South Australian Museum, a co-author of the paper.

The team worked with these fossils before. They published two papers describing the fossilized eyes recovered from the site. The first one looked at isolated eye specimens of up to one centimeter in diameter, which remain unassigned to a species up to now. The second paper analyzed the eyestalks of Anomalocaris, a top predator in its day that grew up to one meter in length. The current paper, according to the authors, identifies that first, unknown species: ‘Anomalocaris’ briggsi, a new genus that “is yet to be formally named,” Prof. Paterson said.

Acute zone–type eye of ‘A.’ briggsi. Image credits John R. Paterson, Gregory D. Edgecombe, and Diego C. García-Bellido, (2020), Science Advances.

“We discovered much larger specimens of these eyes of up to four centimetres in diameter that possess a distinctive ‘acute zone’, which is a region of enlarged lenses in the centre of the eye’s surface that enhances light capture and resolution.”

The large lenses of these animals suggest that they could work in the dim light of the deep sea, and were likely very similar to those of modern amphipod crustaceans (a type of prawn-like creature). Anomalocaris briggsi primarily hunted plankton by filtration through its appendages; its eyes helped it spot its meals from the bottom of the ocean.

The body structure of these fossil species also showcases how different feeding strategies dictated differences in sight.

“The predator has the eyes attached to the head on stalks but the filter feeder has them at the surface of the head. The more we learn about these animals the more diverse their body plan and ecology is turning out to be,” says Dr Greg Edgecombe, a researcher at The Natural History Museum, London and co-author of the study.

“The new samples also show how the eyes changed as the animal grew. The lenses formed at the margin of the eyes, growing bigger and increasing in numbers in large specimens — just as in many living arthropods. The way compound eyes grow has been consistent for more than 500 million years.”

The paper “Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology” has been published in the journal Science Advances.

Fossil friday: ancient feathers help explain how cassowaries got shiny

New research is helping scientists understand what ancient feathers look like — and why cassowaries are so shiny.

Cassowaries are flightless, blue-headed birds, with distinctive feet that are designed to run, not perch. Along with emus, ostriches, and kiwi birds (to whom they’re related) cassowaries are part of a lineage (the paleognath family) that split off from more ‘normal’ birds like chickens, ducks, and songbirds 100 million years ago. And, while we do know that the songbird family produces its iridescent colors through the physical structure of their feathers, we didn’t know how the cassowaries got their shine.

Sampling map of the two fossils from the Green River Formation, Wyoming.
Panels on the right show fossil melanosomes similar to black (sample 5, C) and iridescent melanosomes in livingbirds (samples 7 and 8 / D and E).
Image credits Chad M. Eliason and Julia A. Clarke2, (2020), Science.

But two fossils described in a new study in the journal Science Advances helps answer that question, while also telling us of how birds used to look 52 million years ago.

Old feathers

“A lot of times we overlook these weird flightless birds. When we’re thinking about what early birds looked like, it’s important to study both of these two sister lineages that would have branched from a common ancestor 80 million or so years ago,” says Chad Eliason, a staff scientist at the Field Museum and the paper’s first author.

Humans and other mammals create color in their skin or hair/fur through the use of pigments, mostly melanin. Birds and insects, however, also use the microscopic structure of their tissues to produce some of their colorations, such as the dazzling iridescent, glossy, or rainbow effects on their feathers and wings.

The cellular constructs that carry pigment are called melanosomes, and different shapes or arrays of melanosomes are used to produce the range of colors we see in nature. Birds’ feathers use keratin in a similar way, altering its microscopic structure to change the way it reflects light (and thus the color we perceive them to be). Their structure also creates the perception of texture (such as matte or glossy) through the way they reflect light.

Different mechanisms of gloss production in birds.
Image credits Chad M. Eliason and Julia A. Clarke2, (2020), Science.

But these color-creating structures haven’t been found in fossilized paleognath feathers up to now. The team, who has a background in structural color analysis of birds and dinosaurs, found that cassowary feathers also produce structural colors, but by using a different approach than modern birds. Instead of having these structures in their barbules (tiny structures that cover the feathers), they concentrate them in the rachis, the middle trunk of the feather. Their blue heads are also a product of structural coloring, the team explains.

The team then looked at a 52-million-year-old relative of the cassowary, known as the Claxavis bird. It lived in today’s Wyoming and is known from some exceptionally well-preserved fossils that include feather imprints, making it ideal for this study.

“You can look at a fossil slab and see an outline of where their feathers were, because you kind of see the black stain of melanin that’s left over, even after 50 million years or so,” explains Eliason. “We peeled off little flakes of the fossil from the dark spots of melanin, and then we used scanning electron microscopes to look for remnants of preserved melanosomes.”

The melanosomes in the fossilized barbules were long and thin, having the rough shape of green beans, which the team found is associated with iridescence in modern birds. The team says this is strong evidence in favor of ancient paleognath feathers exhibiting structural color. Furthermore, this study also provides the first evidence of structural color in the feathers of paleognaths, helping us understand how cassowaries got so shiny.

Despite this, the team doesn’t know why the two bird families evolved different mechanisms for such coloration. Eliason believes that flightlessness allowed these birds more room to experiment with their feathers, as they didn’t need to keep them aerodynamic.

“Needing to be able to fly is a very strong stabilizing force on wing shape,” says Eliason. “Losing that constraint, that need to fly, might result in new feather morphologies that produce gloss in a way that a flying bird might not.”

“[The findings] give us a glimpse into the time when dinosaurs were going extinct and the birds were rising,” he adds. “Studying these paleognaths gives us a better understanding of what was happening there because you can’t just study neognaths (modern birds); you need to study both sister clades to understand their ancestors.”

The paper “Cassowary gloss and a novel form of structural color in birds” has been published in the journal Science Advances.

Fossil Friday: oldest-known scorpion was a pioneer of life on dry land

A set of fossils collected 35 years ago belonged to the oldest-known scorpion species to date, a new study reports.

The fossil (left), its respiratory and circulatory organs (center) and a modern-day scorpion (right).
Image credits Andrew Wendruff et al., (2020), Nature.

The scorpion lived around 437 million years ago and was surprisingly versatile, having the ability to breathe both on land and underwater, the team explains. This fossil helps us make better sense not only of the scorpions’ evolutionary path, but also of how animals transitioned from an aquatic lifestyle to living on dry land.

The first scorpion

“We’re looking at the oldest known scorpion — the oldest known member of the arachnid lineage, which has been one of the most successful land-going creatures in all of Earth history,” said Loren Babcock, an author of the study and a professor of earth sciences at The Ohio State University.

In a new study describing the fossils, researchers named the new species Parioscorpio venator, meaning “parent scorpion hunter”. The fossil was first unearthed in 1985 in Wisconsin at a site that was once a shallow pool on the base of an island cliff face. For 30 years, it was kept in a museum at the University of Wisconsin until Andrew Wendruff, paper co-author and now an adjunct professor at Otterbein University in Westerville, decided to examine it in detail.

This scorpion is about 2.5 centimeters long, similar to many wild scorpions today. Wendruff looked at the fossil under a microscope, taking high-resolution photographs of it from different angles. This process helped highlight bits of the animal’s internal organs, allowing Wendruff to identify its venom appendages and the remains of its respiratory and circulatory systems.

The fossil and interpretative drawing.
Image credits Andrew Wendruff et al., (2020), Nature.

This system is almost identical to those of modern scorpions (which are exclusively land-living) but function more closely to those of horseshoe crabs (which are predominantly aquatic but can breathe on dry land for short periods of time).

The discovery provides new information about how animals transitioned from living in the sea to living entirely on land: The scorpion’s respiratory and circulatory systems are almost identical to those of our modern-day scorpions — which spend their lives exclusively on land — but operate similarly to those of a horseshoe crab, which lives mostly in the water, but which is capable of forays onto land for short periods of time.

The oldest-known scorpion prior to this study had been found in Scotland and dated to about 434 million years ago — it was one of the first animals (that we know of) to live fully on land. This fossil, found in Wisconsin in the Brandon Bridge Formation, is between 1 million and 3 million years older, the authors explain. They were likely alive between 436.5 and 437.5 million years ago, during the late Paleozoic era.

“What is of even greater significance is that we’ve identified a mechanism by which animals made that critical transition from a marine habitat to a terrestrial habitat. It provides a model for other kinds of animals that have made that transition including, potentially, vertebrate animals. It’s a groundbreaking discovery.”

The paper “A Silurian ancestral scorpion with fossilised internal anatomy illustrating a pathway to arachnid terrestrialisation” has been published in the journal Scientific Reports.

Fossil Friday: the first dino brain (we’ve ever found)

An inconspicuous brown pebble found on a beach near Bexhill, Sussex could very well be the first piece of fossilized dinosaur brain tissue we’re ever found.

The fossil brain.
Image credits Jamie Hiscocks.

Found in 2004 by an amateur fossil hunter, the rock is a brain cavity cast of an Iguanadon-type dinosaur. While similar fossils have been found before, there’s something that makes this finding unique. A thin layer on its surface appears to be mineralised dinosaur brain tissue — the first time fossilized brain tissue has ever been found for land vertebrates.

“The most striking thing is that something as delicate as brain tissue, and which you wouldn’t expect to ever see, has been preserved,” said paper co-author Alex Liu.

“It just speaks volumes [about] the spectacular preservational quality that can be obtained in the fossil record even 130 million years after this dinosaur is alive.”

Iguanodons were large herbivores which lived 125 million years ago. They could grow up to 8 meters (26.3 feet) long, walk on either two legs or all four, and had fearsome sharp spikes on their thumbs. The cast fossil was discovered near other dinosaur remains, including rib sets and leg bones. It measures roughly 10 by 5 cm (4 by 2 inches), and the team believes it’s about one third the size of the animal’s brain cavity.

Finding the fossil so close to the bones suggest it belonged to an Iguanadon relative, but pinning it on a species has proved a bit tricky. The age of rocks where the cast was found, at 133 million years old, is several million years earlier than the known appearance of Iguanodon, said Liu.

“We can’t say it is from the same organism, but it is from a fairly large dinosaur,” said Liu.

Still, using x-ray investigation techniques, the team produced a virtual 3D model of the fossil to explore its structure and formation. They believe the dinosaur probably toppled into a lake or swamp, with the head coming to rest upside down. In the oxygen-poor, acidic environment, part of the brain was quickly mineralized while the rest decayed, The skull cavity was then filled with sediment, bone fragments and other material.

CT scan of the fossil revealed numerous smaller, complex structures. White bar is 10 mm long.
Image credits University of Cambridge.

Using a technique known as scanning tunneling microscopy, they analyzed the layer of mineralized tissue on the fossil’s surface. They found “very detailed bundles” of assumed collagenous fibers, which are usual in the protective tissues around the brain. Throughout these bundles, there were open tubes that “branch and run around the edges of the specimen”, most likely capillary blood vessels.  According to Liu, the discovery finally offers some hard facts on what dinosaur brains might have looked like.

“Previously, anything we have known about dinosaur brains has had to be inferred from either comparison with what we think are modern relatives – so reptiles and birds – or just guessed from the shape of the structure on the impression of the brain on the brain case itself,” he said.

Up to now, we’ve been relying on observations performed on modern reptiles, the authors write. which have led to some wrong assumptions about dinosaurs. For example, we’ve assumed that they had brains surrounded by a thick membrane, with the actual “brain” part taking up just half of the available space. But the authors note their analysis only reveals a millimeter-thick layer of protective tissue covering what resembles brain underneath.

“That would suggest that the brain of the dinosaur did fill most of the volume of that brain case and therefore it might have had a larger brain that we previously gave it credit for,” said Liu.

The authors note however that it’s possible the features are a result of the upside down burial of the skull — which would have pushed the brain against the skull.

The paper will now undoubtedly come under a lot of scrutiny from the paleontological society. For starters, up to now, we’ve believed that brains simply couldn’t fossilize. But should the paper successfully pass peer review, it will constitute a breakthrough of our understanding of dinosaur and bird brain evolution.

The full paper “Remarkable preservation of brain tissues in an Early Cretaceous iguanodontian dinosaur” has been published by the Geological Society, London, Special Publications.