Tag Archives: trilobite

#FossilFriday: Amazing 429 million-year-old trilobite eye saw the world like modern insects

Aulacopleura kionickii. Credit: Brigitte Schoenemann.

When Brigitte Schoenemann, a paleontologist at the University of Cologne in Germany, bought a trilobite fossil, she meant it as a cute collector’s item. But being an expert on the evolution of vision, the researcher noticed something unusual about her specimen. Turned out that one of the fossil’s eyes revealed the anatomy of the lens and receptor cells. In her new study, Schoenemann shows that the 429-million-year old creature’s eye was remarkably modern, resembling today’s bees and dragonflies.

Most fossils preserve bones, teeth, and other hard tissue. But finding fossilized cellular structures for such a delicate type of tissue such as the eye is truly exceptional.

The fossilized trilobite Aulacopleura koninckii, which is only 1-2 millimeters in height, was discovered in 1846 in the Czech Republic. It has two protruding semi-oval eyes on the back of its head, one of which was broken off.

Using digital microscopy, Schoenemann and colleagues report that a number of internal eye structures are very similar to those of the compound eyes of modern insects and crustaceans.

One such structure is the ommatidia, a visual unit that is made up of light-detecting cells grouped around a transparent tube called a rhabdom (rodlike structures found in the eyes of insects). A thick lens and what looks like a crystalline cone topped each visual unit, directing light through them before being focused onto the rhabdom.

Aulacopleura kionickii’s left eye. Credit: Brigitte Schoenemann

So how did it see? Very differently from humans, that’s for sure. Eyes made up of dozens of facets would have generated a mosaic of images, where each image captures a snapshot of the trilobite’s environment. This would have made the creature well adapted to distinguishing obstacles, shelters, shapes, and other organisms — particularly predatory cephalopods known to feast on trilobites.

These findings point towards the fact that the vision of modern insects and crustaceans is based on adaptations gained over half a billion years ago.

Trilobites were highly successful, first appearing around 520 million years ago during the Cambrian explosion, an age when biodiversity suddenly swelled exponentially. The three-lobed creatures flourished in the ancient seas, ranging in size from as small as a fingernail to as large as a small car. They eventually went extinct about 250 million years ago, before the rise of the dinosaurs.

Drawing from previous examinations of trilobites, the researchers in Germany also inferred the habitat of Aulacopleura. Judging by its eye anatomy, the ancient creatures likely lived in bright and shallow water. It must have also been most active during the day.

The findings were reported in the journal Scientific Reports.

Trilobite and eye.

World’s oldest eye found in a fossil in Estonia is very similar to today’s eyes

A newly-discovered fossil may contain the oldest eye ever found, a new paper reports.

Trilobite and eye.

S. reetae and its compound eye. (B) Head region. (C) Fields of view. (D) Abraded part of the right eye. Arrowheads indicate the ommatidial columns. (E) Lateral view of the right eye with schematic (F).
Image credits Euan Clarkson et al., 2017, PNAS.

An “exceptional” find offers us a unique glimpse into the evolutionary history of the eye. A 530-million-year-old fossil discovered by an international team of researchers could contain the oldest such sensory organ we’ve ever seen, they report. The trilobite (species Schmidtiellus reeta) sports an early model of the eyes still used by many animals today, including crabs, bees, and dragonflies.

Between 541-251 million years ago, during the Paleozoic era, the ancestors of today’s spiders and crabs were enjoying the time’s oceans and seas. They used an early form of compound eye to help them navigate — an organ consisting of tiny visual cells laid out in an array. Judging from the one found in the fossil from Estonia, their eyes were quite similar to what you might see on a modern bee. The team behind the discovery said their findings suggest that compound eyes have changed little over 500 million years.

“This exceptional fossil shows us how early animals saw the world around them hundreds of millions of years ago,” said lead author Professor Euan Clarkson from the Edinburgh University.

“Remarkably, it also reveals that the structure and function of compound eyes has barely changed in half a billion years.”

Only the animal’s right eye was found, and it was partly worn away, which gave the researchers a clear view of its interior. This made it easy for the team to record the details of its internal structure and function, as well as facilitating its comparison with modern compound eyes.

Internal structures of the eye.
Image credits Euan Clarkson et al., 2017, PNAS.

The team believes that the animal had poor vision compared to many animals today, but the eye was very likely more than enough for the trilobite to see predators and obstacles. It consisted of approximately 100 cells (called ommatidia), spaced farther apart than those in contemporary compound eyes.

Unlike most eyes, however, the fossil eye doesn’t have a lens. The team thinks this is because of the species relative primitiveness, as it lacked parts of the shell needed for lens formation.

“This may be the earliest example of an eye that it is possible to find,” said Professor Brigitte Schoenemann of Cologne University, the paper’s co-author. “Older specimens in sediment layers below this fossil contain only traces of the original animals, which were too soft to be fossilised and have disintegrated over time.”

According to the team, a more advanced compound eye capable of capturing images in a higher resolution developed in another trilobite species from the present-day Baltic region a few million years later.

The paper “Structure and function of a compound eye, more than half a billion years old” has been published in the journal PNAS.

Biochemist resurrects ancient trilobites by 3D printing them in metal

We’ve talked about 3D printing being useful in fields like engineering or medicine, but in the right hands it can create amazing pieces of art and bring back to life creatures gone for hundreds of millions of years.

Assistant professor Dr. Allan Drummond studies how cells adapt at the molecular level, focusing on the the translation of cellular genetic information into protein molecules. But as if his day job wasn’t interesting enough, his “night job” is 3D printing trilobites and other ancient beasts — from metal.

“We find their shells fossilized everywhere,” explains Drummond. “They’re museum staples – but we rarely see what they really looked like, with all of their soft tissues (legs, antennae, gills) intact.”

Trilobites emerged in the mid Cambrian, some 520 million years ago, reigning the global waters for over 200 million years before ultimately going extinct. They’re among the most common fossils you can find, but just like Drummond says, fossils are almost always incomplete. So he set out on a valiant quest: to recreate trilobites through 3D printing.

He started out where any serious researcher would: online forums.

The first step was to look at as many trilobites as possible and choose one,” he recalls. “I’ve always loved these fossils, but the moment they turned from fossils, into living organisms for me, was when I saw the new generation of preparations displayed at Chicago’s Field Museum. I couldn’t believe what I was seeing. In my mind, trilobites were flat, if beautiful, primitive creatures. Seeing those preparations made it clear how not-flat and not-primitive they were.”

The first step was deciding on the right species. Many trilobites have fragile spines, so he removed those because they could easily break. Ultimately, he settled on Ceraurus, one of the more iconic and sturdier species.

“Ceraurus is ideal,” he says. “They have long yet substantial genal [head segement] and pygidial [tail segment] spines, complex thoracic armor, gorgeous curves, unmistakable trilobite form. Enough detail to warrant 3D printing, enough structural solidity to survive it.”

The next step was to draw the trilobite – first by hand, and then in Inkscape. The modelling was done in Blender, an open source 3D computer graphics software. It was a very slow and delicate process.

“It was laborious, detail-oriented work over many, many hours,” says Drummond. “With several points where I wondered why I was doing this, and ‘wouldn’t it would be more fun to read a book or watch YouTube?’”

But thankfully, he didn’t give up — because the results are simply stunning.

Through 3D printing, he created molds and ultimately cast the trilobites from steel, bronze, and eventually silver.

“Using liver of sulfur, a poorly understood quasi-alchemic brew, I oxidized these pieces, creating a patina, then polished the patina off of the raised parts,” explains Drummond.

It’s not perfect, but it’s damn close to it — and it’s simply stunning, thrilling paleontologists like Dr. Glenn Brock.

Since then, Drummond went to create a folded scarab, a giant scarab and even a female damselfly, which you can check out and buy from here.

 

Fossil Friday: Dicranurus monstrosus

Dicranurus monstrosus fossil, a balloon’s worst nightmare.
Image credits wikimedia user Daderot

When a species almost one hundred times bigger than you, who has access to nukes and can go to space, discovers your remains a few million years after you die and still decides to call you “monstrosus” you must be doing something very right survival-wise. Dicranurus (meaning “twin headtail”) was a genus of trilobites that lived in the lower Devonian, some 419 to 393 million years ago in a shallow sea, corresponding to today’s Oklahoma and Morocco.

The fossil you see here belongs to species known as Dicranurus monstrosus and for good reason – living in a time when fish started evolving solid jaws and took to preying upon trilobites, Dicranurus‘ answer was to go full out and grow 18 pairs of spikes to deter predators from any direction. The most impressive pair were the occipital spines on the animal’s head, the ones that resemble ram’s horns, for which the genus gets its name.

This specimen was found in Morocco and is currently housed at the Huston Museum of Natural Science.

 

365 million year old trilobites show first signs of molting

Trilobites were some of the most dominant creatures on the face of the planet, thriving from the mid Cambrian 521 million years ago to the start of the Mesozoic, 250 million years ago. Paleontologists have now found the earliest evidence for molting – a trilobite shedding its skin 365 million years ago.

Image credits: B. Błażejowski et al.

Fossils can reveal many things about an ancient environment; they can help you date it, they can reveal how the climate was shaping up, and they can demonstrate a particular behavior frozen in time, as is the case with the piece of shale Błażej Błażejowski excavated. Błażejowski based out of the Institute of Paleobiology at the Polish Academy of Sciences, was working on the Kowala Quarry in Poland’s Holy Cross Mountains when he found this special trilobite.

The trilobite, looking like a big armored bug, was caught in the act of shedding its exoskeleton, a process called molting. Molting refers to an animal routinely casts off a part of its body (often, but not always, an outer layer or covering), either at specific times of the year, or at specific points in its life cycle. Cats do it with their fur, snakes do it with their skin, and chicken do it with their features, but more remarkably, some insects do it with their entire exoskeleton, basically ripping themselves out of their bodies in an alien-like fashion. Błażejowski quickly understood this was also what his trilobite was going through.

Subsequent X-ray analysis confirmed his initial theory and revealed even more information about the fossil. The creature is a Trimerocephalus, an eyeless trilobite roughly 6.3 inches long and 3 inches wide that lived towards the end of the Devonian. Unfortunately for this specimen, the process seems to have killed him.

“The animal died within the sediment shortly after extricating itself from the old exoskeleton,” Błażejowski and his co-authors write. “The cause of mortality is, of course, not known but might be due to stress of molting or possibly, given the context, death by hypoxia or hydrogen sulfide toxicity within the sediment.”

The fact that such a complex process emerged so long ago is not a surprise, as paleontologists suspected trilobites molted just like modern insects, but finding a fossil that actually captures the process is quite fortunate.

Journal Reference: Błażejowski, B. et al. A moment from before 365 Ma frozen in time and space. Sci. Rep. 5, 14191; doi: 10.1038/srep14191 (2015).

New fossil shows 450 million years old mother love

An international team of geologists captured a prehistoric portrait of parental care deep in the fossil record. The team led by Leicester geologist Professor David Siveter revealed a ‘sea nursery’ which features a species new to science.

This new species was found with specimens preserved incubating their eggs together with probable hatched individuals. As a result, the team has named the new species Luprisca incuba after Lucina, goddess of childbirth in Roman mythology, alluding to the fact that in these ancient fossils, the mother literally sits on the eggs.

This fossil find not only highlights a remarkable reproductive and brood-care strategy conserved for at least 450 million years, but it is also the oldest confirmed occurrence of ostracods in the fossil record. Ostracods are a class of crustaceans sometimes known as seed shrimp. Some 70,000 species have been identified, and they are still alive today. Ancient ostracods lived alongside trilobites in poorly oxigenated waters

Professor Siveter, Emeritus Professor of Palaeontology at the University of Leicester, said:

“This a very rare and exciting find from the fossil record. Only a handful of examples are known where eggs are fossilized and associated with the parent. This discovery tells us that these ancient tiny marine crustaceans took particular care of their brood in exactly the same way as their living relatives.”

The new fossils are truly spectacular! They measure 2-3 mm in length, and are exceptionally well preserved – conserving not only the shell but also the soft parts of the animal that are almost always lost in the fossil record.

Journal Reference:

  1. David J. Siveter, Gengo Tanaka, Úna C. Farrell, Markus J. Martin, Derek J. Siveter, Derek E.G. Briggs. Exceptionally Preserved 450-Million-Year-Old Ordovician Ostracods with Brood Care. Current Biology, 13 March 2014 DOI: 10.1016/j.cub.2014.02.040

The first animal to curl into a ball

This defensive strategy has been used for a very long time, but if you were to take a guess, how long would do you think that time was? A thousand years, ten thousand years, one million years? According to a new fossil unearthed by paleontologists, the answer is at least 510 million years!

Trilobites and balls

Specimen of the trilobite Mummaspis muralensis

Trilobites are a well known fossil group which inhabited the planet up until approximately 250 million years ago; no larger than a finger tip, this fossil is the earliest creature known to curl up in a ball, thus pioneering one of the most successful defensive strategies on the planet.

The animal, which is one of the oldest trilobites ever discovered, was found with tail tucked to head in a lump of rock, after it was buried by a sudden mudslide more than half a billion years ago; judging by the fossil, the trilobite hasn’t really perfected this technique, as it left small spaces between the spines in the tail that left parts of the head exposed to danger – but it did a remarkably good job judging by the flexibility of its body. Javier Ortega-Hernández, a paleobiologist at Cambridge University discovered the first fossil, and it didn’t take him a lot to discover the second one.

The Cambrian environment

The Cambrian is the first geological period of the Paleozoic Era, and it marked one of the most profound changes on Earth; previously, organisms were simple, and often unicellular. During the Cambrian, life simply exploded: multicellular life became common, environmental niches were filled, and the fight between predators and prey became much more fierce.

510 million years ago, emerging trilobites were faced with predators and other environmental dangers, and they started to experiment with various defensive techniques. To curl up in a ball proved highly successful, and it evolved to be used even in recent time,s by the ancestors of woodlice, armadillos, hedgehogs and pangolins.

“If you can roll up and protect your vulnerable legs its obviously going to be an evolutionary advantage and the trilobites were the first group of animals to solve this problem,” said Richard Fortey, the British paleontologist at the Natural History Museum in London. “It’s pretty obvious from this paper it was a trick they learned very quickly. They were already doing it by the early Cambrian. Running away is good, but standing your ground and protecting yourself is equally good. It’s been imitated in the animal kingdom many times,” he said.

Actor Johnny Depp gets 505 million years old fossil named after him

Usually, species are named after defining trait, or sometimes, more rarely, after somebody famous in the field, but every once in a while, they get some rather cooky names – like is the case with Kooteninchela deppi.

Cambrian and scrissors

fossil johnny depp

Pronounced Koo-ten-ee-che-la depp-eye, the 505-million-year-old fossil is a distant relative of lobsters and scorpions, and it got this name due to its debatable resemblance of Edward Scissorhands, a character famously played by Johnny Depp.

“When I first saw the pair of isolated claws in the fossil records of this species I could not help but think of Edward Scissorhands. Even the genus name, Kootenichela, includes the reference to this film as ‘chela’ is Latin for claws or scissors. In truth, I am also a bit of a Depp fan and so what better way to honour the man than to immortalise him as an ancient creature that once roamed the sea?”

But it’s not just fun and games. Kooteninchela deppi is helping researchers fill in the puzzle of the Cambrian life puzzle, when life absolutely exploded and most modern species started emerging. The Cambrian is the first geological period of the Paleozoic Era, lasting from 541.0 ± 1.0 to 485.4 ± 1.9 million years ago. The vast majority of animals in the Cambrian period were aquatic, with trilobites as the dominant life form. The biosphere changes that occurred in this period were immense, and towards the end of this period, burrowing animals had destroyed the mats through bioturbation, and gradually turned the seabeds into what they are today; however, as a consequence, very many species depending on these mats went extinct.

So where does Kooteninchela fit in?

fossil johnny depp 2

Our scissory species was approximately 4 cm long, and it lived in very shallow seas, similar to modern coastal environments. However, the sea temperature back then was much hotter than it is today, and even though coral reefs weren’t established yet, it lived in a similar environment consisting of sponges.

It was either a hunter or a scavenger, using its elongated spines to capture prey or search for prey hiding in the sediment, scuttling on the seafloor with its millipede-like legs and going for the occasional swim. It also had large eyes composed of many lenses like the compound eyes of a fly. David Legg adds:

“Just imagine it: the prawns covered in mayonnaise in your sandwich, the spider climbing up your wall and even the fly that has been banging into your window and annoyingly flying into your face are all descendants of Kooteninchela deppi. Current estimates indicate that there are more than one million known insects and potentially 10 million more yet to be categorised, which potentially means that Kooteninchela Deppi has a huge family tree.”