Happy National Fossil Day 2021!

National Fossil Day poster for 2021 by the National Park Service.

Today is International Fossil Day! 

International Fossil Day  is an initiative by the International Paleontological Association and the National Park Service (National Fossil Day in the U.S.), the idea is to spread the interest in the life of the past and many different organisations and museums around the world host events or activities today. Of course we, the Time Scavengers team, have to participate in this, there can never be too much paleo-related fun! 

We want to celebrate IFD by showing off our team members’ favourite extinct species or individual fossils, some facts about the species or individual and why we picked them as our favourites.

Click here to visit the National Park Service website to learn more about National Fossil Day, and here to visit the International Palaeontological Association to learn more about International Fossil Day!

Linda

A fossil cave bear skeleton. Image credit: Wikipedia.

Most of my paleontology lectures during my undergrad took place in small rooms somewhere deep in the side wings of the institute building, on the edge of the paleontological collection/museum that is located within the institute. Whenever me and my friends were waiting for our professors to show up, we would stare and marvel at the exhibited specimens. I vividly remember walking into that area for the first time, it is dominated by a huge, mounted skeleton of an adult cave bear (Ursus spelaeus) and I was completely blown away by the sheer power it radiates. I didn’t care too much about the T. rex skull cast around the corner that most others found so fascinating. From that first day of paleo classes, having my own mounted cave bear skeleton has been on the top of my bucket list. U. spelaeus lived during the Pleistocene across both northern Asia and Europe and went extinct during the Last Glacial Maximum about 24,000 years ago. They are closely related to brown bears (Ursus arctos), the two species have a last common ancestor about 1.2 million years ago. Even though they were huge, powerful bears that were reaching 3.5m (11.5ft) when standing upright, with large teeth and fearsome claws, it’s currently thought that the majority of the western populations were eating an almost exclusively vegetarian diet! Recently, two very well preserved frozen cave bear carcasses have been discovered in two separate areas of thawing permafrost in Russia, an adult and a cub, both with almost all soft tissue present and intact. I’m already excited and looking forward to reading all the new research that will be done on these specimens!

Maggie 

Cast of U. anceps skull. Image credit: Wikipedia.

I worked at the Field Museum of Natural History during the summer of 2015 and that experience was what solidified my interest in paleontology. I worked with my supervisor on Eocene mammals from the western United States and had some of my first experiences doing large scientific outreach events during that summer. Because of that summer I will always have a soft spot for Uintatheres!

Uintatheres (U. anceps) lived during the Eocene in North America and were large browsers. These animals looked similar to rhinos but male U. anceps had six knob-shaped protrusions coming off of their skulls. Part of my experience working with these fossils was reorganizing the collections space that housed the skulls, they are incredibly heavy! I mentioned that U. anceps were browsers, but they also had long canine teeth that resemble the canines of saber tooth cats. These teeth may have been used as a defense mechanism but also may have played a role in how they plucked leaves from plants. While I don’t work on Eocene mammals now, Uintatheres will always be special to me for the role they played in getting me excited about paleontology and scientific outreach!

Whitney

Whitney next to Asteroceras stellare.

I cannot pick just one fossil to highlight right now, so here are two of my favorites! In 2016, I was studying in England and visited the Natural History Museum in London where I saw an incredible ammonite, Asteroceras stellare. Asteroceras was a large ammonite that lived during the Early Jurassic and whose shell reached nearly three feet in diameter. Asteroceras was a nektonic carnivore who might have fed on fish, crustaceans, and bivalves.

Whitney in front of an ichthyosaur!

My favorite vertebrate fossil is the Ichthyosaur. I loved visiting the Jurassic Coast in England and got to explore Lyme Regis, both the birthplace of Mary Anning and a town that had references to paleontology everywhere you looked. You can see ichthyosaur fossils in both the Lyme Regis Museum and the Natural History Museum in London and at the NHM, you can see some of the specimens that Mary Anning and her family had collected along the Jurassic Coast. Ichthyosaurs (Greek for “fish lizard”), are marine reptiles that lived during much of the Mesozoic and were thought to be one of the top aquatic predators of their time.

Mike

Mike in front of an American mastodon statue!

I have three favorite extinct species: the American mastodon (Mammut americanum), the dinosaur Parasaurolophus, and the chalicothere Moropus elatus. Mastodons are distant relatives of the elephants, and they seem to be overshadowed by the wooly mammoth. However, both lived in North America until the end of the Pleistocene epoch. I’ve always thought that Parasaurolophus was an elegant duck-billed dinosaur, and I’ve seen them featured in several movies in the Jurassic Park series. I think that chalicotheres are so bizarre! Distant relatives to horses, rhinos, and tapirs, imagine a big draft horse with giant claws instead of hooves! I’ve seen several skeletons of these over the years. Moropus elatus went extinct in the Miocene epoch.

Mike next to a Moropus elatus skeleton!
A statue of Parasaurolophus.

Alex

Like anyone in paleo would tell you I can’t pick one particular fossil organism as my favorite. Currently my favorite fossil organism is the “bear-dog” known as Amphicyon ingens which would have been a formidable predator during the Mid-Miocene. The cenozoic was a time for innovation in mammals and bear-dogs were the best of both worlds. All the stoic grandeur of a bear and all the cute charm of a dog, what more could you want? The picture shown was taken at the American Museum of Natural History in New York City.

Amphicyon

Jonathan Jordan (Paleo Policy Podcast)

For me, the Mesozoic reigns supreme. However, my recent trip to the La Brea Tar Pits in Los Angeles gave me a greater appreciation for the Cenozoic era and mammalian evolution in general. While it may not be my favorite fossil ever, I was captivated by Panthera atrox’s look and the idea of an American Serengeti 340,000 to 11,000 years ago. Genetic analysis suggests with high likelihood that Panthera atrox is a close relative of the Eurasian Cave Lion (Panthera spelaea). After the Bering Strait land bridge was submerged by rising sea levels, Panthera atrox was isolated from its Eurasian relatives and became a distinct species that has been found as north as Alaska and as south as Mexico. Neat! Check out an image of Panthera atrox’s skull on the Smithsonian Learning Lab site!

Kristina

I’m fortunate to have worked on many different types of animals during my career, starting with dinosaurs, then moving to Devonian brachiopods and their encrusting organisms, and now working on much younger Pleistocene-aged animals that are still alive today. I mostly study biotic interactions, such as predation, so I thought I would share my favourite trace fossil (ichnotaxon), Caedichnus! Trace fossils are different than a body fossil because they show evidence (or traces) of an organism or its behaviour. In the case of Caedichnus, this trace fossil is created by a crab trying to break into the shell of a snail by peeling away at the shell opening (aperture) until it can reach the snail’s soft body. Imagine having a crab try to peel your shell back like an orange – scary! Caedichnus traces are useful for determining how many crabs were in an area, and identifying patterns of crab predation through space and time. I’m now using them to determine the impacts of climate change and human activity on crab fisheries since pre-human times.

Adriane

Like most of my colleagues above, it is incredibly hard for me to say which fossil is my favorite! So instead, I’ll talk about my favorite fossil group, the foraminifera. Foraminifera are single-celled protists that live in the surface ocean (planktic foraminifera) or in/on ocean sediments (benthic foraminifera). Planktic foraminifera are my favorites; they evolved about 175 million years ago, and still live in the global ocean today! One of the ways which we know about past climate states how the ocean behaved to such warming and cooling events of the geologic past is through analyzing the chemistry of fossil foraminifera shells, or tests! Foraminifera are also incredibly useful in studies of evolution, as they have a robust fossil record. Learn more about Foraminifera here!

Various planktic (surface-dwelling) foraminifera (marine plankton) species. Images are 60-100x.

What’s YOUR favourite extinct species? Let us know in the comments, maybe we will feature them in a future post!

How Eurypterids of the Finger Lakes, New York Lived and Died

Paleoecology and Taphonomy of Some Eurypterid-bearing Horizons in the Finger Lakes Region of New York State

Stephen M. Mayer

This news article was summarized by Alexander Favaro. Alexander Favaro is a first-generation student attending the University of South Florida, pursuing a B.S. in Geology. He hopes to follow his passion of being a paleobiologist. His interests have been broadly focused on paleoecology and understanding evolutionary trends. 

What data were used? The study used well-preserved fossils from the upper Silurian Fiddlers Green Formation in New York, the Lower Devonian Olney Member in Finger Lakes New York, Split Rock Quarry near Syracuse New York, and the Samuel J. Ciurca Eurypterid Collection at Yale Peabody Museum of Natural History. These data were used to make interpretations of eurypterid lifestyles and processes of fossilization. 

Methods: Sedimentological variables and the body and trace fossils found within a rock unit were used to interpret the depositional environment (what type of environment the rocks were formed in) of a formation. Field collection was done at the Phelps Member and Cayuga Junction (which are located in the Fiddlers Green Formation), as well as Split Rock Quarry in Syracuse, New York. The Yale Peabody Museum of Natural History was used to supplement eurypterid data through their collection. The position in which each eurypterid was found, as well as their size, was used to describe their age, ecology, and how they likely died.

Figure 1. Eurypterus remipes, which shows the U-shaped body posture. The metasoma (last 7-12 segments of the eurypterid) and telson (spine like protrusion at the end of the abdomen on the right of this image) were twisted 1260 in relation to the prosoma (head section) and mesosoma (first 1-6 segments of the eurypterid). This specimen was found in the Phelps Member, New York.

Results: Many eurypterid exuviae (shed exoskeleton) were found, while eurypterid bodies were less abundant. The most common eurypterid fossils found in Phelps were Eurypterus remipes. Cayuga Junction also possessed Eurypterus remipes but were far less common. At Split Rock Quarry, Erieopterus microphthalmus were found in localized calcareous (chalky limestone) bands. 

 The study found that between 61 carapaces, the average size of eurypterids in the Phelps Member fell between 15-25mm. The variations in size indicated that immature species and adults were living amongst each other. 

Since eurypterids were chelicerate arthropods (like arachnids, sea spiders, and horseshoe crabs), scientists have suggested that eurypterids would undergo a group spawning and then molt (shed their exoskeleton) together (similarly to a horseshoe crab). This would explain the high number of shed exuviae and variable size ranges found in the formations.

Fossil evidence indicated that eurypterid corpses were highly affected by currents, which would cause a variety of contortions in a carcass. The observed eurypterid corpse conditions were categorized as: a non-contorted corpse, an angular contortion up to 900, a U-shaped flexure of the body and tail (as seen in Figure 1), and a contortion where the body and tail flipped above or below the head (though this was rare). Aside from flexure of the body, some contortions were caused by sediment that anchored a section of the eurypterid while the un-covered portions moved freely due to current movement. Eurypterus remipes and Erieopterus microphthalmus both displayed similar contortions and so they were able to determine that the contortion patterns weren’t exclusive to one genus of eurypterid. 

Why is this study important? The study gave insight into the life and death of a once thriving taxon that has close relatives still alive today in the form of arachnids, sea spiders, and horseshoe crabs. Fossil evidence at Phelps suggested that eurypterids may have mass-molted, similarly to horseshoe crabs. The paleoecological evidence found gave a key insight into a behavior which has also been observed in modern, related organisms.

The big picture: The analysis performed on both trace fossils and carcasses gave both paleoecological and taphonomic (how an organism is fossilized after death) insight. Combined, taphonomy and paleoecology provides a more refined idea of how ancient organisms lived, died, and how their bodies would have been fossilized. 

Citation: Mayer, S. M. Paleoecology and Taphonomy of Some Eurypterid-Bearing Horizons in the Finger Lakes Region of New York State.