The Field Museum: Part 1 of 4.

Thanks to the readers of my blog, I got to go to the Field Museum in Chicago for my birthday. I took an airplane there. 

I stayed at a hotel downtown. In this picture I'm looking out the window at all the huge buildings and people and cars. On the window there was a sticker that said, "Due to a higher than normal insect population, we recommend keeping the windows closed." We kept the windows closed. 

I got to the Field Museum at 5:30 pm and waited to check in and stay overnight. Once we checked in, we put our sleeping bags down in the Cambrian area of the Evolving Planet exhibit. After that, we looked around in Evolving Planet. 

In front of the What is an Animal? exhibit

I saw some fossils of Ordovician coral and also one fossil of a huge orthocone nautiloid which was probably about three feet long. 

Here I'm pointing at an illustration of a Devonian lake with Eusthenopteron, Bothriolepis, a tetrapod in the background, and fish that I think are possible acanthodians. 

Ahhhhhhh!

This was an exhibit full of all different kinds of trilobites. They had my four favorite trilobites: Asaphus kowalewskii, Walliserops, Quadrops, and Psychopyge. It also had tiny agnostid trilobites called Peronopsis.  The Peronopsis were fossilized in a group, and this is not uncommon, because I often see photos of gregarious agnostids. 

This is the jawless fish exhibit. In the middle is my favorite one, a huge Drepanaspis fossil. There are also two tiny Tenaspis headshields, which look kind of like Bothriolepis without the arms or the jaws. 

This was a huge Dunkleosteus head shield that was even bigger than the one I saw at the Smithsonian. I slept right next to it because it turned out there was a glowing exit sign in the Cambrian exhibit. But I didn't mind sleeping next to Dunkleosteus! And I was close to a fossil of a huge Orodus shark that was approximately 25 feet long in life. There were also fossils of Stethacanthus, Symorium, Helicoprion, and Bandringa.

Here are the fossils of Helicoprion (on the right), Bandringa (in the middle), and Stethacanthus (on the left). Helicoprion lived from the Carboniferous to the Triassic, Bandringa lived in the Carboniferous Mazon Creek, and Stehacanthus lived from the late Devonian to the early Carboniferous. 

I saw one of the only known fossils of Tiktaalik, a bizarre tetrapod-like fish...  

...and the boomerang-shaped skull of Diplocaulus, a strange amphibian from the late Carboniferous and early Permian. 

I really liked the Carboniferous Forest section of Evolving Planet. The most obvious thing there besides the plants was the four foot long Arthropleura on the floor. There were insect noises coming from up in the "trees." There was also a real fossil of Arthropleura cristata. 

One of my favorite things in the whole museum was a pregnant ray, Heliobatis. 

Next up:


Part 2: My amazing behind-the-scenes tour of the collections room!


A million thanks to: Paul Mayer, Jane Hanna, University of Chicago Secular Student Alliance, Stephen & Kayla & Greta, Casey, Mike, Dave Monroe, PZ Myers, and the 72 incredible people who pitched in to help fund our trip to the Field Museum. 

Cephalaspis.

Cephalaspis (seff-uh-LAS-pis) was a bizarre-looking fish that lived in the early Devonian period in fresh water streams and estuaries. It had a horseshoe-shaped headshield, which it could have used for protection or for digging up prey. It probably dug up worms and other burrowing creatures to eat. There were also sensory organs on this headshield. 


Cephalaspis could grow to about one foot long, about the size of a trout. The headshield probably would have slowed Cephalaspis down, because carrying around a heavy shield would be hard to do, even in water, especially for a small fish. Cephalaspis certainly wasn't very fast, so it probably would have relied on the tough head shield for defense. 

Cephalaspis had two fins right behind the headshield, and also a long, powerful tail with what looks to me like muscle bands, similar to those on a lancelet. They were probably bottom dwellers, hiding among rocks and debris like modern catfish, sturgeon, and stingrays. 

Most fossils of armored fish only preserve the bony headshield, but in the case of Cephalaspis many fossils also reveal the tail. 


Cephaslaspis was a jawless fish, so it probably had to eat very small prey. But with its bony headshield, it still could have been a formidable hunter of these tiny creatures. It could easily dig up these tiny burrowers with its head and then suck them in quickly, like a modern angel shark. 


Cephalaspis probably had a similar lifestyle to Bothriolepis, a bizarre placoderm from the late Devonian.

References:

http://en.wikipedia.org/wiki/Cephalaspis

http://dinosaurs.about.com/od/tetrapodsandamphibians/p/cephalaspis.htm

http://www.prehistoric-wildlife.com/species/c/cephalaspis.html

http://palaeontology.palass-pubs.org/pdf/Vol%201/Pages%2099-105.pdf

Louisella.

Louisella was a priapulid worm that has been found in the Burgess Shale in British Columbia. It was one foot long, which meant it was the largest priapulid in the Burgess Shale. 

Louisella was a slender worm with feathery papillae running down the bottom of its body in two rows. These were possibly gills. It had a long proboscis on its head. Before the proboscis it had a ring of spikes pointing forward, which I think kind of looks like a crown. 

Like most Cambrian priapulids, Louisella was a predator, consuming small creatures such as hyoliths and swallowing them whole, front first. If Louisella swallowed hyoliths from the rear end, the spines of the hyolithid would get stuck in the worm's throat, possibly stab it, and prevent Louisella from eating any more hyoliths. Unlike its ferocious relative Ottoia, Louisella presumably was not as active, but it was almost certainly more active that Selkirkia, which would have found it hard to move in the first place.

© MARIANNE COLLINS

I believe that Louisella's large head spines prevented other priapulids from swallowing it while Louisella was small. The only priapulid that would have been likely to try to eat it would be Ottoia, which swallowed its prey head first. And if for some reason an Ottoia tried to swallow Louisella from the rear end, Louisella could just turn around and stab it. These spines would probably work against any other predator that tried to eat it. Even an arthropod would let Louisella go if it was stabbed in the right place, such as a joint or, as in the case of some arthropods, its softer underbelly. This is similar to the defense of Fieldia, which had a whole head covered in long, needle-like spines. But this is just my hypothesis about the use of the large spines on Louisella's head.

© SMITHSONIAN INSTITUTION – NATIONAL MUSEUM OF NATURAL HISTORY. PHOTOS: JEAN-BERNARD CARON

Some of the fossils of Louisella are very slender, while others are flatter and more sea cucumber-like. The holotype was one of these flattened specimens, which is what probably led Charles Doolittle Walcott to classify it as a holothurian, or sea cucumber. 

FOSSIL MALL

References:

http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=75&ref=i&

http://www.paleo.pan.pl/people/Dzik/Publications/PaleobiologyDzik.pdf

http://www.fossilmall.com/EDCOPE_Enterprises/invertebrates/invert12/invfossil-12.htm

The Crucible of Creation: The Burgess Shale and the Rise of Animals by Simon Conway Morris

http://en.wikipedia.org/wiki/Louisella

Pachytheca.

Pachytheca was a very primitive sphere-shaped plant that lived from the late Silurian to the early Devonian. Pachytheca is related to Prototaxites, so my hypothesis is that it is a fungus. It was up to 6mm long. 


This organism had a prominent outer layer. It's possible that in juvenile specimens this layer was thicker, and on the adults it was thinner. The structure of Pachytheca was made up of tubes. Thicker, stronger tubes on the outer layer, and thinner, more brittle ones on the inner layer. 

Some of the fossils look like marbles, while others look like tiny geodes. At first the organism was thought to have been a piece of a bigger plant or the tooth of a fish. Then it was incorrectly classified as an alga. 

Pachytheca and Prototaxites are now classified as Nematophytes, enigmatic organisms that were either plants or fungi. Pachytheca has been found mostly in western Europe, but they also lived in places such as Canada and Australia. 

References:

http://steurh.home.xs4all.nl/engpach/epachy.html

http://www.chertnews.de/Pachytheca.html

http://de.wikipedia.org/wiki/Pachytheca

Phlegethontia.

Phlegethontia is a snake-like amphibian that lived from the Carboniferous to the Permian period. It lived in swamps and probably, unlike most snakes today, spent most of its time swimming in water, like a frog or a newt. Phlegethontia was about one meter long and it ate small animals and insects.

Phlegethontia was found in the Mazon Creek, in Illinois, among other places. The skull had holes in it, and this made it light. My hypothesis is that Phlegethontia evolved this way because a lighter skull would be easier to lift, and therefore it would be easier for Phlegethontia to snatch a flying insect from the air, much like this adaptation makes it easy for a snake to strike quickly. The skull of Phlegethontia is similar to that of a snake.

Phlegethontia looked very much like a snake, suggesting a similar lifestyle, except more in the water than on land. Amphibians like Phlegethontia cannot permanently live on land without getting wet because they would dry out and die.

At one time there was something called Dolichosoma longissima. But this was an incorrect description and paleontologists realized that it was actually a member of the genus Phlegethontia. Now it is called Phlegethontia longissima.

References:

http://en.wikipedia.org/wiki/Phlegethontia

http://dinosaurs.about.com/od/tetrapodsandamphibians/p/phlegethontia.htm

Siphusauctum.

Siphusauctum is a newly discovered animal from the Burgess Shale. It is one of the weirdest animals from the Burgess Shale ever found. Siphusauctum was described by Jean-Bernard Caron, Curator of Invertebrate Paleontology at the Royal Ontario Museum, and Lorna J. O'Brien from the Department of Ecology and Evolutionary Biology at the University of Toronto, and was just announced.

One of the most obvious things about Siphusauctum is how enigmatic it is. It looked like a ctenophore on a stalk. Some scientists believe that it is related to the mysterious Dinomischus. Siphusauctum and Dinomischus both have a stem and a round calyx, but they are actually very different. Dinomischus's calyx is more like a flower than a ctenophore.

© Marianne Collins

Siphusauctum had a two-layered stem and a holdfast at one end, which was probably used to anchor it to the sea floor. It presumably could draw its holdfast into the stem and move along the sea floor to find a new place to anchor itself.

Siphusauctum had a very simple gut, which was just a tube with a round part at the end, which was the stomach. It just sucked in water along with tiny creatures and plants, which were its food.

The size range for Siphusauctum is 19 mm to 223 mm. There are variable sizes for stems, holdfasts, and calyxes on different individuals of the species. One thing that stands out about it are the comb rows on its calyx, which resemble those of ctenophores. Although the two are unrelated, Siphusauctum has noticeable similarities with the ctenophores.

Siphusauctum are sometimes found in large clusters, suggesting that the animal lived in groups, like the possibly related Herpetogaster, also from the Burgess Shale. Its species name is S. gregarium because it was gregarious, meaning it lived in groups. Siphusauctum also resembles some crinoids, except crinoids had tentacles and Siphusauctum did not.

References:

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0029233

http://news.utoronto.ca/university-torontoroyal-ontario-museum-scientists-discover-unusual-tulip-creature

Protopriapulites.

Protopriapulites (pro-toe-pry-uh-pew-LITE-ees) was a priapulid worm that I think looked more like a peanut than a worm. It was about one centimeter long. Some fossils showing the gut full of mud indicate that Protopriapulites may have fed on detritus from the sea floor in the same way that the spiny Burgess Shale worm Fieldia did.

© Life Before the Dinosaurs 2012

Protopriapulites is known from the Chengjiang in China. It had a ball-shaped posterior, a head similar to that of Ottoia, and a proboscis similar to that of Fieldia. I believe that the ball-shaped posterior of Protopriapulites may have helped anchor it in its burrow, and if a predator tried to grab its head, it would not be able to pull the worm out of its burrow. So the predator would probably be discouraged and look for something else to eat. 

Protopriapulites was noticeably similar to Paleopriapulites, another peanut-shaped worm from the Chengjiang, except Protopriapulites had a spiral gut and Paleopriapulites did not.

Protopriapulites is a common species of priapulid worm in the Chengjiang.

Image from Fossil Mall

Protopriapulites is mentioned in the book The Cambrian Fossils of Chengjiang, China, which I received from Kamakanui, one of my readers. It is an amazing book mentioning some of the weirdest animals in the Chenjiang. It also has many obscure creatures which are hard to find on the internet, such as Protopriapulites. There is a whole section full of the enigmas of the Chengjiang, such as Facivermis. Each section has a certain phylum that the creatures mentioned in it belong to, in this case Protopriapulites would be listed under "priapulida." This book has tons of information on all these mysterious and obscure creatures.

References:

The Cambrian Fossils of Chengjiang, China: The Flowering of Early Animal Life, Blackwell Publishing, pg. 66 & 67.


http://www.fossilmall.com/EDCOPE_Enterprises/Chengjiang/chengjiangfossils91/chengjiangfossils-91.htm