Cameroceras (Part 2).

I've written about Cameroceras before, but there is more about this relative of the modern nautilus that I would like to explain. 


Cameroceras is a species of Ordovician nautiloid that had a straight shell right behind its head. It belongs to a group of nautiloids called orthocones, along with Orthoceras, Endoceras, and Gonioceras. 

© lifebeforethedinosaurs.com

Although the widely accepted size estimate of Cameroceras's length is 20 feet, there is some debate. Paleontologists often find partial shells of Cameroceras, very rarely the whole thing. When they do find a complete specimen of the shell, it is usually of a small individual. Unless we have the living chamber or the tip of the shell in the specimen, we cannot accurately determine the length of the animal. Based on partial specimens of large individuals, we can only know that it could have grown very big, but not the exact length. In the future we may find a way to determine which part of the shell the fossil belonged to. 


In the image below, I drew Cameroceras hunting near the seabed. This individual has successfully caught the eurypterid Megalograptus. Another Megalograptus is swimming away, and Isotelus is crawling on the sea floor directly below the Megalograptus. On the left side, near the head of Cameroceras, there are two rugose corals and one crinoid. 

© lifebeforethedinosaurs.com

Like the modern nautilus, Cameroceras probably had an extremely strong grip with its tentacles. Once something was caught, it would be very hard for the prey to escape. The tentacles were probably stronger than those of the nautilus, because Cameroceras was much bigger (the modern nautilus only has a shell diameter of 8 inches). 


Cameroceras had an amazing way of keeping its head from facing towards the bottom of the ocean and the tip of its shell from facing towards the surface. Cameroceras had a long siphuncle, a kind of tube, running down from its siphon. The siphuncle had traffic cone-shaped blocks of calcium in it, which counter-weighted the body and kept it horizontal. Like all nautiloids, it had upward-facing rings called septa. They were filled with gas and kept Cameroceras afloat. It was a very efficient strategy of locomotion. 

© lifebeforethedinosaurs.com

The siphon, which was connected to the siphuncle, sucked in water and then shot it out again to propel Cameroceras in the opposite direction of whatever way the extremely flexible siphon was pointing. Modern cephalopods can swim backwards and forwards and also steer very well, because of the flexibility of their siphon. Cameroceras probably had a very flexible siphon too, and this extreme maneuverability would have made it an efficient hunter. 




References: 


A Sea Without Fish by David L. Meyer and Richard Arnold Davis, pg. 132-134.


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

Thanks to Paul Mayer at the Field Museum for discussing how paleontologists find out the size of orthocones when they don't have the complete shell. 

New research on Pikaia from Simon Conway Morris and Jean-Bernard Caron.

In Pikaia gracilens Walcott, a stem-group chordate from the Middle Cambrian of British Columbia, published online March 4, 2012, Simon Conway Morris and Jean-Bernard Caron confirmed that Pikaia was a chordate after all. They looked at the anatomy of 114 specimens of Pikaia (I thought there were only 16 known Pikaias!)and found myomeres, v-shaped blocks of skeletal tissue that are only found in chordates. The scientists also found evidence of a vascular system, and found that at least part of the alimentary canal was preserved in almost every specimen. 


Externally, Pikaia was mostly just a flattened, tie-shaped body tapering from a tiny head. It had tentacles on its head, two antennae, and a thin dorsal fin. 


What was first thought to be the notochord in Pikaia is now interpreted as a "dorsal organ," which was possibly hollow. This doesn't mean there's no notochord. Under this dorsal organ there is a thread of tissue that is now interpreted as the notochord and nerve chord. 


I've only read the abstract, but when I read the actual article I'll learn more information. 

Chicago After The Field Museum (Part 4 of 4): Shedd Aquarium.

I went to Shedd Aquarium and it was so cool. They had an exhibit on jellyfish, which I was excited about. They had really weird jellyfish. 

They had a really big tank full of moon jellies and it was packed. There were jellyfish in a huge swarm and each had a bell that was about one foot across. I could even see the orange food that they had eaten because they were so transparent. It was all up inside their stomach, which is in the center of the jellyfish.

The moon jellies were so cool that we took a video of them:

Jellyfish have been around since the Cambrian Period, and I have a couple of fossilized jellyfish from the Carboniferous Mazon Creek.

These are sea nettle jellyfish. Their pulses looked very strong, and that probably helps them drawn water into their bell with plankton, and then push out all the plankton onto their tentacles, where it is then stung and killed, and then fed to the mouth.

These are upside-down jellyfish, a very bizarre kind of jellyfish that spends almost its whole life stuck upside-down to the bottom of the ocean (hence the name upside-down jellyfish). Although this is for a reason. They have algae living inside their bodies which gives them food. In turn, the jellyfish stick upside-down to the bottom and face the light, which helps the algae grow. They have a symbiotic relationship with the algae.

These are called hairy jellyfish, which is obvious when you look at their tentacles, which are very thin and hair-like. They also were very slow, and there was a lot of time between each pulse. They look a lot like some deep sea jellyfish, and they also look like box jellyfish a little bit. 

This is a video of Pacific sea nettle jellyfish, a larger species of sea nettle than the ones in the photograph  I previously mentioned. It's a really cool video. The jellyfish seem even stronger than the other sea nettles, and they are certainly formidable predators of copepods and other plankton. 

This photograph is of two arapaimas, a type of fish from the Amazon River that grows to ten feet long, and is also a living fossil that has its origins in the Cretaceous. The related arowana is also a living fossil. They had those at Shedd Aquarium, but I didn't get a picture. They were about one or two feet long.

This is a picture of me posing next to a freshwater stingray from the Amazon River. It is stuck to the glass, and its mouth and gills are clearly visible. I thought the freshwater stingrays were really amazing.

This was a huge life-sized model of an arapaima, which shows just how big they can get. The scales were huge.

This is an image of a huge school of cardinal tetras, a fish from the Amazon River which is commonly found at pet stores, probably because of how beautiful the shimmering swarms of them can be. I could see them from a long way away. They were so bright. It's almost like they were glowing.

This image shows a moray eel, a beautiful marine eel that grows to ten feet long.

We also saw some electric eels, a type of knifefish that can grow to eight feet long, which makes it the largest knifefish species. They are also deadly because they can shock up to 650 volts.

They had a giant spider crab, the biggest species of crab in the world. In the wild they are often found in the deep sea where they have an opportunistic lifestyle, picking up and eating any scrap of edible debris they can find.

The next day it was time to leave Chicago, and I really didn't want to go. It was so sad to leave.

We went to the airport and the Kronosaurus had to go through the X-ray two times for some reason.

I couldn't stop reading my new book.

Art had a ton of new experiences and a fantastic time in Chicago. 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. 

The Field Museum (Part 3 of 4): Birthday and the Burgess Shale Screen.

When we woke up in the museum after Dozin' with the Dinos, I quickly looked around again in Evolving Planet. Then we went back to the hotel to celebrate my birthday.

Stephen brought me a birthday cake with a spotted lagoon jellyfish and a sea nettle jellyfish on it. I got some presents, like this and this from my parents, this from Stephen, and this from Dave. Then we went back to the Field Museum. 

There's a Burgess Shale video with three screens in Evolving Planet that makes it seem like the creatures are in a huge aquarium. On our first night at the museum, the screen wasn't on and I was very disappointed. We thought it might be broken because somebody told us that. But when we went back the next day it was on! 

Here is Pikaia swimming past. It happens to be about to swim over some Ottoia burrows. 

For some reason we didn't take a video of the screen, but it was really cool. Here is Opabinia (in the lower left corner) and Wiwaxia (in the middle). 

I thought the Burgess Shale screen was really cool, and my two favorite parts where when the Anomalocaris chased all the trilobites and got one, and when the Opabinia tried to catch an Ottoia. It finally caught one, but lost its grip and the worm quickly went back into its burrow. 


Here's a picture of an Ottoia coming out of its burrow in the middle of the screen. It's blurred because it was moving so fast. It went back in as fast as it came out.

This picture is really cool, and not to mention the quote from Charles Darwin is amazing. 

Stephen took us to SushiSamba and it was great. I had sushi for the first time. I got octopus and freshwater eel and I loved it. I also had tuna, striped bass, and crab. I wanted to get sea urchin but they didn't have it that day. 

Sushi platter.

Freshwater eel. 

We went to see "The Bean," which is really called Cloud Gate. It's a giant stainless steel sculpture that's about as old as me. It was designed by Anish Kapoor and I thought it was really cool. The night we were there there was a light show, and I was jumping on the lights. The lights were reflecting off The Bean and The Bean was reflecting the lights of the city and all the people. You could see Chicago just by looking at The Bean. 

Here I'm underneath The Bean and Stephen is holding me up so I can see my reflection at the top of The Bean. 

Behind me and Kayla is a big sculpture made of glass blocks with lights inside. On the sculpture there was a face and it was actually moving. In the summertime, Stephen said the face squirts water out of its mouth, and people can play in it. That's kind of cool, and I think a sculpture with a moving face is kind of weirdly hilarious. 

Thanks so much to Stephen, Kayla, and Dave for traveling to meet us in Chicago. I had an awesome birthday. I like Chicago better than where I live!



Next up:

Part 4 of 4: Bonus day at Shedd Aquarium!

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. 

The Field Museum (Part 2 of 4): Behind the Scenes in the Collections Room!

My friend Dave Monroe introduced me to Paul Mayer, the Fossil Invertebrate Collections Manager at the Field Museum. Paul gave me a tour of the invertebrate fossils behind the scenes. The room was full of cabinets and drawers with around two million fossils in all. 

These drawers are full of Lecthaylus gregarius, which is a Silurian worm that could be a priapulid.

Lecthaylus gregarius

Paul showed me a huge slab of rock which was covered in Canadaspis perfecta fossils, some with the tail preserved.

This is a single fossil of Canadaspis perfecta, preserving only the headshield, or carapace.

This is a huge slab of rock containing fossils of the Burgess Shale enigmatic animal, Pollingeria. The Field Museum had Burgess Shale fossils which I had never actually seen except in pictures or behind glass. Some of these Burgess Shale fossils were found by Charles Doolittle Walcott, who gave them to the Field Museum. I got to touch some of the fossils, which was really cool.

This is a very rare fossil of just the eyebar of Tullimonstrum gregarium. Tullimonstrom was found in the Mazon Creek in Illinois, and the Field Museum has the biggest collection of Mazon Creek fossils in the world. The Field Museum has the type specimens of Tullimonstrum in the collections room, and the Holotype was on display. These were so rare that I couldn't touch them. But Paul showed them to me.

This is a very rare example of a Tullimonstrum with the proboscis complete. It also has the eyebar intact, and part of the body. This fossil of Tullimonstrum was amazing.

Paul said this was his favorite Tullimonstrum. It was curving its long proboscis, and showed that Tullimonstrum was probably very flexible and did not have a shell.

My mom thinks the note on this drawer is funny, but I don't.

This slab of rock contains Uintacrinus, a Cretaceous crinoid from Kansas that did not have a stalk. Instead, they floated about in mid-water, usually in huge colonies like this one. 

These are multiple fossils of holothurians, or sea cucumbers. They were found in the Mazon Creek and were from the Carboniferous Period. They differ little from the sea cucumbers alive today. 

A whole drawer of Arthropleura fossils! Some of these are what looks to me like the mandibles, and the others were of the plates on Arthropleura's sides. All the Arthropleura fossils in this drawer were of Arthropleura cristata. 

In this picture I'm holding a fossil of the side plate of Arthropleura. I thought it was really cool to hold a real Arthropleura fossil. 

Another view of the Arthropleura fossil. 

Paul was really nice, and he showed me what were probably the weirdest fossils I've ever seen.

I really didn't want to go to sleep because there were so many cool fossils on display. It was cool to go behind the scenes and to see the displays in the Field Museum. 

Next up:

Part 3: Celebrating my birthday with...a second day at the Field Museum!


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. 

The Field Museum (Part 1 of 4): Evolving Planet.

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 Asterotrygon. 

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.