Skeemella.

Skeemella is a Cambrian animal that is found in Utah and is known from one specimen. The specimen has two halves: a posterior half and an anterior half. Although some scientists in China believe Skeemella is an arthropod, some American scientists believe it is a Vetulicolian.

Anterior half of Skeemella.
[Source: University of Kansas Division of Invertebrate Paleontology]

Skeemella had a long, skinny tail with two flukes that formed a paddle at the end of the tail. This picture shows Skeemella, the large elongate animal, and a group of the trilobite Peronopsis. The Peronopsis are probably searching for carcasses of Elrathia kingii, because they were some of the most common food sources that a scavenger like Peronopsis would be able to eat.

I believe that Skeemella may have been nocturnal, because its long tail would drag behind and in the day could be seen and grabbed by a predator. But in the nighttime, the big predators were either sluggish, inactive, or could not see well in the darkness, so Skeemella could be safe. But that's just my hypothesis.

My interpretation of Skeemella with a group of Paronopsis.

Skeemella had a tough carapace shaped like a fingernail, a beak-shaped mouth, no eyes, and two lobe-like extensions on the glob-like anterior part of the body.

Skeemella swimming slowly above the Cambrian sea floor in search of detritus or plankton.

References:

http://kumip.ku.edu/cambrianlife/Utah-Vetulicolians.html

http://www.fossilmuseum.net/Fossil_Sites/Chengjiang/Vetulicolia-Fossils.htm

Edaphosaurus.

Edaphosaurus was a genus of sail-back synapsid, a group of animals that includes mammals and their relatives. It lived from the late Carboniferous to the early Permian. Even though Edaphosaurus resembled a dinosaur, they were not dinosaurs. They are actually ancestors of early mammals.

The image below shows Edaphosaurus (the lizard-like one with the sail on its back), and the sail-back amphibian Platyhystrix. For some reason this interpretation of Platyhystrix does not have the sail on its back.

Edaphosaurus had spines that held up its "sail." These spines also had small knobs sticking out of them. Scientists think that Edaphosaurus's "sail" was either for warming its body, for attracting a mate, or both. It's possible that it was for the same purpose as antlers or horns on modern day mammals like deer or goats. But nobody really knows what the "sail" was for.

Edaphosaurus was similar to Dimetrodon, but was smaller. Edaphosaurus was three to eleven feet long, and may have been prey for Dimetrodon.

Edaphosaurus was an early plant-eating tetrapod, but it may have not eaten plants, but instead hunted small animals such a mollusks. Or it could have eaten both and been an omnivore.

Most fossils of this synapsid only show teeth and bits of its backbone. Edaphosaurus is rare and its habits are poorly known.

References:

http://www.utexas.edu/tmm/sponsored_sites/dino_pit/edaphosaurus.html

http://dinosaurs.about.com/od/predinosaurreptiles/p/edaphosaurus.htm

http://www.dinosaurfacts.org/edaphosaurus

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

Fieldia lanceolata.

Fieldia lanceolata is an odd species of Burgess Shale priapulid worm covered almost completely in spines. The longest spines were on Fieldia's head and looked like tiny spears. F. lanceolata was about 5 cm long and is the smallest Burgess Shale priapulid worm I know of. 

When Walcott found the first specimen of this worm, he thought it was an arthropod carapace. When he later found another specimen of Fieldia, he accidentally classified it as a different animal and called it "Ottoia minor." But the species "Ottoia minor" is now called Ancalagon minor, and is a totally different species than Fieldia, but is closely related in the priapulid stem group Archaeopriapulida. 

F. lanceolata had a short proboscis that may or may not have been been retractable or bendable like those of other priapulid worms. Its spines may have enabled it to push itself through the mud and burrow, or protect itself from predators. F. lanceolata devoured large amounts of sediment. We know that because some fossils of this worm have large amounts of mud in their gut. 

My interpretation of Fieldia lanceolata with mud in its gut.
© Life Before the Dinosaurs 2011

References:


http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=54&ref=i&


http://en.wikipedia.org/wiki/Fieldia_(worm)

Naraoia.

Naraoia (nuh-ROY-uh) was a soft-shelled trilobite-like animal with a posterior shield and an anterior shield. Walcott described Naraoia as a crustacean because of its large carapace. But now it is believed to be a trilobite-like animal because scientists know that it had soft parts under the carapace.

Even though Naraoia could swim for a very short period of time, its armor was too heavy to allow Naraoia to swim for very long. Naraoia probably crawled along the sea floor in search of prey. Some specimens of Naraoia show bite marks, so it was probably good prey for predators such as anomalocarids. Naraoia could be up to 4 cm long.

Click the image to see Naraoia crawl across the sea floor.

This fossil of N. compacta is one of the best preserved Burgess Shale fossils. It's a complete specimen and has well-preserved appendages. According to Stephen Jay Gould, it can be photographed unretouched, unlike most other Burgess Shale fossils.

References:

http://www.trilobites.info/naraoia.htm

http://evolution.berkeley.edu/evolibrary/article/_0/cambrian_17

http://paleobiology.si.edu/burgess/naraoia.html

http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=86&ref=i&

Wonderful Life, Stephen Jay Gould, pg. 87

Coelurosauravus.

Coelurosauravus (see-low-row-SORE-uh-vus (or) see-lore-oh-SORE-ay-vus) was a genus of late Permian reptile with "wings" that were either for gliding or display. It was very similar to the Triassic kuehneosaurids, but unlike the kuehneosaurids, it had a crest, like the crest of the dinosaur Protoceratops.

Coelurosauravus's wings resembled those of a moth, but they were made of stretched out bones covered with skin.

Coelurosauravus had sharp claws used for climbing tree bark. It was about 16 inches long.

Coelurosauravus probably ate flying insects like palaeodictyopterans. It was the first reptile to "fly." It could only glide, because it didn't have muscles in its wings which would allow it to actually flap them.

References:

http://www.reptileevolution.com/coelurosauravus.htm

http://dinosaurs.about.com/od/predinosaurreptiles/p/Coelurosauravus.htm

http://www.amazon.com/Complete-Guide-Dinosaurs-CHRIS-MCNAB/dp/184566082X

http://www.surfacevision.com/coelurosauravus-image.html

Herpetogaster.

Herpetogaster is a genus of Burgess Shale animal that cannot be classified. It doesn't look like any known life form alive on earth today. Instead, it looks like an alien life form. It could possibly be related to eldonids like Eldonia.

Herpetogaster had an enormous stomach, like the sack-like Mackenzia, and a long, flexible stalk called as stolon with a disc at the bottom. This disc may have either been used for creeping slowly across hard surfaces like the sea bed, sponges, and rocks, or it could have been used for anchoring Herpetogaster to hard surfaces.

Herpetogaster has been described from 101 specimens. It is extremely rare in the Walcott Quarry--only six specimens come from there. But the rest come from the Raymond Quarry.

Fossils of Herpetogaster have been found near those of the sponge Vauxia, which suggest that Herpetogaster may have attached itself to sponges. My hypothesis is that it may have chosen Vauxia because of Vauxia's bush-like form, which would protect it from predators by keeping it tangled up inside the branches.

Herpetogaster can be loosely translated to "creeping stomach," referring to its enormous stomach and its possible ability to creep.

Herpetogaster was described by Simon Conway Morris, Jean-Bernard Caron, and Degan Shu in 2010.

References:

http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=66&ref=i&sort=date&order=asc&filters=y

http://scienceblogs.com/laelaps/2010/03/your_friday_dose_of_weird_two.php

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009586

Facivermis.

Facivermis is a peculiar genus of Cambrian worm which had ten prickly arms, five on each side of the head area. Fossils of Facivermis are rare and are found in China.

The image below shows a fossil with many specimens of the spiny worm Corynetis brevis and one Facivermis yunnanicus. In this fossil, Facivermis is holding its ten arms against its body, possibly so they wouldn't get in the way of burrowing.

Facivermis may have used its arms to grab prey, but that's just my hypothesis.

Scolecofurca.

Scolecofurca was an odd genus of stem group priapulid worm. It is known from only one specimen from the Burgess Shale.

Scolecofurca rara, its full name, can be translated to "infrequent forked worm." Its genus name, Scolecofurca, is referring to its front end, which looks like a two-pronged fork. The species name, rara, refers to the fact that the species is very rare.

Simon Conway Morris described Scolecofurca from a single specimen in 1977.

Click image to zoom in. [Source: Royal Ontario Museum Fossil Gallery]

Scolecofurca was about 9 cm long and probably burrowed close to the surface of the sediment.

It was very difficult for me to find information on this animal so I could not write very much or find more than one image. I decided to try to reconstruct Scolecofurca myself. My first drawing shows what it would look like if it had long tentacles to entangle prey and then eat it. My second drawing shows what Scolecofurca would look like if it had short, hard, jaw-like tentacles which would crush prey. But these are just my hypotheses based on the fossil.

My interpretations of Scolecofurca with long tentacles grabbing a hyolith.
© Life Before the Dinosaurs 2011

My interpretations of Scolecofurca with short spines.
© Life Before the Dinosaurs 2011

References:

http://burgess-shale.rom.on.ca/en/fossil-gallery/view-species.php?id=112&ref=i&&ref=i

Selkirkia.

Selkirkia is a Cambrian priapulid worm which has been found in the Burgess Shale in Canada, and in Utah and China.

Selkirkia lived in a cone-shaped tube which had a split at the end. This split was the opening that would have allowed feces to go out of the tube. If it did not have the split, feces would have built up inside the tube and eventually poisoned Selkirkia, then killed it. But that's just my hypothesis.

Click image to see a video of Selkirkia

When Selkirkia died and rotted away, agnostid trilobites dug up the tube and then sheltered in it. Scientists know that because some specimens of Selkirkia's tube have agnostids in them. The tubes inhabited by agnostids are horizontal, but the tubes with Selkirkia still in them are vertical in the rock.

Selkirkia was very similar to its relative Paraselkirkia, but there was one huge difference between the two. Paraselkirkia had a ring of spines on the head that were pointing backwards. Selkirkia did not have this.