Lyrarapax.

Lyrarapax is a new anomalocarid described on July 16, 2014. It’s the first known fossil of an anomalocarid that preserved the brain. The muscles of the swimming lobes are also preserved in the fossils. The study was published in the journal Nature, but I didn’t have access to the full article, only the abstract.

©lifebeforethedinosaurs.com

The fossils are from the Chengjiang biota of China and preserve the neural system and brain. The brain of Lyrarapax is very similar to a velvet worm’s brain. There have been some papers published speculating that anomolacarids might have been related to priapulids or certain other groups of worms. However, it was generally accepted that they were either arthropods or onychophorans (velvet worms), and these Lyrarapax fossils give really strong evidence for that.

©lifebeforethedinosaurs.com
My illustration of the head of Lyrarapax showing the brain and neural system.

Lyrarapax was only about 8cm long and did not have the fantail seen in some anomalocarids. Its claws were positioned horizontally, similar to Anomalocaris saron’s claws. In my opinion, Lyrarapax is similar to Amplectobelua, because the first pair of swimming lobes are very large, and the spine closest to the base of the claw is long and skinny. 

References:

Mysterious 500 Million-Year-Old Predators Are the Ancestors of Spiders

Brain structure resolves the segmental affinity of anomalocaridid appendages

Spartobranchus tenuis.

Spartobranchus tenuis was an endobenthic (burrowing) enteropneust (or acorn worm) from the Burgess Shale. It is the earliest known enteropneust worm, predating the previous example by 200 Ma. Although common in the Walcott quarry, with a few thousand specimens known, it was nicknamed "Ottoia" tenuis until scientifically described in March 2013.

Unlike living enteropneusts, Spartobranchus made fibrous tubes in the sediment. It looked much like its modern counterparts, except for the fact that it had a posterior bulb that could probably expand to anchor the worm in its burrow so that it would not be extracted by predators such as Opabinia.

Spartobranchus was a hemicordate, and the third hemicordate from the Burgess Shale (one is Chaunograptus, a benthic graptolite, the other was Oesia, a vermiform animal that appears to belong somewhere in hemicordata). Spartobranchus was a deposit feeder and may have played a role similar to modern earthworms.

Although previously thought to have evolved from the colonial pterobranch hemicordates, fossils of Spartobranchus tell us that enteropneusts were present in the Cambrian Period and common in at least one place, the Burgess Shale community. The fact that S. tenuis built tubes suggests pterobranchs evolved from enteropneusts that built similar tubes.


Here are some cool images of the fossils:
http://www.nature.com/nature/journal/v495/n7442/images/nature12017-f2.2.jpg
and
http://www.nature.com/nature/journal/v495/n7442/images/nature12017-f1.2.jpg

Note from The Mom: New blog post?! Art didn't dictate this to me, but wrote it out himself. 

References:

Tubicolous enteropneusts from the Cambrian period

Figure 2: Spartobranchus tenuis (Walcott, 1911) individuals associated with tubular structures, from the Burgess Shale.

Burgess Shale worm provides crucial missing link

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