Burgess Shale’s Weird Wonders

The fossils found in the Burgess Shale include the 500-million-year-old ancestors of most modern animals

Cambrian Period
Painting by D.W. Miller. Courtesy of Smithsonian Institution


Cambrian Period
(Maura McCarthy)
This painting is a 1997 illustration of an assortment of Cambrian era creatures by D.W. Miller. The large animal in the top right corner is known as Anomalocaris, and Hallucigenia, Wiwaxia and Ottoia are also pictured.


Claws of Anomalocaris canadensis
(Maura McCarthy)
This fossil is a pair of claws from Anomalocaris canadensis, the largest Cambrian predator reaching lengths up to three feet, and the first of its type to be discovered at the Stanley Glacier site, by Caron and crew. Among its distinctive features, this animal had a pair of large eyes at the front and a rounded mouth with sharp teeth.


Haplophrentis carinatus
(Maura McCarthy)
Haplophrentis carinatus, a one-inch fossil found at the Stanley Glacier site, was probably related to an extinct group of mollusks. The preserved parts consist of a conical shell, a lid and a pair of curved elements projecting sideways. This animal is abundant at the site and lived on the seafloor.


Sidneyia inexpectans
(Maura McCarthy)
Sidneyia inexpectans is thought to be a carnivorous animal about four inches long that ate prey larger than trilobites and lived at the bottom of the ocean during the Cambrian Period. Sidneyia is potentially an ancestral member of a group of arthropods that include today’s spiders and horseshoe crabs.


Diagonella cyathiformis
(Maura McCarthy)
At about three inches long, Diagonella cyathiformis, or this “exquisite sponge” as Caron calls it, is nearly complete and consists of diagonally oriented spicules that form the skeletal elements of the body.


Anomalocaris canadensis
(Maura McCarthy)
Anomalocaris canadensis was one of the largest of the Burgess Shale specimens (its claws were shown in the second slide) and one of the most widely distributed, having been found in China, Greenland and Utah. It was placed in a class of an extinct group of primitive, ocean-dwelling arthropods. This fossil was discovered in 1992 by a ROM team in the Raymond Quarry, just above the Walcott Quarry.


Marrella splendes
(Maura McCarthy)
Charles Walcott discovered the Burgess Shale in 1909, and one of the first fossil species he found was Marrella splendes. Marrella, also called the “lace crab” by Walcott, is an arthropod and could be ancestral to any of the three major groups of aquatic arthropods: crustaceans (like shrimp and crabs), trilobites (which are now extinct) or chelicerates (like spiders and scorpions).


Hallucigenia sparsa
(Maura McCarthy)
Hallucigenia sparsa was originally described by Walcott as a polychaete annelid. Today, Hallucigenia is identified as an armored lobopod — related to today's land-based velvet worms. Hallucigenia gained fame as Stephen Jay Gould’s classic “weird wonder” in his 1989 book, Wonderful Life.

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