Last week, the Royal Ontario Museum (ROM) finalized plans to build The Willner Madge Gallery, Dawn of Life. As its name suggests, the Dawn of Life will feature fossils from the start of life about four billion years ago until the appearance of dinosaurs over 200 million years ago.

Professor in the Department of Ecology & Evolutionary Biology and Department of Earth Sciences Jean-Bernard Caron and his research team travelled to the Burgess Shale and collected some of the fossils that will become a focus of Dawn of Life.

“Without the close relationship we have with U of T, this would not be possible,” said Caron, who is also the Richard M. Ivey Curator of Invertebrate Paleontology at the ROM. “Without students, my collection would be a pile of rocks.”’

Showcasing Canada’s ancient past

The Cambrian Explosion occured 542 million years ago. This period marked the rapid appearance of diversified animals and mineralized fossils.

The Burgess Shale in British Columbia contains a myriad of fossils from the Cambrian period. In particular, the Burgess Shale is known for its intricate preservation of soft-bodied animals. Many of the fossils from this UNESCO World Heritage site provide a wealth of information that cannot be found anywhere else.

Caron initiated the Burgess Shale projects after joining the ROM in 2006, providing insight into Canada’s ancient past.

In addition to the Burgess Shale, fossils from Mistaken Point in Newfoundland, Parc national de Miguasha and Anticosti island in Québec, and Joggins Fossil Cliffs in Nova Scotia will also be on display.

Featured fossils

The fossils in this exhibit are not only relics of the past, but are also representative of Canada’s rich archaeological history.

In 1886, Canadian geologist Richard G. McConnell collected fossils from the Mount Stephen Trilobite Beds in the Canadian Rockies. McConnell ended up with a collection of trilobites, one of the earliest arthropods. But he also recovered fossils that didn’t belong to trilobites. These fossils had unusual appendages and created confusion among researchers who followed in McConnell’s tracks.

In 1892, Joseph Whiteaves described the specimen as a shrimp. In 1911, Charles Walcott found a complete version of the specimen and described it as a sea cucumber. Other researchers throughout the twentieth century described the specimen as a sponge or jellyfish.

It wasn’t until 1985 that researchers Harry Whittington and Derek Briggs described two of the species in full, one of which is Anomalocaris canadensis, a basal arthropod related to spiders and shrimp.

Anomalocaridids were large predators that dominated the Cambrian seas roughly 535 million years ago.

In the 1990s, researchers from the ROM collected several, complete Anomalocaridids specimens. And in 1996, researcher Desmond Collins described Anomalocaris canadensis in detail.

This specimen is one of many treasures that will be on display in Dawn of Life.

PHOTO BY JEAN BERNARD CARON, COURTESY OF THE ROM (Click to Expand)

Visitors will also be able to view banded iron formation — from the Nuvvuagittuq Greenstone Belt in northern Québec — which contains the earliest evidence of life on earth.

PHOTO BY DR. JONATHAN O’NEIL & PITUVIK LANDHOLDING, COURTESY OF THE ROM (Click to Expand)

At the preview last week, visitors had the chance to see Acutiramus macrophthalmus in person. The fossil is the world’s largest specimen of its kind. It’s not evident from its large size, but the 420-million-year-old specimen is a distant relative to horseshoe crabs.

PHOTO COURTESY OF THE ROM (Click to Expand)

A 370-million-year-old Eusthenopteron fish and a Xenasaphus devexus trilobite are examples of some of the other fossils that will be featured.

SRIVINDHYA KOLLURU/THE VARSITY (Click to Expand)

PHOTO BY BRIAN BOYLE, COURTESY OF THE ROM (Click to Expand)

Construction of the Dawn of Life is slated to begin in 2019 and the ROM hopes to open the exhibit in 2021. Meanwhile, a preview of the gallery is located on the second-floor rotunda.

Diplodocids are a group of sauropods that include giants such as Diplodocus and Supersaurus — some of the longest creatures ever to walk the Earth.

Archaeologists have uncovered hundreds of fossils from this dinosaur group, but little is known about their origin or development into adult form.

In a study published in Scientific Reports, researchers including U of T PhD candidate Cary Woodruff analyzed a young diplodocid’s skull remains — unearthed in 2010 in Montana — and found that younger diplodocids may have had different diets than their older counterparts.

The skull remains, dubbed ‘Andrew,’ demonstrate that cranial dimensions did not develop on a fixed scale or at equal measures.

The dental and cranial differences between a mature and immature diplodocid can give the impression that they are of different species, but Andrew reveals that there are implications for cranial ecology as young diplodocids grow.

Woodruff and his team were able to determine specific differences between Andrew and adult skulls discovered earlier, including an extended tooth row, taller jaw bones, and peg tooth formation.

In fact, the authors state that if the fragments of the skull had been discovered separately, they would have likely been misidentified.

This is mostly because these distinct traits were common to other species — taxa — in the same clade as diplodocids, such as Eusauropoda and Macronaria. To a non-expert, it would seem strange that younger dinosaurs may horizontally integrate in taxa.

However, the researchers describe that this may be due to either recapitulation or, most likely, dietary niche partitioning between the young and adults.

Recapitulation theory suggests that an organism takes on forms of its ancestors — forms that were critical for survival in evolutionary past but are no longer needed — as it grows from embryo to adult, reaching the latest derived state during adulthood.

As such, it has been suggested that the skulls of adult diplodocids are taking the same form as their ancestors’.

The researchers in this study outline how dietary levels of specialization are what determined skull sizes, and that this is a form of recapitulation.

The younger diplodocids, like their relatives in the same clade and their common ancestors, ate more plants and lived in forested areas.

But as they got older, they gravitated to open space habitats and developed a more specific diet. Dietary specialization is the latest in the evolutionary timeline of diplodocid behavioural development, and is only found in fully mature individuals.

Woodruff explained why so many diplodocid skeletons have been discovered, but so little is known about their cranial ontogeny.

“The greatest difficulty in studying diplodocid — any sauropod — skulls are their rarity. We have loads of Diplodocus skeletons (well over 100), but fewer than 10 skulls are known. So it’s difficult to even have specimens to study in the first place,” he wrote.

The fragility of these fossils is also a significant limitation. “Dinosaur skulls are made up of dozens of thin, fragile, and delicate bones. The skull could easily get damaged or destroyed long before it’s even buried and begins the fossilisation process,” wrote Woodruff.

Some of Andrew’s bones were missing, “and those that remained were greatly squished” from being underground for millions of years. Bones can also become warped or distorted after long periods.

The work done by Woodruff and his team to draw out the cranial ontogeny and dietary habits of these animals have significant scientific implications. It reveals that diplodocid adults most likely gave birth and then separated from their young early on. It also shows us that herds were mostly segregated according to age.

The work done with Andrew highlights how the fossil record can impart indicators of behaviour and animal sociology. But the questions don’t end here.

“Andrew is not some missing link, nor does it fill in all of the remaining questions — it doesn’t even come close. Each new discovery, finding, and bit of research is like finding a piece to our puzzle. With every piece our picture becomes more and more complete,” wrote Woodruff.