NUNAVUT: LAND OF ICE AND SNOW

A lone polar bear moves with quiet power across the snow and sea ice of Nunavut, its massive paws spreading its weight to keep it light atop the frozen surface. 

These apex predators have roamed the Arctic for hundreds of thousands of years, evolving from brown bear ancestors to master the shifting icescapes of the Pleistocene. 

Their range once spread wider during colder glacial ages, but Nunavut remains a stronghold of their territory, a place where bears still hunt seals, den in snowdrifts, and continue an ancient lineage intertwined with the rhythms of ice, ocean, and sky.

Nunavut, Canada’s northernmost territory, is a land that wears deep time on its sleeve. Its stark landscapes—wind-scoured ridges, icy fjords, and tundra plains—may appear empty at first glance, but beneath this silence lies one of Earth’s richest archives of geological and paleontological history. 

Stretching across nearly two million square kilometers of Arctic terrain, Nunavut preserves rocks that span more than three billion years, recording the birth of continents, the rise of early life, and the survival of animals through ancient seas and ice ages.

Nunavut’s remarkable geology and paleontology, from the planet’s earliest beginnings to Ice Age megafauna, tracing how this northern land has shaped and preserved Earth’s story.

Nunavut’s rocks are among the oldest on Earth. Much of its bedrock belongs to the Canadian Shield, a vast geological core of North America composed of Archean and Proterozoic rocks more than 2.5 to 3.9 billion years old. 

In regions such as the Acasta Gneiss Complex, which straddles the Northwest Territories and Nunavut, scientists have found rocks dated to around 4.0 billion years—nearly as old as the Earth itself.

These rocks tell the story of Earth’s early crustal formation, long before the emergence of complex life. They preserve the remnants of volcanic arcs, ancient oceans, and the slow suturing of microcontinents into larger continental plates. 

The geology of Nunavut is not uniform but instead a patchwork quilt of greenstone belts, granitic intrusions, and sedimentary basins, each marking different chapters in the planet’s tectonic evolution.

During the Paleozoic Era (541–252 million years ago), much of Nunavut lay beneath shallow tropical seas. Thick accumulations of limestone and shale from this time preserve fossils that record the explosion of marine biodiversity—from trilobites and brachiopods to early corals and cephalopods. Later, in the Mesozoic and Cenozoic Eras, tectonic shifts, rifting, and glaciation sculpted the modern Arctic landscape. 

Glacial scouring during the Pleistocene left behind U-shaped valleys, moraines, and eskers, reshaping the terrain and influencing how fossils are exposed today.

Cambrian Seas and the Rise of Early Life — Some of Nunavut’s most important paleontological treasures come from the Cambrian Period (541–485 million years ago). At sites such as Northwest Ellesmere Island, researchers have uncovered trilobites, archaeocyathids (reef-building sponges), and early echinoderms that once thrived in warm equatorial seas. These fossils highlight Nunavut’s role in documenting the Cambrian Explosion, the evolutionary burst when most major animal groups first appeared in the fossil record.

Devonian Coral Reefs — During the Devonian Period (419–359 million years ago), the region hosted extensive reef systems, comparable to modern-day Great Barrier Reef environments. Fossil corals, stromatoporoids (sponge-like reef builders), and early fishes—including the armored placoderms—have been found in the limestone deposits of Nunavut’s Arctic islands. These fossils provide insights into marine biodiversity during the so-called “Age of Fishes,” when vertebrates began diversifying rapidly.

Qikiqtania, a remarkable fossil fish discovered on southern Ellesmere Island in Nunavut, closely related to Tiktaalik, the famous “fishapod” that represents a key step in the transition from water to land is one of Nunavut's most significant Devonian fossils. Dating to about 375 million years ago in the Late Devonian, Qikiqtania wakei had a streamlined body and fins built for swimming, but unlike Tiktaalik, it lacked the robust limb bones that could have supported it on land. 

This begs the question of what those early vertebrates were up to and it seems their evolutionary path was experimenting with shallow-water or terrestrial habitats, while Qikiqtania remained fully aquatic, showing the diversity of evolutionary pathways at this pivotal moment in vertebrate history. Its name honors both the Qikiqtaaluk Region of Nunavut, where it was found, and the late evolutionary biologist David Wake, linking local geography with global science.

Jurassic and Cretaceous Dinosaurs of the Arctic — One of the most striking aspects of Nunavut’s fossil record is the presence of dinosaurs at high latitudes. On Bylot Island and Axel Heiberg Island, paleontologists have discovered hadrosaur (duck-billed dinosaur) remains dating to the Late Cretaceous, about 75 million years ago. These finds demonstrate that large herbivorous dinosaurs lived well within the Arctic Circle, enduring months of seasonal darkness and cooler climates than their relatives farther south.

Tracks preserved in sandstone also reveal the presence of theropods (predatory dinosaurs) that stalked these northern landscapes. The question of how dinosaurs adapted to Arctic conditions—whether through migration or physiological adaptations such as warm-bloodedness—remains an active field of study.

Fossil Forests of the High Arctic — Perhaps Nunavut’s most evocative paleontological record comes not from bones but from trees. On Axel Heiberg Island, paleontologists have uncovered the remains of Eocene-aged fossil forests dating to about 50 million years ago. These forests, preserved in remarkable detail, include upright stumps, leaf litter, and even mummified wood that still retains organic compounds.

At that time, the Arctic was much warmer, with a greenhouse climate that supported redwoods, dawn sequoias, and ginkgo trees. The fossil forests demonstrate that the Arctic once hosted lush ecosystems, challenging our assumptions about polar environments and providing crucial analogues for studying climate change today.

Marine Reptiles and Ancient Whales — The Cretaceous and early Cenozoic deposits of Nunavut also preserve marine reptiles such as plesiosaurs and mosasaurs, apex predators of the inland seas. Moving into the Cenozoic, fossils of early whales, including basilosaurids, have been recovered, highlighting the transition of mammals from land back to the ocean. These finds place Nunavut within the global story of marine evolution during a time when the Arctic Ocean was ice-free and biologically rich.

Fast forward to the Pleistocene (2.6 million–11,700 years ago), and Nunavut was home to a range of Ice Age megafauna. Fossils and subfossil remains of muskoxen, mammoths, caribou, and giant beavers have been found across the territory. These animals grazed tundra and steppe ecosystems during glacial cycles, coexisting with early human populations that migrated into the Arctic.

Human History and Fossil Knowledge — Nunavut’s paleontological heritage is intertwined with Indigenous knowledge. Inuit communities have long encountered fossils while traveling across the land, recognizing bones and shells as part of the natural history of their environment. Some fossils, like petrified wood or unusual stone shapes, carry cultural meanings and have been used in tools, carvings, or storytelling.

Nunavut’s population are Inuit, whose traditional language is Inuktut, which includes several dialects such as Inuktitut and Inuinnaqtun, still widely spoken across communities alongside English and French. Inuit knowledge of the land, sea, ice, and animals is profound, extending to fossils and unusual stones encountered on the tundra, which are often recognized and woven into oral traditions. 

Visitors interested in seeing fossils and learning more about Nunavut’s natural and cultural history can explore the Nunatta Sunakkutaangit Museum in Iqaluit, which preserves Inuit art and heritage alongside natural history exhibits, or the Canadian Museum of Nature in Ottawa, which holds important fossil collections from Nunavut that are not always displayed locally due to preservation and accessibility challenges.

A wave of scientific exploration of Nunavut’s fossils began in earnest in the 19th and 20th centuries with expeditions by geologists and paleontologists. Today, fossil research in Nunavut requires collaboration with Inuit communities, recognizing their stewardship of the land and the cultural importance of these discoveries.

Climate Change and the Future of Arctic Paleontology — As the Arctic warms, melting permafrost and retreating glaciers are exposing fossils at an unprecedented rate. While this accelerates discoveries—such as well-preserved Ice Age bones—it also threatens the long-term preservation of delicate specimens. Increased accessibility has also raised ethical and legal questions about fossil collection, ownership, and conservation.

Nunavut stands at the forefront of these challenges. Its fossils not only record the history of life but also offer lessons for the present: how species adapt (or fail to adapt) to climate shifts, how ecosystems respond to warming, and how biodiversity rebounds after mass extinctions. Protecting this paleontological heritage is essential for both science and culture. It is a remote part of the world that I would love to explore more of and see its rugged, natural beauty in all its splendor.

DINOSAUR EGGS: FRAGILE LINKS TO DINOSAUR REPRODUCTION

Hadrosaur Eggs

Standing before a clutch of fossilized dinosaur eggs for the first time is a deeply moving experience. Unlike towering skeletons or fearsome teeth, eggs speak to vulnerability and the quiet promise of life that never came to be.

I have found many fossil feathers (another personal fav) but have yet to find dino eggs or any egg for that matter. While my track record here is beyond sparse, dinosaur eggs have been found on nearly every continent, from the deserts of Mongolia to the floodplains of Montana and the nesting grounds of Patagonia. 

The discovery of dinosaur eggs offers one of the most intimate glimpses into the life history of these long-extinct animals. Unlike bones or teeth, eggs preserve direct evidence of reproduction, nesting strategies, and even embryonic development. 

Over the last century, paleontologists and citizen scientists have uncovered thousands of fossilized eggs and eggshell fragments across the globe, revealing that dinosaurs laid their clutches in diverse environments ranging from deserts to floodplains.

Early Discoveries — The first scientifically recognized dinosaur eggs were discovered in the 1920s by the American Museum of Natural History’s Central Asiatic Expeditions to Mongolia’s Gobi Desert. 

Led by Roy Chapman Andrews, these expeditions unearthed clutches of round, fossilized eggs in the Djadokhta Formation. Initially misattributed to Protoceratops, later discoveries showed they belonged to the bird-like and immensely cool theropod Oviraptor. This corrected attribution changed the understanding of dinosaur nesting, particularly with the revelation of adults preserved brooding on nests.

Asia: The Richest Record — Asia remains the richest continent for dinosaur eggs.

Mongolia: The Gobi Desert has yielded numerous oviraptorid and hadrosaurid eggs, often preserved in nesting sites.

China: The Henan and Guangdong Provinces have produced abundant eggs, including complete clutches of hadrosaurs, theropods, and titanosaurs. Some sites, such as the Xixia Basin, contain thousands of eggshell fragments, telling us that these were long-term nesting grounds. Embryos preserved within eggs, like those of Beibeilong sinensis, provide rare developmental insights.

India: Extensive titanosaur nests from the Lameta Formation demonstrate colonial nesting behavior and some of the largest known egg accumulations.

North America has also yielded important dinosaur egg sites. Montana: The Two Medicine Formation preserves fossilized nests of hadrosaurids like Maiasaura peeblesorum, discovered by Jack Horner in the late 1970s. These finds gave rise to the concept of “good mother lizard,” as evidence suggested parental care and extended nesting.

Utah and Colorado: Eggshell fragments and isolated eggs of sauropods and theropods have been reported, though less commonly than in Asia.

South America: Sauropod Hatcheries — Argentina is home to some of the most significant sauropod nesting sites. In Patagonia, the Auca Mahuevo locality preserves thousands of titanosaur eggs, many with fossilized embryos inside. This site demonstrates large-scale nesting colonies and offers clues to sauropod reproductive strategies, including shallow burial of eggs in soft sediment.

Europe: A Widespread Record — Europe has produced diverse dinosaur egg finds, particularly in France, Spain, and Portugal. In southern France, sauropod egg sites such as those in the Provence region reveal clutches laid in sandy floodplains. Spain’s Tremp Formation contains both hadrosaurid and sauropod eggs, some associated with trackways, linking nesting and movement behavior.

Africa: Expanding the Map — Egg discoveries in Africa are less common but significant. In Morocco and Madagascar, titanosaur eggs have been recovered, suggesting a widespread distribution of sauropod nesting across Gondwana.

Dinosaur eggs fossilize under specific conditions. Burial by sediment soon after laying, mineral-rich groundwater for permineralization, and relative protection from erosion. Eggshell microstructure, pore density, and arrangement allow paleontologists to infer incubation strategies, from buried clutches similar to modern crocodilians to open nests akin to modern birds.

These fossils are remarkable for their beauty and rarity but also for the wealth of biological information they provide. These elusive fossils help us to understand dinosaur reproduction, nesting behaviour, and evolutionary ties to modern birds. I will continue my hunt and post pics to share with all of you if the Paleo Gods smile on me!

STEGOSAURUS: PLATED GIANT OF THE JURASSIC

Few dinosaurs are as instantly recognizable as Stegosaurus, with its double row of towering bony plates and spiked tail. 

This impressive herbivore, whose name means “roofed lizard,” roamed western North America about 155–150 million years ago during the Late Jurassic. 

Fossils of Stegosaurus have been found primarily in the Morrison Formation, a magnificent rock unit famous for preserving one of the most diverse dinosaur ecosystems ever discovered.

Stegosaurus could reach up to 9 meters (30 feet) in length but had a disproportionately small head with a brain roughly the size of a walnut. 

Despite this, it thrived as a low-browser, feeding on ferns, cycads, and other ground-level plants using its beak-like mouth and peg-shaped teeth. Its most iconic features were the dermal plates, some nearly a meter tall, running down its back. Their function remains debated—some have proposed they were used for display, species recognition, or thermoregulation.

At the end of its tail, Stegosaurus bore four long spikes, known as the thagomizer. 

Evidence from fossilized injuries on predator bones suggests these were formidable weapons, capable of piercing the flesh of even the largest carnivores.

Stegosaurus did not live in isolation. It shared its world with a cast of iconic dinosaurs and other ancient animals:

• Sauropods such as Apatosaurus, Diplodocus, and Brachiosaurus dominated the floodplains, their long necks sweeping across the tree canopy.
• Predators like Allosaurus and Ceratosaurus stalked the ecosystem, preying on herbivores. The spikes of Stegosaurus would have been a key defense against these hunters.
• Ornithopods, including Camptosaurus and Dryosaurus, grazed alongside Stegosaurus, representing smaller, quicker plant-eaters.
• Early mammals, small and shrew-like, scurried through the underbrush, while flying pterosaurs soared overhead.
• Freshwater systems hosted fish, turtles, and crocodile relatives, rounding out the ecosystem.

Interesting Facts

• The brain-to-body ratio of Stegosaurus is one of the smallest of any dinosaur, fueling the myth that it had a “second brain” in its hips—an idea no longer supported by science.
• Tracks attributed to stegosaurs suggest they may have moved in small groups, possibly for protection.
• Despite its fearsome appearance, Stegosaurus was strictly an herbivore. Its teeth were too weak to chew tough vegetation, meaning it likely swallowed food in large chunks.
• And, being one of my best loved dinosaurs, I chose Stegosaurus as one of my logos for the Fossil Huntress. This gentle giant is one of my all time favourites!

Stegosaurus lived tens of millions of years before the rise of dinosaurs like Tyrannosaurus rex, and remains one of the most beloved prehistoric creatures. Its strange mix of delicate feeding adaptations and heavy defensive weaponry highlights the balance of survival in the Jurassic ecosystem.

For those that love paleo art, check out the work of Daniel Eskridge (shared with permission here) to see more of his work and purchase some to bring into your world by visiting: https://daniel-eskridge.pixels.com/

LIVING FOSSILS: METASEQUOIA

Autumn is a wonderful time to explore Vancouver. It is a riot of yellow, orange and green. The fallen debris you crunch through send up wafts of earthy smells that whisper of decomposition, the journey from leaf to soil.

It is a wonderful time to be out and about. I do love the mountain trails but must confess to loving our cultivated gardens for their colour and variety. 

We have some lovely native plants and trees and more than a few exotics at Vancouver's arboreal trifecta — Van Dusen, Queen E Park and UBC Botanical Gardens. One of those exotics, at least exotic to me, is the lovely conifer you see here is Metasequoia glyptostroboides — the dawn redwood. 

Of this long lineage, this is the sole surviving species in the genus Metasequoia and one of three species of conifers known as redwoods. Metasequoia are the smaller cousins of the mighty Giant Sequoia, the most massive trees on Earth. 

As a group, the redwoods are impressive trees and very long-lived. The President, an ancient Giant Sequoia, Sequoiadendron giganteum, and granddaddy to them all has lived for more than 3,200 years. While this tree is named The President, a worthy name, it doesn't really cover the magnitude of this giant by half.   

This tree was a wee seedling making its way in the soils of the Sierra Nevada mountains of California before we invented writing. It had reached full height before any of the Seven Wonders of the Ancient World, those remarkable constructions of classical antiquity, were even an inkling of our budding human achievements. And it has outlasted them all save the Great Pyramid of Giza, the oldest and last of those seven still standing, though the tree has faired better. Giza still stands but the majority of the limestone façade is long gone.

Aside from their good looks (which can really only get you so far), they are resistant to fire and insects through a combined effort of bark over a foot thick, a high tannin content and minimal resin, a genius of evolutionary design. 

While individual Metasequoia live a long time, as a genus they have lived far longer. 

Like Phoenix from the Ashes, the Cretaceous (K-Pg) extinction event that wiped out the dinosaurs, ammonites and more than seventy-five percent of all species on the planet was their curtain call. The void left by that devastation saw the birth of this genus — and they have not changed all that much in the 65 million years since. Modern Metasequoia glyptostroboides looks pretty much identical to their late Cretaceous brethren.

Dawn Redwood Cones with scales paired in opposite rows

They are remarkably similar to and sometimes mistaken for Sequoia at first glance but are easily distinguishable if you look at their size (an obvious visual in a mature tree) or to their needles and cones in younger specimens. 

Metasequoia has paired needles that attach opposite to each other on the compound stem. Sequoia needles are offset and attached alternately. Think of the pattern as jumping versus walking with your two feet moving forward parallel to one another. 

Metasequoia needles are paired as if you were jumping forward, one print beside the other, while Sequoia needles have the one-in-front-of-the-other pattern of walking.

The seed-bearing cones of Metasequoia have a stalk at their base and the scales are arranged in paired opposite rows which you can see quite well in the visual above. Coast redwood cone scales are arranged in a spiral and lack a stalk at their base.

Although the least tall of the redwoods, it grows to an impressive sixty meters (200 feet) in height. It is sometimes called Shui-sa, or water fir by those who live in the secluded mountainous region of China where it was rediscovered.

Fossil Metasequoia, McAbee Fossil Beds

Metasequoia fossils are known from many areas in the Northern Hemisphere and were one of my first fossil finds as a teenager. 

And folk love naming them. More than twenty fossil species have been named over time —  some even identified as the genus Sequoia in error — but for all their collective efforts to beef up this genus there are just three species: Metasequoia foxii, Metasequoia milleri, and Metasequoia occidentalis.

During the Paleocene and Eocene, extensive forests of Metasequoia thrived as far north as Strathcona Fiord on Ellesmere Island and sites on Axel Heiberg Island in Canada's far north around 80° N latitude.

We find lovely examples of Metasequoia occidentalis in the Eocene outcrops at McAbee near Cache Creek, British Columbia, Canada. I shared a photo here of one of those specimens. Once this piece dries out a bit, I will take a dental pick to it to reveal some of the teaser fossils peeking out.

The McAbee Fossil Beds are known for their incredible abundance, diversity and quality of fossils including lovely plant, insect and fish species that lived in an old lake bed setting. While the Metasequoia and other fossils found here are 52-53 million years old, the genus is much older. It is quite remarkable that both their fossil and extant lineage were discovered in just a few years of one another. 

Metasequoia was first described as a new genus from a fossil specimen found in 1939 and published by Japanese paleobotanist Shigeru Miki in 1941. Remarkably, the living version of this new genus was discovered later that same year. 

Professor Zhan Wang, an official from the Bureau of Forest Research was recovering from malaria at an old school chum's home in central China. His friend told him of a stand of trees discovered in the winter of 1941 by Chinese botanist Toh Gan (干铎). The trees were not far away from where they were staying and Gan's winter visit meant he did not collect any specimen as the trees had lost their leaves. 

The locals called the trees Shui-sa, or water fir. As trees go, they were reportedly quite impressive with some growing as much as sixty feet tall. Wang was excited by the possibility of finding a new species and asked his friend to describe the trees and their needles in detail. Emboldened by the tale, Wang set off through the remote mountains to search for his mysterious trees and found them deep in the heart of  Modaoxi (磨刀溪; now renamed Moudao (谋道), in Lichuan County, in the central China province of Hubei. He found the trees and was able to collect living specimens but initially thought they were from Glyptostrobus pensilis (水松). 

A few years later, Wang showed the trees to botanist Wan-Chun Cheng and learned that these were not the leaves of s Glyptostrobus pensilis (水松 ) but belonged to a new species. 

While the find was exciting, it was overshadowed by China's ongoing conflict with the Japanese that was continuing to escalate. With war at hand, Wang's research funding and science focus needed to be set aside for another two years as he fled the bombing of Beijing. 

When you live in a world without war on home soil it is easy to forget the realities for those who grew up in it. 

Zhan Wang and his family lived to witness the 1931 invasion of Manchuria, then the 1937 clash between Chinese and Japanese troops at the Marco Polo Bridge, just outside Beijing. 

That clash sparked an all-out war that would grow in ferocity to become World War II. 

Within a year, the Chinese military situation was dire. Most of eastern China lay in Japanese hands: Shanghai, Nanjing, Beijing, Wuhan. As the Japanese advanced, they left a devastated population in their path where atrocity after atrocity was the norm. Many outside observers assumed that China could not hold out, and the most likely scenario was a Japanese victory over China.

Yet the Chinese hung on, and after the horrors of Pearl Harbor, the war became genuinely global. The western Allies and China were now united in their war against Japan, a conflict that would finally end on September 2, 1945, after Allied naval forces blockaded Japan and subjected the island nation to intensive bombing, including the utter devastation that was the Enola Gay's atomic payload over Hiroshima. 

With World War II behind them, the Chinese researchers were able to re-focus their energies on the sciences. Sadly, Wang was not able to join them. Instead, two of his colleagues, Wan Chun Cheng and Hu Hsen Hsu, the director of Fan Memorial Institute of Biology would continue the work. Wan-Chun Cheng sent specimens to Hu Hsen Hsu and upon examination realised they were the living version of the trees Miki had published upon in 1941. 

Hu and Cheng published a paper describing a new living species of Metasequoia in May 1948 in the Bulletin of Fan Memorial Institute of Biology.

That same year, Arnold Arboretum of Harvard University sent an expedition to collect seeds and, soon after, seedling trees were distributed to various universities and arboreta worldwide. 

Today, Metasequoia grow around the globe. When I see them, I think of Wang and all he went through. He survived the conflict and went on to teach other bright, young minds about the bountiful flora in China. I think of Wan Chun Cheng collaborating with Hu Hsen Hsu in a time of war and of Hu keeping up to date on scientific research, even published works from colleagues from countries with whom his country was at war. Deep in my belly, I ache for the huge cost to science, research and all the species impacted on the planet from our human conflicts. Each year in April, I plant more Metasequoia to celebrate Earth Day and all that means for every living thing on this big blue orb.  

References: 

• https://web.stanford.edu/group/humbioresearch/cgi-bin/wordpress/?p=297
• https://humboldtredwoods.org/redwoods

LOWER LIAS LYTOCERAS AMMONITE

A superbly prepped and extremely rare Lytoceras (Suess, 1865) ammonite found as a green ammonite nodule by Matt Cape in the Lower Lias of Dorset. 

Lytoceras are rare in the Lower Lias of Dorset — apart from the Belemnite Stone horizon — so much so that Paul Davis, whose skilled prep work you see here, initially thought it might be a Becheiceras hidden within the large, lumpy nodule. 

One of the reasons these lovelies are rarely found from here is that they are a Mediterranean Tethyian genus. The fossil fauna we find in the United Kingdom are dominated by Boreal Tethyian genera. 

We do find Lytoceras sp. in the Luridum subzone of the Pliensbachian showing that there was an influx of species from the Mediterranean realm during this time. This is the first occurrence of a Lytoceras that he has ever seen in a green nodule and Paul's seen quite a few. 

This absolutely cracking specimen was found and is in the collections of the awesome Matt Cape. Matt recognized that whatever was hidden in the nodule would take skilled and careful preparation using air scribes. Indeed it did. It took more than five hours of time and skill to unveil the lovely museum-worthy specimen you see here. 

We find Lytoceras in more than 1,000 outcrops around the globe ranging from the Jurassic through to the Cretaceous, some 189.6 to 109.00 million years ago. Once this specimen is fully prepped with the nodule material cut or scraped away, you can see the detailed crinkly growth lines or riblets on the shell and none of the expected coarse ribbing. 

Lytoceras sp. Photo: Craig Chivers

If you imagine running your finger along these, you would be tracing the work of decades of growth of these cephalopods. 

While we cannot know their actual lifespans, but we can make a healthy guess. 

The nautilus, their closest living cousins live upwards of 20 years — gods be good — and less than three years if conditions are poor.

The flanges, projecting flat ribs or collars, develop at the edge of the mouth border on the animal's mantle as they grow each new chamber. 

Each delicate flange grows over the course of the ammonites life, marking various points in time and life stages as the ammonite grew. There is a large variation within Lytoceras with regards to flanges. They provide both ornamentation and strength to the shell to protect it from water pressure as they moved into deeper seas.

The concretion prior to prep

This distinctive genus with its evolute shells are found in the Cretaceous marine deposits of: 

Antarctica (5 collections), Austria (19), Colombia (1), the Czech Republic (3), Egypt (2), France (194), Greenland (16), Hungary (25), Italy (11), Madagascar (2), Mexico (1), Morocco (4), Mozambique (1), Poland (2), Portugal (1), Romania (1), the Russian Federation (2), Slovakia (3), South Africa (1), Spain (24), Tanzania (1), Trinidad and Tobago (1), Tunisia (25); and the United States of America (17: Alaska, California, North Carolina, Oregon).

We also find them in Jurassic marine outcrops in:

Austria (15), Canada (9: British Columbia), Chile (6), France (181), Germany (11), Greenland (1), Hungary (189), India (1), Indonesia (1), Iran (1), Italy (50), Japan (14), Kenya (2), Luxembourg (4), Madagascar (2), Mexico (1), Morocco (43), New Zealand (15), Portugal (1), Romania (5), the Russian Federation (1), Slovakia (1), Spain (6), Switzerland (2), Tunisia (11), Turkey (12), Turkmenistan (1), Ukraine (5), the United Kingdom (12), United States (11: Alaska, California) — in at least 977 known collections. 

References:

Sepkoski, Jack (2002). "A compendium of fossil marine animal genera (Cephalopoda entry)". Bulletins of American Paleontology. 363: 1–560. Archived from the original on 2008-05-07. Retrieved 2017-10-18.

Paleobiology Database - Lytoceras. 2017-10-19.

Systematic descriptions, Mesozoic Ammonoidea, by W.J Arkell, Bernhard Kummel, and C.W. Wright. 1957. Treatise on Invertebrate Paleontology, Part L. Geological Society of America and University of Kansas press.

SEA OTTERS: PLAYFUL TUMBLERS IN KELP

In a kingdom of waves and drifting kelp, the sea otters reign—rolling, tumbling, and spinning like acrobats in the surf. 

With shells for drums and sunlight for spotlight, they turn survival into play, joy into power. Tiny jesters of the ocean, yet fierce enough to hold an entire ecosystem in their grasp.

Sea otters (Enhydra lutris) are more than just charismatic charmers of the Pacific Coast; they are living links to an ancient evolutionary journey. Their playful demeanor hides a lineage that stretches back millions of years, into a fossil record that tells a story of transformation from river to sea.

The tale begins with their ancestors in the family Mustelidae—the same diverse group that gave us weasels, badgers, martens, and wolverines. The earliest otter-like mustelids appeared around 18 million years ago in the Miocene. Among them was Enhydriodon, a giant otter that roamed rivers and wetlands of Eurasia and Africa, weighing over 200 pounds—far larger than today’s sea otters.

By the late Miocene to early Pliocene, otter evolution was branching out. Fossils of Enhydra, the direct ancestor of modern sea otters, show up in the North Pacific around 5 million years ago. Unlike their freshwater kin, these otters were already well adapted to marine life: short, robust limbs for swimming, strong jaws for crushing mollusks, and teeth built for a diet of hard-shelled prey.

By the Pleistocene (2.6 million to 11,700 years ago), sea otters had fully taken to the sea. They developed one of nature’s thickest pelts—up to a million hairs per square inch—allowing them to survive frigid northern waters without relying on the blubber used by seals and whales. Fossil remains and genetic studies suggest that their range was once broader than it is today, extending along vast stretches of the North Pacific Rim.

These adaptations made sea otters not only survivors but keystone species. By preying on sea urchins, they keep kelp forests thriving, shaping entire marine ecosystems with their appetites. Without them, underwater forests collapse into barren urchin wastelands. With them, the kelp sways tall and green, sheltering fish, seabirds, and countless invertebrates.

It is a joy to watch them crack open a clam on its belly or twirl through kelp in a flurry of bubbles. 

From Miocene rivers to Pleistocene shores, for me sea otters embody resilience and adaptation, carrying forward the legacy of their fossil kin.

Sea otters are tender and attentive parents, especially the mothers who cradle their pups on their bellies as they float in the swells. 

A newborn pup’s fur is so dense and buoyant that it cannot dive, so the mother becomes both raft and refuge. 

She grooms the pup constantly, blowing air into its coat to keep it dry and warm, and when she needs to forage, she may wrap her young in strands of kelp to keep it from drifting away. 

This intimate bond, played out on the rolling surface of the sea, is one of the most endearing sights in the animal kingdom—proof that even in the wild’s ceaseless struggle for survival, tenderness finds its place. 

We call these playful relatives, ḵ̓asa, in Kwak'wala, the language of the Kwakwakaʼwakw (those who speak Kwak'wala), First Nations along the Pacific Northwest Coast.

NOOTKA: FOSSILS AND FIRST NATIONS HISTORY

Nootka Fossil Field Trip. Photo: John Fam

The rugged west coast of Vancouver Island offers spectacular views of a wild British Columbia. Here the seas heave along the shores slowly eroding the magnificent deposits that often contain fossils. 

Just off the shores of Vancouver Island, east of Gold River and south of Tahsis is the picturesque and remote Nootka Island.

This is the land of the proud and thriving Nuu-chah-nulth First Nations who have lived here always. 

Always is a long time, but we know from oral history and archaeological evidence that the Mowachaht and Muchalaht peoples lived here, along with many others, for many thousands of years — a time span much like always. 

While we know this area as Nootka Sound and the land we explore for fossils as Nootka Island, these names stem from a wee misunderstanding. 

Just four years after the 1774 visit by Spanish explorer Juan Pérez — and only a year before the Spanish established a military and fur trading post on the site of Yuquot — the Nuu-chah-nulth met the Englishman, James Cook.  

Captain Cook sailed to the village of Yuquot just west of Vancouver Island to a very warm welcome. He and his crew stayed on for a month of storytelling, trading and ship repairs. Friendly, but not familiar with the local language, he misunderstood the name for both the people and land to be Nootka. In actual fact, Nootka means, go around, go around. 

Two hundred years later, in 1978, the Nuu-chah-nulth chose the collective term Nuu-chah-nulth — nuučaan̓uł, meaning all along the mountains and sea or along the outside (of Vancouver Island) — to describe themselves. 

It is a term now used to describe several First Nations people living along western Vancouver Island, British Columbia. 

It is similar in a way to the use of the United Kingdom to refer to the lands of England, Scotland and Wales — though using United Kingdom-ers would be odd. Bless the Nuu-chah-nulth for their grace in choosing this collective name.  

An older term for this group of peoples was Aht, which means people in their language and is a component in all the names of their subgroups, and of some locations — Yuquot, Mowachaht, Kyuquot, Opitsaht. While collectively, they are the Nuu-chah-nulth, be interested in their more regional name should you meet them. 

But why does it matter? If you have ever mistakenly referred to someone from New Zealand as an Aussie or someone from Scotland as English, you have likely been schooled by an immediate — sometimes forceful, sometimes gracious — correction of your ways. The best answer to why it matters is because it matters.

Each of the subgroups of the Nuu-chah-nulth viewed their lands and seasonal migration within them (though not outside of them) from a viewpoint of inside and outside. Kla'a or outside is the term for their coastal environment and hilstis for their inside or inland environment.

It is to their kla'a that I was most keen to explore. Here, the lovely Late Eocene and Early Miocene exposures offer up fossil crab, mostly the species Raninid, along with fossil gastropods, bivalves, pine cones and spectacularly — a singular seed pod. These wonderfully preserved specimens are found in concretion along the foreshore where time and tide erode them out each year.

Five years after Spanish explorer Juan Pérez's first visit, the Spanish built and maintained a military post at Yuquot where they tore down the local houses to build their own structures and set up what would become a significant fur trade port for the Northwest Coast — with the local Chief Maquinna's blessing and his warriors acting as middlemen to other First Nations. 

Following reports of Cook's exploration British traders began to use the harbour of Nootka (Friendly Cove) as a base for a promising trade with China in sea-otter pelts but became embroiled with the Spanish who claimed (albeit erroneously) sovereignty over the Pacific Ocean. 

Dan Bowen searching an outcrop. Photo: John Fam

The ensuing Nootka Incident of 1790 nearly led to war between Britain and Spain (over lands neither could actually claim) but talk of war settled and the dispute was settled diplomatically. 

George Vancouver on his subsequent exploration in 1792 circumnavigated the island and charted much of the coastline. His meeting with the Spanish captain Bodega y Quadra at Nootka was friendly but did not accomplish the expected formal ceding of land by the Spanish to the British. 

It resulted however in his vain naming the island "Vancouver and Quadra." The Spanish captain's name was later dropped and given to the island on the east side of Discovery Strait. Again, another vain and unearned title that persists to this day.

Early settlement of the island was carried out mainly under the sponsorship of the Hudson's Bay Company whose lease from the Crown amounted to 7 shillings per year — that's roughly equal to £100.00 or $174 CDN today. Victoria, the capital of British Columbia, was founded in 1843 as Fort Victoria on the southern end of Vancouver Island by the Hudson's Bay Company's Chief Factor, Sir James Douglas. 

With Douglas's help, the Hudson's Bay Company established Fort Rupert on the north end of Vancouver Island in 1849. Both became centres of fur trade and trade between First Nations and solidified the Hudson's Bay Company's trading monopoly in the Pacific Northwest.

The settlement of Fort Victoria on the southern tip of Vancouver Island — handily south of the 49th parallel — greatly aided British negotiators to retain all of the islands when a line was finally set to mark the northern boundary of the United States with the signing of the Oregon Boundary Treaty of 1846. Vancouver Island became a separate British colony in 1858. British Columbia, exclusive of the island, was made a colony in 1858 and in 1866 the two colonies were joined into one — becoming a province of Canada in 1871 with Victoria as the capital.

Dan Bowen, Chair of the Vancouver Island Palaeontological Society (VIPS) did a truly splendid talk on the Fossils of Nootka Sound. With his permission, I have uploaded the talk to the ARCHEA YouTube Channel for all to enjoy. Do take a boo, he is a great presenter. Dan also graciously provided the photos you see here. The last of the photos you see here is from the August 2021 Nootka Fossil Field Trip. Photo: John Fam, Vice-Chair, Vancouver Paleontological Society (VanPS).

Know Before You Go — Nootka Trail

The Nootka Trail passes through the traditional lands of the Mowachaht/Muchalat First Nations who have lived here since always. They share this area with humpback and Gray whales, orcas, seals, sea lions, black bears, wolves, cougars, eagles, ravens, sea birds, river otters, insects and the many colourful intertidal creatures that you'll want to photograph.

This is a remote West Coast wilderness experience. Getting to Nootka Island requires some planning as you'll need to take a seaplane or water taxi to reach the trailhead. The trail takes 4-8 days to cover the 37 km year-round hike. The peak season is July to September. Permits are not required for the hike. 

Access via: Air Nootka floatplane, water taxi, or MV Uchuck III

• Dan Bowen, VIPS on the Fossils of Nootka: https://youtu.be/rsewBFztxSY
• https://www.thecanadianencyclopedia.ca/en/article/sir-james-douglas
• file:///C:/Users/tosca/Downloads/186162-Article%20Text-199217-1-10-20151106.pdf
• Nootka Trip Planning: https://mbguiding.ca/nootka-trail-nootka-island/#overview

SHAGGY TITANS OF THE GRASSLANDS: BISON

Bison move across the prairie like living storms, vast and steady, with the weight of centuries in their stride. 

Their dark eyes hold a quiet, unwavering depth—as if they’ve looked into the heart of time itself and carry its secrets in silence. Look into the eyes of this fellow and tell me you do not see his deep intelligence as he gives the camera a knowing look.

Shaggy fur ripples in the wind, rich and earthy, brushed by sun and shadow, a cloak woven from wilderness. When they breathe, clouds rise in the cold air, soft and ephemeral, like whispered promises that vanish but leave warmth behind.

There is something profoundly romantic in their presence: strength wrapped in gentleness, endurance softened by grace.  To watch them is to feel the wild itself lean closer, reminding us of a love as vast as the horizon, as eternal as the ground beneath our feet.

When we think of bison today, images of great herds roaming the North American plains come to mind—dark, shaggy shapes against sweeping prairies. But the story of bison goes back far deeper in time. 

These massive grazers are part of a lineage that stretches millions of years into the past, their fossil record preserving the tale of their rise, spread, and survival.

Bison belong to the genus Bison, within the cattle family (Bovidae). Their story begins in Eurasia during the late Pliocene, around 2.6 million years ago, when the first true bison evolved from earlier wild cattle (Bos-like ancestors). 

Fossils suggest they descended from large bovids that roamed open grasslands of Eurasia as forests retreated and cooler, drier climates expanded.

The earliest known species, Bison priscus, or the Steppe Bison, was a giant compared to modern bison, sporting long horns that could span over six feet tip to tip. These animals thrived across Europe, Asia, and eventually crossed into North America via the Bering Land Bridge during the Pleistocene Ice Age.

The fossil record of bison stretches back about 2 million years in Eurasia and at least 200,000 years in North America, where they became one of the most successful large herbivores of the Ice Age. Fossil evidence shows that at least seven different species of bison once lived in North America, including the iconic Bison latifrons with its massive horns, and Bison antiquus, which is considered the direct ancestor of the modern American bison (Bison bison).

Some of the richest fossil bison deposits come from Siberia and Eastern Europe – home to abundant Bison priscus fossils, often preserved in permafrost with soft tissues intact. They are also found in Alaska, USA and in Canada's Yukon region – where Ice Age bison fossils are found alongside mammoth, horse, and muskox remains.

The Great Plains of the United States and Canada are rich in Bison antiquus and later species, often in mass bone beds where entire herds perished. We also find their remains in California and the American Southwest at sites like the La Brea Tar Pits. La Brea preserves bison remains from the Late Pleistocene and their museum of the same name has a truly wonderful display of Pleistocene wolves. Definitely worthy of a trip!

One particularly famous fossil site is the Hudson-Meng Bison Kill Site in Nebraska, where remains of over 600 Bison antiquus dating to about 10,000 years ago provide a window into Ice Age hunting practices and herd behavior.

By the end of the Ice Age, many megafauna species disappeared, but bison endured. Bison antiquus gradually gave rise to the modern American bison (Bison bison), which still carries echoes of its Ice Age ancestors. Though smaller than their Pleistocene relatives, today’s bison remain the largest land mammals in North America.

GIANT SLOTH: MEGATHERIUM

In 1788, a remarkable specimen of Megatherium americanum, one of the largest known terrestrial sloths, was shipped from the Viceroyalty of the Río de la Plata (present-day Argentina and Uruguay) to the Royal Cabinet of Natural History in Madrid, Spain. 

This fossil would become the type specimen for the species and a cornerstone in the early study of extinct megafauna.

Megatherium belonged to the order Pilosa within the superorder Xenarthra—a group that includes modern sloths, anteaters, and armadillos. 

These colossal herbivores thrived in South America from the Pliocene to the end of the Pleistocene, approximately 2 million to 10,000 years ago. Megatherium, whose name means "great beast," could grow up to 6 meters (20 feet) in length and weigh over 4 tons, rivaling modern elephants in size.

This sloth's immense skeletal structure, including robust pelvic and femoral bones, suggests it could rear up on its hind limbs, using its tail as a supportive tripod. This stance allowed it to browse high vegetation, possibly stripping branches and reaching tree canopies with its elongated forelimbs and curved claws. Such a feeding adaptation was critical, as an adult Megatherium required vast quantities of plant matter to sustain its bulk.

Intriguingly, the Megatherium may have played a key role in the dispersal of large-fruited plants like Persea americana—the avocado. Its gut was capable of processing such large fruits, and it likely defecated the intact pits over great distances, contributing to the avocado’s prehistoric range. Modern ecological studies support the idea that many now-domesticated fruit species evolved in tandem with megafaunal seed dispersers (Guimarães et al., 2008).

The specimen sent to Spain was assembled and illustrated by Spanish artist and anatomist Juan Bautista Bru de Ramón. Though Bru’s reconstruction, completed in 1788, was not anatomically correct by today’s standards—it depicts the sloth standing upright with straight legs and a curved spine—it was a pioneering attempt at skeletal reconstruction. 

The mount remains on display at the Museo Nacional de Ciencias Naturales in Madrid in its original form, preserving its historical and scientific significance.

French naturalist Georges Cuvier, often regarded as the father of paleontology, later studied Bru’s illustrations and used them to describe Megatherium scientifically in 1796. Cuvier recognized the sloth’s herbivorous nature and its relation to modern tree sloths, a conclusion that helped shape early theories of extinction and comparative anatomy (Cuvier, 1796).

Today, the Megatherium skeleton in Madrid stands not only as a monument to a vanished giant but also as a testament to international collaboration in the early days of paleontology—where artists, anatomists, and naturalists together unveiled the grandeur of life’s ancient past.

If you look closely, you'll see it is not anatomically correct. But all good paleontology is teamwork. Based upon the drawings of Juan Bautista Bru, George Cuvier used this specimen to describe the species for the very first time.

References:

Cuvier, G. (1796). Mémoire sur le squelette d’une très grande espèce de quadrupède inconnue jusqu’à présent. Mémoires de l’Institut National des Sciences et Arts.

Fariña, R. A., Vizcaíno, S. F., & Bargo, M. S. (1998). Body mass estimations in Lujanian (late Pleistocene–early Holocene of South America) mammal megafauna. Mastozoología Neotropical, 5(2), 87–108.

Guimarães Jr, P. R., Galetti, M., & Jordano, P. (2008). Seed dispersal anachronisms: Rethinking the fruits extinct megafauna ate. PLoS ONE, 3(3), e1745. https://doi.org/10.1371/journal.pone.0001745

McDonald, H. G. (2005). Paleoecology of extinct xenarthrans and the Great American Biotic Interchange. Bulletin of the Florida Museum of Natural History, 45, 313–333.

FOSSILS WHALES FROM SOUTHERN VANCOUVER ISLAND

Modern Whale Vertebrae

The air is heavy with salt spray at Muir Creek, just west of Sooke on southern Vancouver Island. Waves tumble over barnacle-crusted boulders, and eagles wheel overhead. 

Thick layers of sandstone and conglomerate preserve a rich assemblage of marine fossils. Local collectors have long explored these beaches, spotting fossilized ribs and vertebrae protruding from the cliffs. 

My first trip here was back in the mid 1990s with the Vancouver Paleontological Society. It is a regular haunt for the Victoria Paleontological Society and other regional fossil collecting groups.

It’s a place where the modern Pacific feels timeless—but buried in the cliffs are the remains of creatures that swam here more than 25 million years ago. 

They are whales, yes, but not quite the whales we know today. Their bones tell the story of an ocean in transition and of whales caught mid-evolution—halfway between toothed predators and the filter-feeders that now dominate the seas.

Southern Vancouver Island’s fossil-bearing rocks belong largely to the Sooke Formation, a marine deposit dating to the late Oligocene (around 25–23 million years ago). At that time, much of the region lay beneath shallow coastal waters. Sediments settled over the remains of sea creatures, entombing shells, bird bones, shark teeth, and occasionally the massive bones of early whales.

These are not fossils of the gigantic blue whales or humpbacks we know today, but their ancestors—smaller, stranger, and crucial to the story of whale evolution.

One of the most remarkable finds from Vancouver Island is Aetiocetus, a small whale that lived during the late Oligocene. Aetiocetus is a classic “transitional fossil”—a whale that still had teeth, yet also shows evidence of developing baleen. This makes it a key player in understanding how modern filter-feeding whales (like gray whales and blue whales) evolved from their toothed ancestors.

Imagine a creature about 3–4 meters long, sleek like a dolphin but with a skull showing both sharp teeth and grooves that hint at primitive baleen plates. It likely hunted fish and squid but may have supplemented its diet by gulping in small prey from the water column. 

Fossils of Aetiocetus have been found in Oregon and Japan, but southern Vancouver Island provides some of the northernmost evidence of this important lineage.

Alongside these early baleen whales, researchers have also found evidence of primitive odontocetes—the group that includes dolphins, porpoises, and sperm whales. These small, agile predators were experimenting with echolocation, the same sonar-like ability modern toothed whales use to hunt in dark or murky waters.

The whales preserved on southern Vancouver Island belong to a lineage with an extraordinary backstory. Around 50 million years ago, in what is now Pakistan and India, the ancestors of whales were land-dwelling, hoofed mammals (related to early hippos). Over millions of years, these animals waded into rivers and seas, evolving into the fully aquatic forms we recognize as whales.

By the time the Sooke Formation was laid down, whales had already colonized oceans worldwide. But the fossils here capture them in the middle of another transformation—the split between toothed whales (odontocetes) and baleen whales (mysticetes). Vancouver Island’s cliffs are, in a sense, a library shelf containing one of evolution’s most important chapters.

Fossil Gastropods, Photo: John Fam

Standing at Muir Creek today, it’s hard not to draw parallels between past and present. Offshore, humpback whales spout on their summer migration. Orcas patrol the Strait of Juan de Fuca, hunting salmon with precision. Gray whales feed along kelp beds in shallow waters. These are the direct descendants of the fossil whales entombed in the cliffs.

That continuity of life—millions of years stretching unbroken from fossil Aetiocetus to the humpback breaching offshore—gives southern Vancouver Island a special place in the story of the Pacific.

The cliffs of Muir Creek and other fossil sites are constantly eroding, revealing new fossils—but also destroying them. Without careful collection and preservation, many specimens are lost to the sea. 

It is for this reason that we encourage citizen scientists to report significant finds rather than attempt to remove them — and in the case of the Muir Creek fossil site, to avoid collecting from the cliffs. 

Fossils are protected under British Columbia’s Heritage Conservation Act, meaning they belong to the province and its people.

Next time you stand on those windswept cliffs, watching an orca’s dorsal fin slice through the surf, remember: you are standing on an ancient whale highway. Beneath your feet, locked in stone, are the bones of their ancestors—whales that swam here long before the Salish Sea had a name.

AVES: LIVING DINOSAURS

Cassowary, Casuariiformes

Wherever you are in the world, it is likely that you know your local birds. True, you may call them des Oiseaux, pássaros or uccelli — but you'll know their common names by heart.

You will also likely know their sounds. The tweets, chirps, hoots and caws of the species living in your backyard.

Birds come in all shapes and sizes and their brethren blanket the globe. It is amazing to think that they all sprang from the same lineage given the sheer variety. 

If you picture them, we have such a variety on the planet — parrots, finches, wee hummingbirds, long-legged waterbirds, waddling penguins and showy toucans. 

But whether they are a gull, hawk, cuckoo, hornbill, potoo or albatross, they are all cousins in the warm-blooded vertebrate class Aves. 

The defining features of the Aves are feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton. The best features, their ability to dance, bounce and sing, are not listed, but it is how I see them in the world.

These modern dinosaurs live worldwide and range in size from the 5 cm (2 in) bee hummingbird to the 2.75 m (9 ft) ostrich. 

There are about ten thousand living species, more than half of which are passerine, or "perching" birds. Birds have wings whose development varies according to species; the only known groups without wings are the extinct moa and elephant birds.

Wings evolved from forelimbs giving birds the ability to fly

Wings, which evolved from forelimbs, gave birds the ability to fly, although further evolution has led to the loss of flight in some birds, including ratites, penguins, and diverse endemic island species. 

The digestive and respiratory systems of birds are also uniquely adapted for flight. Some bird species of aquatic environments, particularly seabirds and some waterbirds, have further evolved for swimming.

Wee Feathered Theropod Dinosaurs

We now know from fossil and biological evidence that birds are a specialized subgroup of theropod dinosaurs, and more specifically, they are members of Maniraptora, a group of theropods that includes dromaeosaurs and oviraptorids, amongst others. As palaeontologists discover more theropods closely related to birds, the previously clear distinction between non-birds and birds has become a bit muddy.

Recent discoveries in the Liaoning Province of northeast China, which include many small theropod feathered dinosaurs — and some excellent arty reproductions — contribute to this ambiguity. 

Still, other fossil specimens found here shed a light on the evolution of Aves. Confuciusornis sanctus, an Early Cretaceous bird from the Yixian and Jiufotang Formations of China is the oldest known bird to have a beak.

Like modern birds, Confuciusornis had a toothless beak, but close relatives of modern birds such as Hesperornis and Ichthyornis were toothed, telling us that the loss of teeth occurred convergently in Confuciusornis and living birds.

The consensus view in contemporary palaeontology is that the flying theropods, or avialans, are the closest relatives of the deinonychosaurs, which include dromaeosaurids and troodontids.

Together, these form a group called Paraves. Some basal members of this group, such as Microraptor, have features that may have enabled them to glide or fly. 

The most basal deinonychosaurs were wee little things. This raises the possibility that the ancestor of all paravians may have been arboreal, have been able to glide, or both. Unlike Archaeopteryx and the non-avialan feathered dinosaurs, who primarily ate meat, tummy contents from recent avialan studies suggest that the first avialans were omnivores. Even more intriguing...

Avialae, which translates to bird wings, are a clade of flying dinosaurs containing the only living dinosaurs, the birds. It is usually defined as all theropod dinosaurs more closely related to modern birds — Aves — than to deinonychosaurs, though alternative definitions are occasionally bantered back and forth.

The Earliest Avialan: Archaeopteryx lithographica

Archaeopteryx, bird-like dinosaur from the Late Jurassic

Archaeopteryx lithographica, from the late Jurassic Period Solnhofen Formation of Germany, is the earliest known avialan that may have had the capability of powered flight. 

However, several older avialans are known from the Late Jurassic Tiaojishan Formation of China, dating to about 160 million years ago.

The Late Jurassic Archaeopteryx is well-known as one of the first transitional fossils to be found, and it provided support for the theory of evolution in the late 19th century. 

Archaeopteryx was the first fossil to clearly display both traditional reptilian characteristics — teeth, clawed fingers, and a long, lizard-like tail—as well as wings with flight feathers similar to those of modern birds. It is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor.

Unlikely yet true, the closest living relatives of birds are the crocodilians. Birds are descendants of the primitive avialans — whose members include Archaeopteryx — which first appeared about 160 million years ago in China.

DNA evidence tells us that modern birds — Neornithes — evolved in the Middle to Late Cretaceous, and diversified dramatically around the time of the Cretaceous–Paleogene extinction event 66 mya, which killed off the pterosaurs and all non-avian dinosaurs.

In birds, the brain, especially the telencephalon, is remarkably developed, both in relative volume and complexity. Unlike most early‐branching sauropsids, the adults of birds and other archosaurs have a well‐ossified neurocranium. In contrast to most of their reptilian relatives, but similar to what we see in mammals, bird brains fit closely to the endocranial cavity so that major external features are reflected in the endocasts. What you see on the inside is what you see on the outside.

This makes birds an excellent group for palaeoneurological investigations. The first observation of the brain in a long‐extinct bird was made in the first quarter of the 19th century. However, it was not until the 2000s and the application of modern imaging technologies that avian palaeoneurology really took off.

Understanding how the mode of life is reflected in the external morphology of the brains of birds is but one of several future directions in which avian palaeoneurological research may extend.

Although the number of fossil specimens suitable for palaeoneurological explorations is considerably smaller in birds than in mammals and will very likely remain so, the coming years will certainly witness a momentous strengthening of this rapidly growing field of research at the overlap between ornithology, palaeontology, evolutionary biology and the neurosciences.

Reference: Cau, Andrea; Brougham, Tom; Naish, Darren (2015). "The phylogenetic affinities of the bizarre Late Cretaceous Romanian theropod Balaur bondoc (Dinosauria, Maniraptora): Dromaeosaurid or flightless bird?". PeerJ. 3: e1032. doi:10.7717/peerj.1032. PMC 4476167. PMID 26157616.

Reference: Ivanov, M., Hrdlickova, S. & Gregorova, R. (2001) The Complete Encyclopedia of Fossils. Rebo Publishers, Netherlands. p. 312

INDEX FOSSILS: AMMONITES

Argonauticeras besairei, Collection of José Juárez Ruiz.

An exceptional example of fractal building of an ammonite septum, in this clytoceratid Argonauticeras besairei from the awesome José Juárez Ruiz.

Ammonites were predatory, squid-like creatures that lived inside coil-shaped shells.

Like other cephalopods, ammonites had sharp, beak-like jaws inside a ring of squid-like tentacles that extended from their shells. They used these tentacles to snare prey, — plankton, vegetation, fish and crustaceans — similar to the way a squid or octopus hunt today.

Catching a fish with your hands is no easy feat, as I'm sure you know. But the Ammonites were skilled and successful hunters. They caught their prey while swimming and floating in the water column. Within their shells, they had a number of chambers, called septa, filled with gas or fluid that were interconnected by a wee air tube. By pushing air in or out, they were able to control their buoyancy in the water column.

They lived in the last chamber of their shells, continuously building new shell material as they grew. As each new chamber was added, the squid-like body of the ammonite would move down to occupy the final outside chamber.

They were a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids — octopuses, squid, and cuttlefish) than they are to shelled nautiloids such as the living Nautilus species.

The Ammonoidea can be divided into six orders:

• Agoniatitida, Lower Devonian - Middle Devonian
• Clymeniida, Upper Devonian
• Goniatitida, Middle Devonian - Upper Permian
• Prolecanitida, Upper Devonian - Upper Triassic
• Ceratitida, Upper Permian - Upper Triassic
• Ammonitida, Lower Jurassic - Upper Cretaceous

Ammonites have intricate and complex patterns on their shells called sutures. The suture patterns differ across species and tell us what time period the ammonite is from. If they are geometric with numerous undivided lobes and saddles and eight lobes around the conch, we refer to their pattern as goniatitic, a characteristic of Paleozoic ammonites.

If they are ceratitic with lobes that have subdivided tips; giving them a saw-toothed appearance and rounded undivided saddles, they are likely Triassic. For some lovely Triassic ammonites, take a look at the specimens that come out of Hallstatt, Austria and from the outcrops in the Humboldt Mountains of Nevada.

Hoplites bennettiana (Sowby, 1826).

If they have lobes and saddles that are fluted, with rounded subdivisions instead of saw-toothed, they are likely Jurassic or Cretaceous. If you'd like to see a particularly beautiful Lower Jurassic ammonite, take a peek at Apodoceras. Wonderful ridging in that species.

One of my favourite Cretaceous ammonites is the ammonite, Hoplites bennettiana (Sowby, 1826). This beauty is from Albian deposits near Carrière de Courcelles, Villemoyenne, near la région de Troyes (Aube) Champagne in northeastern France.

At the time that this fellow was swimming in our oceans, ankylosaurs were strolling about Mongolia and stomping through the foliage in Utah, Kansas and Texas. Bony fish were swimming over what would become the strata making up Canada, the Czech Republic and Australia. Cartilaginous fish were prowling the western interior seaway of North America and a strange extinct herbivorous mammal, Eobaatar, was snuffling through Mongolia, Spain and England.

In some classifications, these are left as suborders, included in only three orders: Goniatitida, Ceratitida, and Ammonitida. Once you get to know them, ammonites in their various shapes and suturing patterns make it much easier to date an ammonite and the rock formation where is was found at a glance.

Ammonites first appeared about 240 million years ago, though they descended from straight-shelled cephalopods called bacrites that date back to the Devonian, about 415 million years ago, and the last species vanished in the Cretaceous–Paleogene extinction event.

They were prolific breeders that evolved rapidly. If you could cast a fishing line into our ancient seas, it is likely that you would hook an ammonite, not a fish. They were prolific back in the day, living (and sometimes dying) in schools in oceans around the globe. We find ammonite fossils (and plenty of them) in sedimentary rock from all over the world.

In some cases, we find rock beds where we can see evidence of a new species that evolved, lived and died out in such a short time span that we can walk through time, following the course of evolution using ammonites as a window into the past.

For this reason, they make excellent index fossils. An index fossil is a species that allows us to link a particular rock formation, layered in time with a particular species or genus found there. Generally, deeper is older, so we use the sedimentary layers rock to match up to specific geologic time periods, rather the way we use tree-rings to date trees. A handy way to compare fossils and date strata across the globe.

References: Inoue, S., Kondo, S. Suture pattern formation in ammonites and the unknown rear mantle structure. Sci Rep 6, 33689 (2016). https://doi.org/10.1038/srep33689
https://www.nature.com/articles/srep33689?fbclid=IwAR1BhBrDqhv8LDjqF60EXdfLR7wPE4zDivwGORTUEgCd2GghD5W7KOfg6Co#citeas

Photo: Hoplites Bennettiana from near Troyes, France. Collection de Christophe Marot