Showing posts with label fish. Show all posts
Showing posts with label fish. Show all posts

Thursday, March 21, 2024

FRACTAL BUILDING: 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

Wednesday, February 28, 2024

FOLKSTONE GAULT CLAY AMMONITES

This lovely wee 2.6 cm ammonite is Anahoplites planns from the Cretaceous Folkstone Gault Clay, county of Kent, southeast England. Joining him on this bit of matrix is a 3.2 cm section of Hamites sp. 

This matrix you see here is the Gault Clay, known locally as the Blue Slipper. This fine muddy clay was deposited 105-110 million years ago during the Lower Cretaceous (Upper and Middle Albian) in a calm, fairly deep-water continental shelf that covered what is now southern England and northern France.

Lack of brackish or freshwater fossils indicates that the gault was laid down in open marine environments away from estuaries. The maximum depth of the Gault is estimated 40-60m a figure which has been reached by the presence of Borings made by specialist Algal-grazing gastropods and supported by a study made by Khan in 1950 using Foraminifera. Estimates of the surface water temperatures in the Gault are between 20-22°c and 17-19°c on the seafloor. These estimates have been reached by bulk analysis of sediments which probably register the sea surface temperature for calcareous nanofossils.

It is responsible for many of the major landslides around Ventnor and Blackgang the Gault is famous for its diverse fossils, mainly from mainland sites such as Folkestone in Kent.

Folkestone, Kent is the type locality for the Gault clay yielding an abundance of ammonites, the same cannot be said for the Isle of Wight Gault, however, the south-east coast of the island has proved to be fossiliferous in a variety of ammonites, in particular, the Genus Hoplites, Paranahoplites and Beudanticeras.

While the Gault is less fossiliferous here on the island it can still produce lovely marine fossils, mainly ammonites and fish remains from these muddy mid-Cretaceous seas. The Gault clay marine fossils include the ammonites (such as Hoplites, Hamites, Euhoplites, Anahoplites, and Dimorphoplites), belemnites (such as Neohibolites), bivalves (notably Birostrina and Pectinucula), gastropods (including the lovely Anchura), solitary corals, fish remains (including shark teeth), scattered crinoid remains, and crustaceans (look for the crab Notopocorystes).

Occasional fragments of fossil wood may also be found. The lovely ammonite you see here is from the Gault Clays of Folkstone. Not all who name her would split the genus Euhoplites. There’s a reasonable argument for viewing this beauty as a very thick form of E. loricatus with Proeuhoplites being a synonym of Euhoplites. 

Jack Wonfor shared a wealth of information on the Gault and has many lovely examples of the ammonites found here in his collections. If you wish to know more about the Gault clay a publication by the Palaeontological Association called 'Fossils of the Gault clay' by Andrew S. Gale is available in Dinosaur Isle's gift shop.

There is a very good website maintained by Fred Clouter you can look at for reference. It also contains many handy links to some of the best fossil books on the Gault Clay and Folkstone Fossil Beds. Check it out here: http://www.gaultammonite.co.uk/

Friday, January 19, 2024

YING YANG: ZYCHASPISES

Zenaspis pololica
A Devonian bony fish mortality plate showing a lower shield of Zenaspis podolica (Lankester, 1869) from Lower Devonian deposits of Podolia, Ukraine.

While war rages on in the Ukraine, our hearts go out to those who live and work here contributing much to our understanding of Podolia, a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine, in northeastern Moldova. 

As I write this, thousands of Ukrainians are arriving at the Palanca border crossing in Moldova on Ukraine's western border to escape the fighting and pincher advance of the Russian military in the north, south and east. 

Looking at a map of the Ukraine, I imagine a torch touching the edges that mental map alighting it with flame — the edges slowly burning and curling in as the world watches and good people on both sides feel that burn.

We look to the Ukraine with our modern lens as we are want to do. Ukraine emerged as the concept of a nation and the Ukrainians as a nationality with the Ukrainian National Revival in the mid-18th century, in the wake of the peasant revolt of 1768-1769 and the eventual partition of the Polish–Lithuanian Commonwealth. They have known a tense love/hate relationship with their neighboring nations for a long while, sharing culture and language but desiring freedom and independence. 

It became an independent state in 1991 with the collapse of the Soviet Union. This fertile part of the world has an archaeology record of human habitation that goes back to the first millennium BC — the oldest known main inhabitants of Ukraine were Cimmerians. They were replaced in Fifth Century BC by Scythians who ruled till 2nd Century BC. The Sarmatian tribes replaced them. Wars, battles and skirmishes ensued until the tribesmen of the dominant horde, the Alanis, could be said to rule in the First Century AD. While our recorded history, our ancestors likely hunted and past through here far earlier. 

Beneath our human habitation and current military action is bedrock that tells the story of the Earth's violent past. The fauna here are from the Silurian and record a time in our Earth's history where the planet suffered a major mass extinction event that wiped out 23 percent of all marine life. It is the only region in Ukraine where 420 million-year-old remains of ichthyofauna can be found near the surface, making them accessible to collection and study. 

Zenaspis is an extinct genus of jawless fish which thrived during the early Devonian. Being jawless, Zenaspis was probably a bottom feeder, dining on debris from the seafloor similar to how flounder, groupers, bass and other bottom-feeding fish make a living.

For the past 150 years, vertebrate fossils have been found in more than 90 localities situated in outcrops along banks of the Dniester River and its northern tributaries, and in sandstone quarries. 

At present, the faunal list of Early Devonian agnathans and fishes from Podolia number seventy-two species, including 8 Thelodonti, 39 Heterostraci, 19 Osteostraci, 4 Placodermi, 1 Acanthodii, and 1 Holocephali (Voichyshyn 2001a).

In Podolia, the Lower Devonian Redbeds strata (the Old Red Formation or Dniester Series) are 1800 metres thick and range from Lochkovian to Eifelian in age (Narbutas 1984; Drygant 2000, 2003).

In their lower part, the Ustechko and Khmeleva members of the Dniester Series are built from lovely multicoloured, mainly red, fine-grained cross-bedded massive quartz sandstones and siltstones with seams of argillites (Drygant 2000).

We see fossils of Zenaspis in the early Devonian of Western Europe. Both Zenaspis pagei and Zenaspis poweri can be found up to 25 centimetres long in Devonian outcrops of Scotland.

Reference: Voichyshyn, V. 2006. New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica 51 (1): 131–142. Photo care of the awesome Fossilero Fisherman, a fossil hunter devoted to collecting the Lower Devonian Creek exposures of the Ukraine

Saturday, December 30, 2023

ZENASPIS PODOLICA HEAD SHIELD

A Devonian bony fish mortality plate showing a lower shield of Zenaspis podolica (Lankester, 1869) from Lower Devonian deposits of Podolia, Ukraine.

Podolia or Podilia is a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine, in northeastern Moldova. Podolia is the only region in Ukraine where 420 million-year-old remains of ichthyofauna can be found near the surface, making them accessible to collection and study. Zenaspis is an extinct genus of jawless fish which thrived during the early Devonian. Being jawless, Zenaspis was probably a bottom feeder, snicking on debris from the seafloor similar to how flounder, groupers, bass and other bottom-feeding fish make a living.

For the past 150 years, vertebrate fossils have been found in more than 90 localities situated in outcrops along banks of the Dniester River and its northern tributaries, and in sandstone quarries. At present, the faunal list of Early Devonian agnathans and fishes from Podolia number seventy-two species, including 8 Thelodonti, 39 Heterostraci, 19 Osteostraci, 4 Placodermi, 1 Acanthodii, and 1 Holocephali (Voichyshyn 2001a).

In Podolia, Lower Devonian redbeds strata (the Old Red Formation or Dniester Series) are up to 1800 m thick and range from Lochkovian to Eifelian in age (Narbutas 1984; Drygant 2000, 2003).

In their lower part (Ustechko and Khmeleva members of the Dniester Series) they consist of lovely multicoloured, mainly red, fine-grained cross-bedded massive quartz sandstones and siltstones with seams of argillites (Drygant 2000).

We see fossils of Zenaspis in the early Devonian of Western Europe. Both Zenaspis pagei and Zenaspis poweri can be found up to 25 centimetres long in Devonian outcrops of Scotland.

Reference: Voichyshyn, V. 2006. New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica 51 (1): 131–142. Photo care of the awesome Fossilero Fisherman.

Monday, December 18, 2023

TETRAPODS & FIRST NATION FOSSILS

Elpistostege watsoni

In the late 1930s, our understanding of the transition of fish to tetrapods — and the eventual jump to modern vertebrates — took an unexpected leap forward. The evolutionary a'ha came from a single partial fossil skull found on the shores of a riverbank in Eastern Canada. 

Meet the Stegocephalian, Elpistostege watsoni, an extinct genus of finned tetrapodomorphs that lived during the Late Givetian to Early Frasnian of the Late Devonian — 382 million years ago. 

Elpistostege watsoni — perhaps the sister taxon of all other tetrapods — was first described in 1938 by British palaeontologist and elected Fellow of the Royal Society of London, Thomas Stanley Westoll. Westoll's research interests were wide-ranging. He was a vertebrate palaeontologist and geologist best known for his innovative work on Palaeozoic fishes and their relationships with tetrapods. 

As a specialist in early fish, Westoll was asked to interpret that single partial skull roof discovered at the Escuminac Formation in Quebec, Canada. His findings and subsequent publication named Elpistostege watsoni and helped us to better understand the evolution of fishes to tetrapods — four-limbed vertebrates — one of the most important transformations in vertebrate evolution. 

Hypotheses of tetrapod origins rely heavily on the anatomy of but a few tetrapod-like fish fossils from the Middle and Late Devonian, 393–359 million years ago. These taxa — known as elpistostegalians — include Panderichthys, Elpistostege and Tiktaalik — none of which had yet to reveal the complete skeletal anatomy of the pectoral fin. 

Elpistostege watsoni
None until 2010 that is, when a complete 1.57-metre-long articulated specimen was found and described by Richard Cloutier et al. in 2020. 

The specimen helped us to understand the origin of the vertebrate hand. Stripped from its encasing stone, it revealed a set of paired fins of Elpistostege containing bones homologous to the phalanges (finger bones) of modern tetrapods and is the most basal tetrapodomorph known to possess them. 

Once the phalanges were uncovered, prep work began on the fins. The fins were covered in wee scales and lepidotrichia (fin rays). The work was tiresome, taking more than 2,700 hours of preparation but the results were thrilling. 

Origin of the Vertebrate Hand
We could now clearly see that the skeleton of the pectoral fin has four proximodistal rows of radials — two of which include branched carpals — as well as two distal rows organized as digits and putative digits. 

Despite this skeletal pattern — which represents the most tetrapod-like arrangement of bones found in a pectoral fin to date blurring the line between fish and land vertebrates — the fin retained lepidotrichia (those wee fin rays) distal to the radials. 

This arrangement confirmed an age-old question — showing us for the first time that the origin of phalanges preceded the loss of fin rays, not the other way around.

E. watsoni is very closely related to Tiktaalik roseae found in 2004 in the Canadian Arctic — a tetrapodomorpha species also known as a Choanata. These were advanced forms transitional between fish and the early labyrinthodonts playfully referred to as fishapods — half-fish, half-tetrapod in appearance and limb morphology. 

Up to that point, the relationship of limbed vertebrates (tetrapods) to lobe-finned fish (sarcopterygians) was well known, but the origin of major tetrapod features remained obscure for lack of fossils that document the sequence of evolutionary changes — until Tiktaalik. While Tiktaalik is technically a fish, this fellow is as far from fish-like you can be and still be a card-carrying member of the group. 

Tiktaalik roseae
Complete with scales and gills, this proto-fish lacked the conical head we see in modern fish but had a rather flattened triangular head more like that of a crocodile. 

Tiktaalik had scales on its back and fins with fin webbing but like early land-living animals, it had a distinctive flat head and neck. He was a brawny brute. The shape of his skull and shoulder look part fish and part amphibian.

The watershed moment came as Tiktaalik was prepped. Inside Tiktaalik's fins, we find bones that correspond to the upper arm, forearm and even parts of the wrist — all inside a fin with webbing — remarkable! 

Its fins have thin ray bones for paddling like most fish, but with brawny interior bones that gave Tiktaalik the ability to prop itself up, using his limbs for support. I picture him propped up on one paddle saying, "how you doing?" 

Six years after Tiktaalik was discovered by Neil Shubin and team in the ice-covered tundra of the Canadian Arctic on southern Ellesmere Island, a team working the outcrops at Miguasha on the Gaspé Peninsula discovered the only fully specimen of E. watsoni found to date — greatly increasing our knowledge of this finned tantalizingly transitional tetrapodomorph. 

E. watsoni fossils are rare — this was the fourth specimen collected in over 130 years of hunting. Charmingly, the specimen was right on our doorstop — extracted but a few feet away from the main stairs descending onto the beach of Miguasha National Park. 

L'nu Mi’gmaq First Nations of the Gespe’gewa’gi Region

Miguasha is nestled in the Gaspésie or Gespe’gewa’gi region of Canada — home to the Mi’gmaq First Nations who self-refer as L’nu or Lnu. The word Mi’gmaq or Mi’kmaq means the family or my allies/friends in Mi'kmaw, their native tongue (and soon to be Nova Scotia's provincial first language). They are the people of the sea and the original inhabitants of Atlantic Canada having lived here for more than 10,000 years. 

The L'nu were the first First Nation people to establish contact and trade with European explorers in the 16th and 17th centuries — and perhaps the Norse as early as the turn of the Millenium. Sailing vessels filled with French, British, Scottish, Irish and others arrived one by one to lay claim to the region — settling and fighting over the land. As each group rolled out their machinations of discovery, tensions turned to an all-out war with the British and French going head to head. I'll spare you the sordid details but for everyone caught in the crossfire, it went poorly.

North America Map 1775 (Click to Enlarge)
Cut to 1760, the British tipped the balance with their win at the Battle of the Restigouche, the last naval battle between France and England for possession of the North American continent — Turtle Island. 

The bittersweet British victory sparked the American War of Independence. 

For the next twenty years, the L'nu would witness and become embroiled in yet another war for these lands, their lands — first as bystanders, then as American allies, then intimidated into submission by the British Royal Navy with a show of force by way of a thirty-four gun man-of-war, encouraging L'nu compliance — finally culminating in an end to the hostilities with the 1783 Treaty of Paris. 

The peace accord held no provisions for the L'nu, Métis and First Nations impacted. None of these newcomers was Mi'kmaq — neither friends nor allies.

It was to this area some sixty years later that the newly formed Geological Survey of Canada (GSC) began exploring and mapping the newly formed United Province of Canada. Geologists in the New Brunswick Geology Branch traipsed through the rugged countryside that would become a Canadian province in 1867. 

It was on one of these expeditions that the Miguasha fossil outcrops were discovered. They, too, would transform in time to become Miguasha National Park or Parc de Miguasha, but at first, they were simply the promising sedimentary exposures on the hillside across the water —  a treasure trove of  Late Devonian fauna waiting to be discovered.

In the summer of 1842, Abraham Gesner, New Brunswick’s first Provincial Geologist, crossed the northern part of the region exploring for coal. Well, mostly looking for coal. Gesner also had a keen eye for fossils and his trip to the Gaspé Peninsula came fast on the heels of a jaunt along the rocky beaches of Chignecto Bay at the head of the Bay of Fundy and home to the standing fossil trees of the Joggins Fossil Cliffs. 

Passionate about geology and chemistry, he is perhaps most famous for his invention of the process to distil the combustible hydrocarbon kerosene from coal oil — a subject on which his long walks exploring a budding Canada gave him a great deal of time to consider. We have Gesner to thank for the modern petroleum industry. He filed many patents for clever ways to distil the soft tar-like coal or bitumen still in use today.

He was skilled in a broad range of scientific disciplines — being a geologist, palaeontologist, physician, chemist, anatomist and naturalist — a brass tacks geek to his core. Gesner explored the coal exposures and fossil outcrops across the famed area that witnessed the region become part of England and not France — and no longer L'nu.

Following the Restigouche River in New Brunswick through the Dalhousie region, Gesner navigated through the estuary to reach the southern coast of the Gaspé Peninsula into what would become the southeastern coast of Quebec to get a better look at the cliffs across the water. He was the first geologist to lay eyes on the Escuminac Formation and its fossils.

In his 1843 report to the Geologic Survey, he wrote, “...I found the shore lined with a coarse conglomerate. Farther eastward the rocks are light blue sandstones and shales, containing the remains of vegetables. (...) In these sandstone and shales, I found the remains of fish and a small species of tortoise with fossil foot-marks.”

We now know that this little tortoise was the famous Bothriolepis, an antiarch placoderm fish. It was also the first formal mention of the Miguasha fauna in our scientific literature. Despite the circulation of his report, Gesner’s discovery was all but ignored — the cliffs and their fossil bounty abandoned for decades to come. Geologists like Ells, Foord and Weston, and the research of Whiteaves and Dawson, would eventually follow in Gesner's footsteps.

North America Map 1866 (Click to Enlarge)
Over the past 180 years, this Devonian site has yielded a wonderfully diverse aquatic assemblage from the Age of Fishes — five of the six fossil fish groups associated with the Devonian including exceptionally well-preserved fossil specimens of the lobe-finned fishes. 

This is exciting as it is the lobe-finned fishes — the sarcopterygians — that gave rise to the first four-legged, air-breathing terrestrial vertebrates – the tetrapods. 

Fossil specimens from Miguasha include twenty species of lower vertebrates — anaspids, osteostra-cans, placoderms, acanthodians, actinopterygians and sarcopterygians — plus a limited invertebrate assemblage, along with terrestrial plants, scorpions and millipedes.

Originally interpreted as a freshwater lacustrine environment, recent paleontological, taphonomic, sedimentological and geochemical evidence corroborates a brackish estuarine setting — and definitely not the deep waters of the sea. This is important because the species that gave rise to our land-living animals began life in shallow streams and lakes. It tells us a bit about how our dear Elpistostege watsoni liked to live — preferring to lollygag in cool river waters where seawater mixed with fresh. Not fully freshwater, but a wee bit of salinity to add flavour.  

  • Photos: Elpistostege watsoni (Westoll, 1938 ), Upper Devonian (Frasnian), Escuminac formation, Parc de Miguasha, Baie des Chaleurs, Gaspé, Québec, Canada. John Fam, VanPS
  • Origin of the Vertebrate Hand Illustration, https://www.nature.com/articles/s41586-020-2100-8
  • Tiktaalik Illustration: By Obsidian Soul - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=47401797

References & further reading:

  • From Water to Land: https://www.miguasha.ca/mig-en/the_first_discoveries.php
  • UNESCO Miguasha National Park: https://whc.unesco.org/en/list/686/
  • Office of L'nu Affairs: https://novascotia.ca/abor/aboriginal-people/
  • Cloutier, R., Clement, A.M., Lee, M.S.Y. et al. Elpistostege and the origin of the vertebrate hand. Nature 579, 549–554 (2020). https://doi.org/10.1038/s41586-020-2100-8
  • Daeschler, E. B., Shubin, N. H. & Jenkins, F. A. Jr. A Devonian tetrapod-like fish and the evolution of the tetrapod body plan. Nature 440, 757–763 (2006).
  • Shubin, Neil. Your Inner Fish: A Journey into the 3.5 Billion History of the Human Body.
  • Evidence for European presence in the Americas in AD 1021: https://www.nature.com/articles/s41586-021-03972-8

Thursday, June 8, 2023

VANCOUVER ISLAND'S FABULOUS FOSSILS: TRENT RIVER PALAEONTOLOGY

Dan Bowen, Chair, VIPS, Trent River
The rocks that make up the Trent River on Vancouver Island are on the move. They were laid down near of the equator as small, tropical islands. They rode across the Pacific heading north and slightly east over the past 85 million years to where we find them today.

The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. And it is massive. At 103 million km2 (40 million sq mi), it is the largest tectonic plate and continues to grow fed by volcanic eruptions that piggyback onto its trailing edge.

This relentless expansion pushes the Pacific Plate into the North American Plate. The pressure subducts it beneath our continent where it then melts back into the earth. Plate tectonics are slow but powerful forces. 

The island chains that rode the plates across the Pacific smashed into our coastline and slowly built the province of British Columbia. And because each of those islands had a different origin, they create pockets of interesting and diverse geology.

It is these islands that make up the Insular Belt — a physio-geological region on the northwestern North American coast. It consists of three major island groups — and many smaller islands — that stretches from southern British Columbia up into Alaska and the Yukon. These bits of islands on the move arrived from the Late Cretaceous through the Eocene — and continues to this day.

The rocks that form the Insular Superterrane are allochthonous, meaning they are not related to the rest of the North American continent. The rocks we walk over along the Trent River are distinct from those we find throughout the rest of Vancouver Island, Haida Gwaii, the rest of the province of British Columbia and completely foreign to those we find next door in Alberta.

To discover what we do find on the Trent takes only a wee stroll, a bit of digging and time to put all the pieces of the puzzle together. The first geological forays to Vancouver Island were to look for coal deposits, the profitable remains of ancient forests that could be burned to the power industry.

Jim Monger and Charlie Ross of the Geological Survey of Canada both worked to further our knowledge of the complex geology of the Comox Basin. They were at the cutting edge of west coast geology in the 1970s. It was their work that helped tease out how and where the rocks we see along the Trent today were formed and made their way north.

We know from their work that by 85 million years ago, the Insular Superterrane had made its way to what is now British Columbia. 

The lands were forested much as they are now but by extinct genera and families. The fossil remains of trees similar to oak, poplar, maple and ash can be found along the Trent and Vancouver Island. We also see the lovely remains of flowering plants such as Cupanities crenularis, figs and breadfruit.

Heading up the river, you come to a delineation zone that clearly marks the contact between the dark grey marine shales and mudstones of the Haslam Formation where they meet the sandstones of the Comox Formation. Fossilized material is less abundant in the Comox sandstones but still contains some interesting specimens. Here you begin to see fossilized wood and identifiable fossil plant material.

Further upstream, there is a small tributary, Idle Creek, where you can find more of this terrestrial material in the sandy shales. As you walk up, you see identifiable fossil plants beneath your feet and jungle-like, overgrown moss-covered, snarly trees all around you.

Walking west from the Trent River Falls at the bottom, you pass the infamous Ammonite Alley, where you can find Mesopuzosia sp. and Kitchinites sp. of the Upper Cretaceous (Santonian), Haslam Formation. Minding the slippery green algae covering some of the river rocks, you can see the first of the Polytychoceras vancouverense zone.

Continuing west, you reach the first of two fossil turtle sites on the river — amazingly, one terrestrial and one marine. If you continue, you come to the Inland Island Highway.

The Trent River has yielded some very interesting marine specimens, and significant terrestrial finds. We have found a wonderful terrestrial helochelydrid turtle, Naomichelys speciosa, and the caudal vertebrae of a Hadrosauroid dinosaur. Walking down from the Hadrosaur site you come to the site of the fossil ratfish find — one of the ocean's oddest fish.

Ratfish, Hydrolagus Collie, are chimaera found in the north-eastern Pacific Ocean today. The fossil specimen from the Trent would be considered large by modern standards as it is a bruiser in comparison to his modern counterparts. 

This robust fellow had exceptionally large eyes and sex organs that dangled enticingly between them. You mock, but there are many ratfish who would differ. While inherently sexy by ratfish standards, this fellow was not particularly tasty to their ancient marine brethren (or humans today) — so not hugely sought after as a food source or prey.

A little further again from the ratfish site we reach the contact of the two Formations. The rocks here have travelled a long way to their current location. With them, we peel away the layers of the geologic history of both the Comox Valley and the province of British Columbia.

The Trent River is not far from the Puntledge, a river whose banks have also revealed many wonderful fossil specimens. The Puntledge is also the name used by the K'ómoks First Nation to describe themselves. They have lived here since time immemorial. Along with Puntledge, they refer to themselves as Sahtloot, Sasitla and Ieeksun.

References: Note on the occurrence of the marine turtle Desmatochelys (Reptilia: Chelonioidea) from the Upper Cretaceous of Vancouver Island Elizabeth L. Nicholls Canadian Journal of Earth Sciences (1992) 29 (2): 377–380. https://doi.org/10.1139/e92-033; References: Chimaeras - The Neglected Chondrichthyans". Elasmo-research.org. Retrieved 2017-07-01.

Directions: If you're keen to explore the area, park on the side of Highway 19 about three kilometres south of Courtenay and hike up to the Trent River. Begin to look for parking about three kilometres south of the Cumberland Interchange. There is a trail that leads from the highway down beneath the bridge which will bring you to the Trent River's north side.

Sunday, May 21, 2023

OKANAGAN HIGHLAND FOSSIL LOCALITIES

Fossils from the Okanagan Highlands, an area centred in the Interior of British Columbia, provide important clues to our ancient climate. 

Okanagan Highlands refers to an arc of Eocene lakebed sites that extend from Smithers in the north, down to the fossil site of Republic Washington. 

The grouping includes the fossil sites of Driftwood Canyon, Quilchena, Allenby, Tranquille, McAbee, Princeton and Republic.

These fossil sites range in time from Early to Middle Eocene, and the fossil they contain give us a snapshot of what was happening in this part of the world because of the varied plant fossils they contain.

We can infer the difference in climates between the sites. McAbee was not as warm as some of the other Middle Eocene sites, a fact inferred by what we see and what is conspicuously missing. In looking at the plant species, it has been suggested that the area of McAbee had a more temperate climate, slightly cooler and wetter than other Eocene sites to the south at Princeton, British Columbia and Republic and Chuckanut, Washington. Missing are the tropical Sabal (palm), seen at Princeton and the impressive Ensete (banana) and Zamiaceae (cycad) found at Republic in north-central Washington, in the Swauk Formation near Skykomish and the Chuckanut Formation of northern Washington state.

Thursday, January 19, 2023

CERATIOCARIS, YE KEN

This braw fellow is Ceratiocaris papilio (Salter in Murchison, 1859) a pod Shrimp from the Silurian mudstones of the Kip Burn Formation in the Midland Valley of Scotland. He would have swam in rising seas filled with crinoids, coral reefs, brachiopods, trilobites and new and exotic fish -- some sporting jaws for the first time.

Ceratiocaris is a genus of extinct paleozoic phyllocarid crustacean whose fossils are found in marine strata from the Upper Ordovician through to the Silurian.

They are typified by eight short thoracic segments, seven longer abdominal somites and an elongated pretelson somite. Their carapace is slightly oval shaped; they have many ridges parallel to the ventral margin and possess a horn at the anterior end.

This tidy specimen is from the Silurian mudstones that characterise the Kip Burn Formation with it's dark laminated silty bands. The lower part of the Kip Burn houses the highly fossiliferous ‘Ceratiocaris beds’, that yield the arthropods Ceratiocaris, Dictyocaris, Pterygotus, Slimonia and the fish Birkenia and Thelodus.

The upper part of the formation, the ‘Pterygotus beds’, contain abundant eurypterid fauna together with the brachiopods Lingula and Ceratiocaris. The faunas in the Kip Burn Formation reflect the start of the transition from marine to quasi- or non-marine conditions in the group.

Ceratiocaris are also well known from the Silurian Eramosa Formation of Ontario, Canada (which also has rather nice eurypterids). Photo credit / collection of: York Yuxi Wang and Tianyi Zhang

Joseph H. Collette; David M. Rudkin (2010). "Phyllocarid crustaceans from the Silurian Eramosa Lagerstätte (Ontario, Canada): taxonomy and functional morphology". Journal of Paleontology. 84 (1): 118–127. doi:10.1666/08-174.1.

M. Copeland; T. E. Bolton (1985). Fossils of Ontario part 3: the eurypterids and phyllocarids. Volume 48 of Life Sciences Miscellaneous Publications. Royal Ontario Museum. ISBN 0-88854-314-X.

Monday, September 26, 2022

EARTH'S FIRST FOUR-LEGGED, AIR-BREATHING VERTEBRATES

Elpistostege watsoni

In the late 1930s, our understanding of the transition of fish to tetrapods — and the eventual jump to modern vertebrates — took an unexpected leap forward. The evolutionary a'ha came from a single partial fossil skull found on the shores of a riverbank in Eastern Canada. 

Meet the Stegocephalian, Elpistostege watsoni, an extinct genus of finned tetrapodomorphs that lived during the Late Givetian to Early Frasnian of the Late Devonian — 382 million years ago. 

Elpistostege watsoni — perhaps the sister taxon of all other tetrapods — was first described in 1938 by British palaeontologist and elected Fellow of the Royal Society of London, Thomas Stanley Westoll. Westoll's research interests were wide-ranging. He was a vertebrate palaeontologist and geologist best known for his innovative work on Palaeozoic fishes and their relationships with tetrapods. 

As a specialist in early fish, Westoll was asked to interpret that single partial skull roof discovered at the Escuminac Formation in Quebec, Canada. His findings and subsequent publication named Elpistostege watsoni and helped us to better understand the evolution of fishes to tetrapods — four-limbed vertebrates — one of the most important transformations in vertebrate evolution. 

Hypotheses of tetrapod origins rely heavily on the anatomy of but a few tetrapod-like fish fossils from the Middle and Late Devonian, 393–359 million years ago. These taxa — known as elpistostegalians — include Panderichthys, Elpistostege and Tiktaalik — none of which had yet to reveal the complete skeletal anatomy of the pectoral fin. 

Elpistostege watsoni
None until 2010 that is, when a complete 1.57-metre-long articulated specimen was found and described by Richard Cloutier et al. in 2020. 

The specimen helped us to understand the origin of the vertebrate hand. Stripped from its encasing stone, it revealed a set of paired fins of Elpistostege containing bones homologous to the phalanges (finger bones) of modern tetrapods and is the most basal tetrapodomorph known to possess them. 

Once the phalanges were uncovered, prep work began on the fins. The fins were covered in wee scales and lepidotrichia (fin rays). The work was tiresome, taking more than 2,700 hours of preparation but the results were thrilling. 

Origin of the Vertebrate Hand
We could now clearly see that the skeleton of the pectoral fin has four proximodistal rows of radials — two of which include branched carpals — as well as two distal rows organized as digits and putative digits. 

Despite this skeletal pattern — which represents the most tetrapod-like arrangement of bones found in a pectoral fin to date blurring the line between fish and land vertebrates — the fin retained lepidotrichia (those wee fin rays) distal to the radials. 

This arrangement confirmed an age-old question — showing us for the first time that the origin of phalanges preceded the loss of fin rays, not the other way around.

E. watsoni is very closely related to Tiktaalik roseae found in 2004 in the Canadian Arctic — a tetrapodomorpha species also known as a Choanata. These were advanced forms transitional between fish and the early labyrinthodonts playfully referred to as fishapods — half-fish, half-tetrapod in appearance and limb morphology. 

Up to that point, the relationship of limbed vertebrates (tetrapods) to lobe-finned fish (sarcopterygians) was well known, but the origin of major tetrapod features remained obscure for lack of fossils that document the sequence of evolutionary changes — until Tiktaalik. While Tiktaalik is technically a fish, this fellow is as far from fish-like you can be and still be a card-carrying member of the group. 

Tiktaalik roseae
Complete with scales and gills, this proto-fish lacked the conical head we see in modern fish but had a rather flattened triangular head more like that of a crocodile. 

Tiktaalik had scales on its back and fins with fin webbing but like early land-living animals, it had a distinctive flat head and neck. He was a brawny brute. The shape of his skull and shoulder look part fish and part amphibian.

The watershed moment came as Tiktaalik was prepped. Inside Tiktaalik's fins, we find bones that correspond to the upper arm, forearm and even parts of the wrist — all inside a fin with webbing — remarkable! 

Its fins have thin ray bones for paddling like most fish, but with brawny interior bones that gave Tiktaalik the ability to prop itself up, using his limbs for support. I picture him propped up on one paddle saying, "how you doing?" 

Six years after Tiktaalik was discovered by Neil Shubin and team in the ice-covered tundra of the Canadian Arctic on southern Ellesmere Island, a team working the outcrops at Miguasha on the Gaspé Peninsula discovered the only fully specimen of E. watsoni found to date — greatly increasing our knowledge of this finned tantalizingly transitional tetrapodomorph. 

E. watsoni fossils are rare — this was the fourth specimen collected in over 130 years of hunting. Charmingly, the specimen was right on our doorstop — extracted but a few feet away from the main stairs descending onto the beach of Miguasha National Park. 

L'nu Mi’gmaq First Nations of the Gespe’gewa’gi Region

Miguasha is nestled in the Gaspésie or Gespe’gewa’gi region of Canada — home to the Mi’gmaq First Nations who self-refer as L’nu or Lnu. The word Mi’gmaq or Mi’kmaq means the family or my allies/friends in Mi'kmaw, their native tongue (and soon to be Nova Scotia's provincial first language). They are the people of the sea and the original inhabitants of Atlantic Canada having lived here for more than 10,000 years. 

The L'nu were the first First Nation people to establish contact and trade with European explorers in the 16th and 17th centuries — and perhaps the Norse as early as the turn of the Millenium. Sailing vessels filled with French, British, Scottish, Irish and others arrived one by one to lay claim to the region — settling and fighting over the land. As each group rolled out their machinations of discovery, tensions turned to an all-out war with the British and French going head to head. I'll spare you the sordid details but for everyone caught in the crossfire, it went poorly.

North America Map 1775 (Click to Enlarge)
Cut to 1760, the British tipped the balance with their win at the Battle of the Restigouche, the last naval battle between France and England for possession of the North American continent — Turtle Island. 

The bittersweet British victory sparked the American War of Independence. 

For the next twenty years, the L'nu would witness and become embroiled in yet another war for these lands, their lands — first as bystanders, then as American allies, then intimidated into submission by the British Royal Navy with a show of force by way of a thirty-four gun man-of-war, encouraging L'nu compliance — finally culminating in an end to the hostilities with the 1783 Treaty of Paris. 

The peace accord held no provisions for the L'nu, Métis and First Nations impacted. None of these newcomers was Mi'kmaq — neither friends nor allies.

It was to this area some sixty years later that the newly formed Geological Survey of Canada (GSC) began exploring and mapping the newly formed United Province of Canada. Geologists in the New Brunswick Geology Branch traipsed through the rugged countryside that would become a Canadian province in 1867. 

It was on one of these expeditions that the Miguasha fossil outcrops were discovered. They, too, would transform in time to become Miguasha National Park or Parc de Miguasha, but at first, they were simply the promising sedimentary exposures on the hillside across the water —  a treasure trove of  Late Devonian fauna waiting to be discovered.

In the summer of 1842, Abraham Gesner, New Brunswick’s first Provincial Geologist, crossed the northern part of the region exploring for coal. Well, mostly looking for coal. Gesner also had a keen eye for fossils and his trip to the Gaspé Peninsula came fast on the heels of a jaunt along the rocky beaches of Chignecto Bay at the head of the Bay of Fundy and home to the standing fossil trees of the Joggins Fossil Cliffs. 

Passionate about geology and chemistry, he is perhaps most famous for his invention of the process to distil the combustible hydrocarbon kerosene from coal oil — a subject on which his long walks exploring a budding Canada gave him a great deal of time to consider. We have Gesner to thank for the modern petroleum industry. He filed many patents for clever ways to distil the soft tar-like coal or bitumen still in use today.

He was skilled in a broad range of scientific disciplines — being a geologist, palaeontologist, physician, chemist, anatomist and naturalist — a brass tacks geek to his core. Gesner explored the coal exposures and fossil outcrops across the famed area that witnessed the region become part of England and not France — and no longer L'nu.

Following the Restigouche River in New Brunswick through the Dalhousie region, Gesner navigated through the estuary to reach the southern coast of the Gaspé Peninsula into what would become the southeastern coast of Quebec to get a better look at the cliffs across the water. He was the first geologist to lay eyes on the Escuminac Formation and its fossils.

In his 1843 report to the Geologic Survey, he wrote, “...I found the shore lined with a coarse conglomerate. Farther eastward the rocks are light blue sandstones and shales, containing the remains of vegetables. (...) In these sandstone and shales, I found the remains of fish and a small species of tortoise with fossil foot-marks.”

We now know that this little tortoise was the famous Bothriolepis, an antiarch placoderm fish. It was also the first formal mention of the Miguasha fauna in our scientific literature. Despite the circulation of his report, Gesner’s discovery was all but ignored — the cliffs and their fossil bounty abandoned for decades to come. Geologists like Ells, Foord and Weston, and the research of Whiteaves and Dawson, would eventually follow in Gesner's footsteps.

North America Map 1866 (Click to Enlarge)
Over the past 180 years, this Devonian site has yielded a wonderfully diverse aquatic assemblage from the Age of Fishes — five of the six fossil fish groups associated with the Devonian including exceptionally well-preserved fossil specimens of the lobe-finned fishes. 

This is exciting as it is the lobe-finned fishes — the sarcopterygians — that gave rise to the first four-legged, air-breathing terrestrial vertebrates – the tetrapods. 

Fossil specimens from Miguasha include twenty species of lower vertebrates — anaspids, osteostra-cans, placoderms, acanthodians, actinopterygians and sarcopterygians — plus a limited invertebrate assemblage, along with terrestrial plants, scorpions and millipedes.

Originally interpreted as a freshwater lacustrine environment, recent paleontological, taphonomic, sedimentological and geochemical evidence corroborates a brackish estuarine setting — and definitely not the deep waters of the sea. This is important because the species that gave rise to our land-living animals began life in shallow streams and lakes. It tells us a bit about how our dear Elpistostege watsoni liked to live — preferring to lollygag in cool river waters where seawater mixed with fresh. Not fully freshwater, but a wee bit of salinity to add flavour.  

  • Photos: Elpistostege watsoni (Westoll, 1938 ), Upper Devonian (Frasnian), Escuminac formation, Parc de Miguasha, Baie des Chaleurs, Gaspé, Québec, Canada. John Fam, VanPS
  • Origin of the Vertebrate Hand Illustration, https://www.nature.com/articles/s41586-020-2100-8
  • Tiktaalik Illustration: By Obsidian Soul - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=47401797

References & further reading:

  • From Water to Land: https://www.miguasha.ca/mig-en/the_first_discoveries.php
  • UNESCO Miguasha National Park: https://whc.unesco.org/en/list/686/
  • Office of L'nu Affairs: https://novascotia.ca/abor/aboriginal-people/
  • Cloutier, R., Clement, A.M., Lee, M.S.Y. et al. Elpistostege and the origin of the vertebrate hand. Nature 579, 549–554 (2020). https://doi.org/10.1038/s41586-020-2100-8
  • Daeschler, E. B., Shubin, N. H. & Jenkins, F. A. Jr. A Devonian tetrapod-like fish and the evolution of the tetrapod body plan. Nature 440, 757–763 (2006).
  • Shubin, Neil. Your Inner Fish: A Journey into the 3.5 Billion History of the Human Body.
  • Evidence for European presence in the Americas in AD 1021: https://www.nature.com/articles/s41586-021-03972-8

Thursday, May 26, 2022

SALMON: FRESH, DRIED, BOILED, STEAMED... AND FOSSILIZED

Salmon permeate First Nations mythology and have been a prized food source for thousands of years — fresh, dried, boiled, steamed or smoked — the bones carefully returned to the river or sea to continue the lifecycle of these immortal beings. 

In the Kwak'wala language of the Kwakiutl First Nations of the Pacific Northwest — or Kwakwaka'wakw, speakers of Kwak'wala — sockeye salmon are known as ma̱łik. 

For the Tk'emlúps te Secwépemc First Nation, people of the confluence, of the Interior of British Columbia, near Kamloops, salmon was the most important of the local fishing stock and the salmon fishing season was a significant social event that warranted the nomination of a Salmon Chief who directed the construction of the hooks, weirs and traps and the distribution of the catch.

In the Interior of the province, archaeological evidence dates the use of salmon as a food source back a mere 3,500 years. While the First Nation groups have an oral history telling us they have lived here since always, 3,500 years falls short of the mark. 

The truth, it seems, needed to be teased from the rock. Sheri Burton and Catherine Carlson were able to isolate and amplify mitochondrial DNA from the salmon remains at archaeological sites near Kamloops. The DNA came from the species as Oncorhynchus nerka or Sockeye salmon, preserved in concretion and collected along the southern shores of Kamloops Lake.

The concretions were originally dated as Miocene (24 – 5.5 million years old) by the Geological Survey of Canada, based on pollen grain analysis. However, many local experts, including UBC geology professor W.R. (Ted) Danner (my mentor), W.H. Mathews and Richard Hughes, suspected the remains were much more recent, perhaps the Late Pleistocene. It was a topic that provided lively debate for many years and much pounding on tables during dinner. But it was not until the early 1990s that Catherine Carlson and Ken Klein found definitive proof of this.

Oncorhynchus nerka
By good luck, the fish remains in the Kamloops Lake concretions had not been completely replaced by minerals — enough of the original organic bone collagen remained for radiocarbon dating. 

For those on either side of the debate, the results were startling — 18,000 years. It is likely that erosion during the time of deposition had carried pollen down from Miocene layers in surrounding hills, to be deposited around the dead fish, causing the initial over-estimation of the age of the concretions.

This lovely specimen is Oncorhynchus nerka, a Late Pleistocene Fossil Sockeye Salmon, from the fine-grained, silty clays on the south shore of Kamloops Lake, British Columbia, Canada. The site was originally collected in the 1970s by the late geologist and palaeontologist Richard Hughes. I was introduced to the site much later after its rediscovery by Catherine Carlson and Kenneth Klein in the fall of 1991 with the help of local and gracious host, Bill Huxley.

They later wrote up and published a chapter in Rolf Ludvigsen's "Life in Stone: A Natural History of British Columbia's Fossils." It was Huxley who shared its location with John Leahy — a local Kamloops resident and avid fossil hunter — and him with me. 

This specimen was collected by John in the 1990s, his tenth partial salmon from this site and the sole one in my collection.

An age of 18,000 plus years sets the fossils firmly as the only salmonids of the Late Pleistocene in North America, a very significant find. The date also changed our ideas about the early climate of the Interior; the Thompson Valley could not have been covered by glacial ice for as long as originally thought. Indeed, it makes the Interior ice-free only 2,000 years after the Last Glacial Maximum and some 4,000 years before our western continental coastline and the Rocky Mountain Foothills.  

It has long been accepted that the most recent series of ice ages began approximately 1.6 million years ago, beginning as ice accumulations at higher altitudes with the gradual cooling of the climate. Four times the ice advanced and receded, most recently melting away somewhere around 10,000 years ago. Ice retreated from southwestern British Columbia and the Puget Sound area around 15,000 years ago. 

In the southern Interior, ice built up first in the northern Selkirk Mountains, then slowly flowed down into the valleys. Once the valleys were filled, the depth of the ice increased until it began to climb to the highlands and finally covered most of the Interior of British Columbia. Between ice advances, there were times when the Kamloops area was ice-free and the climate warm and hospitable. 

Glacial ice was believed to have initiated its most recent retreat from the South Thompson area around 11,000 to 12,000 years ago, but salmon remains from 18,000 years ago suggest that it may have actually begun its northwest decline much earlier — and presenting the possibility of a much warmer climate in the Interior than archaeologists or geologists had originally thought.

Eighteen thousand-year-old salmon also challenge the archaeological notion that the First Nation people of the Interior have had access to salmon as a significant protein source for only a few thousand years. 

In the popular view, people living in the Okanagan and Thompson Valleys were felt to have moved to settlements that were semi-permanent about 4,500 years ago. By that time they would have had a seasonally regulated diet composed primarily of salmon and supplemented by local game — deer, elk, small mammals — and available shellfish, birds and plant foods, roots and berries. If salmon were present much earlier, it is possible that this pattern of food utilization may have arisen earlier than thought.

Richard Hughes had originally identified the fossilized Kamloops salmon as Oncorhynchus nerka or Sockeye salmon, the same species found in the 3,500-year-old archaeological sites. But, using the carbon-13 isotope ratio, Klein and Carlson were able to determine that these salmon did not feed on protein from a marine source and relied solely on a freshwater diet. 

In other words, they could not have spent part of their life in the ocean, as modern Sockeye salmon do. Based on the specimens’ smaller heads and stunted bodies, the longest measuring in at a pint-sized 11.5 cm, Klein and Carlson feel that the fossils are likely Kokanee — a modern landlocked variety of Sockeye.

If you are wondering about the traditional First Nation use of salmon, this McGill University link is outstanding:http://traditionalanimalfoods.org/fish/searun-fish/page.aspx?id=6446


Tuesday, March 22, 2022

SACRED CEPHALOPODS: OCTOPUS / TAK'WA

This lovely with her colourful body is an octopus. Like ninety-seven percent of the world's animals, she lacks a backbone. 

To support their bodies, these spineless animals — invertebrates — have skeletons made of protein fibres. 

This flexibility can be a real advantage when slipping into nooks and crannies for protection and making a home in seemingly impossible places.

On the east side of Vancouver Island, British Columbia, Canada, there is an area called Madrona Point where beneath the surface of the sea many octopus have done just that. This is the home of the Giant Pacific Octopus, Enteroctopus dofleini, the largest known octopus species.

The land above is the home of the Snuneymuxw First Nation of the Coast Salish who live here, on the Gulf Islands, and along the Fraser River. In Hul'q'umin'um' — the lingua franca of the Snuneymuxw First Nation, a living language that expresses their worldview and way of life — the word for octopus is sqi'mukw'. In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, further north on Vancouver Island, octopus or devil fish are known as ta̱k̕wa.

I have gone scuba diving at Madrona Point many times and visited the octopus who squeeze into the eroded sections of a sandstone ledge about 18 metres or 60 feet below the surface. 

On one of those trips, my friend Suzanne Groulx ran into one of the larger males swimming just offshore. I was surfacing as I heard her shriek clear as a bell. Sound moves through water about four times faster than it does through the air — faster than a jet plane. 

On that day, I suspect Suzanne was neck and neck both in sound and motion. Seconds later, she popped up a good three feet above the surf, still screaming. I have never seen anyone surface quite so quickly — dangerous and impressive in equal measure. It was on another of those trips that I met Philip Torrens, with whom I would later co-author, In Search of Ancient BC.     

While the entire coastline is beautiful to explore, it was visiting the octopus that drew me back time and time again. I have seen wee octopus the size of the palm of your hand, large males swimming and feeding and the lovely females tucked into their nursery homes.

After forty days of mating, the female Giant Pacific Octopus attach strings of small fertilized eggs to the rocks within these crevices and call it home for a time — generally five months or 160 days. When I visit, I sometimes bring crab or sea urchin for her to snack on as the mothers guarding these eggs do not leave to hunt, staying ever vigilante protecting their brood from predators. All the while she is here, she gently blows fresh water over the eggs.

And sadly, this will be her only brood. Octopus breed once in their too-short lives. Males die directly after mating and females die once their young have hatched. They live in all the world's oceans and no matter the species, their lifespans are a brief one to five years. I rather hope they evolve to live longer and one day outcompete the humans who like to snack on them.

Octopus are soft-bodied, eight-limbed molluscs of the order Octopoda. They have one hard part, their beaks, which they use to crack open clams, crab and crustaceans. They are ninja-level skilled at squeezing through very tight holes, particularly if it means accessing a tasty snack. The size of their beaks determines exactly how small a hole they can fit through. Looking, you would likely guess it could not be done, but they are amazing — and mesmerizing!

At the Vancouver Aquarium, they have been known to unscrew lids, sneak out of one tank to feed in another then slip back so you do not notice, open simple hooks and latches — burglars of the sea. They can also change the colour and texture of their skin to blend perfectly into their surroundings. You can look for them around reefs and rocky shores. There are 300 species of octopus grouped within the class Cephalopoda, along with squid, cuttlefish, and nautiloids. 

The oldest fossil octopus at 300 million years old is Pohlsepia mazonensis from Carboniferous Mazon Creek fossil beds in Illinois. The only known specimen resembles modern octopuses with the exception of possessing eight arms and two tentacles (Kluessendorf and Doyle 2000).

My favourite fossil octopus is the darling Keuppia levante (Fuchs, Bracchi & Weis, 2009), an extinct genus of octopus that swam our ancient seas back in the Cretaceous.

Tuesday, January 25, 2022

FOSSIL SALMON OF SKOKOMISH

This toothy specimen is an Oncorhynchus nerka, a Pleistocene Sockeye Salmon from outcrops along the South Fork Skokomish River, Olympic Peninsula, Washington State, USA.

The area is home to the Skokomish — one of nine tribes of the Twana, Coast Salish First Nations in the northern-mid Puget Sound area of western Washington state in the United States. 

Each of the Tribal Nations are known by their locations — Dabop, Quilcene or salt-water people, Dosewallips, Duckabush, Hoodsport, Skokomish or Skoko'bsh, Vance Creek, Tahuya, and Duhlelap or Tule'lalap. The name Skokomish means river people or people of the river in the language of the Twana, sqʷuqʷóbəš or sqWuqWu'b3sH.

Closer to my home farther north in the Pacific Northwest on northern Vancouver Island are the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala. Here, sockeye salmon are known as ma̱łik. You would likely recognize these fossils' modern counterparts from their distinctive red bodies and greenish heads. 

Their descendants had been absent from the Skokomish River for more than a decade up to 2014 when construction to augment the negative impact of the Cushman Reservoir was undertaken to restore their natural habitat.

The fossil specimens include individuals with enlarged breeding teeth and worn caudal fins. It is likely that these salmon acted very similar to their modern counterparts with males partaking in competitive and sneaky tactics to gain access to the sexiest (large and red) females who were ready to mate. These ancient salmon had migrated, dug their nests, spawned and defended their eggs prior to their death. For now, we're referring to the species found here as Oncorhynchus nerka, as they have many of the characteristics of sockeye salmon, but also several minor traits of the Pink Salmon, Oncorhynchus gorbuscha.

I had expected to learn that the locality contained a single or just a few partial specimens, but the fossils beds are abundant with large, 45–70 cm, four-year-old adult salmon concentrated in a beautiful sequence of death assemblages.

Oncorhynchus nerka, Pleistocene Sockeye Salmon
Gerald Smith, a retired University of Michigan professor was shown the specimens and recognized them as Pleistocene, a time when the northern part of North America was undergoing a series of glacial advances and retreats that carved their distinctive signature into the Pacific Northwest.

It looks as though this population diverged from the original species about one million years ago, possibly when the salmon were deposited at the head of a proglacial lake impounded by the Salmon Springs advancement of a great glacier known as the Puget lobe of the Cordilleran Ice Sheet. 

Around 17,000 years ago, this 3,000 foot-thick hunk of glacial ice had made its way down from Canada, sculpting a path south and pushing its way between the Cascade and Olympic Mountains. The ice touched down as far south as Olympia, stilled for a few hundred years, then began to melt.

After the ice began melting and retreating north, the landscape slowly changed —  both the land and sea levels rising — and great freshwater lakes forming in the lowlands filled with glacial waters from the melting ice. The sea levels rose quite considerably, about one and a half centimetres per year between 18,000 and 13,000 years ago. The isostatic rebound (rising) of the land rose even higher with an elevation gain of about ten centimetres per year from 16,000 to 12,500 years ago.

Around 14,900 years ago, sea levels had risen to a point where the salty waters of Puget Sound began to slowly fill the lowlands. Both the land and sea continued to rise and by 5,000 years ago, the sea level was about just over 3 meters lower than it is today. The years following were an interesting time in the geologic history of the Pacific Northwest. The geology of the South Fork Skokomish River continued to shift, undergoing a complicated series of glacial damming and river diversions after these salmon remains were deposited.

Today, we find their remains near the head of a former glacial lake at an elevation of 115 metres on land owned by the Green Diamond Company. The first fossil specimens were found back in 2001 by locals fishing for trout along the South Fork Skokomish River.

Upon seeing the fossil specimens, Smith teamed up with David Montgomery of the University of Washington, Seattle, along with N. Phil Peterson and Bruce Crowley, a Late Oligocene Mysticete specialist from the Burke Museum, to complete fieldwork and author a paper.

The fossil specimen you see here is housed in the Burke Museum collection. They opened the doors to their new building and exhibitions in the Fall of 2019. These photos are by the deeply awesome John Fam from a trip to see the newly opened exhibits this year. If you fancy a visit to the Burke Museum, check out their website here: https://www.burkemuseum.org/.

David B. Williams did up a nice piece on historylink.org on the Salmon of the Puget lowland. You can find his work here: https://www.historylink.org/File/20263

If you'd like to read more of the papers on the topic, check out:

  • Smith, G., Montgomery, D., Peterson, N., and Crowley, B. (2007). Spawning sockeye salmon fossils in Pleistocene lake beds of Skokomish Valley, Washington. Quaternary Research, 68(2), 227-238. doi:10.1016/j.yqres.2007.03.007.
  • Easterbrook, D.J., Briggs, N.D., Westgate, J.A., and Gorton, M.P. (1981). Age of the Salmon Springs Glaciation in Washington. Geology 9, 87–93.
  • Hikita, T. (1962). Ecological and morphological studies of the genus Oncorhynchus (Salmonidae) with particular consideration on phylogeny. Scientific Reports of the Hokkaido Salmon Hatchery 17, 1–97.

If you fancy a read of Crowley's work on Late Oligocene Mysticete from Washington State, you can check out:  Crowley, B., & Barnes, L. (1996). A New Late Oligocene Mysticete from Washington State. The Paleontological Society Special Publications, 8, 90-90. doi:10.1017/S2475262200000927

Saturday, January 8, 2022

FROM FISH TO TETRAPODS: ELPISTOSTEGE WATSONI

Elpistostege watsoni

In the late 1930s, our understanding of the transition of fish to tetrapods — and the eventual jump to modern vertebrates — took an unexpected leap forward. The evolutionary a'ha came from a single partial fossil skull found on the shores of a riverbank in Eastern Canada. 

Meet the Stegocephalian, Elpistostege watsoni, an extinct genus of finned tetrapodomorphs that lived during the Late Givetian to Early Frasnian of the Late Devonian — 382 million years ago. 

Elpistostege watsoni — perhaps the sister taxon of all other tetrapods — was first described in 1938 by British palaeontologist and elected Fellow of the Royal Society of London, Thomas Stanley Westoll. Westoll's research interests were wide-ranging. He was a vertebrate palaeontologist and geologist best known for his innovative work on Palaeozoic fishes and their relationships with tetrapods. 

As a specialist in early fish, Westoll was asked to interpret that single partial skull roof discovered at the Escuminac Formation in Quebec, Canada. His findings and subsequent publication named Elpistostege watsoni and helped us to better understand the evolution of fishes to tetrapods — four-limbed vertebrates — one of the most important transformations in vertebrate evolution. 

Hypotheses of tetrapod origins rely heavily on the anatomy of but a few tetrapod-like fish fossils from the Middle and Late Devonian, 393–359 million years ago. These taxa — known as elpistostegalians — include Panderichthys, Elpistostege and Tiktaalik — none of which had yet to reveal the complete skeletal anatomy of the pectoral fin. 

Elpistostege watsoni
None until 2010 that is, when a complete 1.57-metre-long articulated specimen was found and described by Richard Cloutier et al. in 2020. 

The specimen helped us to understand the origin of the vertebrate hand. Stripped from its encasing stone, it revealed a set of paired fins of Elpistostege containing bones homologous to the phalanges (finger bones) of modern tetrapods and is the most basal tetrapodomorph known to possess them. 

Once the phalanges were uncovered, prep work began on the fins. The fins were covered in wee scales and lepidotrichia (fin rays). The work was tiresome, taking more than 2,700 hours of preparation but the results were thrilling. 

Origin of the Vertebrate Hand
We could now clearly see that the skeleton of the pectoral fin has four proximodistal rows of radials — two of which include branched carpals — as well as two distal rows organized as digits and putative digits. 

Despite this skeletal pattern — which represents the most tetrapod-like arrangement of bones found in a pectoral fin to date blurring the line between fish and land vertebrates — the fin retained lepidotrichia (those wee fin rays) distal to the radials. 

This arrangement confirmed an age-old question — showing us for the first time that the origin of phalanges preceded the loss of fin rays, not the other way around.

E. watsoni is very closely related to Tiktaalik roseae found in 2004 in the Canadian Arctic — a tetrapodomorpha species also known as a Choanata. These were advanced forms transitional between fish and the early labyrinthodonts playfully referred to as fishapods — half-fish, half-tetrapod in appearance and limb morphology. 

Up to that point, the relationship of limbed vertebrates (tetrapods) to lobe-finned fish (sarcopterygians) was well known, but the origin of major tetrapod features remained obscure for lack of fossils that document the sequence of evolutionary changes — until Tiktaalik. While Tiktaalik is technically a fish, this fellow is as far from fish-like you can be and still be a card-carrying member of the group. 

Tiktaalik roseae
Complete with scales and gills, this proto-fish lacked the conical head we see in modern fish but had a rather flattened triangular head more like that of a crocodile. 

Tiktaalik had scales on its back and fins with fin webbing but like early land-living animals, it had a distinctive flat head and neck. He was a brawny brute. The shape of his skull and shoulder look part fish and part amphibian.

The watershed moment came as Tiktaalik was prepped. Inside Tiktaalik's fins, we find bones that correspond to the upper arm, forearm and even parts of the wrist — all inside a fin with webbing — remarkable! 

Its fins have thin ray bones for paddling like most fish, but with brawny interior bones that gave Tiktaalik the ability to prop itself up, using his limbs for support. I picture him propped up on one paddle saying, "how you doing?" 

Six years after Tiktaalik was discovered by Neil Shubin and team in the ice-covered tundra of the Canadian Arctic on southern Ellesmere Island, a team working the outcrops at Miguasha on the Gaspé Peninsula discovered the only fully specimen of E. watsoni found to date — greatly increasing our knowledge of this finned tantalizingly transitional tetrapodomorph. 

E. watsoni fossils are rare — this was the fourth specimen collected in over 130 years of hunting. Charmingly, the specimen was right on our doorstop — extracted but a few feet away from the main stairs descending onto the beach of Miguasha National Park. 

L'nu Mi’gmaq First Nations of the Gespe’gewa’gi Region

Miguasha is nestled in the Gaspésie or Gespe’gewa’gi region of Canada — home to the Mi’gmaq First Nations who self-refer as L’nu or Lnu. The word Mi’gmaq or Mi’kmaq means the family or my allies/friends in Mi'kmaw, their native tongue (and soon to be Nova Scotia's provincial first language). They are the people of the sea and the original inhabitants of Atlantic Canada having lived here for more than 10,000 years. 

The L'nu were the first First Nation people to establish contact and trade with European explorers in the 16th and 17th centuries — and perhaps the Norse as early as the turn of the Millenium. Sailing vessels filled with French, British, Scottish, Irish and others arrived one by one to lay claim to the region — settling and fighting over the land. As each group rolled out their machinations of discovery, tensions turned to an all-out war with the British and French going head to head. I'll spare you the sordid details but for everyone caught in the crossfire, it went poorly.

North America Map 1775 (Click to Enlarge)
Cut to 1760, the British tipped the balance with their win at the Battle of the Restigouche, the last naval battle between France and England for possession of the North American continent — Turtle Island. 

The bittersweet British victory sparked the American War of Independence. 

For the next twenty years, the L'nu would witness and become embroiled in yet another war for these lands, their lands — first as bystanders, then as American allies, then intimidated into submission by the British Royal Navy with a show of force by way of a thirty-four gun man-of-war, encouraging L'nu compliance — finally culminating in an end to the hostilities with the 1783 Treaty of Paris. 

The peace accord held no provisions for the L'nu, Métis and First Nations impacted. None of these newcomers was Mi'kmaq — neither friends nor allies.

It was to this area some sixty years later that the newly formed Geological Survey of Canada (GSC) began exploring and mapping the newly formed United Province of Canada. Geologists in the New Brunswick Geology Branch traipsed through the rugged countryside that would become a Canadian province in 1867. 

It was on one of these expeditions that the Miguasha fossil outcrops were discovered. They, too, would transform in time to become Miguasha National Park or Parc de Miguasha, but at first, they were simply the promising sedimentary exposures on the hillside across the water —  a treasure trove of  Late Devonian fauna waiting to be discovered.

In the summer of 1842, Abraham Gesner, New Brunswick’s first Provincial Geologist, crossed the northern part of the region exploring for coal. Well, mostly looking for coal. Gesner also had a keen eye for fossils and his trip to the Gaspé Peninsula came fast on the heels of a jaunt along the rocky beaches of Chignecto Bay at the head of the Bay of Fundy and home to the standing fossil trees of the Joggins Fossil Cliffs. 

Passionate about geology and chemistry, he is perhaps most famous for his invention of the process to distil the combustible hydrocarbon kerosene from coal oil — a subject on which his long walks exploring a budding Canada gave him a great deal of time to consider. We have Gesner to thank for the modern petroleum industry. He filed many patents for clever ways to distil the soft tar-like coal or bitumen still in use today.

He was skilled in a broad range of scientific disciplines — being a geologist, palaeontologist, physician, chemist, anatomist and naturalist — a brass tacks geek to his core. Gesner explored the coal exposures and fossil outcrops across the famed area that witnessed the region become part of England and not France — and no longer L'nu.

Following the Restigouche River in New Brunswick through the Dalhousie region, Gesner navigated through the estuary to reach the southern coast of the Gaspé Peninsula into what would become the southeastern coast of Quebec to get a better look at the cliffs across the water. He was the first geologist to lay eyes on the Escuminac Formation and its fossils.

In his 1843 report to the Geologic Survey, he wrote, “...I found the shore lined with a coarse conglomerate. Farther eastward the rocks are light blue sandstones and shales, containing the remains of vegetables. (...) In these sandstone and shales, I found the remains of fish and a small species of tortoise with fossil foot-marks.”

We now know that this little tortoise was the famous Bothriolepis, an antiarch placoderm fish. It was also the first formal mention of the Miguasha fauna in our scientific literature. Despite the circulation of his report, Gesner’s discovery was all but ignored — the cliffs and their fossil bounty abandoned for decades to come. Geologists like Ells, Foord and Weston, and the research of Whiteaves and Dawson, would eventually follow in Gesner's footsteps.

North America Map 1866 (Click to Enlarge)
Over the past 180 years, this Devonian site has yielded a wonderfully diverse aquatic assemblage from the Age of Fishes — five of the six fossil fish groups associated with the Devonian including exceptionally well-preserved fossil specimens of the lobe-finned fishes. 

This is exciting as it is the lobe-finned fishes — the sarcopterygians — that gave rise to the first four-legged, air-breathing terrestrial vertebrates – the tetrapods. 

Fossil specimens from Miguasha include twenty species of lower vertebrates — anaspids, osteostra-cans, placoderms, acanthodians, actinopterygians and sarcopterygians — plus a limited invertebrate assemblage, along with terrestrial plants, scorpions and millipedes.

Originally interpreted as a freshwater lacustrine environment, recent paleontological, taphonomic, sedimentological and geochemical evidence corroborates a brackish estuarine setting — and definitely not the deep waters of the sea. This is important because the species that gave rise to our land-living animals began life in shallow streams and lakes. It tells us a bit about how our dear Elpistostege watsoni liked to live — preferring to lollygag in cool river waters where seawater mixed with fresh. Not fully freshwater, but a wee bit of salinity to add flavour.  

  • Photos: Elpistostege watsoni (Westoll, 1938 ), Upper Devonian (Frasnian), Escuminac formation, Parc de Miguasha, Baie des Chaleurs, Gaspé, Québec, Canada. John Fam, VanPS
  • Origin of the Vertebrate Hand Illustration, https://www.nature.com/articles/s41586-020-2100-8
  • Tiktaalik Illustration: By Obsidian Soul - Own work, CC BY 4.0, https://commons.wikimedia.org/w/index.php?curid=47401797

References & further reading:

  • From Water to Land: https://www.miguasha.ca/mig-en/the_first_discoveries.php
  • UNESCO Miguasha National Park: https://whc.unesco.org/en/list/686/
  • Office of L'nu Affairs: https://novascotia.ca/abor/aboriginal-people/
  • Cloutier, R., Clement, A.M., Lee, M.S.Y. et al. Elpistostege and the origin of the vertebrate hand. Nature 579, 549–554 (2020). https://doi.org/10.1038/s41586-020-2100-8
  • Daeschler, E. B., Shubin, N. H. & Jenkins, F. A. Jr. A Devonian tetrapod-like fish and the evolution of the tetrapod body plan. Nature 440, 757–763 (2006).
  • Shubin, Neil. Your Inner Fish: A Journey into the 3.5 Billion History of the Human Body.
  • Evidence for European presence in the Americas in AD 1021: https://www.nature.com/articles/s41586-021-03972-8