Showing posts with label archea. Show all posts
Showing posts with label archea. Show all posts

Sunday, 2 March 2025

FOSSIL BIRDS OF SOUTHERN VANCOUVER ISLAND

Stemec suntokum, Sooke Formation
The diving bird you see here is Stemec suntokum, a Fossil Plopterid from Sooke, British Columbia, Canada.

We all dream of finding new species, and new fossil species in particular. This happens more than you think. As impossible as it sounds, it has happened numerous times at many fossils sites in British Columbia including Sooke on Vancouver Island.

The upper Oligocene Sooke Formation outcrops at Muir Beach on southwestern Vancouver Island, British Columbia where it is flanked by the cool, clear waters of the Strait of Juan de Fuca.

While the site has been known since the 1890s, my first trip here was in the early 1990s as part of a Vancouver Paleontological Society (VanPS) fossil field trip. 

This easy, beach walk locality is a wonderful place to collect fossils and is especially good for families. If you are solar-powered, you will enjoy the sun playing off the surf from May through September. If you are built of hardier stuff, then the drizzle of Spring or Autumn is a lovely, un-people-y time to walk the beachfront.

As well as amazing west coast scenery, the beach site outcrop has a lovely soft matrix with well-preserved fossil molluscs, often with the shell material preserved (Clark and Arnold, 1923).

By the Oligocene ocean temperatures had cooled to near modern levels and the taxa preserved here as fossils bear a strong resemblance to those found living beneath the Strait of Juan de Fuca today. Gastropods, bivalves, echinoids, coral, chitin and limpets are common-ish — and on rare occasions, fossil marine mammals, cetacean and bird bones are discovered.

Fossil Bird Bones 

Back in 2013, Steve Suntok and his family found fossilized bones from a 25-million-year-old wing-propelled flightless diving bird while out strolling the shoreline near Sooke. Not knowing what they had found but recognizing it as significant, the bones were brought to the Royal British Columbia Museum to identify.

The bones found their way into the hands of Gary Kaiser. Kaiser worked as a biologist for Environment Canada and the Nature Conservatory of Canada. After retirement, he turned his eye from our extant avian friends to their fossil lineage. The thing about passion is it never retires. Gary is now a research associate with the Royal British Columbia Museum, published author and continues his research on birds and their paleontological past.

Kaiser identified the well-preserved coracoid bones as the first example from Canada of a Plotopteridae, an extinct family that lived in the North Pacific from the late Eocene to the early Miocene. In honour of the First Nations who have lived in the area since time immemorial and Steve Suntok who found the fossil, Kaiser named the new genus and species Stemec suntokum.

Magellanic Penguin Chick, Spheniscus magellanicus
This is a very special find. Avian fossils from the Sooke Formation are rare. We are especially lucky that the bird bone was fossilized at all.  These are delicate bones and tasty. Scavengers often get to them well before they have a chance and the right conditions to fossilize.

Doubly lucky is that the find was of a coracoid, a bone from the shoulder that provides information on how this bird moved and dove through the water similar to a penguin. It's the wee bit that flexes as the bird moves his wing up and down.

Picture a penguin doing a little waddle and flapping their flipper-like wings getting ready to hop near and dive into the water. Now imagine them expertly porpoising —  gracefully jumping out of the sea and zigzagging through the ocean to avoid predators. It is likely that the Sooke find did some if not all of these activities.

When preservation conditions are kind and we are lucky enough to find the forelimbs of our plotopterid friends, their bones tell us that these water birds used wing-propelled propulsion to move through the water similar to penguins (Hasegawa et al., 1979; Olson and Hasegawa, 1979, 1996; Olson, 1980; Kimura et al., 1998; Mayr, 2005; Sakurai et al., 2008; Dyke et al., 2011).

Kaiser published on the find, along with Junya Watanabe, and Marji Johns. Their work: "A new member of the family Plotopteridae (Aves) from the late Oligocene of British Columbia, Canada," can be found in the November 2015 edition of Palaeontologia Electronica. If you fancy a read, I've included the link below.

The paper shares insights into what we have learned from the coracoid bone from the holotype Stemec suntokum specimen. It has an unusually narrow, conical shaft, much more gracile than the broad, flattened coracoids of other avian groups. This observation has led some to question if it is, in fact, a proto-cormorant of some kind. We'll need to find more of their fossilized lineage to make any additional comparisons.

Sooke, British Columbia and Juan de Fuca Strait
Today, fossils from these flightless birds have been found in outcrops in the United States and Japan (Olson and Hasegawa, 1996). They are bigger than the Sooke specimens, often growing up to two metres.

While we'll never know for sure, the wee fellow from the Sooke Formation was likely about 50-65 cm long and weighed in around 1.72-2.2 kg — so roughly the length of a duck and weight of a small Magellanic Penguin, Spheniscus magellanicus, chick. 

To give you a visual, I have included a photo of one of these cuties here showing off his full range of motion and calling common in so many young.

The first fossil described as a Plotopteridae was from a wee piece of the omal end of a coracoid from Oligocene outcrops of the Pyramid Hill Sand Member, Jewett Sand Formation of California (LACM 8927). Hildegarde Howard (1969) an American avian palaeontologist described it as Plotopterum joaquinensis. Hildegarde also did some fine work in the La Brea Tar Pits, particularly her work on the Rancho La Brea eagles.

In 1894, a portion of a pelagornithid tarsometatarsus, a lower leg bone from Cyphornis magnus (Cope, 1894) was found in Carmanah Group on southwestern Vancouver Island (Wetmore, 1928) and is now in the collections of the National Museum of Canada as P-189401/6323. This is the wee bone we find in the lower leg of birds and some dinosaurs. We also see this same bony feature in our Heterodontosauridae, a family of early and adorably tiny ornithischian dinosaurs — a lovely example of parallel evolution.


While rare, more bird bones have been found in the Sooke Formation over the past decade. In 2013, three avian bones were found in a single year. The first two were identified as possibly being from a cormorant and tentatively identified as Phalacrocoracidae tibiotarsi, the large bone between the femur and the tarsometatarsus in the leg of a bird.

They are now in the collections of the Royal BC Museum as (RBCM.EH2013.033.0001.001 and RBCM.EH2013.035.0001.001). These bones do have the look of our extant cormorant friends but the specimens themselves were not very well-preserved so a positive ID is tricky.

The third (and clearly not last) bone, is a well-preserved coracoid bone now in the collection at the RBCM as (RBCM.EH2014.032.0001.001).

The fossil bird find was the first significant find by the Suntok family but not their last. Just last year, they found part of a fish dental plate was studied by Russian researcher Evgeny Popov who named this new genus and species of prehistoric fish Canadodus suntoki, which translates to the "Tooth from Canada." Perhaps not quite as inspired as Kaiser, but a lovely homage to these Citizen Scientists.

Sooke Fossil Fauna

Along with these rare bird bones, the Paleogene sedimentary deposits of the Carmanah Group on southwestern Vancouver Island have a wonderful diversity of delicate fossil molluscs (Clark and Arnold, 1923). Walking along the beach, look for boulders with white shelly material in them. You'll want to collect from the large fossiliferous blocks and avoid the cliffs. The lines of fossils you see in those cliffs tell the story of deposition along a strandline. Collecting from them is both unsafe and poor form as it disturbs nearby neighbours and is discouraged.

Sooke Formation Gastropods, Photo: John Fam
We find nearshore and intertidal genera such as Mytilus (mussels) and barnacles, as well as more typically subtidal predatory globular moon snails (my personal favourite), surf clams (Spisula, Macoma), and thin, flattened Tellin clams.

The preservation here formed masses of shell coquinas that cemented together but are easily worked with a hammer and chisel. Remember your eye protection and I'd choose wellies or rubber boots over runners or hikers.

You may be especially lucky on your day out. Look for the larger fossil bones of marine mammals and whales that lived along the North American Pacific Coast in the Early Oligocene (Chattian).

Concretions and coquinas on the beach have yielded desmostylid, an extinct herbivorous marine mammal, Cornwallius sookensis (Cornwall, 1922) and 40 cm. skull of a cetacean Chonecetus sookensis (Russell, 1968), and a funnel whale, a primitive ancestor of our Baleen whales. 

A partial lower jaw and molar possibly from a large, bear-like beach-dwelling carnivore, Kolponomos, was also found here. A lovely skull from a specimen of Kolponomos clallamensis (Stirton, 1960) was found 60 km southwest across the Strait of Juan de Fuca in the early Miocene Clallam Formation and published by Lawrence Barnes and James Goedert. That specimen now calls the Natural History Museum of Los Angeles County home and is in their collections as #131148.

Directions to Muir Creek Fossil Site at Sooke: 

From the town of Sooke west of Victoria, follow Highway 14 for about 14 kilometres. Just past the spot where the highway crosses Muir Creek, you will see a gravel parking area on your left. Pull in and park here. 

From the barrier, walk out to the beach and turn right (west) and walk until you see the low yellow-brown sandstone cliffs about 400 metres ahead. 

Look at the grey sandstone boulders on the beach with bits of white flecks in them. The fossil material here will most often be a whitish cream colour. Check for low tide before heading out and choose rubber boots for this beach adventure.

References: 

L. S. Russell. 1968. A new cetacean from the Oligocene Sooke Formation of Vancouver Island, British Colombia. Canadian Journal of Earth Science 5:929-933
Barnes, Lawrence & Goedert, James. (1996). Marine vertebrate palaeontology on the Olympic Peninsula. Washington Geology, 24(3):17-25.

Fancy a read? Here's the link to Gary Kaiser's paper: https://palaeo-electronica.org/content/2015/1359-plotopterid-in-canada. If you'd like to head to the beach site, head to: 48.4°N 123.9°W, paleo-coordinates 48.0°N 115.0°W.

Tuesday, 25 February 2025

BEAUTIFUL QUENSTEDTOCERAS AMMONITE WITH PATHOLOGY

What you are seeing here is a protuberance extruding from the venter of Quenstedtoceras cf. leachi (Sowerby). 

It is a pathology in the shell from hosting immature bivalves that shared the seas with these Middle Jurassic, Upper Callovian, Lamberti zone fauna from the Volga River basin. The collecting site is the now inactive Dubki commercial clay quarry and brickyard near Saratov, Russia. 

The site has produced thousands of ammonite specimens. A good 1,100 of those ended up at the Black Hills Institute of Geological Research in Hill City, South Dakota. 

Roughly 1,000 of those are Quenstedtoceras (Lamberticeras) lamberti and the other 100 are a mix of other species found in the same zone. These included Eboraciceras, Peltoceras, Kosmoceras, Grossouvria, Proriceras, Cadoceras and Rursiceras

What is especially interesting is the volume of specimens — 167 Quenstedtoceras (Lamberticeras) lamberti and 89 other species in the Black Hills collection — with healed predation injuries. It seems Quenstedtoceras (Lamberticeras) lamberti are the most common specimens found here and so not surprisingly the most common species found injured. Of the 1,000, 655 of the Quenstedtoceras (Lamberticeras) lamberti displayed some sort of deformation or growth on the shell or had grown in a tilted manner. 

Again, some of the Q. lamberti had small depressions in the centre likely due to a healed bite and hosting infestations of the immature bivalve Placunopsis and some Ostrea

The bivalves thrived on their accommodating hosts and the ammonites carried on, growing their shells right up and over their bivalve guests. This relationship led to some weird and deformities of their shells. They grow in, around, up and over nearly every surface of the shell and seem to have lived out their lives there. It must have gotten a bit unworkable for the ammonites, their shells becoming warped and unevenly weighted. Over time, both the flourishing bivalves and the ammonite shells growing up and over them produced some of the most interesting pathology specimens I have ever seen.    

In the photo here from Emil Black, you can see some of the distorted shapes of Quenstedtoceras sp. Look closely and you see a trochospiral or flattened appearance on one side while they are rounded on the other. 

All of these beauties hail from the Dubki Quarry near Saratov, Russia. The ammonites were collected in marl or clay used in brick making. The clay particles suggest a calm, deep marine environment. One of the lovely features of the preservation here is the amount of pyrite filling and replacement. It looks like these ammonites were buried in an oxygen-deficient environment. 

The ammonites were likely living higher in the water column, well above the oxygen-poor bottom. An isotopic study would be interesting to prove this hypothesis. 

There's certainly enough of these ammonites that have been recovered to make that possible. It's estimated that over a thousand specimens have been recovered from the site but that number is likely much higher. But these are not complete specimens. We mostly find the phragmocones and partial body chambers. Given the numbers, this may be a site documenting a mass spawning death over several years or generations.

If you fancy a read on all things cephie, consider picking up a copy of Cephalopods Present and Past: New Insights and Fresh Perspectives edited by Neil Landman and Richard Davis. Figure 16.2 is from page 348 of that publication and shows the hosting predation quite well. 

Photos: Courtesy of the deeply awesome Emil Black. These are in his personal collection that I hope to see in person one day. 

It was his sharing of the top photo and the strange anomaly that had me explore more about the fossils from Dubki and the weird and wonderful hosting relationship between ammonites and bivalves. Thank you, my friend!

Sunday, 16 February 2025

WARRIOR CRABS: KU'MIS

Look how epic this little guy is! 

He is a crab — and if you asked him, the fiercest warrior that ever lived. While that may not be strictly true, crabs do have the heart of a warrior and will raise their claws, sometimes only millimetres into the air, to assert dominance over their world. 

Crabs are decapod crustaceans of the Phylum Arthropoda. 

In the Kwak'wala language of the Kwakwaka'wakw of the Pacific Northwest, this brave fellow is ḵ̓u'mis — both a tasty snack and familiar to the supernatural deity Tuxw'id, a female warrior spirit. Given their natural armour and clear bravery, it is a fitting role.

They inhabit all the world's oceans, sandy beaches, many of our freshwater lakes and streams. Some few prefer to live in forests.

Crabs build their shells from highly mineralized chitin — and chitin gets around. It is the main structural component of the exoskeletons of many of our crustacean and insect friends. Shrimp, crab, and lobster all use it to build their exoskeletons.

Chitin is a polysaccharide — a large molecule made of many smaller monosaccharides or simple sugars, like glucose. 

It is handy stuff, forming crystalline nanofibrils or whiskers. Chitin is actually the second most abundant polysaccharide after cellulose. It is interesting as we usually think of these molecules in the context of their sugary context but they build many other very useful things in nature — not the least of these are the hard shells or exoskeletons of our crustacean friends.

Crabs in the Fossil Record

The earliest unambiguous crab fossils date from the Early Jurassic, with the oldest being Eocarcinus from the early Pliensbachian of Britain, which likely represents a stem-group lineage, as it lacks several key morphological features that define modern crabs. 

Most Jurassic crabs are only known from dorsal — or top half of the body — carapaces, making it difficult to determine their relationships. Crabs radiated in the Late Jurassic, corresponding with an increase in reef habitats, though they would decline at the end of the Jurassic as the result of the decline of reef ecosystems. Crabs increased in diversity through the Cretaceous and represented the dominant group of decapods by the end.

We find wonderful fossil crab specimens on Vancouver Island. The first I ever collected was at Shelter Point, then again on Hornby Island, down on the Olympic Peninsula and along Vancouver Island's west coast near Nootka Sound. They are, of course, found globally and are one of the most pleasing fossils to find and aggravating to prep of all the specimens you will ever have in your collection. Bless them.


Wednesday, 12 February 2025

SLOTHS AND BLUE GREEN ALGAE

Ever wonder why the slow moving sloth has a slightly greenish hue? Ever consider the sloth at all? Well, perhaps not. Location, location, location, is the mantra for many of us in our macro world, but it is also true for the small world of algae.

Blue green algae is a term used to describe any of a large, heterogeneous group of prokaryotic, principally photosynthetic organisms.

These little oxygenic (oxygen-producing) fellows appeared about 2,000,000,000 to 3,000,000,000 years ago and are given credit for greatly increasing the oxygen content of the atmosphere, making possible the development of aerobic (oxygen-using) organisms and some very special relationships with some of the slowest moving mammals on the planet, the sloths or Folivora.

The tribes of South America who live close to these insect and leaf-eaters, call these arboreal browsers "Ritto, Rit or Ridette, which roughly translates to variations on sleep, sleepy, munching and filthy. Not all that far off when you consider ths sloth and their lifestyle.

The sloth's body and shaggy coat, or pelage, provides a comfy habitat to two types of wee blue-green algae along with various other invertebrates. The hairs that make up the sloth's coat have grooves that help foster algal growth.

And, while Kermit the Frog says, "it's not easy being green," it couldn't be further from the truth for this slow-moving tree dweller. The blue-green algae gives the sloth a natural greenish camouflage, an arrangement that is certainly win-win.

Saturday, 8 February 2025

NANAIMO MOTOR CROSS PIT FOSSIL SITE

Steller's Jay, Cyanocitta stelleri
One of the classic Vancouver Island fossil localities is the Santonian-Maastrichtian, Upper Cretaceous Haslam Formation Motocross Pit near Brannen Lake, Nanaimo, British Columbia, Canada.

The quarry is no longer active as such though there is a busy little gravel quarry a little way down the road closer to Ammonite falls near Benson Creek Falls.

Today it is an active motocross site and remains one of the classic localities of the Nanaimo Group. 

In these easily accessible (with permission) outcrops we find well-preserved nautiloids and ammonites — Canadoceras, Pseudoschloenbachia, Epigoniceras — the bivalves — Inoceramus, Sphenoceramus— gastropods, and classic Nanaimo Group decapods — Hoploparia, Linuparus. We also find fossil fruit and seeds which tell the story of the terrestrial history of Vancouver Island.

Upper Cretaceous Haslam Formation Motocross Pit near Brannen Lake
It was John Fam, Vice-Chair, Vancouver Island Paleontological Society (VanPS), who originally told me about the locality. John is one of the most delightful and knowledgeable people you'd be well-blessed to meet.

While he lived on Vancouver Island, he was an active member of the VanPS back when I was Chair. Several of the best joint VIPS/VanPS paleontological expeditions were planned with or instigated by his passion for fossils. I tip my hat to him for that drive to see so many of the hard to reach but incredibly beautiful and scientifically important sites—and shared love of all things paleo.

John grew up 15 minutes from the motocross locality and used to collect there a few times a week with his father. John has wonderful parents and since marrying his childhood sweetheart, the amazing Grace, those excellent genetics, curiosity and love of fossils are now being passed to a new generation. It's lovely to see John and Grace continuing tradition with two boys of their own.

I met John way back then and did an overnight at his parent's house the Friday before a weekend field trip to Jurassic Point. It was a joy to have him walk me through his collections and tell his stories from earlier years. After learning about the site from John, I headed up to the Motocross Pit with my Uncle Doug. He was a delightful man who grew up on the coast and had explored much of it but not the fossil site just 10-minutes from his home. It was wonderful to walk through time with him so many years ago and then again solo this past year with sadness in my belly that one of the best I've ever known has left this Earth.

Upper Cretaceous Haslam Formation Motocross Pit near Brannen Lake
There were some no trespassing signs up but no people around, so I walked the periphery looking for the bedrock of the Haslam.

The rocks we find here were laid down south of the equator as small, tropical islands. They rode across the Pacific heading north and slightly east over the past 80 million years to where we find them today.

Jim Haggart and Peter Ward have done much to increase our understanding of the molluscan fauna of the Nanaimo Group. Personally, both personify the charming Indiana Jones school of rugged manly palaeontologists you picture in popular film. Professionally, their singular contributions and collaborative efforts have helped shape our understanding of the correlation of Nanaimo Group fauna to those we find in the Gulf Islands of British Columbia and down in the San Juan Islands of Washington State.

Their work builds on the work of Usher (1952), Matsumoto (1959a, 1959b) and Mallory (1977). A healthy nod goes out to the work of Muller and Jeletzky (1970) for untangling the lithostratigraphic and biostratigraphic foundation for our knowledge of the Nanaimo Group.

Candoceras yokoyama, Photo: John Fam, VanPS
As I walked along the bedrock of the Haslam, a Steller's Jay, Cyanocitta stelleri, followed me from tree to tree making his guttural shook, shook, shook call. Instructive, he seemed to be encouraging me, timing his hoots to the beat of my hammer.

If you fancy some additional reading, check out a paper published in the Journal of Paleontology back in 1989 by Haggard and Ward on new Nanaimo Group Ammonites from British Columbia and Washington State.

In it, they look at the ammonite species Puzosia (Mesopuzosia) densicostata Matsumoto, Kitchinites (Neopuzosia) japonicus Spath, Anapachydiscus cf. A. nelchinensis Jones, Menuites cf. M. menu (Forbes), Submortoniceras chicoense (Trask), and Baculites cf. B. boulei Collignon are described from Santonian--Campanian strata of western Canada and northwestern United States.

Stratigraphic occurrences and ranges of the species are summarized and those taxa important for correlation with other areas in the north Pacific region and Late Cretaceous ammonite fauna of the Indo-Pacific region. Here's the link: https://www.jstor.org/stable/1305358?seq=1

Peter Ward is a prolific author, both of scientific papers and more popularized works. I highly recommend his book Gorgon: Paleontology, Obsession, and the Greatest Catastrophe in Earth's History. It is an engaging romp through a decade's research in South Africa's Karoo Desert. It looks like Peter will be at the 15th BCPA Symposium giving a talk and perhaps some paleo-battle with Jim Haggart as we tease through the pros and cons for the Baja California—Baja BC origin story for some of the strata we find further north today.

Photo: Candoceras yokoyamai from the Upper Cretaceous Haslam Formation (Lower Campanian) near Nanaimo, British Columbia. One of the earliest fossils collected by John Fam (1993) and a classic fossil found at the site. This lovely was prepared using only a cold chisel and hammer. Photo & collection of John Fam, VIPS.

Thursday, 30 January 2025

TRACKING WHALES WITH BARNACLES

We can trace the lineage of barnacles back to the Middle Cambrian. That is half a billion years of data to sift through. 

If you divide that timeline in half yet again, we begin to understand barnacles and their relationship to other sea-dwelling creatures — with a lens that reveals ancient migration patterns.

Barnacles are in the infraclass Cirripedia in the class Maxillopoda and phylum Crustacea. The name "Cirripedia" comes from the Latin and translates to "curl-footed," an apt description of some from this class. They are marine arthropods related to crabs and lobsters. 

In the Kwak̓wala language of the Kwakwaka'wakw First Nations, speakers of Kwak'wala, of the Pacific Northwest, barnacles are known as k̕wit̕a̱'a and broken barnacle shells are known as t̕sut̕su'ma. 

Unless scraped off, barnacles live on one single sturdy object for their entire lives — 8 to 20 years — while chowing down on tasty snacks like plankton and algae they absorb from the surrounding water.

One of the most interesting aha moments in paleontology came from the study of 270,000 million-year-old k̕wit̕a̱'as. These sticky wee crustaceans have enabled us to trace the course of ancient whale migration. 

University of California Berkeley doctoral student Larry Taylor published some clever findings on how fossil barnacles hitched a ride on the backs of humpback and grey whales millions of years ago and used this data to reconstruct the migrations of ancient whale populations.

The barnacles record details about the whales’ yearly travels in the fossil record. By following this barnacle trail, Taylor et al. were able to reconstruct migration routes of whales from millions of years in the past.

Today, Humpback whales come from both the Southern Hemisphere (July to October with over 2,000 whales) and the Northern Hemisphere (December to March about 450 whales along with Central America) to Panama (and Costa Rica). They undertake annual migrations from polar summer feeding grounds to winter calving and nursery grounds in subtropical and tropical coastal waters.

One surprising find is that the coast of Panama has been a meeting ground for humpback whales going back at least 270,000 years. To see how the barnacles have travelled through the migration routes of ancient whales, the team used oxygen isotope ratios in barnacle shells and measured how they changed over time with ocean conditions. 

Did the whale migrate to warmer breeding grounds or colder feeding grounds? Barnacles retain this information even after they fall off the whale, sink to the ocean bottom, and become fossils. As a result, the travels of fossilized barnacles can serve as a proxy for the journeys of whales in the distant past.

Barnacles can play an important role in estimating paleo-water depths. The degree of disarticulation of fossils suggests the distance they have been transported, and since many species have narrow ranges of water depths, it can be assumed that the animals lived in shallow water and broke up as they were washed down-slope. 

Barnacles have few predators, with their one nemesis being whelks—a type of carnivorous sea snail in the family Muricidae. Whelks feasting on barnacles reads like a bit of a horror movie thriller. The whelks bore through the barnacle's shell and ingest digestive enzymes to make a slushy barnacle stew then such up all that barnacle goodness using their proboscis like a bit of a straw.

Not surprisingly then, the offer of catching a lifetime's ride on a passing whale has both evolutionary and survival appeal. Add to that the locals facilitation of feeding on plankton within arms reach—or cirri's reach in their case as they have these lovely feather-like appendages to sweep plankton out of the water—whelk-free. All in all a much more attractive choice than being cemented to a rock on the sea floor.

Sunday, 12 January 2025

GENAL SPINES A GO GO

Cibelella Coronata / Photo: Alexei Molchanov
A spectacular creamy toned specimen of the trilobite Cibelella Coronata striking a very animated pose. 

The Genal spines give this fellow a bit of a starship look as though taking off in flight. 

This beauty is from upper Ordovician deposits along the Neva River at the head of the Gulf of Finland on the Baltic Coast, Saint Petersburg, Russia.


Tuesday, 31 December 2024

BIOLUMINESCENCE: CHEMICAL POETRY

Light in the oceans? It is chemistry, my friends. 

In the inky blackness of the deep sea, more than 90% of the animals are luminescent. It is quite a startling number but makes good sense when you think of the edge bioluminescence provides. 

The ability to generate light helps umpteen animals find mates, attract prey and avoid predation. Handy stuff, light. 

What you know about light above the surface does not hold true for the light you see as bioluminescence. Its energy and luminosity come from a chemical reaction. 

In a luminescent reaction, two types of chemicals — luciferin and luciferase — combine together. Together, they produce cold light — light that generates less than 20% thermal radiation or heat. 

The light you see is produced by a compound called Luciferin. It is the shiny, showy bit in this chemical show. Luciferase acts as an enzyme, the substance that acts as a catalyst controlling the rate of chemical reactions, allowing the luciferin to release energy as it is oxidized. The colour of the light depends on the chemical structures of the chemicals. There are more than a dozen known chemical luminescent systems, meaning that bioluminescence evolved independently in different groups of organisms.

Coelenterazine is the type of luciferin we find in shrimp, fish and jellyfish. Dinoflagellates and krill share another class of unique luciferins, while ostracods or firefleas and some fish have a completely different luciferin. 

The luciferase found in dinoflagellates is related to the green chemical chlorophyll found in plants. Bioluminescent dinoflagellates are a type of plankton — teensy marine organisms that make the seaways shimmer like the Milky Way as you swim through them. 

Their twinkling lights are brief, each containing about 100 million photons that shine for a tenth of a second. While each individual flicker is here and gone in the wink of an eye, en masse they are awe-inspiring. I have spent many wondrous evenings scuba diving amongst these glittering denizens off our shores. 

Cotylorhiza Tuberculata Jellyfish
In this close up of a Cotylorhiza Tuberculata Jellyfish, you can see the luminosity of her blue and white tentacles. The occurrence of identical luciferins for different types of organisms may suggest a dietary source for some groups strengthening the adage, you are what you eat, or perhaps you glow how you eat

Bacteria and fireflies have unique luminescent chemistries. Fireflies light up when oxygen combines with calcium, adenosine triphosphate (ATP) and luciferin in the presence of luciferase. 

For bacteria, the world stage of luminosity is quite small — and a bit gormless. Just how much light they emit and when is a free-for-all. Not so for the rest of our bioluminescent friends who have very precise control over when they shine and just how bright. 

Bioluminescence comes in a variety of colours, from blue through red. The colour is based on the chemistry, which involves a substrate molecule called luciferin, the source of energy that goes into light, and an enzyme called luciferase or photoprotein. 

Most of this lighting up of our world happens on land or in saltwater. There are almost no bioluminescent organisms native to freshwater.

In terrestrial plants and animals — fireflies, beetles and fungi like this Ghost Fungus, Omphalotus nidiformis, a gilled basidiomycete mushroom — we commonly find green, yellow, and sometimes red. 

In the ocean, bioluminescence is mostly blue-green or green. You would think that blues and green would not show up all that well in our seas but, surprisingly, they do. While sound travels better through saltwater than air, it is the reverse for light. 

Various colours of light do not transmit equally through saltwater. Once we move deeper than the top layer of the ocean warmed by the sun and brimming with nutrients, the epipelagic zone, and move deeper through the mesopelagic, deeper and deeper still to the bathypelagic, frigid abyssalpelagic and finally the deep trenches of the icy pressure and all but inhospitable hadalpelagic, less and less light — until no light — gets through.

It is the twilight of the mesopelagic, 200 - 1000 metres below the surface, that is the sweet spot for most of our bioluminescent friends. Here, only very faint sunlight gets through. The water pressure is higher than at the surface but still lacks the crushing intensity of the lower zones. It is here that bioluminescence becomes a real advantage — good real estate and the showmanship of light pays gold.

We know that the deeper you go in our oceans, less and less sunlight gets through, so if the purpose of bioluminescence is to provide a signal that is noticed by prey, potential mates and predators alike, it is important that the light moves through the seawater, and not be absorbed or scattered — and this plays out in the colours evolved to be seen here. 

If you have spent any time underwater, you will know that blue-green light transmits best through seawater. The deeper you go, the colours fade. Gone are the reds and yellows until everything looks brown or blue-green. Because of this, it is no surprise that blue-green is the most common colouring of bioluminescence in our oceans. 

There are some exceptions to the blue-green/green colour rule — minuscule planktonic polychaete worms, Tomopteris helgolandica, emit yellow light, and deep-sea fish Malacosteus niger in the family Stomiidae, the barbeled dragonfishes, produce both red and blue. 

Malacosteus niger's unique adaptation of producing red bioluminescence is only found in two other deep-sea dwelling creatures, Aristostomias and Pachystomias

This rare form of bioluminescence can reach up to 700 nm in the deep-sea and cannot be perceived by green and blue bioluminescent organisms — granting M. niger a considerable advantage while hunting at depth.

The red light may function as an invisible searchlight of sorts because most animals in the ocean cannot see red light, while the eyes of M. niger are red-sensitive. It is much easier to find and eat something that cannot see you, particularly if it is lit up like a tasty red holiday snack.

Reference: https://latzlab.ucsd.edu/bioluminescence/

Sunday, 22 December 2024

ANCIENT ARAGONITE: FOSSIL PEARLS

One of my favourite pairs of earrings are a simple set of pearls. I have worn them pretty much every day since 2016 when I received them as a gift. What is it about pearls that makes them so appealing? I am certainly not alone in this. 

A simple search will show you a vast array of pearls being used for their ornamental value in cultures from all over the world. I suppose the best answer to why they are appealing is just that they are

If you make your way to Paris, France and happen to visit the Louvre's Persian Gallery, do take a boo at one of the oldest pearl necklaces in existence — the Susa necklace. It hails from a 2,400-year-old tomb of long lost Syrian Queen. It is a showy piece with three rows of 72 pearls per strand strung upon a bronze wire. 

A queen who truly knew how to accessorize

I imagine her putting the final touches of her outfit together, donning the pearls and making an entrance to wow the elite of ancient Damascus. The workmanship is superb, intermixing pure gold to offset the lustre of the pearls. It is precious and ancient, crafted one to two hundred years before Christ. Perhaps a gift from an Egyptian Pharaoh or from one of the Sumerians, Eblaites, Akkadians, Assyrians, Hittites, Hurrians, Mitanni, Amorites or Babylonian dignitaries who sued for peace but brought war instead. 

Questions, good questions, but questions without answers. So, what can we say of pearls? We do know what they are and it is not glamorous. Pearls form in shelled molluscs when a wee bit of sand or some other irritant gets trapped inside the shell, injuring the flesh. As a defensive and self-healing tactic, the mollusc wraps it in layer upon layer of mother-of-pearl — that glorious shiny nacre that forms pearls. 

They come in all shapes and sizes from minute to a massive 32 kilograms or 70 pounds. While a wide variety of our mollusc friends respond to injury or irritation by coating the offending intruder with nacre, there are only a few who make the truly gem-y pearls. 

These are the marine pearl oysters, Pteriidae and a few freshwater mussels. Aside from Pteriidae and freshwater mussels, we sometimes find less gem-y pearls inside conchs, scallops, clams, abalone, giant clams and large marine gastropods.

Pearls are made up mostly of the carbonate mineral aragonite, a polymorphous mineral — the same chemical formula but different crystal structure — to calcite and vaterite, sometimes called mu-calcium carbonate. These polymorphous carbonates are a bit like Mexican food where it is the same ingredients mixed in different ways. Visually, they are easy to tell apart — vaterite has a hexagonal crystal system, calcite is trigonal and aragonite is orthorhombic.

As pearls fossilize, the aragonite usually gets replaced by calcite, though sometimes by vaterite or another mineral. When we are very lucky, that aragonite is preserved with its nacreous lustre — that shimmery mother-of-pearl we know and love.  

Molluscs have likely been making pearls since they first evolved 530 million years ago. The oldest known fossil pearls found to date, however, are 230-210 million years old. 

This was the time when our world's landmass was concentrated into the C-shaped supercontinent of Pangaea and the first dinosaurs were calling it home. In the giant ancient ocean of Panthalassa, ecosystems were recovering from the high carbon dioxide levels that fueled the Permian extinction. Death begets life. With 95% of marine life wiped out, new species evolved to fill each niche.  

While this is where we found the oldest pearl on record, I suspect we will one day find one much older and hopefully with its lovely great-great grandmother-of-pearl intact. 

Wednesday, 18 December 2024

CHARLES DARWIN: A TASTE FOR STUDIES

Chelonia. Schildkröten by Ernst Haeckel, 1904
Care for some tarantula with that walrus? No? how about some Woolly mammoth?

While eating study specimens is not de rigueur today, it was once common practice for researchers in the 1700-1880s. 

The English naturalist, Charles Darwin belonged to an elite men's club dedicated to tasting exotic meats. In his first book, Darwin wrote almost three times as much about dishes like armadillo and tortoise urine as he did on the biogeography of his Galapagos finches. 

From his great love of gastronomy, I am surprised any of his tasty specimens made it back from his historic voyage on the HMS Beagle — particularly the turtles.

One of the most famous scientific meals occurred one Saturday evening on the 13th of January, 1951. This was at the 47th Explorers Club Annual Dinner (ECAD) when members purportedly dined on a frozen woolly mammoth. 

Commander Wendell Phillips Dodge was the promotor of the banquet. He sent out press notices proclaiming the event's signature dish would be a selection of prehistoric meat. Whether Dodge did this simply to gain attendees or play a joke remains a mystery. 

The prehistoric meat was supposedly found at Woolly Cove on Akutan in the Aleutians Islands of Alaska, USA, by the eminent polar explorers' Father Bernard Rosecrans Hubbard, American geologist, explorer sometimes called the Glacier Priest, and polar explorer Captain George Francis Kosco of the United States Navy.

Fried Tarantula & Goat Eyeballs

This much-publicized meal captured the public’s imagination and became an enduring legend and source of pride for the Club, popularizing an annual menu of exotics that continues today. The Club is well-known for its notorious hors d’oeuvres like fried tarantulas and goat eyeballs as it is for its veritable whose who of notable members — Teddy Roosevelt, Neil Armstrong, Buzz Aldrin, Roy Chapman Andrews, Thor Heyerdahl, James Cameron.

The Yale Peabody Museum holds a sample of meat preserved from the 1951 meal, interestingly labelled as a South American Giant Ground Sloth, Megatherium, not Mammoth. The specimen of meat from that famous meal was originally designated BRCM 16925 before a transfer in 2001 from the Bruce Museum to the Yale Peabody Museum of Natural History (New Haven, CT, USA) where it gained the number YPM MAM 14399.

The specimen is now permanently deposited in the Yale Peabody Museum with the designation YPM HERR 19475 and is accessible to outside researchers. The meat was never fixed in formalin and was initially stored in isopropyl alcohol before being transferred to ethanol when it arrived at the Peabody Museum. DNA extraction occurred at Yale University in a clean room with equipment reserved exclusively for aDNA analyses.

In 2016, Jessica Glass and her colleagues sequenced a fragment of the mitochondrial cytochrome-b gene and studied archival material to verify its identity, which if genuine, would extend the range of Megatherium over 600% and alter views on ground sloth evolution. 

Mammoth, Megatherium — Green Sea Turtle

Their results showed that the meat was not Mammoth or Megatherium, but a bit of Green Sea Turtle, Chelonia mydas. So much for elaborate legends. The prehistoric dinner was likely meant as a publicity stunt. 

Glass's study emphasizes the value of museums collecting and curating voucher specimens, particularly those used for evidence of extraordinary claims. Not so long before Glass et al. did their experiment, a friend's mother (and my kayaking partners) served up a venison steak from her freezer to dinner guests in Castlegar that hailed from 1978. Tough? Inedible? I have it on good report that the meat was surprisingly divine.

Reference: Glass, J. R., Davis, M., Walsh, T. J., Sargis, E. J., & Caccone, A. (2016). Was Frozen Mammoth or Giant Ground Sloth Served for Dinner at The Explorers Club?. PloS one, 11(2), e0146825. https://doi.org/10.1371/journal.pone.0146825

Image: Chelonia. Schildkröten by Ernst Haeckel, 1904, Prints & Photographs Division, Library of Congress, LC-DIG-ds-07619.

Join the Explorer's Club

Fancy yourself an explorer who should join the club? Here is a link to their membership application. The monied days of old are still inherent, but you will be well pleased to learn you can now join for as little as $50 US.

Link: https://www.explorers.org/wp-content/uploads/Membership-Application_2021-11-19.pdf

Tuesday, 26 November 2024

BARNACLES: CUVIER TO DARWIN

Barnacles All Closed Up
One of the most interesting and enigmatic little critters we find at the seashore are barnacles. 

They cling to rocks at the waters' edge, closed to our curiosity, their domed mounds like little closed beaks shut to the water and the world.

They choose their permanent homes as larvae, sticking to hard substrates that will become their permanent homes for the rest of their lives. It has taken us a long time to find how they actually stick or what kind of "glue" they were using.

A clever fellow from Duke University's Marine Laboratory in Durhan, North Carolina finally cracked that puzzle. Instead of chopping up barnacles to see what makes them stick, he observed and collected the oozing glue from some Amphibalanus amphitrite as they secreted it.

Remarkably, the barnacle glue sticks to rocks in a similar way to how red cells bind together. Red blood cells bind and clot with a little help from some enzymes. These work to create long protein fibres that first blind, clot then form a scab. The mechanism barnacles use, right down to the enzyme, is very similar. That's especially interesting as about a billion years separate our evolutionary path from theirs.

So, with the help of their clever enzymes, they can affix to most anything – ship hulls, rocks, and even the skin of whales. If you find them in tidepools, you begin to see their true nature as they open up, their delicate feathery finger-like projections flowing back and forth in the surf.

Barnacle Cirri Seeking Tasty Plankton
Those wee feather-like bits you see are called cirri. Eight pairs of these thoracic limbs help barnacles to filter tasty bits of plankton from the surrounding water into their mouths.

Barnacles are cirripedes, a kind of crustacean that is covered with hard plates of calcium carbonate. Named for their cirri, they live stuck to hard surfaces in and around our world's oceans. While they do not look like crustaceans, they are definitely part of this taxonomic grouping that includes crab, lobster, crayfish, prawn, krill, and woodlice.

BARNACLES IN KWAK'WALA

In the Kwak̓wala language of the Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, barnacles are known as k̕wit̕a̱'a and broken barnacle shells are known as t̕sut̕su'ma.

BARNACLES IN THE FOSSIL RECORD

They have an old history. Their ancestors can be traced back to animals such as Priscansermarinus that lived during the Middle Cambrian – some 510 to 500 million years ago. I found my first barnacle fossil at a fossil site called Muir Creek on the south end of Vancouver Island. The fossil exposures at Muir are Oligocene, 20-25 million years old. This is about the time that barnacles can be found more readily as skeletal remains.

One of the reasons for the limited number of barnacle remains in the fossil record is their preferred habitat – high energy, shallow ocean environments. These tend to see a lot of tidal action that leads to erosion and barnacles being broken apart, slowly eroded down to bits too small to recognize for what they are.

One of the fossil remains we do find are not the barnacles themselves, but trace fossils of acrothoracican barnacle borings from Rogerella. These are commonly found in the fossil record beginning in the Devonian right up to today. Rogerella is a small pouch-shaped boring (a type of trace fossil) with a slit-like aperture currently produced by acrothoracican barnacles. 

These crustaceans extrude their legs upwards through the opening for filter-feeding (Seilacher, 1969; Lambers and Boekschoten, 1986). They are known in the fossil record as borings in carbonate substrates (shells and hardgrounds) from the Devonian to the Recent (Taylor and Wilson, 2003).

Barnacle Ancestry Goes Back to the Middle Cambrian
FROM MOLLUSCA TO ARTICULATA

Barnacles were originally classified by Linnaeus and Cuvier as Mollusca, but in 1830 John Vaughan Thompson published observations showing the metamorphosis of the nauplius and cypris larvae into adult barnacles. He noted how these larvae were similar to those of crustaceans.

In 1834 Hermann Burmeister published further information, reinterpreting these findings. The effect was to move barnacles from the phylum of Mollusca to Articulata, showing naturalists that detailed study was needed to reevaluate their taxonomy.

Charles Darwin took up this challenge in 1846 and developed his initial interest in a major study published as a series of monographs in 1851 and 1854. Darwin undertook this study, at the suggestion of his friend Joseph Dalton Hooker, to thoroughly understand at least one species before making the generalizations needed for his theory of evolution by natural selection.

BARNACLES IN A NUT SHELL

Barnacles are suspension feeders, sweeping small food into their mouth with their curved 'feet'. They are cemented to rock (usually), and covered with hard calcareous plates, which they shut firmly when the tide goes out. The barnacles reproduce sexually and produce little nauplius larvae that disperse in the plankton. Eventually, the larvae change into cypris form and attach on other hard surfaces to form new barnacles.

Friday, 22 November 2024

NUU-CHAH-NULTH FIRST NATIONS, HISTORY AND FOSSILS ON CANADA'S WEST COAST

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


Monday, 18 November 2024

RAISE YOUR CLAWS: WARRIOR CRABS

Look how epic this little guy is! 

He is a crab — and if you asked him, the fiercest warrior that ever lived. While that may not be strictly true, crabs do have the heart of a warrior and will raise their claws, sometimes only millimetres into the air, to assert dominance over their world. 

Crabs are decapod crustaceans of the Phylum Arthropoda. 

In the Kwak'wala language of the Kwakwaka'wakw of the Pacific Northwest, this brave fellow is ḵ̓u'mis — both a tasty snack and familiar to the supernatural deity Tuxw'id, a female warrior spirit. Given their natural armour and clear bravery, it is a fitting role.

They inhabit all the world's oceans, sandy beaches, many of our freshwater lakes and streams. Some few prefer to live in forests.

Crabs build their shells from highly mineralized chitin — and chitin gets around. It is the main structural component of the exoskeletons of many of our crustacean and insect friends. Shrimp, crab, and lobster all use it to build their exoskeletons.

Chitin is a polysaccharide — a large molecule made of many smaller monosaccharides or simple sugars, like glucose. 

It is handy stuff, forming crystalline nanofibrils or whiskers. Chitin is actually the second most abundant polysaccharide after cellulose. It is interesting as we usually think of these molecules in the context of their sugary context but they build many other very useful things in nature — not the least of these are the hard shells or exoskeletons of our crustacean friends.

Crabs in the Fossil Record

The earliest unambiguous crab fossils date from the Early Jurassic, with the oldest being Eocarcinus from the early Pliensbachian of Britain, which likely represents a stem-group lineage, as it lacks several key morphological features that define modern crabs. 

Most Jurassic crabs are only known from dorsal — or top half of the body — carapaces, making it difficult to determine their relationships. Crabs radiated in the Late Jurassic, corresponding with an increase in reef habitats, though they would decline at the end of the Jurassic as the result of the decline of reef ecosystems. Crabs increased in diversity through the Cretaceous and represented the dominant group of decapods by the end.

We find wonderful fossil crab specimens on Vancouver Island. The first I ever collected was at Shelter Point, then again on Hornby Island, down on the Olympic Peninsula and along Vancouver Island's west coast near Nootka Sound. They are, of course, found globally and are one of the most pleasing fossils to find and aggravating to prep of all the specimens you will ever have in your collection. Bless them.


Wednesday, 6 November 2024

LIVING FOSSILS: MASTERS OF MASS EXTINCTION EVENTS

Horseshoe crabs are marine and brackish water arthropods of the order Xiphosura — a slowly evolving, conservative taxa.

Much like (slow) Water Striders (Aquarius remigis), (relatively sluggish) Coelacanth (Latimeria chalumnae) and (the current winner on really slow evolution) Elephant Sharks (Callorhinchus milii), these fellows have a long history in the fossil record with very few anatomical changes. 

But slow change provides loads of great information. It makes our new friend, Yunnanolimulus luoingensis, an especially interesting and excellent reference point for how this group evolved. 

We can examine their genome today and make comparisons all the way back to the Middle Triassic (with this new find) and other specimens from further back in the Ordovician — 445 million years ago. 

These living fossils have survived all five mass extinction events. They are generalists who can live in shallow or deep water and will eat pretty much anything they can find on the seafloor.

The oldest horseshoe crab fossil, Lunataspis aurora, is found in outcrops in Manitoba, Canada. Charmingly, the name means crescent moon shield of the dawn. It was palaeontologist Dave Rudkin and team who chose that romantic name. Finding them as fossils is quite remarkable as their shells are made of protein which does not mineralized like typical fossils.

Even so, the evolution of their exoskeleton is well-documented by fossils, but appendage and soft-tissue preservation are extremely rare. 

A new study analyzes details of the appendage and soft-tissue preservation in Yunnanolimulus luoingensis, a Middle Triassic (ca. 244 million years old) horseshoe crab from Yunnan Province, SW China. The remarkable anatomical preservation includes the chelicerae, five pairs of walking appendages, opisthosomal appendages with book gills, muscles, and fine setae permits comparison with extant horseshoe crabs.

The close anatomical similarity between the Middle Triassic horseshoe crabs and their recent analogues documents anatomical conservatism for over 240 million years, suggesting persistence of lifestyle.

The occurrence of Carcinoscorpius-type claspers on the first and second walking legs in male individuals of Y. luoingensis tells us that simple chelate claspers in males are plesiomorphic for horseshoe crabs, and the bulbous claspers in Tachypleus and Limulus are derived.

As an aside, if you hadn't seen an elephant shark before and were shown a photo, you would likely say, "that's no freaking shark." You would be wrong, of course, but it would be a very clever observation.

Callorhinchus milii look nothing like our Great White friends and they are not true sharks at all. Rather, they are ghost sharks that belong to the subclass Holocephali (chimaera), a group lovingly known as ratfish. They diverged from the shark lineage about 400 million years ago.

If you have a moment, do a search for Callorhinchus milii. The odd-looking fellow with the ironic name, kallos, which means beautiful in Greek, sports black blotches on a pale silver elongate body. And their special feature? It is the fishy equivalent of business in the front, party in the back, with a dangling trunk-like projection at the tip of their snout and well-developed rectal glands near the tail.

As another small point of interest with regards to horseshoe crabs, John McAllister collected several of these while working on his MSc to see if they had microstructures similar to trilobites (they do) and whether their cuticles were likewise calcified. He found no real calcification in their cuticles, in fact, he had a rather frustrating time getting anything measurable to dissolve in acid in his hunt for trace elements. 

Likewise, when looking at oxygen isotopes (16/18) to get a handle on water salinity and temperature, his contacts at the University of Waterloo had tons of fun getting anything at all to analyze. It made for some interesting findings. Sadly, for a number of reasons, he abandoned the work, but you can read his very interesting thesis here: https://dr.library.brocku.ca/handle/10464/1959

Ref: Hu, Shixue & Zhang, Qiyue & Feldmann, Rodney & Benton, Michael & Schweitzer, Carrie & Huang, Jinyuan & Wen, Wen & Zhou, Changyong & Xie, Tao & Lü, Tao & Hong, Shuigen. (2017). Exceptional appendage and soft-tissue preservation in a Middle Triassic horseshoe crab from SW China. Scientific Reports. 7. 10.1038/s41598-017-13319-x.

Tuesday, 5 November 2024

CTENOPHORES: COMB JELLIES

Cannibalistic Comb Jellies
This festive lantern looking lovely belongs to a group of invertebrates known as comb jellies.

Comb jellies are named for their unique plates of giant fused cilia, or combs, which run in eight rows up and down the length of their bodies. They are armed with sticky cells or colloblasts, that do not sting but display wonderful bioluminescent colouring as they move through the sea.

Ctenophores or comb jellies are one of the phylogenetically most important and controversial metazoan groups. They are not jellyfish and are not closely related, though they do share some characteristics with the gelatinous members of the subphylum Medusozoa. 

Comb jellies are not picky eaters. Their tastes range to what is at hand, including cannibalizing other comb jellies. They will feast on their kin along with tasty plankton, zooplankton, crustaceans and wee fish.

Interest in their fossil record has been catalysed by spectacularly preserved soft-bodied specimens from Cambrian Lagerstätten of the 518-million-years-old Chengjiang Biota, the 505-million-years-old Burgess Shale and other Burgess Shale-like deposits. 

We find them in the Late Devonian Escuminac Formation at Miguasha National Park, Quebec, Canada — a UNESCO world heritage site famous for its abundance of well-preserved vertebrate fossils including most major evolutionary groups of Devonian lower vertebrates from jawless fish to stem-tetrapods.

Based on morphological similarities of this Canadian fossil with stem-ctenophore fossils from the Cambrian Lagerstätte of the Chinese locality Chengjiang, they have been assessed for their affinity to stem-group ctenophores (dinomischids, Siphusauctum, scleroctenophorans) and early crown-group ctenophores. Modern ctenophores and many fossil forms lack mineralized hard parts, which renders the rare fossils that have been extracted from several Lagerstätten quite remarkable. 

Like the soft bodies of jellyfish and the polyps of hydrozoans and anthozoans, the probability for such soft bodies (or body regions) to become fossilized is extremely low. In spite of this low preservation potential, remains of stem-ctenophores have become known from several Cambrian and younger conservation deposits, and with even older candidate ctenophores in the Ediacaran. 

While Cambrian Lagerstätten have yielded several genera, ctenophore remains are much rarer in the Devonian; in particular, two studies, describing material from the German Hunsrück Slate. 

Bioluminescent Comb Jellies
This Early Devonian material, however, appears to belong to crown ctenophores morphologically similar to living forms such as Pleurobrachia, unlike the stem Cambrian taxa and the new Devonian stem taxon described here.

The most basal stem ctenophores are the dinomischids: sessile benthic petaloid invertebrates, many of which are equipped with a stalk. This group first was described from the Middle Cambrian Burgess Shale. Based on the genus Dinomischus, these early stalked forms were commonly called ‘dinomischids’. 

Zhao et al. shared that dinomischids "form a grade in the lower part of the ctenophore stem group” and include taxa such as Xianguangia, Daihua, and Dinomischus that have hexaradiate-based symmetry (e.g., sixfold, 18-fold). 

Some later, skeletonised stem-ctenophores were termed ‘Scleroctenophora’; ‘scleroctenophorans’ have a shorter stalk, lack the ‘petals’ and have no bracts and might be monophyletic. 

To date, all known dinomischids and scleroctenophorans are Cambrian. Remarkably, analysis of the material described here suggests it is a very late-surviving member of this part of the ctenophore tree, occurring in strata over a hundred million years younger with no intervening known record, thus making it a Lazarus taxon with an extensive ghost lineage. 

Palaeozoic sediments yield a growing number of fossil invertebrates with radial symmetries, some being quite enigmatic with body plans differing radically from those of extant organisms.

The morphological similarities to Cambrian forms and the mix of characters regarding overall shape and symmetries render this discovery important. The aims of this study are to describe the only known specimen of this Devonian ctenophore, discuss its phylogenetic and systematic position, and the impact of fossil data for ctenophore affinities, and assess its palaeoecological role.