Showing posts with label fossil. Show all posts
Showing posts with label fossil. Show all posts

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.

Friday, 1 November 2024

SHONISAURUS OF NEVADA

The beauties you see here are ichthyosaurs. The largest of their lineage is the genus Shonisaurus who ruled our ancient seas 217 million years ago.

At least 37 incomplete fossil specimens of the marine reptile have been found in hard limestone deposits of the Luning Formation, in far northwestern Nye County of Nevada. This formation dates to the late Carnian age of the late Triassic period when present-day Nevada and parts of the western United States were covered by an ancient ocean.

The first researcher to recognize the Nevada fossil specimens as ichthyosaurs was Siemon W. Muller of Stanford University. He had the work of Sir Richard Owen and others to build on. That being said, there are very few contenders for a species that boasts vertebrae over a foot wide and weighing in at almost 10 kg or 21 lbs. Muller contacted the University of California Museum of Paleontology at Berkeley. Surface collecting by locals continued at the site but no major excavation was planned.

Sir Richard Owen, the British biologist, comparative anatomist and paleontologist, coined the name ichthyopterygia, or "fish flippers," one hundred and fourteen years earlier, but that wee bit of scientific knowledge hadn't made its way west to the general population. The finds at Luning were still, "marine monsters."

Owen, too, was building on research going back to 1699, the very first recorded fossil fragments found of these beasties in Wales. Shortly thereafter, fossil vertebrae were published in 1708 from the Lower Jurassic.

The first complete skeleton was discovered in the early 19th century by Mary Anning and her brother Joseph along the Dorset Jurassic Coast. Mary's find was described by a British surgeon, Sir Everard Home, an elected Fellow of the Royal Society, in 1814. The specimen is now on display at the Natural History Museum in London bearing the name Temnodontosaurus platyodon, or “cutting-tooth lizard.”

In 1821, William Conybeare and Henry De La Beche, a friend of Mary's, published a paper describing three new species of unknown marine reptiles based on the Anning's finds. The Rev. William Buckland would go on to describe two small ichthyosaurs from the Lias of Lyme Regis, Ichthyosaurus communis and Ichthyosaurus intermedius. All of this early work was instrumental in aiding the researchers who would join the project at Luning.

Owen is considered to have been an outstanding naturalist with a remarkable gift for interpreting fossils. Contrary to common belief, advanced study does help with identifying fossils, but what is truly needed is a keen eye. The finds at Luning were blessed to be seen by an enthusiastic local with just that right kind of keen eye.

Almost a quarter of a century after Muller's initial reports, Dr. Charles L. Camp from UCMP received correspondence further detailing the finds from a lovely Mrs. Margaret Wheat of Fallon. She wrote to Camp in September of 1928 to say that she'd been giving the quarry section a bit of a sweep, as you do, and had uncovered a nice aligned section of vertebrae with her broom. The following year, Dr. Charles L. Camp went out to survey the finds and began working on the specimens, his first field season of many, in 1954.

Back in the 1950s, these large marine reptiles were rumoured to be "marine monsters," as the concept of an ichthyosaur was not well understood by the local townsfolk. Excitement soon hit West Union Canyon as the quarry began to reveal the sheer size of these mighty beasts. Four of the specimens were fully excavated. Most of the ichthyosaur bones were left in situ, partially because the work was tremendously difficult, and partially to allow others to see how the specimens were laid down over 200 million years ago.

Camp continued to work with Wheat at the site and brought on Sam Welles and a host of students to help with excavations. The team understood the need for protection at the site. They canvassed the Nevada Legislature to establish the Ichthyosaur Paleontological State Monument. You can see one of the Park Rangers above giving a tour within the lovely Fossil Hut building they built on the site to protect the fossils.

In 1957, the site was incorporated into the State Park System and Berlin-Ichthyosaur State Park was born. The park Twenty years later, in 1977, the population of Nevada weighed in and the Legislature designated Shonisaurus popularis as the State Fossil of Nevada. Visitors are welcome to collect fossils from the exposures of the Upper Triassic (Early Norian, Kerri Zone) of the Luning Formation, West Union Canyon, just outside Berlin-Ichthyosaur State Park.

Address: State route 844, Austin, NV 89310, United States. Area: 4.58 km². Open 24 hours;
Elevation: 6,975 ft (2,126 m); Tel: +1 775-964-2440; http://parks.nv.gov/parks/berlin-ichthyosaur

Tuesday, 29 October 2024

SAKARA MADAGASGAR: OXFORDIAN OUTCROPS

This big beastie is a superb specimen of the ammonite Lobolytoceras costellatum showing the intricate fractal pattern of its septa. 

This lovely measures to a whopping 230 mm and hails from Oxfordian outcrops near Sakara, Madagascar. Lovingly prepped by the supremely talented José Juárez Ruiz.

Ammonites were predatory, squidlike 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. Ammonites did the equivalent, catching prey in their tentacles. They 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) then they are to shelled nautiloids such as the living Nautilus species.

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.

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.

Monday, 28 October 2024

SMILODON NORTH OF THE 49TH PARALLEL

This fierce predator with the luxurious coat is Smilodon fatalis — a compact but robust killer that weighed in around 160 to 280 kg and was 1.5 - 2.2 metres long.

Smilodon is a genus of the extinct machairodont subfamily of the felids. It is one of the most famous prehistoric mammals and the best known saber-toothed cat. Although commonly known as the saber-toothed tiger, it was not closely related to the tiger or other modern cats.

Up until a few years ago, all the great fossil specimens of this apex predator were found south of us in the United States. That was until some interesting bones from Medicine Hat, Alberta got a second look.

A few years ago, a fossil specimen caught the eye of researcher Ashley Reynolds as she was rummaging through the collections at the Royal Ontario Museum in Toronto. 

Back in the 1960s,  University of Toronto palaeontologist C.S. Churcher and his team had collected and donated more than 1,200 specimens from their many field seasons scouring the bluffs of the South Saskatchewan River near Medicine Hat, Alberta.

Churcher is a delightful storyteller and a palaeontologist with a keen eye. I had the very great pleasure of listening to many of his talks out at the University of British Columbia and a few Vancouver Paleontological Society meetings in the mid-2000s. 

"Rufus" was a thoroughly charming storyteller and shared many of his adventures from the field. 

He moved out to the West Coast for his retirement, first to Gabriola Island then to Victoria, but his keen love of the science kept him giving talks to enthralled listeners keen to hear about his survey of the Dakhleh Oasis in the Western Desert of Egypt, geomorphology, stratigraphy, recent biology, Pleistocene and Holocene lithic cultures, insights learned from Neolithic Islamic pottery to Roman settlements.

The specimens he had collected had been roughly sorted but never examined in detail. Reynolds, who was researching the growth patterns and life histories of extinct cats saw a familiar-looking bone from an ancient cat's right front paw. That tiny paw bone had reached through time and was positively identified as Canada's first Smilodon.

These Apex Predators used their exceptionally long upper canine teeth to hunt large mammals. 

Isotopes preserved in the bones of S. fatalis in the La Brea Tar Pits in California tell us that they liked to dine on bison (Bison antiquus) and camels (Camelops) along with deer and tapirs. Smilodon is thought to have killed its prey by holding it still with its forelimbs and biting it. And that was quite the bite!

Their razor-sharp incisors were arranged in an arch. Once they bit down, the teeth would hold their prey still and stabilize it while the canine bite was delivered — and what a bite that was. They could open their mouths a full 120 degrees.

Smilodon died out at the same time that most North and South American megafauna disappeared, about 10,000 years ago. Its reliance on large animals has been proposed as the cause of its extinction, along with climate change and competition with other species. 

Thursday, 24 October 2024

BRONZE BEAUTY: EIFELIAN PARALEJURUS

This bronzed beauty is the Middle Devonian, Eifelian (~395 mya) trilobite, Paralejurus rehamnanus (Alberti, 1970) from outcrops near Issoumour, Alnif, Morocco in North Africa. 

It was the colour of this amazing trilobite that captured the eye of David Appleton in whose collection it now resides. He is an avid collector and coming into his own as a macro photographer. I have shared three of his delightful photos for you here.

It initially thought that the gold we see here was added during prep, particularly considering the colouration of the matrix, but macro views of the surface show mineralization and the veins running right through the specimen into the matrix. There is certainly some repairs but that is common in the restoration of these specimens. Many of the trilobites I have seen from Morocco have bronze on black colouring but not usually this pronounced. Even so, there is a tremendous amount of fine anatomy to explore and enjoy in this wonderfully preserved specimen.  

Paralejurus is a genus of trilobite in the phylum Arthropoda from the Late Silurian to the Middle Devonian of Africa and Europe. These lovelies grew to be up to nine centimetres, though the fellow you see here is a wee bit over half that size at 5.3 cm. 

Paralejurus specimens are very pleasing to the eye with their long, oval outline and arched exoskeletons. 

Their cephalon or head is a domed half circle with a smooth surface.  The large facet eyes have very pleasing crescent-shaped lids. You can see this rather well in the first of the photos here. The detail is quite remarkable.

As you move down from his head towards the body, there is an almost inconspicuous occipital bone behind the glabella in the transition to his burnt bronze thorax.

The body or thorax has ten narrow segments with a clearly arched and broad axial lobe or rhachis. The pygidium is broad, smooth and strongly fused in contrast to the genus Scutellum in the family Styginidae, which has a pygidium with very attractive distinct furrows that I liken to the look of icing ridges on something sweet — though that may just be me and my sweet tooth talking. In Paralejurus, they look distinctly fused — or able to fuse — to add posterior protection against predators with both the look and function of Roman armour.

In Paralejurus, the axillary lobe is rounded off and arched upwards. It is here that twelve to fourteen fine furrows extend radially to complete the poetry of his body design. 

Trilobites were amongst the earliest fossils with hard skeletons and they come in many beautiful forms. While they are extinct today, they were the dominant life form at the beginning of the Cambrian. 

As a whole, they were amongst some of the most successful of all early animals — thriving and diversifying in our ancient oceans for almost 300 million years. The last of their brethren disappeared at the end of the Permian — 252 million years ago. Now, we enjoy their beauty and the scientific mysteries they reveal about our Earth's ancient history.

Photos and collection of the deeply awesome David Appleton. Specimen: 5.3 cm. 

Sunday, 20 October 2024

ALCIDS AUKS: PUFFLINGS AND DUTIFUL PARENTS

Puffins are any of three small species of alcids or auks in the bird genus Fratercula with a brightly coloured beak during the breeding season.

Their sexy orange beaks shift from a dull grey to bright orange when it is time to attract a mate. While not strictly monogamous, most Puffins choose the same mate year upon year producing adorable chicks or pufflings (awe) from their mating efforts.

Female Puffins produce one single white egg which the parents take turns to incubate over a course of about six weeks. Their dutiful parents share the honour of feeding the wee pufflings five to eight times a day until the chick is ready to fly. Towards the end of July, the fledgeling Puffins begin to venture from the safety of their parents and dry land. Once they take to the seas, mom and dad are released from duty and the newest members of the colony are left to hunt and survive on their own.

These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crevices among rocks or in burrows in the soil. Two species, the tufted puffin and horned puffin are found in the North Pacific Ocean, while the Atlantic puffin is found in the North Atlantic Ocean. 

This lovely fellow, with his distinctive colouring, is an Atlantic Puffin or "Sea Parrot" from Skomer Island near Pembrokeshire in the southwest of Wales. Wales is bordered by Camarthenshire to the east and Ceredigion to the northeast with the sea bordering everything else. It is a fine place to do some birding if it's seabirds you're after.

These Atlantic Puffins are one of the most famous of all the seabirds and form the largest colony in Southern Britain. They live about 25 years making a living in our cold seas dining on herring, hake and sand eels. Some have been known to live to almost 40 years of age. They are good little swimmers as you might expect, but surprisingly they are great flyers, too! They are hindered by short wings, which makes flight challenging but still possible with effort. Once they get some speed on board, they can fly up to 88 km an hour.

The oldest alcid fossil is Hydrotherikornis from Oregon dating to the Late Eocene while fossils of Aethia and Uria go back to the Late Miocene. Molecular clocks have been used to suggest an origin in the Pacific in the Paleocene. Fossils from North Carolina were originally thought to have been of two Fratercula species but were later reassigned to one Fratercula, the tufted puffin, and a Cerorhinca species. Another extinct species, Dow's puffin, Fratercula dowi,  was found on the Channel Islands of California until the Late Pleistocene or early Holocene.

The Fraterculini are thought to have originated in the Pacific primarily because of their greater diversity in the region. There is only one extant species in the Atlantic, compared to two in the Pacific. The Fraterculini fossil record in the Pacific extends at least as far back as the middle Miocene, with three fossil species of Cerorhinca, and material tentatively referred to that genus, in the middle Miocene to late Pliocene of southern California and northern Mexico.

Although there no records from the Miocene in the Atlantic, a re-examination of the North Carolina material indicated that the diversity of puffins in the early Pliocene was as great in the Atlantic as it is in the Pacific today. This diversity was achieved through influxes of puffins from the Pacific; the later loss of species was due to major oceanographic changes in the late Pliocene due to closure of the Panamanian Seaway and the onset of severe glacial cycles in the North Atlantic.

Wednesday, 16 October 2024

NEVADA: AMMONOIDS AND CONODONTS

Nevada is a wonderful place to explore our palaeontological history. The state spans a broad spectrum of exposures showcasing the depth of geologic time. It is an interesting cross-section of young and old — and interestingly, a lovely comparison to the Triassic outcrops in British Columbia.

Exposures of the Upper Triassic, Early Norian, Kerri zone, Luning formation, West Union Canyon, just outside Berlin-Ichthyosaur State Park, Nevada.

The Berlin-Ichthyosaur State Park in central Nevada is a very important locality for the understanding of the Carnian-Norian boundary (CNB) in North America.

Rich ammonoid faunas from this site within the Luning Formation were studied by Silberling (1959) and provided support for the definition of the Schucherti and Macrolobatus zones of the latest Carnian, which are here overlain by well-preserved faunas of the earliest Norian Kerri Zone. Despite its importance, no further investigations have been done at this site during the last 50 years.

Jim Haggart, Mike Orchard and Paul Smith collaborated on a project that took them down to Nevada to look at the conodonts and ammonoids; the group then published a paper, "Towards the definition of the Carnian/Norian Boundary: New data on Ammonoids and Conodonts from central Nevada," which you can find in the proceedings of the 21st Canadian Paleontology Conference; by Haggart, J W (ed.); Smith, P L (ed.); Canadian Paleontology Conference Proceedings no. 9, 2011 p. 9-10.

They conducted a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October 2010. The eastern side of the canyon provides the best record of the Macrolobatus Zone, which is represented by several beds yielding ammonoids of the Tropites group, together with Anatropites div. sp. conodont faunas from both these and higher beds are dominated by ornate 'metapolygnthids' that would formerly have been collectively referred to Metapolygnathus primitius, a species long known to straddle the CNB. Within this lower part of the section, they resemble forms that have been separated as Metapolygnathus mersinensis. Slightly higher, forms close to 'Epigondolella' orchardi and a single 'Orchardella' n. sp. occur. This association can be correlated with the latest Carnian in British Columbia.

Ammonoids of the Luning Formation
Higher in the section, the ammonoid fauna shows a sudden change and is dominated by Tropithisbites. Few tens of metres above, but slightly below the first occurrence of Norian ammonoids Guembelites jandianus and Stikinoceras, two new species of conodonts (Gen et sp. nov. A and B) appear that also occur close to the favoured Carnian/Norian boundary at Black Bear Ridge, British Columbia. Stratigraphically higher collections continue to be dominated by forms close to M. mersinensis and 'E.' orchardi.

The best exposure of the Kerri Zone is on the western side of the West Union Canyon. Ammonoids, dominated by Guembelites and Stikinoceras div. sp., have been collected from several fossil-bearing levels. Conodont faunas replicate those of the east section. The collected ammonoids fit perfectly well with the faunas described by Silberling in 1959, but they differ somewhat from the coeval faunas of the Tethys and Canada.

The genus Gonionotites, very common in the Tethys and British Columbia, is for the moment unknown in Nevada. More in general, the Upper Carnian faunas are dominated by Tropitidae, while Juvavitidae are lacking.

After years of reading about the correlation between British Columbia and Nevada, I had the very great pleasure of walking through these same sections in October 2019 with members of the Vancouver Paleontological Society and Vancouver Island Palaeontological Society. It was with that same crew that I had originally explored fossil sites in the Canadian Rockies in the early 2000s. Those early trips led to paper after paper and the exciting revelations that inspired our Nevada adventure.

Saturday, 12 October 2024

NATURAL DYES: INDIGO

Natural dyes are dyes or colourants derived from plants, invertebrates, or minerals. The colours they give us range from muddy to vibrant and have been used to enhance our visual world for many years.

The majority of natural dyes are vegetable dyes from plant sources — roots, berries, bark, leaves, and wood — and other biological sources such as fungi and lichens.

Archaeologists have found evidence of textile dyeing dating back to the Neolithic period. 

In China, dyeing with plants, barks and insects has been traced back more than 5,000 years and by all accounts is our first attempt at the practice of chemistry.

The essential process of dyeing changed little over time. Typically, the dye material is put in a pot of water and then the textiles to be dyed are added to the pot, which is heated and stirred until the colour is transferred. Sometimes, we use workers with stout marching legs to mix this up.

Traditional dye works still operate in many parts of the world. There is a revival of using natural indigo in modern Egypt — although their indigo dye is mostly imported. The same is true further south in Sudan. They've been importing cloth from Upper Egypt as far back as we have written records and continue the practice of the cloth and dye imports today. Clean white cotton is more the style of western Sudan and Chad, but they still like to throw in a bit of colour.

Traditional Dye Vats
So do the folk living in North Africa. Years ago, I was travelling in Marrakesh and saw many men with noticeably orange, blueish or purplish legs. It wasn't one or two but dozens of men and I'd wondered why this was.

My guide took me to the top of a building so I could look down on rows and rows of coloured vats. In every other one was a man marching in place to work the dye into the wool. Their legs took on the colour from their daily march in place in huge tubs of liquid dye and sheared wool. 

This wool would be considered textile fibre dyed before spinning — dyed in the wool — but most textiles are yarn-dyed or piece-dyed after weaving. In either case, the finished product is quite fetching even if the dyer's legs are less so. 

Many natural dyes require the use of chemicals called mordants to bind the dye to the textile fibres; tannin from oak galls, salt, natural alum, vinegar, and ammonia from stale urine were staples of the early dyers.

Many mordants and some dyes themselves produce strong odours. Urine is a bit stinky. Not surprisingly, large-scale dyeworks were often isolated in their own districts.

Woad, Isatis tinctoria
Plant-based dyes such as Woad, Isatis tinctoria, indigo, saffron, and madder were raised commercially and were important trade goods in the economies of Asia and Europe. 

Across Asia and Africa, patterned fabrics were produced using resist dyeing techniques to control the absorption of colour in piece-dyed cloth.

Dyes such as cochineal and logwood, Haematoxylum campechianum, were brought to Europe by the Spanish treasure fleets, and the dyestuffs of Europe were carried by colonists to America.

Throughout history, people have dyed their textiles using common, locally available materials, but scarce dyestuffs that produced brilliant and permanent colours such as the natural invertebrate dyes. Crimson kermes became highly prized luxury items in the ancient and medieval world. Red, yellow and orange shades were fairly easy to procure as they exist as common colourants of plants. It was blue that people sought most of all and purple even more so.

Indigofera tinctoria, a member of the legume or bean family proved just the trick. This lovely plant —  named by the famous Swedish botanist Carl Linneaus, the father of formalized binomial nomenclature — grows in tropical to temperate Asia and subtropical regions, including parts of Africa.

The plants contain the glycoside indican, a molecule that contains a nitrogenous indoxyl molecule with some glucose playing piggyback. 

Indigo dye is a product of the reaction of indoxyl by a mild oxidizing agent, usually just good old oxygen.

To make the lovely blue and purple dyes, we harvest the plants and ferment them in vats with urine and ash. The fermentation splits off the glucose, a wee bit of oxygen mixes in with the air (with those sturdy legs helping) and we get indigotin — the happy luxury dye of royalty, emperors and kings.

While much of our early dye came from plants — now it is mostly synthesized — other critters played a role. Members of the large and varied taxonomic family of predatory sea snails, marine gastropod mollusks, commonly known as murex snails were harvested by the Phoenicians for the vivid dye known as Tyrian purple.

While the extant specimens maintained their royal lineage for quite some time; at least until we were able to manufacture synthetic dyes, it was their fossil brethren that first captured my attention. There are about 1,200 fossil species in the family Muricidae. 

They first appear in the fossil record during the Aptian of the Cretaceous. Their ornate shells fossilize beautifully. I first read about them in Addicott's Miocene Gastropods and Biostratigraphy of the Kern River Area, California. It is a wonderful survey of 182 early and middle Miocene gastropod taxa.

References:

George E. Radwin and Anthony D'Attilio: The Murex shells of the World, Stanford University press, 1976, ISBN 0-8047-0897-5

Pappalardo P., Rodríguez-Serrano E. & Fernández M. (2014). "Correlated Evolution between Mode of Larval Development and Habitat in Muricid Gastropods". PLoS ONE 9(4): e94104. doi:10.1371/journal.pone.0094104

Miocene Gastropods and Biostratigraphy of the Kern River Area, California; United States Geological Survey Professional Paper 642  

Friday, 11 October 2024

TIKTAALIK: FOSSIL FISHAPODS

Qikiqtania wakei, a fishapod & relative to tetrapods
You will likely recall the amazing tetrapodomorpha fossil found on Ellesmere Island in the Canadian Arctic in 2004, Tiktaalik roseae

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 significant tetrapod features remained obscure for the 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 as you can be and still be a card-carrying member of the group. 

Interestingly, while Neil Shubin and crew were combing the icy tundra for Tiktaalik, another group was trying their luck just a few kilometres away. 

A week before the eureka moment of Tiktaalik's discovery, Tom Stewart and Justin Lemberg unearthed material that we now know to be a relative of Tiktaalik's. 

Meet Qikiqtania wakei, a fishapod and close relative to our dear tetrapods — and cousin to Tiktaalik — who shares features in the flattened triangular skull, shoulders and elbows in the fin. 

Qikiqtania (pronounced kick-kick-TAN-ee-ya)
But, and here’s the amazing part, its upper arm bone (humerus) is specialised for open water swimming, not walking. 

The story gets wilder when we look at Qikiqtania’s position on the evolutionary tree— all the features for this type of swimming are newly evolved, not primitive. 

This means that Qikiqtania secondarily reentered open water habitats from ancestors that had already had some aspect of walking behaviour. 

And, this whole story was playing out 365 million years ago — the transition from water to land was going both ways in the Devonian.

Why is this exciting? You and I descend from those early tetrapods. We share the legacy of their water-to-land transition and the wee bony bits in their wrists and paddles that evolved to become our hands. I know, mindblowing!

Thomas Stewart and Justin Lemberg put in thousands of hours bringing Qikiqtania to life. 

The analysis consisted of a long path of wild events— from a haphazard moment when it was first spotted, a random collection of a block that ended up containing an articulated fin, to a serendipitous discovery three days before Covid lockdowns in March 2020.

Both teams acknowledge the profound debt owed to the individuals, organizations and indigenous communities where they had the privilege to work — Grise Fiord and Resolute Bay— Ellesmere Island in Nunavut, the largest and northernmost territory of Canada. 

Part of that debt is honoured in the name chosen for this new miraculous species. 

Aerial View of Ellesmere Island
The generic name, Qikiqtania (pronounced kick-kick-TAN-ee-ya), is derived from the Inuktitut words Qikiqtaaluk and Qikiqtani which are the traditional place name of the region where the fossil was discovered. 

The specific name, wakei, is in memory of the evolutionary biologist David Wake — colleague, mentor and friend. 

He was a professor of integrative biology and Director and curator of herpetology at the Museum of Vertebrate Zoology at the University of California, Berkeley who passed away in April 2021. 

Wake is known for his work on the biology and evolution of salamanders and vertebrate evolutionary biology. 

If you look at the photo on the left you can imagine visiting these fossil localities in Canada's far north.

Qikiqtania was found on Inuit land and belongs to the community. Thomas Stewart and his colleagues were able to conduct this research because of the generosity and support of individuals in the hamlets of Resolute Bay and Grise Fiord, the Iviq Hunters and Trappers of Grise Fiord, and the Department of Heritage and Culture, Nunavut.

To them, on behalf of the larger scientific community — Nakurmiik. Thank you! 

Here is the link to Tom Stewart's article in The Conversation & paper in Nature that dropped yesterday:

  1. Stewart, Thomas A.; Lemberg, Justin B.; Daly, Ailis; Daeschler, Edward B.; Shubin, Neil H. (2022-07-20). "A new elpistostegalian from the Late Devonian of the Canadian Arctic". Naturedoi:10.1038/s41586-022-04990-wISSN 0028-0836.
  2. Stewart, Thomas. "Meet Qikiqtania, a fossil fish with the good sense to stay in the water while others ventured onto land" The Conversation. Retrieved 2022-07-20.

Image One: An artist’s vision of Qikiqtania enjoying its fully aquatic, free-swimming lifestyle. Alex Boersma, CC BY-ND

Image Two: A new elpistostegalian from the Late Devonian of the Canadian Arctic, T. A. Stewart, J. B. Lemberg, A. Daly, E. B. Daeschler, & N. H. Shubin.

A huge shout out to the deeply awesome Neil Shubin who shared that the paper had been published and offered his insights on what played out behind the scenes!

Friday, 4 October 2024

FOSSILS, LIMESTONE AND SALT: HALLSTATT

Hallstatt Salt Mines, Austria / Permian Salt Diapir
The Hallstatt Limestone is the world's richest Triassic ammonite unit, yielding specimens of more than 500 ammonite species.

Along with diversified cephalopod fauna  — orthoceratids, nautiloids, ammonoids — we also see gastropods, bivalves, especially the late Triassic pteriid bivalve Halobia (the halobiids), brachiopods, crinoids and a few corals. We also see a lovely selection of microfauna represented. 

For microfauna, we see conodonts, foraminifera, sponge spicules, radiolaria, floating crinoids and holothurian sclerites —  polyp-like, soft-bodied invertebrate echinozoans often referred to as sea cucumbers because of their similarities in size, elongate shape, and tough skin over a soft interior. 

Franz von Hauer’s exhaustive 1846 tome describing Hallstatt ammonites inspired renowned Austrian geologist Eduard Suess’s detailed study of the area’s Mesozoic history. That work was instrumental in Suess being the first person to recognize the former existence of the Tethys Sea, which he named in 1893 after the sister of Oceanus, the Greek god of the ocean. As part of the Northern Limestone Alps, the Dachstein rock mass, or Hoher Dachstein, is one of the large karstic mountains of Austria and the second-highest mountain in the Northern Limestone Alps. It borders Upper Austria and Styria in central Austria and is the highest point in each of those states.

Parts of the massif also lie in the state of Salzburg, leading to the mountain being referred to as the Drei-Länder-Berg or three-state mountain. Seen from the north, the Dachstein massif is dominated by the glaciers with the rocky summits rising beyond them. By contrast, to the south, the mountain drops almost vertically to the valley floor. The karst limestones and dolomites were deposited in our Mesozoic seas. The geology of the Dachstein massif is dominated by the Dachstein-Kalk Formation — the Dachstein limestone — which dates back to the Triassic.

Hallstatt and the Hallstatt Sea, Austria
There were several phases of mountain building in this part of the world pushing the limestone deposits 3,000 metres above current sea level. The rock strata were originally deposited horizontally, then shifted, broken up and reshaped by the erosive forces of ice ages and erosion.

The Hallstatt mine exploits a Permian salt diapir that makes up some of this area’s oldest rock. 

The salt accumulated by evaporation in the newly opened, and hence shallow, Hallstatt-Meliata Ocean. This was one of several small ocean basins that formed in what is now Europe during the late Paleozoic and early Mesozoic when the world’s landmasses were welded together to form the supercontinent Pangea. 

Pangea was shaped like a crescent moon that cradled the famous Tethys Sea. Subduction of Tethyian oceanic crust caused several slivers of continental crust to separate from Pangea, forming new “back-arc basins” (small oceans formed by rifting that is associated with nearby subduction) between the supercontinent and the newly rifted ribbon continents.

The Hallstatt-Meliata Ocean was one such back-arc basin. As it continued to expand and deepen during the Triassic, evaporation ceased and reefs flourished; thick limestone deposits accumulated atop the salt. When the Hallstatt-Meliata Ocean closed in the Late Jurassic, the compression squeezed the low-density salt into a diapir that rose buoyantly, injecting itself into the Triassic limestones above.

The Hallstatt salt diapir and its overlying limestone cap came to rest in their present position in the northern Austrian Alps when they were shoved northward as nappes (thrust sheets) during two separate collision events, one in the Cretaceous and one in the Eocene, that created the modern Alps. It is from the Hallstatt salt diapir that Hallstatt, like so many cities and towns, gets its name.

Deposits of rock salt or halite, the mineral name of sodium chloride with the chemical formula of NaCl, are found and mined around the globe. These deposits mark the dried remains of ancient oceans and seas. Names of rivers, towns and cities in Europe — Salzburg, Halle, Hallstatt, Hallein, La Salle, Moselle — all pay homage to their connection to halite and salt production. The Greek word for salt is hals and the Latin is sal. The Turkish name for salt is Tuz, which we see in the naming of Tuzla, a salt-producing region of northeastern Bosnia-Herzegovina and in the names of towns that dot the coast of Turkey where it meets the Black Sea. Hallstatt with its salt diapir is no exception.

The salt-named town of Hallstatt sits on the shores of the idyllic Hallstätter Sea at the base of the Dachstein massif. Visiting it today, you experience a quaint traditional fishing village built in the typical upper Austrian style. Tourism drives the economy as much as salt as this area of the world is picture-perfect from every angle.

Space is at a minimum in the town. For centuries, every ten years the local cemetery exhumes the bones of those buried there and moves them to an ossuary to make room for new burials. The Hallstatt Ossuary is called Karner, Charnel House, or simply Beinhaus (Bone House). Karners are places of secondary burials. They were once common in the Eastern Alps, but that custom has largely disappeared.

Hallstatt Beinhaus Ossuary, Hallstatt, Austria
A collection of over 700 elaborately decorated skulls rest inside the ossuary. They are lined up on rows of wooden shelves that grace the walls of the chapel. Another 500 undecorated skulls, bare and without any kind of adornment, are stacked in the corners.

Each is inscribed and attached to a record with the deceased's name, profession and date of death. The Bone House is located in a chapel in the basement of the Church of Saint Michael. The church dates from the 12th century CE. 

Decorating the skulls was traditionally the job of the local gravedigger and an honour granted to very few. At the family's request, garlands of flowers were painted on the skulls of deceased as decorative crowns if they were female. The skulls of men and boys were painted wreaths of oak or ivy.

Every building in Hallstatt looks out over the Hallstätter Sea. This beautiful mountain lake considered one of the finest of Austria's Salzkammergut region. It lies at the northern foot of the Dachstein mountain range, sitting eight-and-a-half kilometres long and two kilometres wide. The shoreline is dotted by the villages of  Obertraun, Steeg, and Hallstatt.

The region is habitat to a variety of diverse flora and fauna, including many rare species such as native orchids, in the wetlands and moors in the south and north.

Linked by road to the cities of Salzburg and Graz, Hallstatt and its lake were declared one of the World Heritage sites in Austria in 1997 and included in the Hallstatt-Dachstein Salzkammergut Alpine UNESCO World Heritage Site. The little market village of Hallstatt takes its name from the local salt mine.

Hallstatt, Salzkammergut region, Austria
The town is a popular tourist destination with its quaint shops and terraced cafes. In the centre of town, the 19th-century Evangelical Church of Hallstatt with its tall, slender spire is a lakeside landmark. You can see it here in the photo on the left.

Above the town are the Hallstatt Salt mines located within the 1,030-meter-tall Salzburg Salt Mountain. They are accessible by cable car or a three-minute journey aboard the funicular railway. There is also a wonderful Subterranean Salt Lake.

In 1734, there was a corpse found here preserved in salt. The fellow became known as the Man in Salt. Though no archaeological analysis was performed at the time — the mummy was respectfully reburied in the Hallstatt cemetery — based on descriptions in the mine records, archaeologists suspect the miner lived during the Iron Age. This Old Father, Senos ph₂tḗr, 'ɸatīr 'father' may have been a local farmer, metal-worker, or both and chatted with his friends and family in Celtic or Proto-Celtic.

Salt mining in the area dates back to the Neolithic period, from the 8th to 5th Centuries BC. This is around the time that Roman legions were withdrawing from Britain and the Goths sacked Rome. In Austria, agricultural settlements were dotting the landscape and the alpine regions were being explored and settled for their easy access to valuable salt, chert and other raw materials.

The salt-rich mountains of Salzkammergut and the upland valley above Hallstatt were attractive for this reason. The area was once home to the Hallstatt culture, an archaeological group linked to Proto-Celtic and early Celtic people of the Early Iron Age in Europe, c.800–450 BC.
Bronze Age vessel with cow and calf

In the 19th century, a burial site was discovered with 2,000 individuals, many of them buried with Bronze Age artefacts of amber and ivory.

It was this find that helped lend the name Hallstatt to this epoch of human history. The Late Iron Age, between around 800 and 400 BC, became known as the Hallstatt Period.

For its rich history, natural beauty and breathtaking mountainous geology, Hallstatt is a truly irresistible corner of the world.

Salzbergstraße 1, 4830 Hallstatt.  https://www.salzwelten.at/en/home/

Photo: Bronze vessel with cow and calf, Hallstatt by Alice Schumacher - Naturhistorisches Museum Wien - A. Kern – K. Kowarik – A. W. Rausch – H. Reschreiter, Salz-Reich. 7000 Jahre Hallstatt, VPA 2 (Wien, 2008) Seite 133 Abbildung 6. Hallstatt Village & Ossuary Photos: P. McClure Photography ca. 2015.

Bernoulli D, Jenkyns HC (1974) Alpine, Mediterranean, and Central Atlantic Mesozoic facies in relation to the early evolution of the Tethys. Soc Econ Paleont Mineral Spec Publ 19:129–160

Bernoulli D, Jenkyns H (2009) Ancient oceans and continental margins of the Alpine-Mediterranean Tethys: deciphering clues from Mesozoic pelagic sediments and ophiolites. Sedimentology 56:149–190

Tuesday, 1 October 2024

CANADA'S GREAT BEARS

Look at how this protective mamma bear holds her cub in her arms to give him a bit of a wash. 

Her gentle maternal care is truly touching. This mamma has spent late Autumn to Spring in a cave, having birthed them while still hibernation and staying in the den to feed them on her milk.

Black bear cubs stay with their mamma for the first one to three years of their lives while she protects them and teaches them how to thrive in the wild using their keen sense of smell, hearing, vision and strength. Once they are old enough, they will head off into the forest to live solo until they are ready to mate and start a family of their own. 

Mating is a summer affair with bears socializing shoulder to shoulder with potential mates. Once they have mated, black bears head off on their own again to forage and put on weight for their winter hibernation. If the black bear lives in the northern extent of their range, hibernation lasts longer — they will stay in their dens for seven to eight months longer than their southern counterparts. For those that enjoy the warmer climes in the south, hibernation is shorter. If food is available year-round, the bears do not hibernate at all.

The American black bear, Ursus americanus, is native to North America and found in Canada and the United States. 

They are the most common and widely distributed of the three bear species found in Canada. 

There are roughly 650,000 roaming our forests, swamps and streams — meaning there is a good chance of running into them if you spend any amount of time in the wild. 

Full-grown, these fuzzy monkeys will be able to run 48 kilometres (30 miles)  an hour and smell food up to 32 kilometres (20 miles) away.

With their excellent hearing, black bears usually know you are near well before you realize the same and generally take care to avoid you. Those that come in contact with humans often tend to want to check our garbage and hiking supplies for tasty snacks — hey, a free meal is a free meal.    

In British Columbia, we share our province with nearly half of all black bears and grizzly bears that reside in Canada. The 120,000 - 150,000 black bears who live in the province keep our Conservation Officers busy. They account for 14,000 - 25,000 of the calls the service receives each year. Most of those calls centre around their curiosity for the tasty smells emanating from our garbage. They are omnivores with vegetation making up 80-85% of their diet, but they are flexible around that — berries and seeds, salmon or Doritos — bears eat it all. 

And, as with all wild animals, diet is regional. In Labrador, the local black bear population lives mostly on caribou, rodents and voles. In the Pacific Northwest, salmon and other fish form a large part of the protein in their diet versus the bees, yellow jackets and honey others prefer. The braver of their number have been known to hunt elk, deer and moose calves — and a few showy bears have taken on adults of these large mammals. 

Bears hold a special place within our culture and in First Nation mythology in particular — celebrated in art, dance and song. In the Kwak'wala language of the Kwakiutl First Nations of the Pacific Northwest, the word for black bear is t̕ła'yimother is a̱bas and łaxwa̱lap̓a means to love each other

Kermode or Spirit Bear, Ursus americanus kermodei
From the photos here you can see that black bears are not always black —  ranging in colour from cinnamon to brown, tan, blonde, red — and even white. 

The Kermode or Spirit Bear, Ursus americanus kermodei, a subspecies of black bear found only in British Columbia — and our official provincial mammal — is a distinctive creamy white. 

They are not albinos, their colouring stems from a recessive mutant gene — meaning that if they receive two copies it triggers a single, nonsynonymous nucleotide substitution that halts all melanin production. Well, not all. They have pigmented eyes and skin but no colour in their fur. The white colour is an advantage when you are hunting salmon by day. Salmon will shy away from their black cousins knowing their intention is to enjoy them as a tasty snack. 

Spirit Bears live in the Great Bear Rainforest on British Columbia's north and central coast alongside the Kitasoo/Xai’xais First Nation who call the Kermode moskgm’ol or white bear.

The Kitasoo/Xai’xais have a legend that tells of Goo-wee, Raven making one in every ten black bears white to remind us of the time glaciers blanketed the land then slowly retreated — their thaw giving rise to the bounty we harvest today.  

Black bears of any colour are a wee bit smaller than their brown bear or grizzly bear cousins, with males weighing in at 45 to 400 kilograms (100 to 900 pounds) and females ranging from 38 to 225 kilograms (85 to 500 pounds). 

Small by relative standards but still very large animals. And they are long-lived or at least can be. Bears in captivity can live up to 30 years but those who dwell in our forests tend to live half as long or less from a mixture of local hazards and humans. 

Reference: Wild Safe BC: https://wildsafebc.com/species/black-bear/


Monday, 30 September 2024

DOLPHIN VERTEBRAE FROM THE NORTH SEA

A lovely 17 cm deep chocolate brown fossil Bottlenose Dolphin, Tursiops sp. vertebrae found in the Brown Bank area of the North Sea, one of the busiest seaways in the world. The beautiful specimen you see here is in the collections Wendy Phillips of Vancouver Island.

Bottlenose dolphins first appeared during the Miocene and swam the shallow seas of this region. 

We still find them today in warm and temperate seas worldwide though unlike narwhal, beluga and bowhead whales, Bottlenose dolphins avoid the Arctic and Antarctic Circle regions. 

Their name derives from the Latin tursio (dolphin) and truncatus for their characteristic truncated teeth. In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest — and part of my heritage — dolphin are hatsawe'. 

On the north end of Vancouver Island, we have pods of 50-100 Pacific White-Sided dolphins, cousins of the Bottlenose, who frolic and jump alongside your boat if you are out on the water. Similar to their southern cousins, Pacific White-Sided dolphins feed on salmon, herring, pilchards, anchovies, needlefish, squid, shrimp, pollock, sablefish, rock cod and other small fish — a tasty menu that reflects my own. 

Bottlenose dolphins are the most common dolphin species in the Pacific Northwest but do not often venture farther north than Oregon. We have two populations of bottlenose dolphins here, the California coastal population and those that prefer to live offshore. It is as exciting to see them playing in our oceans today as it is to see the fossil remains of their ancestors from the Brown Bank sediments of the North Sea. 

Brown Bank, North Sea, Pleistocene Dredging Area
There are two known fossil species from Italy that include Tursiops osennae (late Miocene to early Pliocene) from the Piacenzian coastal mudstone, and Tursiops miocaenus (Miocene) from the Burdigalian marine sandstone.

Many waterworn vertebrae from the Harbour Porpoise Phocoena sp., (Cuvier, 1816), Bottlenose dolphin Tursiops sp. (Gervais, 1855), and Beluga Whale, Delphinapterus sp. (Lacépède‎, 1804‎) are found by fishermen as they dredge the bottom of the Brown Bank, one of the deepest sections of the North Sea.  

The North Sea is a sea of the Atlantic Ocean located between the United Kingdom, Denmark, Norway, Germany, the Netherlands, Belgium and France. An epeiric sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north.

The fishermen use small mesh trawl nets that tend to scoop up harder bits from the bottom. This technique is one of the only ways this Pleistocene and other more recent material is recovered from the seabed, making them relatively uncommon. The most profitable region for fossil mammal material is in the Brown Bank area of the North Sea. I have circled this area on the map below to give you an idea of the region.

These specimens are often found by fishermen in the North Sea. Using a small mesh trawl net is often the only time these come up from the seabed, hence they are uncommon. ​Size: 17.0cm. Age: 30-40,000 Years old. 

Saturday, 28 September 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