INNER EAR HESPERORNIS

If palaeontologists had a wish list, it would likely include insights into two particular phenomena: how dinosaurs interacted with each other and how they began to fly. 

By all accounts, it is a very long bucket list of wants, but these two would certainly make mine.

The problem is, using fossils to deduce such behaviour is a tricky business. But a new, Yale-led study offers a promising entry point — the inner ear of an ancient reptile. The shape of the inner ear offers reliable signs as to whether an animal soared gracefully through the air, flew only fitfully, walked on the ground, or sometimes went swimming. In some cases, the inner ear even indicates whether a species did its parenting by listening to the high-pitched cries of its babies.

The inner ear of Hesperornis, an 85-million-year-old aquatic bird first discovered by the Peabody’s O.C. Marsh, is helping us to better understand how these ancient species moved, parented, and communicated. 

The Peabody is a marvellous museum — home to the world’s only Hesperornis fossil that preserves the tiny structure in all three dimensions. It was used in a just-published study, led by Yale University Ph.D. student Michael Hanson and curator Bhart-Anjan Bhullar.

Photo: Hesperornis, Yale Peabody Museum of Natural History.  Photographer: Robert Lorenz

Care to read all about it? Here's the link:

https://news.yale.edu/2021/05/06/what-can-dinosaurs-inner-ear-tell-us-just-listen?fbclid=IwAR0ZqbxsMkBoLRhxGCiKWoj5s3F7BfXE-Sahk9R15LC0i_7bOjRvZOqBLZE

NORWAY: HAPPY NATIONAL DAY

The 17th of May is National Day in Norway. It is a time of celebrations, flags, parades, dressing up and eating ice cream. 

Back in 1814, the day originally honoured the independence of Norway and her new constitution but now honours the Royal Family and is a celebration for families and children.

Children have enjoyed a special role in the celebrations for many years. Initially, the children's parade was all boys. Now, boys and girls participate and the greater part of the event is dedicated to them. The children’s parades include a whole lot of marching, waving homemade red, navy and white Norwegian flags and proudly carrying school banners.

Parades vary in size from a few dozen people in the villages to several tens of thousands of participants in Oslo. Children in Oslo pass the Royal Palace, where royal family members wave back from the balcony. 

The Royal Family and ordinary folk dress in Bunads, traditional costumes of red, white, black, blue and green. Sometimes, other costumes are worn. The Norwegians love to dress up!

Each year, around 40,000 graduating high school students called “Russ” can be recognized with their Russ hats and uniforms. The traditional Russ celebration starts in spring and ends on the 17th of May. The day is marked by Russ parties, Russ buses, Russ newspapers and Russ Cards.

The colour of the uniform matches the graduate’s line of study: Red for students geared towards higher education — the most common colour — blue for those going into business, economics or management, white for medical and social studies, black for engineering and green for agricultural fields.

Amongst Norwegians, the day is referred to simply as syttende mai, Nasjonaldagen or Grunnlovsdagen, although the latter is used less frequently. To help get you into the spirit of Norge, I am sharing the cold, stark and beautiful fishing village of Hamnoy in the Lofoten Islands, Norway. So, feel free to enjoy it while eating some hotdogs, ice cream and a tasty beverage today. Skal!

TUSK SHELL: OYSTER BAY FORMATION

The lovely large creamy tusk shell, Dentalium sp., you see here is in the collections of John Fam, Vice-Chair, Vancouver Paleontological Society.  

This particular scaphopod, or Tusk Shell, is one of many species of molluscs helping to untangle the complex geology of Vancouver Island. He hails from Early Paleocene - Early Eocene, Oyster Bay Formation, Appian Way Beds, near Cambell River, Vancouver Island, British Columbia, Canada. 

This area was mapped by the Geological Survey of Canada and initially included as part of the Cretaceous Nanaimo group. 

It was extensive collecting by members of the Vancouver Island Palaeontological Society that led to a revision of the geology of this area. Many of the fossils found in more recent years are a match for those found in the early Cenozoic of western North America, including the beautiful marine community captured in the block you see here.

Tusk shells are members of a class of shelled marine mollusc with a global distribution. Shells of species within this class range from about 0.5 to 15 cm in length. This fellow is 8 cm end to end, so near smack dab in the centre of his cohort.

The Scaphopoda get their nickname "tusk shells" because their shells are conical and slightly curved to the dorsal side, making the shells look like tiny tusks (picture a walrus or mammoth tusk in your mind’s eye). The scientific name Scaphopoda means "shovel foot," a term that refers to the "head" of the animal, which lacks eyes and is used for burrowing in marine sediments.

The most distinctive feature of scaphopods, however, and one that differentiates them from most molluscs, is the duo openings on their tubular shells. Most molluscs are open at just one end.

We could call scaphopods the great deniers. They live their adult lives with their heads literally buried in the sand. A tiny bit of their posterior end sticks up into the seawater for water exchange. Water is circulated around the mantle cavity by the action of numerous cilia.

When the available dissolved oxygen runs low for this fellow he ejects water from the top end of his shell by contraction of his "foot."

AMMONITES FROM THE GAULT

The chunky ammonite Proeuhoplites subtuberculatus, bed II (iv), Folkstone Gault Clay, county of Kent, southeast England.

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

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

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

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

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

Occasional fragments of fossil wood may also be found. The lovely ammonite you see here is from the Gault Clays of Folkstone. Not all who name her would split the genus Euhoplites. There’s a reasonable argument for viewing this beauty as a very thick form of E. loricatus with Proeuhoplites being a synonym of Euhoplites. Collected, photographed and prepped by Thomas Miller. Approx 35mm across.

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

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

ANCIENT ARMADILLOS

Glyptodonts are the early ancestors of our modern armadillos that roamed North and South America during the Pleistocene. 

Armadillos, both living and extinct, range in size from the size of an armoured car to the size of a small, family dog. As they evolved over time, the smaller they have become. 

Glyptodonts became extinct at the end of the last ice age. They, along with a large number of other megafaunal species, including pampatheres, the giant ground sloths, and the Macrauchenia, left this Earth but their bones tell a story of brief and awesome supremacy.

Today, Glyptodonts live on through their much smaller, more lightly armoured and flexible armadillo relatives. They defended themselves against Sabre Tooth Cats and other predators but could not withstand the arrival of early humans in the Americas. Archaeological evidence suggests that these humans made use of the animal's armoured shells and enjoyed the meat therein. Glyptodonts possessed a tortoise-like body armour, made of bony deposits in their skin called osteoderms or scutes. Beneath that hard outer coating was a food source that our ancestors sought for their survival.

Each species of glyptodont had a unique osteoderm pattern and shell type. With this protection, they were armoured like turtles; glyptodonts could not withdraw their heads, but their armoured skin formed a bony cap on the top of their skull. Glyptodont tails had a ring of bones for protection. Doedicurus possessed a large mace-like spiked tail that it would have used to defend itself against predators and, possibly, other Doedicurus. Glyptodonts had the advantage of large size.

Many, such as the type genus, Glyptodon, were the size of modern automobiles. The presence of such heavy defences suggests they were the prey of a large, effective predator. At the time that glyptodonts evolved, the apex predators in the island continent of South America were phorusrhacids, a family of giant flightless carnivorous birds.

The ancient Armadillo Glyptodon asper

In physical appearance, glyptodonts superficially resembled the much earlier dinosaurian ankylosaurs and, to a lesser degree, the recently extinct giant meiolaniid turtles of Australia.

These are examples of the convergent evolution of unrelated lineages into similar forms. The largest glyptodonts could weigh up to 2,000 kilograms. Like most of the megafauna in the Americas, they all became extinct at the end of the last ice age 10,000 years ago. The deeper you get in time, the larger they were. Twenty thousand years ago, they could have ambled up beside you in what would become Argentina and outweighed a small car.

A few years back, some farmers found some interesting remains in a dried-out riverbed near Buenos Aires. The find generated a ton of palaeontological excitement. Fieldwork revealed this site to contain two adults and two younger specimens of an ancient armadillo. These car-size beasties would have been living and defending themselves against predators like Sabre Tooth Cats and other large predators of the time by employing their spiked club-like tails and thick bony armour.

Glyptodonts were unlikely warriors. They were grazing herbivores. Like many other xenarthrans, they had no incisor or canine teeth but had a number of cheek teeth that would have been able to grind up tough vegetation, such as grasses. They also had distinctively deep jaws, with large downward bony projections that would have anchored their powerful chewing muscle.

Image Two: By Arentderivative work: WolfmanSF (talk) -  http://de.wikipedia.org/wiki/Bild:Glyptodon-1.jpg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=665483

GIANT TORTOISES & THE ISLAND RULE

Giant tortoises and other organisms that live and evolve on islands undergo a different set of selective pressures than those who live on our continental land masses. We call this the 'island rule'. Species develop unusual traits, becoming larger or smaller than their continental brethren.

Food is often restrictive or unvaried and predators are often reduced or all together absent. We see the evolutionary impact in the Giant tortoises of the Aldabra Atoll and Fregate Island in the Seychelles and Galápagos Islands in Ecuador.

They belong to an ancient group of reptiles, appearing about 250 million years ago and evolving to their large size by the Late Cretaceous, 70 or 80 million years ago. And they are big, weighing as much as 417 kg (919 lb) and can grow to be 1.3 m (4 ft 3 in) long. The Galapagos giant tortoise is a wee bit smaller, weighing 215 kg (475 lb) with the males generally outweighing the females. They snack on plants and some have a slight curve to the shell behind their heads to allow them to reach up a wee bit higher to reach more food. The females lay their eggs in a pit dug specifically for this purpose. Once the hatchlings have incubated, they dig themselves out. I'm sure you've seen the adorable photos or videos of them hatching then making their way to the sea. 

BALEARITES OF MOROCCO

Collection of José Juárez Ruiz. The specimen is 202 mm.

This beautifully prepped specimen of a Balearites cf. balearis (Nolan, 1984) ammonite is from Upper Hauterivian deposits near Tamri, a small seaside town and rural commune in Agadir-Ida Ou Tanane Prefecture, Souss-Massa, Morocco. Aside from wonderful fossil localities, this area of Morocco has some of the most amazing surfing and banana plantations.

Balearites, with their planispiral shell (conch) and compressed whorls, is an extinct ancyloceratin genus ammonite in the family Crioceratitidae, suborder Ancyloceratina.

We find fossils of this genera in Romania, Slovakia, Austria, France, Spain, Switzerland, Hungary, Italy, Russia, Bulgaria and Morocco. This specimen is in the collection of José Juárez Ruiz and is roughly 202 mm. If you find this lovely interesting, you'll enjoy reading more on this genus and others in Arkell, W. J. et al., 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L, Mollusca 4. 1957.

GREEK MYTHOLOGY AND ANCIENT BONES

Tetralophodon

During the Miocene and Pliocene, 12-1.6 million years ago, a diverse group of extinct proboscideans, elephant-like animals walked the Earth.

Most of these large beasts had four tusks and likely a trunk similar to modern elephants. They were creatures of legend, inspiring myths and stories of fanciful creatures to the first humans to encounter them.

Beyond our Neanderthal friends, one such fellow was Quintus Sertorius, a Roman statesman come general, who grew up in Umbria. Born into a world at war just two years before the Romans sacked Corinth to bring Greece under Roman rule, Quintus lived much of his life as a military man far from his native Norcia. Around 81 BC, he travelled to Morocco, the land of opium, massive trilobites and the birthplace of Antaeus, the legendary North African ogre who was killed by the Greek hero Heracles.

The locals tell a tale that Quintus requested proof of Antaeus, hard evidence he could bring back to Rome to support their tales so they took him to a mound near Tingis, the ancient name for Tangier, Morocco. It was here they unearthed the bones of an extinct elephantoid, Tetralophodon.

Tetralophodon bones are large and skeletons singularly impressive. Impressive enough to be taken for something else entirely. By all accounts, these proboscidean remains were that of the mythical giant, Antaeus, son of the gods Poseidon and Gaea and were thus reported back to Rome as such. Antaeus went on to marry the goddess Tinge and it is from her, in part, that Tangier in northwestern Morocco gets its name. Together, Antaeus and Tinge had a son, Sophax. He is credited with having the North Africa city take her name. Rome was satisfied with the find. It would be hundreds of years later before the bones true ancestry was known and in that time, many more wonderful ancient proboscideans remains were unearthed..

There were other early proboscideans, of course. The earliest known proboscidean is Eritherium, followed by Phosphatherium, a small animal about the size of a fox. Both date from late Paleocene deposits of Morocco.

Proboscideans evolved in Africa, where they increased in size and diversity during the Eocene and early Oligocene. Several primitive families from these epochs have been described, including the Numidotheriidae, Moeritheriidae, and Barytheriidae, all found exclusively in Africa. 

The Anthracobunidae from the Indian subcontinent were also believed to be a family of proboscideans, but were excluded from the Proboscidea by Shoshani and Tassy (2005) and have more recently been assigned to the Perissodactyla.

When Africa became connected to Europe and Asia after the shrinking of the Tethys Sea, proboscideans migrated into Eurasia, with some families eventually reaching the Americas. Proboscideans found in Eurasia as well as Africa include the Deinotheriidae, which thrived during the Miocene and into the early Quaternary, Stegolophodon, an early genus of the disputed family Stegodontidae; the highly diverse Gomphotheriidae and Amebelodontidae; and the much loved Mammutidae, or mastodons.

I traveled and hiked through much of Morocco to explore the countryside, ancient Roman ruins and many splendid outcrops when I was eighteen. I wish I had known more of the fossil sites before that trip but many had yet to be discovered. I will share more of those stories — and there are plenty — in future posts.

Photo: Henan Geological Museum, Zhengzhou, China. Complete indexed photo collection at WorldHistoryPics.com.

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. 

LEANCHOILIA: CHENGJIANG

This lovely specimen, with the remarkable strippy black and purple body, is the arthropod Leanchoilia illecebrosa from the Early Cambrian (~525 million years) Chengjiang Lagerstätte, Quiongzhusi Section, Yu’anshan Member, Heilinpu Formation, Jiansghan, Anning, Kunming, Yunnan Province, southwestern China.  

Leanchoilia is a megacheiran arthropod who we first met from Cambrian deposits in the Burgess Shales of Canada where they make up about 0.1% of the fauna of the Greater Phyllopod beds. These distinctive predatory arthropods are about 5 centimetres (2.0 in) in length with whip-like feelers mounted on frontal arm-like appendages. You can see the amazing level of detail in the preservation here. If we are very lucky, we sometimes from their internal organs preserved in three dimensions which adds a whole host of data to explore.

Several species are tentatively accepted today: the type species L. superlata, L. obesa and the recently revalidated and poetically named, L. persephone. Naming is a tricky business when we are dealing with fossilized specimens as ontogeny and sexual dimorphism can confuse the issue. It is not always clear if we are seeing a new species, a juvenile or noting differences between mature males and females. 

Specimen: 5.2 cm. Photo and collection of York Yuxi Wang.

References:

"Burgess Shale: Leanchoilia superlata (an arthropod)". Smithsonian Institution National Museum of Natural History. Retrieved 6 July 2017.

Nicholas J. Butterfield (2002). "Leanchoilia guts and the interpretation of three-dimensional structures in Burgess Shale-type fossils". Paleobiology. 28 (1): 155–171. doi:10.1666/0094-8373(2002)028<0155:LGATIO>2.0.CO;2.

Brigitte Schoenemann & Euan N. K. Clarkson (2012). "The eyes of Leanchoilia". Lethaia. 45 (4): 524–531. doi:10.1111/j.1502-3931.2012.00313.x.

Diego C. García-Bellido & Desmond Collins (2007). "Reassessment of the genus Leanchoilia (Arthropoda, Arachnomorpha) from the Middle Cambrian Burgess Shale, British Columbia, Canada". Palaeontology. 50 (3): 693–709. doi:10.1111/j.1475-4983.2007.00649.x.

Caron, Jean-Bernard; Jackson, Donald A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS. 21 (5): 451–65. doi:10.2110/palo.2003.P05-070R. JSTOR 20173022.

THE LURE OF THE SEA

Our dear penguins, seals, sea lions, walruses, whales, crocodiles and sea turtles were once entirely terrestrial. Yes, they lived mostly or entirely on land. 

Many of these once land-dwelling animals returned to the sea throughout evolutionary history. We have beautifully documented cases from amphibians, reptiles, birds and mammals from over 30 different lineages over the past 250 million years.

Some dipped a toe or two into freshwater ponds, but make no mistake, they were terrestrial. Each of these animals had ancestors that tried out the sea and decided to stay. They evolved and employed a variety of adaptations to meet their new saltwater challenges. Some adapted legs as fins, others became more streamlined, and still, others developed specialized organs to extract dissolved oxygen from the water through their skin or gills. The permutations are endless.

Returning to the sea comes with a whole host of benefits but some serious challenges as well. Life at sea is very different from life on land. Water is denser than air, impacting how an animal moves, sees and hears. More importantly, it impacts an air-breathing animal's movement on a pretty frequent basis. If you need air and haven't evolved gills, you need to surface frequently. Keeping your body temperature at a homeostatic level is also a challenge as water conducts heat much better than air. Even with all of these challenges, the lure of additional food sources and freedom of movement kept those who tried the sea in the sea and they evolved accordingly.

Most major animal groups appear for the first time in the fossil record half a billion years ago. We call this flourishing of species the Cambrian Explosion. While this was a hugely intense period of species radiation, the evolutionary origins of animals are likely to be significantly older. About 700 million years ago the Earth was covered in ice and snow. This was an ice age so intense we refer to this time in our ancient history as Snowball Earth. Once that ice receded, it exposed rocks that contained a variety of weird and wonderful fossils that speak to ancient animals that are only now being studied.

Dr Frankie Dunn, a palaeontologist and an Early Career Research Fellow at the Oxford University Museum of Natural History and Merton College is one of the folks who are examining this early history of some of our first animals. Her research focuses on the origin and early evolution of animals and particularly on the fossil record of the late Ediacaran Period (570 – 540 million years ago).  Dr Dunn's research is exploring ancient species like the long-extinct Rangeomorpha to help understand how animal body plans evolved in deep time well before the divergence of the extant (living) animal lineages.

VERTEBRATES AND INVERTEBRATES

You and I are vertebrates, we have backbones. Having a backbone or spinal column is what sets apart you, me and almost 70,000 species on this big blue planet.

So, which lucky ducks evolved one? Well, ducks for one. Warm-blooded birds and mammals cheerfully claim those bragging rights. They're joined by our cold-blooded, ectothermic friends, the fish, amphibians and reptiles. All these diverse lovelies share this characteristic.

And whether they now live at sea or on land, all of these lineages evolved from a marine organism somewhere down the line, then went on to develop a notochord and spinal column. Notochords are flexible rods that run down the length of chordates and vertebrates. They are handy adaptations for muscle attachment, helping with signalling and coordinating the development of the embryonic stage. The cells from the notochord play a key role in the development of the central nervous system and the formation of motor neurons and sensory cells. Alas, we often take our evolution for granted.

Let's take a moment to appreciate just how marvellous this evolutionary gift is and what it allows us to do. Your backbone gives your body structure, holds up that heavy skull of yours and connects your tasty brain to your body and organs. Eating, walking, fishing, hunting, your morning yoga class, are all made possible because of this adaptation. Pick pretty near anything you love to do and it is only possible because of your blessed spine.

And it sets us apart from our invertebrate friends.

While seventy thousand may seem like a large number, it represents less than three to five per cent of all described animal species. The rest is made up of the whopping 97%'ers, our dear invertebrates who include the arthropods (insects, arachnids, crustaceans, and myriapods), molluscs (our dear chitons, snails, bivalves, squid, and octopus), annelids (the often misunderstood earthworms and leeches), and cnidarians (our beautiful hydras, jellyfish, sea anemones, and corals). 

You will have noticed that many of our invertebrate friends occur as tasty snacks. Having a backbone provides a supreme advantage to your placement in the food chain. Not always, as you may include fish and game on your menu. But generally, having a backbone means you're more likely to be holding the menu versus being listed as an appetizer. So, enjoy your Sunday 'downward dog' and thank your backbone for the magical gift it is.

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, 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. 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

GORGONS OF THE GREAT KAROO

Gorgons or Gorgonopsia were sabre-toothed therapsids who roamed our ancient Earth from the Middle to Upper Permian — 265 to 252 million years ago — with their long claws, lizard eyes and massive canines. 

I learned about the Karoo, and indeed the Gorgons, by a book of the same name by the deeply awesome Peter Ward. His introduction to what life and fieldwork are like in the arid, inhospitable ancestral home of the Gorgons in South Africa made me laugh out loud. It is a highly enjoyable read. The Great Karoo was formed in a vast inland basin 320 million years ago, at a time when the part of Gondwana which would eventually become Africa lay over the South Pole. 

The Karoo records a wonderful time in our evolutionary history when the world was inhabited by interesting amphibians and mammal-like reptiles — including the apex predators of the day, the Gorgons.

The link below will take you to the Fossil Huntress Podcast where you can travel back in time to visit the Great Karoo with me. Here's the link: https://anchor.fm/.../The-Great-Karoo-of-South-Africa...

Photo: National Geographic Society

ACANTHOHOPLITES BIGOURETI

A very pleasing example of the Ammonite Acanthohoplites bigoureti (Seunes, 1887). Lower Cretaceous, Upper Aptian, from a riverbed concretion, Kurdzhips River, North Caucasus Mountains, Republic of Adygea, Russia. 

Geologically, the Caucasus Mountains belong to a system that extends from southeastern Europe into Asia and is considered a border between them. The Greater Caucasus Mountains are mainly composed of Cretaceous and Jurassic rocks with the Paleozoic and Precambrian rocks in the higher regions. 

Some volcanic formations are found throughout the range. On the other hand, the Lesser Caucasus Mountains are formed predominantly of the Paleogene rocks with a much smaller portion of the Jurassic and Cretaceous rocks. 

The evolution of the Caucasus began from the Late Triassic to the Late Jurassic during the Cimmerian orogeny at the active margin of the Tethys Ocean while the uplift of the Greater Caucasus is dated to the Miocene during the Alpine orogeny.

The Caucasus Mountains formed largely as the result of a tectonic plate collision between the Arabian plate moving northwards with respect to the Eurasian plate. As the Tethys Sea was closed and the Arabian Plate collided with the Iranian Plate and was pushed against it and with the clockwise movement of the Eurasian Plate towards the Iranian Plate and their final collision, the Iranian Plate was pressed against the Eurasian Plate. 

As this happened, the rocks that had been deposited in this basin from the Jurassic to the Miocene were folded to form the Greater Caucasus Mountains. This collision also caused the uplift and the Cenozoic volcanic activity in the Lesser Caucasus Mountains.

The preservation of this Russian specimen is outstanding. Acanthohoplites bigoureti are also found in Madagascar, Mozambique, in the Rhone-Alps of France and the Western High Atlas Mountains and near Marrakech in Morocco. This specimen measures 55mm and is in the collection of the deeply awesome Emil Black.

ANAHOPLITES PLANUS OF FRANCE

A beautiful specimen of the ammonite, Anahoplites planus (Mantell, 1822) from Albian deposits in Villemoyenne Quarry, Courcelles, Aube, north-central France. Anahoplites (Hyatt, 1900) is a genus of compressed hoplitid ammonites with flat sides, narrow, flat or grooved venters, and flexious ribs or striae arising from weak umbilical tubercles that end in fine dense ventrolateral nodes.

This lovely has attracted some roommates — an oyster, some bryozoans and worm tubes are attached to her shell.

Anahoplites is now included in the subfamily Anahoplitinae and separated from the Hoplitinae where it was placed in the older in the 1957 edition of the Treatise on Invertebrate Paleontology, Part L (Ammonoidea). Genera of the Hoplitinae tend to be more robust, with broader whorls and stronger ribs.

Anahoplites is found in Cretaceous (Middle to the Late Albian) deposits from England, through Europe, all the way to the Transcaspian Oblast region in Russia to the east of the Caspian Sea. The Aube department, named after the local river, is the type locality of the Albian stage (d'ORBIGNY, 1842). 

A. planus from the French Coast

Two formations are recognized in the clay facies (the "Gault" auct.) of the stratotype, the Argiles tégulines de Courcelles (82 m), overlain by the Marnes de Brienne (43 m). The boundary between the two formations is well-defined at the top of an indurated bed and readily identifiable in the field.

This involute (113 mm) specimen shows evidence of cohabitation by some of his marine peers. We see two different bryozoa, an oyster and some serpulids making a living and leaving trace fossils on her flat sides. The top specimen was prepared with potase by José Juárez Ruiz of Spain. 

The lovely Anahoplites planus you see here to the lower right was found by Bertus op den Dries on the French coast in Albian deposits near Wissant, P5 and measures in at 8 cm. This on edge view gives you a very good sense of the keel.

FREE RESOURCES FOR TEACHERS AND STUDENTS

Hello you! Are you a teacher or student looking for information or images for an educational project? You are more than welcome to use any of the images on this site that have the Fossil Huntress logo on them. The only catch is that they must be for school projects and not be printed more than 500,000 times. 

I have started to include the logo so you can know for sure it is okay to use. If I credit the photo to someone, you would need to ask them first before using it. 

I also post over on the Fossil Huntress Facebook page and will begin putting together teaching sets by album of related content. It is mostly palaeontology, earth history, earth science and natural history. Feel free to use what works best for you and good luck!

GRAPTOLITES

Graptolites (Graptolita) are colonial animals. The biological affinities of the graptolites have always been debatable. Originally regarded as being related to the hydrozoans, graptolites are now considered to be related to the pterobranchs, a rare group of modern marine animals.

The graptolites are now classed as hemichordates (phylum Hemichordata), a primitive group that probably shares a common ancestry with the vertebrates.

In life, many graptolites appear to have been planktonic, drifting freely on the surface of ancient seas or attached to floating seaweed by means of a slender thread. Some forms of graptolite lived attached to the seafloor by a root-like base. Graptolite fossils are often found in shales and slates. The deceased planktonic graptolites would sink down to and settle on the seafloor, eventually becoming entombed in the sediment and are thus well preserved.

Graptolite fossils are found flattened along the bedding plane of the rocks in which they occur. They vary in shape, but are most commonly dendritic or branching (such as Dictoyonema), saw-blade like, or "tuning fork" shaped, such as Didymograptus murchisoni.

ICHTHYOSAUR VERTEBRAE

A wee ichthyosaur vertebrae from Berlin-Ichthyosaur State Park, Nevada, USA. This area in central Nevada is a very important locality for our understanding of the Carnian-Norian boundary (CNB) in North America. 

To picture our world at this time, most continents were merged into the supercontinent Pangaea, and there was a single global ocean, Panthalassa. Swimming in that ocean were the large marine reptiles we find in these Nevada exposures — and indeed worldwide — today.

On the land, we meet the earliest dinosaurs, Herrerasaurus and Eoraptor — around 230 Ma. 

The oldest well documented dinosaurian assemblage, in the Ischigualasto Formation, a Late Triassic fossiliferous formation and Lagerstätte in the Ischigualasto-Villa Unión Basin of the southwestern La Rioja Province and northeastern San Juan Province in northwestern Argentina, dates to this time as well.

If you are considering a visit to Berlin-Ichthyosaur State Park or indeed, Nevada, choose October. Not too hot, nor too cold — but it is tarantula breeding season — so step lively! 

Know Before You Go — Berlin-Ichthyosaur State Park

This is a wonderful place to explore for a very reasonable sum of $5.00 US. Open year-round (though check regarding accessibility during Covid).  

Contact information: Tel: 775-964-2440 / Email: bisp@parks.nv.gov. Pop these coordinates into your GPS to make your travel easier: HC-61 Box 61200, Austin, NV 89310

SAURAVUS: SAURAVUS COSTEI

The type species of Sauravus, Sauravus costei, is known from Blanzy, a town in the Saône-et-Loire department of France. 

This town and its adjacent community Montceau-les-Mines possess containing abundant Carboniferous fossils. These fossils are believed to have been from the Stephanian B stage of the Late Carboniferous, approximately 305 to 304 million years ago.

Sauravus cambrayi is known from Les Télots, a mine near Autun, Saône-et-Loire, France. 

Télots is the type locality of the Autunian stage, a period of time which is believed to correspond to part of the early Permian period. The geological formation to which Télots fossils belong is known as the Millery Formation. 

The specific part of the Permian to which this formation belongs to was unclear for many years. In 2014, Schneider et al. suggested that the Millery Formation dated to the middle Artinskian age, about 290 to 286 million years ago.

Sauravus spinosus is a rename of Scincosaurus spinosus, a Montceau-les-Mines scincosaurid described by C. Civet in 1982. Although that author considered the species to belong to Scincosaurus, in 1994 Jean-Michel Dutuit and D. Heyler believed considered it a species of Sauravus.

CHARIOCRINUS: FRANCE

Chariocrinus andrae, Collection: David Appleton

Crinoids are one of my favourite echinoderms. It is magical when all the elements come together to preserve a particularly lovely specimen in such glorious detail. 

This impressive block, chock full of lovely, well-preserved specimens of the crinoid, Chariocrinus andrae, hails from Bathonian outcrops in Beaune, Saône-et-Loire in the Bourgogne-Franche-Comté region of central-eastern France. They are intertwined to cover most of the surface area of the citrus coloured matrix. 

Crinoids are unusually beautiful and graceful members of the phylum Echinodermata. They resemble an underwater flower swaying in an ocean current. But make no mistake they are marine animals. Picture a flower with a mouth on the top surface that is surrounded by feeding arms. Awkwardly, add an anus right beside that mouth. That's him!

Crinoids with root-like anchors are called Sea Lilies. They have graceful stalks that grip the ocean floor. Those in deeper water have longish stalks up to 3.3 ft or a meter in length.

Then there are other varieties that are free-swimming with only vestigial stalks. They make up the majority of this group and are commonly known as feather stars or comatulids. 

Unlike the sea lilies, the feather stars can move about on tiny hook-like structures called cirri. It is these same cirri that allow crinoids to latch to surfaces on the seafloor. Like other echinoderms, crinoids have pentaradial symmetry. The aboral surface of the body is studded with plates of calcium carbonate, forming an endoskeleton similar to that in starfish and sea urchins.

These make the calyx somewhat cup-shaped, and there are few, if any, ossicles in the oral (upper) surface, an area we call the tegmen. It is divided into five ambulacral areas, including a deep groove from which the tube feet project, and five interambulacral areas between them. 

Crinoids are alive and well today. They are also some of the oldest fossils on the planet. We have lovely fossil specimens dating back to the Ordovician — if one ignores the enigmatic Echmatocrinus of the Burgess Shale. And they can be quite plentiful. Crinoid fossils, and in particular disarticulated crinoid columnals, can be so abundant that they at times serve as the primary supporting clasts in sedimentary rocks

This beautiful 7" x 6" piece was photographed in natural sunlight to help show off the amazing detail. Photo and collection of the deeply awesome David Appleton.

DELGADOCRINUS OPORTOVINUM

This exceptionally well-preserved crinoid, Delgadocrinus oportovinum, was found on October 11, 1905, by Nery Delgado during his work mapping the geology and paleontology of Portugal.

His find resulted in the creation of a new family, Delgadocrinoinidae, a new genus and a new species.

Ausich et al. published on New and Revised Occurrences of Ordovician Crinoids from Southwestern Europe in the Journal of Paleontology, November 2007. In their work, they honour Delgado. His find was the first record of an Ordovician crinoid from Portugal, Delgadocrinus oportovinum, marking it as the oldest known crinoid from the Iberian Peninsula, Arenigian/Oretanian boundary, early Darriwilian.

The team took a comprehensive look at the Ordovician crinoids of southwestern Europe, including taxa based on articulated crowns and stems. This summary incorporates new material, new localities, and a revision of some southwestern Europe occurrences and is well worth a read. The Type Specimen you see here is now housed in the Natural History Museum of Lisbon. Luis Lima shared a photo of his recent visit to their beautiful collections and kindly granted permission to share the photo.

Reference: Ausich, William & Sá, Artur & Gutiérrez-Marco, Juan. (2007). New and revised occurrences of Ordovician crinoids from southwestern Europe. Journal of Paleontology - J PALEONTOL. 81. 1374-1383. 10.1666/05-038.1.

UNRAVELLING THE CARNIAN-NORIAN BOUNDARY

Berlin-Ichthyosaur State Park

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

The area is also known worldwide as one of the most important ichthyosaur Fossil-Lagerstätte because of the sheer volume of remarkably well-preserved, fully articulated specimens of Shonisaurus popularis.

Rich ammonoid faunas outcrop in the Upper Triassic (Early Norian, Kerri zone), Luning Formation, West Union Canyon, Nevada. They were studied by N. J. Silberling (1959) and provide 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. 

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

Middle Triassic Ammonoids

Despite its importance, no further investigations had been done at this site for a good 50 years. That changed in 2010 when Jim Haggart, Mike Orchard and Paul Smith — all local Vancouverites — collaborated on a project that took them down to Nevada to look at the conodonts and ammonoids. They did a bed-by-bed sampling of ammonoids and conodonts in West Union Canyon during October of that year.

October is an ideal time to do fieldwork in this area. There are a few good weeks between screaming hot and frigid cold. It is also tarantula breeding season so keep your eyes peeled. Those sweet little burrows you see are not from rodents but rather largish arachnids. 

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.

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 after BC's own Mike Orchard.

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 coeval faunas of the Tethys and Canada. 

The ammonoid fauna paints a compelling picture of Tethyan influence with a series of smoking guns. We see an abundance of Tropitidae in the Carnian, a lack of Pterosirenites in the Norian, copious Guembelites, the Tethyan species G. philostrati, the stratigraphic position of G. clavatus and the rare occurrence of Gonionotites. Their hallelujah moment was likely finding an undescribed species of the thin-shelled bivalve Halobia similar to Halobia beyrichi — the clincher that perhaps seals this deal on Tethyan influence. 

I'll take a boo to see what Christopher McRoberts published on the find. A jolly good idea to have him on this expedition as it would have been easy to overlook if the focus remained solely on the conodonts and ammonoids. McRoberts has published on the much-studied Pardonet Formation up in the Willison Lake Area of Northeastern, British Columbia. He knows a thing or two about Upper Triassic Bivalvia and the correlation to coeval faunas elsewhere in the North American Cordillera, and to the Boreal, Panthalassan and Tethyan faunal realms. 

If you fancy a read, they 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.

Fig. 1. Location map of Berlin-Ichthyosaur State Park

Marco Balini, James Jenks, Riccardo Martin, Christopher McRoberts, along with Mike Orchard and Norman Siberling, did a bed by bed sampling in 2013 and published on The Carnian/Norian boundary succession at Berlin-Ichthyosaur State Park (Upper Triassic, central Nevada, USA) and published in January 2014 in Paläontologische Zeitschrift 89:399–433. That work is available for download from ResearchGate. The original is in German, but there is a translation available.

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'd 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.

If you plan your own adventure, you'll want to keep an eye out for some of the other modern fauna — mountain lions, snakes, lizards, scorpions, wolves, coyotes, foxes, ground squirrels, rabbits, falcons, hawks, eagles, bobcats, sheep, deer and pronghorns.

Figure One: Location map of Berlin-Ichthyosaur State Park. A detailed road log with access information for this locality is provided in Lucas et al. (2007).

CEPHALOPODS OF HALLSTATT

This beautiful slab of well-preserved Triassic, Carnian, upper Tuvalian ammonoids hails limestone outcrops near the salt-mining town of Hallstatt, Salzburgerland, Austria.

This area of the world boasts one of the richest deposits of Triassic ammonite units — more than five hundred magnificent ammonite species are found here along with a diversified selection of cephalopod fauna  — orthoceratids, nautiloids, ammonoids — we also see gastropods, bivalves (including lovely halobiids), brachiopods, crinoids and a few corals. For microfauna, we see conodonts, foraminifera, sponge spicules, radiolaria, floating crinoids and holothurian sclerites —  polyp-like, soft-bodied "wormy" invertebrate echinozoans. On the left, you can see two specimens of Jovites bosniensis MOJS. The ammonoid in the middle of the plate is Juvavites sp. The right side of the block shows two Hypocladiscites subtornatus MOJS.

The larger specimen (15cm) is a phragmocone. Within its badly crushed body chamber (removed during prep) there are two washed in specimens of Disotropites plinii (MOJS.) You can see them visible in the side view on the top right. The Disotropites plinii subzone is the lower ammonoid subzone of the Tuvalian III.

The second picture here shows Hypocladiscites subtornatus from when it was first described as Arcestes subtornatus, in Mojs, 1873.

In the North American literature (after Tim Tozer) the Tuvalian is split into three Zones; starting with the Dilleri Zone, then the Welleri Zone and finally the Macrolobatus Zone on the very top.

The Dilleri zone is characterized by the rise of the genus Tropites sp. together with later members of the genus Neoprotrachyceras sp.

In the Welleri zone, Neoprotrachyceras sp. disappears and Tropites becomes a very common faunal element. The Macrolobatus zone is named after Klamathites macrolobatus, an endemic ammonite of the North American strata. Other genera of this zone are comparable to the time frame of the latest Tuvalian and the earliest Norian of the Alps. In the Hallstatt (Tethys) realm the following Division is made:

Dilleri Zone= Tuvalian I (literature gives little evidence for this zone). Subbullatus Zone = Tuvalian II — corresponding in most parts to the North American Welleri Zone. These are followed by the Anatropites Zone or Tuvalian III — corresponding in part to the North American Macrolobatus Zone.

In the Alps, the strata are divided between Tuvalian II and Tuvalian III. It is up for debate if all three North American zones can be included in these two alpine zones. It has been postulated by Spatzenegger that there is little evidence for a time gap in the lower Tuvalian of the Alpine strata.

Discotropites sandlingense is in the North America zone — a clear Dilleri faunal element. In the Alps, it is ranged into Tuvalian II (Welleri Zone). The same is true for the genus Traskites sp. — corresponding to alpine Sandlingites sp. Some ammonites of the upper part of the Macrolobatus zone are also placed within the alpine Norian stage. The correlation between the North American and Alpine zones is problematic and matching up the Tuvalian fauna is a tricky business.

Sirenites sp., Upper Triassic, Lower Carnian Julian Zone

Tuvalian 1 is recognizable in the Alps by the composition of the faunal spectrum — the quantity of some special genera. We see more of some, less of others, and this gives us a general sense of time.

In some strata, Trachysagenites sp. Sagenites inermis, Sandlingites sp. occur frequently together, with scarce Tropites sp. and Sirenites sp. and (very rarely) Neoprotrachyceras cf. thyrae.

The transition from Tuvalian to the Norian is confirmed only in one location in the Hallstatt limestone. Clustered onto blocks, the ammonoids show us the faunal mix and allow us to place them in time. The bedded profile of Tuvalian fauna (which is overlain by a Norian fauna) hails from the Feuerkogel near Hallstatt. Here we also find the lower transition of Julian to Tuvalian. Not far from this site are limestone outcrops that show the transition between the Carnian and Norian. Here the latest Tuvalian and lowermost Norian are confirmed only by the microfossil fauna.

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 (esp. halobiids), brachiopods, crinoids and a few corals.

Along with an amazing assortment of macrofossils, we see microfauna that are incredibly helpful in teasing out the geologic history of the area. Fossil conodonts, foraminifera, sponge spicules, radiolaria, floating crinoids and the bizarre 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 — can be found here.

Eduard Suess, Gondwana / Tethys Sea

Franz Ritter 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 supercontinent of Gondwana (proposed in 1861) and the existence of the Tethys Sea, which he named in 1893 after the sister of Oceanus, the Greek god of the ocean.

Suess Land in Greenland, as well as the lunar crater Suess and Suess crater on Mars, are named after him.

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.

This area has a rich and interesting geological and human history. I'm sure more studies will be done on the fossil marine fauna to untangle and standardize the Carnian subdivisions. For now, we'll muddle along with regional stratigraphies employing a two-substage subdivision, the Julian and Tuvalian. Others will continue to employ a three-substage organization of the stage: Cordevolian, Julian and Tuvalian. 

As I've pieced together this interesting Tuvalian tale, I have to thank Andreas Spatzenegger from Salzburg, Austria for his insights, work and amazing photos of the area. Kudos to you, my friends. I'd be mesmerized but still well confused about the Carnian subdivisions if not for you!

The genus Hypocladiscites ranges from the base Carnian to the lower Norian stage of the Upper Triassic. Photos and collection of the deeply awesome Andreas Spatzenegger of Salzburg, Austria.

Superfamilia: Arcestaceae MOJSISOVICS, 1875; Familia: Cladiscitidae ZITTEL, 1884; Subfamilia: Cladiscites GAMSJÄGER, 1982; Genus: Hypocladiscites MOJSISOVICS, 1896

Photo: A spectacular example of Sirenites sp., Upper Triassic, Lower Carnian, Julian Zone of Trachyceras aonoides. From Hallstatt Limestone of Austria. This specimen is about 5cm. Photo and collection of the deeply awesome Andreas Spatzenegger.

Photo: Eduard Suess (1831–1914), lithograph by Josef Kriehuber (1800–1876) c. 1869 by Josef Kriehuber - File:Eduard Sueß.jpg (cropped), Public Domain https://commons.wikimedia.org/w/index.php?curid=31526345

TRIASSIC EPIGYMNITES OF HALLSTATT

Epigymnites arthaberi (MOJS.) and Epigymnites moelleri (MOJS.) Photo: Andreas

It was the Austrian geologist, Alexander Bittner, a contemporary of Mojsisovics, who introduced the term Ladinian into literature. 

The name Ladinian was chosen by Bittner after the Ladinian folk of the Southern Alps/Dolomites. At the time, this area was part of the Austrian-Hungarian monarchy with its capital in Vienna. The “Vienna school” of thinking dominated the palaeontology institutions there at the time.

Bittner's introduction of the name Ladinian arose from his recognition of many of the false assumptions of Mojsisovics — assumptions which led to misguided views regarding the ammonoid zones within the Norian timescale well into the 20th century. It was the lovely Tim Tozer who took the time to correct these long lasting errors through his work teasing out the North American Triassic timescale. Tozer used North American, mainly Canadian Triassic ammonoid locations as the basis for his work. Once complete, a correlation with the European Triassic timescale was finally realized.