Wednesday, 30 June 2021

FOSSILS, TEXTILES AND URINE

Yorkshire Coast
You may recall the eight-metre Type Specimen of the ichthyosaur, Temnodontosaurus crassimanus, found in an alum quarry in Yorkshire, northern England.

The Yorkshire Museum was given this important ichthyosaur fossil back in 1857 when alum production was still a necessary staple of the textile industry. Without that industry, many wonderful specimens would likely never have been unearthed.

These quarries are an interesting bit of British history as they helped shape the Yorkshire Coast, created an entirely new industry and gave us more than a fixative for dyes. With them came the discovery of many remarkable fossil specimens and, oddly, local employment in the collection of urine.

In the 16th century, alum was essential in the textile industry as a fixative for dyes. 

By the first half of the 16th century, the clothing of the Low Countries, German states, and Scandinavia had developed in a different direction than that of England, France, and Italy, although all absorbed the sobering and formal influence of Spanish dress after the mid-1520s. Those fashions held true until the Inquisition when religious persecution, politics and fashion underwent a much-needed overhaul to something lighter.

Fashion in Medieval Livonia (1521): Albrecht Dürer
Elaborate slashing was popular, especially in Germany. In the depiction you see here, an artist pokes a bit of fun at Germanic fashion from the time. Bobbin lace arose from passementerie in the mid-16th century in Flanders, the Flemish Dutch-speaking northern portion of Belgium. Black was increasingly worn for the most formal occasions.

This century saw the rise of the ruff, which grew from a mere ruffle at the neckline to immense, slightly silly, cartwheel shapes. They adorned the necklines of the ultra-wealthy and uber-stylish men and women of the age.

At their most extravagant, ruffs required wire supports and were made of fine Italian reticella, a cutwork linen lace.

16th Century Fashion / Ruff Collars and Finery
In contrast to all that ruff, lace and cutwork linen, folk needed dyed fabrics. And to fix those dyes, they needed Alum. For a time, Italy was the source of that alum.

The Pope held a tidy monopoly on the industry, supplying both alum and the best dyes. He also did a nice trade in the colourful and rare pigments for painting. And for a time, all was well with dandy's strutting their finery to the local fops in Britain.

All that changed during the Reformation. Great Britain, heathens as they were, were cut-off from their Papal source and found themselves needing to fend for themselves.

The good Thomas Challoner took up the charge and set up Britain's first Alum works in Guisborough. Challoner looked to paleontology for inspiration. Noticing that the fossils found on the Yorkshire coast were very similar to those found in the Alum quarries in Europe, he hatched a plan to set-up an alum industry on home soil. As the industry grew, sites along the coast were favoured as access to the shales and subsequent transportation was much easier.

Alum House, Photo: Joyce Dobson and Keith Bowers
Alum was extracted from quarried shales through a large scale and complicated process which took months to complete. The process involved extracting then burning huge piles of shale for 9 months, before transferring it to leaching pits to extract an aluminum sulphate liquor. This was sent along channels to the alum works where human urine was added.

At the peak of alum production, the industry required 200 tonnes of urine every year. That's the equivalent of all the potty visits of more than 1,000 people. Yes, strange but true.

The steady demand was hard to keep up with and urine became an imported resource from markets as far away as London and Newcastle upon Tyne in the northeast of England. Wooden buckets were left on street corners for folk to do their business then carted back to the south to complete the alum extraction process. The urine and alum would be mixed into a thick liquid. Once mixed, the aromatic slosh was left to settle and then the alum crystals were removed.

I'm not sure if this is a folktale or plain truth, but as the story goes, one knows when the optimum amount of alum had been extracted as you can pop an egg in the bucket and it floats on its own.

Alum House. Photo: Ann Wedgewood and Keith Bowers
The last Alum works on the Yorkshire Coast closed in 1871. This was due to the invention of manufacturing synthetic alum in 1855, then subsequently the creation of aniline dyes that contained their own fixative.

There are many sites along the Yorkshire Coast which bear evidence of the alum industry. These include Loftus Alum Quarries where the cliff profile is drastically changed by extraction and huge shale tips remain.

Further South are the Ravenscar Alum Works, which are well preserved and enable visitors to visualize the processes which took place. The photos you see here are of Alum House at Hummersea. The first shows the ruin of Alum House printed on a postcard from 1906. The second (bottom) image shows the same ruin from on high with Cattersty Point in the background.

The good folk at the National Trust in Swindon are to thank for much of the background shared here. If you'd like to learn more about the Yorkshire area or donate to a very worthy charity, follow their link below.

Reference: https://www.nationaltrust.org.uk/yorkshire-coast/features/how-alum-shaped-the-yorkshire-coast

Tuesday, 29 June 2021

TEMNODONTOSAURUS CRASSIMANUS

Temnodontosaurus crassimanus
This big beastie is the ichthyosaur, Temnodontosaurus crassimanus, who graced our ancient oceans 180 million years ago. The species was originally named by Richard Owen, the first superintendent of the Natural History Museum. Owen lived at the height of the gentleman scientist and it was Owen who first coined the name dinosaur. Dean Lomax did some work with this specimen as part of his research leading up to his PhD.

The fellow you see here is the Type Specimen for the species and he lives on display in the Yorkshire Museum. As the reference specimen for the species, all hopeful specimens that may belong to this species are checked against the Type Specimen to see if they share diagnostic features.

The Yorkshire Museum was given this important ichthyosaur fossil back in 1857, albeit in bits and pieces. The first bits of fossil bones were found near Whitby on the North Yorkshire coast by workmen quarrying alum. They recognized the bones as belonging to a fossilized reptile and alerted local authorities who in turn alerted the good Master Owen.

It was quite an undertaking to recover as it was found in more than fifty pieces in massive shale blocks and the alum quarry was active at the time. Alum quarrying helped share the Yorkshire Coast as an important staple of the textile industry going back to the 16th-century. By the 1860s, alum quarrying was slowing down. The ability to manufacture synthetic alum by 1855 had shifted the industry and it died out entirely by 1871. Lucky for us, the last years of alum production gifted us this well-preserved eight-metre specimen, one of the largest ichthyosaurs ever discovered in the UK.

Paleo-coordinates: 54.5° N, 0.6° W: paleocoordinates 42.4° N, 9.3° E

Monday, 28 June 2021

CAMBRIAN MYSTERIES OF THE CANADIAN ROCKIES

Mount Stephen, Canadian Rockies
High up on the mountain tops of the Canadian Rockies of southeastern British Columbia — on the western edge of Western Canada's Sedimentary Basin — there are mysteries more than half a billion years old. 

Here, for more than a century, palaeontologists have been exploring over a dozen geologic outcrops that speak of a world when arthropods ruled the seas. 

The rocks we walk across are made of shale, thin-bedded limestone, and siltstone deposited during the Middle Cambrian — 513 to 497 million years ago. And these are no ordinary rocks for what they contain — exceptionally preserved soft-bodied fossils of the Burgess Shale biota. 

Charles Doolittle Walcott will be forever remembered for his extraordinary 1909 discovery of the Middle Cambrian Burgess Shale of Yoho National Park in southern British Columbia — delivering to the world one of the most important biota of soft-bodied organisms in the fossil record. Here we find a fairly complete look at an ancient ecosystem with algae, grazers and filter feeders, scavengers and active predators. Remarkably, soft-bodied organisms make up 98% of individuals and 85% of the genera. These animals lived and died in the deep waters at the base of what would later become the Cathedral Escarpment.

In 1908, Walcott wrote, "Nearly every fragment of shale found on the slopes from 2000 to 2600 feet above Field has fossils upon it; not only fragments but usually entire specimens of trilobites.” It was for this reason he returned the following year to collect and the rest, as they say, is history.

The sheer volume and level of preservation were unknown at the time. Walcott's material came from a single section on the west side of the ridge between Mount Wapta and Mount Field and was collected from the main quarry in the Phyllopod bed and the smaller Raymond quarry some 23 m above. 

The Burgess Shale section occurs in the lower two-thirds of the Stephen Formation where the basinal shales abut against the steep face of the adjacent dolomite reef of the Cathedral Formation. The conditions necessary for the preservation of the soft parts of the organisms appear to have been controlled by the proximity of this reef front. Away from the reef front, exceptional preservation is less common.

A view to Mount Stephen, Canadian Rockies
The Burgess Shale was long considered to be a unique occurrence. Then in 1977, Canadian geologist, Ian McIlreath, found that the Cathedral Escarpment or reef front, could be traced for about 20 km southeast of Walcott's quarry and that the contact between the reef and basinal shales cropped out again on Mount Field, Mount Stephen, Mount Odaray, Park Mountain and Curtis Peak. 

Des Collins speculated that more localities of soft-bodied fossils might be found in the basinal shales near these contacts, and, indeed, a few indications were later reported by Aitken and McIlreath (1981) along the line of the Escarpment. 

In 1981 and 1982, we expanded our knowledge of the region. Des Collins and others organized fieldwork that led to the discovery of about a dozen new localities, which Collins et al. published in 1983.

The most promising of the new localities occurred in a large in situ block of pale grey-blue siliceous shale about 1500 m southwest of the outcrop of the Cathedral Escarpment on the north shoulder of Mount Stephen. 

This is about 5 km almost directly south of the Burgess Shale quarries. The site was excavated by a Royal Ontario Museum party in the summer of 1983. Further fieldwork in 1986 led to the discovery of the arthropod Sanctacaris was first described by Briggs and Collins in 1988. 

Sanctacaris uncata, Mount Stephen Fossil Beds

The stratigraphic level where the block occurred is characterized by the trilobite, Glossopleura, which is the local zone fossil for the basal part of the basinal Stephen Formation (Fritz, 1971). 

In the Stephen Formation section of about 1000 m to the north on Mount Stephen measured by Fritz, the top of the Glossopleura Zone is 40 m below the level equivalent to the main Burgess Shale quarry. 

The block excavated was at least 40 m below the top of the Glossopleura Zone. This puts it 80 m or more stratigraphically below the level of the Burgess Shale Phyllopod bed.

The faunal assemblage from the block is dominated by the arthropods, Alalcomenaeua and Branchiocaris, which are very rare in the Burgess Shale. Many other Burgess Shale animals were found (Collins et al. 1983) but surprisingly not the most common — Marrella. They did find many new forms and published their finds in 1986 (Collins, 1986). By all accounts, this fauna is distinct from those in the Burgess Shale — and a shade older

But as we learn and gain insight, we also realize how much we have yet to learn. These outcrops help us to gain an understanding of the biology, ecology, diversity and evolution of Cambrian animals in a way that other Cambrian sites cannot. Without this insight, we would have a very limited view of the Cambrian Explosion and see only the shelly fossil assemblages. The unique conditions in the Burgess Shale record species that under typical circumstances, would never have fossilized and would be lost to us forever.

There has been no end of mysteries and riddles to be solved in the designating and correlating units within the Stephen Formation, Burgess Shale Formation, and the Cathedral Formation. Much of the controversy stems from the extensive faulting in the area and especially from environmental (facies) differences between the stratigraphic units. 

There are shelf platform sequences that include shallow water inner detrital belt, middle carbonate belt, and carbonate shelf edge facies, as well as deeper water (basinal) outer detrital belt facies. These have all have posed problems in correlation and descriptions of the formations in the area.

What used to be known as the Stephen Formation is now restricted to what was known as the "thin" Stephen Formation. The Stephen Formation now includes the Narao and Wapituk Members. What was formerly the "thick" Stephen Formation (basinal Stephen) is now called the Burgess Shale Formation. 

Pirania sp., extinct sea sponges, Burgess Shale
This formation comprises units that include the classic Burgess Shale localities (Walcott Quarry (including the "phyllopod bed"), Raymond Quarry), the Mt. Stephen Trilobite Beds, as well as most of the soft-bodied faunas (Collins Quarry, S7, Ehmaniella Zone faunas, etc.).

The Burgess Shale is a UNESCO World Heritage site. The Burgess Shale and Stephen Formations outcrop mainly in Banff and Yoho National Parks in the Alberta-British Columbia border area. All known outcrops are in Canada's Rocky Mountain Parks, so collecting is strictly forbidden. 

While you cannot collect in the parks, you can join in on a guided tour to hike, explore, capturing the beautiful scenery and fossils with your camera and through rubbings. If you fancy a hike to these exalted cliffs, follow the link below.

If an armchair visit is more your thing, pick up a copy of, A Geoscience Guide To The Burgess Shale. This illustrated guide immerses the reader in the history, geology, environment and, most importantly, fossils of the Burgess Shale in an easy-to-read, concise summary of life as it was over 500 million years ago. Excellent colour images of 3D interpretations of the organisms and photos of the fossils make this resource a must-have for anyone interested in the Burgess Shale. 

Burgess Shale Hikes: https://www.burgess-shale.bc.ca/burgess-shale-hikes/  / Toll free: 1 (800) 343-3006; Tel: 1 (250) 343-6006; Email: info@burgess-shale.bc.ca

A Burgess Shale Primer: History, Geology and Research Highlights; Jean-Bernard Caron & Dave Rudkin: https://www.rom.on.ca/sites/default/files/imce/burgess_shale_primer.pdf

References: Palaeontology, Vol 31, Part 3. 1988, pp 779-798, pls 71-73) was discovered by Collins (1986),http://palaeontology.palass-pubs.org/pdf/Vol 31/Pages 779-798.pdf

Image: Reconstruction of Sanctacaris uncata, a Cambrian Habeliidan arthropod (stem-Chelicerata: Habeliida). by Junnn11 @ni075; Pirania sp. & photos: @Fossil Huntress

Sunday, 27 June 2021

IN PRAISE OF FOSSIL LAGERSTÄTTEN


A Lagerstätte is a sedimentary deposit with extraordinary fossils with exceptional preservation — sometimes preserving soft tissues when we are very lucky. 

When you see a specimen and it makes you go 'whoah' — that is a good indication that you are likely seeing one of the wonderfully preserved goodies from these marvellous sites.

There are about 50 sites we collectively describe as Lagerstätten — though there are many more sites that could reasonably be argued for — and they are. The list below gives you a place to start but it is by no means exhaustive and will grow as more sites are found and explored.

If you are curious about checking out these wonderfully preserved sites, pay a visit to @FossilBonanza, the Twitter home of Andy, an educator at NHMU. On both his @FossilBonanza Twitter stream and his podcast of the same name, Andy gushes about Lagerstätten from around the globe.

He's also created a rather clever interactive map of the world’s Lagerstätten divided by time period. You can visit here: https://maphub.net/FossilBonanza/Lagerstatte. To listen to the Fossil Bonanza Podcast: https://podcasts.apple.com/.../fossil-bonanza/id1535645906

Saturday, 26 June 2021

CAMBRIAN BIVALVED ARTHROPODS

Bivalved Cambrian Arthropods had a carapace that covered their cephalothorax — their fused head and thorax — and is most often the only structure preserved in the fossil record. It is the exceptional preservation at sites like the Burgess Shale — and other Cambrian Lagerstätten — that has opened up our understanding and allowed us to know more about these ancient marine animals. 

The image you see here is a composite from many publications that have been pulled together into a full composite with scaling by the talented Alejandro Izquierdo, an evolutionary biologist fast-tracking his way to a PhD at the University of Toronto's Invertebrate Palaeontology lab. The Canadaspis shadow you see here is from Derek Brigg's 1975 reconstruction. I have modified the image further still and you are welcome to use it as a teaching tool — but please do credit Alejandro as he did all the heavy lifting in putting it together.

I caught up with Alejandro this week to ask about the origins of this image — which I have modified a bit further still — and to talk about Pakucaris apatis and Fibulacaris nereidis — two recent additions to our knowledge of bivalved arthropods. Both show us how "bizarre" some of these animals can be. Pakucaris presents different features — frontal filaments, a pygidium — which may be important in the future to understand early arthropod evolution.

Beyond his research into our Cambrian friends, Alejandro is a science writer and prog-rock aficionado. Should you want to catch up with him, find him on Twitter @trichodes or for all sorts of yummy evolutionary biology goodness seek out the site he co-runs with Marc Riera, an ecologist and PhD student looking at biological invasions at CREAF — a public research centre that exists as a consortium between different public entities — administrations, universities, and research centres and institutes. You can find Marc @bitoptera and their combined work at @ElephaBacteria. 

Do visit their delightful website — On elephants and bacteria — a feast of interdisciplinary topics that gather evolutionary biology, astronomy, history with a mission to advance scientific thinking. It is well worth exploring. Here is the link: https://onelephantsandbacteria.net/

Friday, 25 June 2021

CHELICERATES: EURYPTERIDS, SPIDERS AND HORSESHOE CRABS

Sanctacaris uncata, (Briggs & Collins, 1988)
Chelicerates first emerged in our ancient oceans some 508 million years ago, as the arthropod Sanctacaris uncata (Briggs & Collins, 1988) known from the Glossopleura Zone, Stephen Formation of Mount Stephen in the Canadian Rockies of British Columbia, Canada. 

Sanctacaris is proof positive that chelicerates, although rare, were present in our Middle Cambrian seas. 

Even at this early stage of evolution, Sanctacaris had the number and type of head appendages found — though in modified form — in eurypterids and xiphosurids, the major Palaeozoic groups that succeeded it. Even more interesting is that Sanctacaris had all the characteristics of later chelicerates except chelicerae — placing this early arthropod in a primitive sister group of all other chelicerates.

An extinct marine creature half a billion years old may sound otherworldly, but you know some of their more well-known marine brethren — sea spiders, the sexy eurypterids, chasmataspidids and horseshoe crabs — and some of their terrestrial cousins — spiders, scorpions, harvestmen, mites and ticks. 

They are grouped together because, like all arthropods, they have a segmented body and segmented limbs and a thick chitinous cuticle called an exoskeleton. Add those characteristics to a body system with two body segments — a cephalothorax and an abdomen. 

Like all arthropods, chelicerates' bodies and appendages are covered with a tough cuticle made mainly of chitin and chemically hardened proteins. 

Since this cannot stretch, the animals must moult to grow. In other words, they grow new but still soft cuticles, then cast off the old one and wait for the new one to harden. 

Until the new cuticle hardens the animals are defenceless and almost immobilized.  

This also helps to explain why you find so many cephalons or moulted head shields — or whatever else our good arthropod friends shed and regrow — in the field and far fewer body fossils of the whole animal.

Some chelicerate are predatory animals that patrol the warm waters near thermal vents. They can be found feeding upon other predators and fish. Although the group were originally solely predatory, they have diversified to use all sorts of feeding strategies: predation, parasitism, herbivory, scavenging and dining on bits of decaying organic matter. 

Although harvestmen can digest solid food it is more akin to a mashed pulp by the time they do. The guts of most modern chelicerates are too narrow to digest solid food, instead, they generally liquidize their chosen meal by grinding it with their chelicerae and pedipalps then flooding it with digestive enzymes. 

To conserve water, air-breathing chelicerates excrete waste as solids that are removed from their blood by Malpighian tubules, structures that also evolved independently in insects — another case of convergent evolution.

The evolutionary origins of chelicerates from the early arthropods have been debated for decades. And although there is considerable agreement about the relationships between most chelicerate sub-groups, the inclusion of the Pycnogonida in this taxon has recently been questioned and the exact position of scorpions is still controversial — though they have long been considered the most primitive or basal of the arachnids. 

We still have much to explore to sort out their evolutionary origins and placement within the various lineages but we will get there in time.

Image One: Reconstruction of Sanctacaris uncata, a Cambrian Habeliidan arthropod (stem-Chelicerata: Habeliida). by Junnn11 @ni075; Image Two: Chelicerata by Fossil Huntress

Aria C, Caron JB (December 2017). "Mandibulate convergence in an armoured Cambrian stem chelicerate". BMC Evolutionary Biology. 17 (1): 261. doi:10.1186/s12862-017-1088-7. PMC 5738823. PMID 29262772.

Legg DA (December 2014). "Sanctacaris uncata: the oldest chelicerate (Arthropoda)". Die Naturwissenschaften. 101 (12): 1065–73. doi:10.1007/s00114-014-1245-4. PMID 25296691.

Briggs DE, Collins D (August 1988). "A Middle Cambrian chelicerate from Mount Stephen, British Columbia" (PDF). Palaeontology. 31 (3): 779–798. Archived from the original (PDF) on July 16, 2011. Retrieved April 4, 2010.

Briggs DE, Erwin DH, Collier FJ (1995). Fossils of the Burgess Shale. Washington: Smithsonian Institution Press. ISBN 1-56098-659-X. OCLC 231793738.

Thursday, 24 June 2021

FIBULACARIS NEREIDIS: A NEW BIVALVED CAMBRIAN ARTHROPOD

Fibulacaris nereidis / Artwork by Danielle Dufault @MesozoicMuse
Fibulacaris nereidis is a new species joining the ranks of the Cambrian bivalved arthropod. Alejandro Izquierdo-López and Jean-Bernard Caron published on this new species, closely related to Pakucaris back in 2019. 

The wonderful illustration above by the talented Danielle Dufault shows how bizarre or alien some of these animals can be. 

The origin of the arthropod carapace, an enlargement of cephalic tergites, can be traced back to the Cambrian period. Even so, its disparity and evolution are still not fully understood. It is the detailed study of species such as this new ‘bivalved’ arthropod, Fibulacaris nereidis gen. et sp. nov., that will help us get closer to the truth. 

Interpretive Cladogram
The team had plenty of material to work with for this analysis. This new species is based upon 102 specimens from the middle Cambrian, Wuliuan Stage,  Burgess Shale, Marble Canyon area in British Columbia's Kootenay National Park, Canada. 

The laterally compressed carapace covers most of the body. It is fused dorsally and merges anteriorly into a conspicuous postero-ventrally recurved rostrum as long as the carapace and positioned between a pair of backwards-facing pedunculate eyes. 

The body is homonomous, with approximately 40 weakly sclerotized segments bearing biramous legs with elongate endopods, and ends in a pair of small flap-like caudal rami. Fibulacaris nereidis is interpreted as a suspension feeder possibly swimming inverted, in a potential case of convergence with some branchiopods. 

A Bayesian phylogenetic analysis places it within a group closely related to the extinct Hymenocarina. Fibulacaris nereidis is unique in its carapace morphology and overall widens the ecological disparity of Cambrian arthropods and suggests that the evolution of a ‘bivalved' carapace and an upside-down lifestyle may have occurred early in stem-group crustaceans.

Fibulacaris nereidis contributes to the increasing morphological, functional, ecologic and taxonomic diversity of bivalved arthropods known from the Cambrian period. The shape of the carapace, with its single posteriorly directed ventral rostrum, appears to be morphologically unique not only among Cambrian and other fossil species but similarly rare across extant crustaceans or other arthropods. The carapace, including the rostrum, most probably had a protective role, but as in other extant arthropods, could have contributed to swimming performance and the creation of feeding currents. 

F. nereidis may have moved through our ancient seas swimming in an inverted position — rare across arthropods and analogous to that observed in anostracans and some cladocerans. This highlight the importance of the carapace morphology in palaeo-ecological reconstructions and show that the arthropod carapace was already both a morphologically and functionally diverse character in the Cambrian period. 

Bivalved Cambrian Arthropods / Alejandro  Izquierdo-López

Their phylogenetic analysis reveals a potential new group of mandibulate deposits and suspension feeders with homonomous legs and segments — some lacking certain mandibulate characters, such as antennae or mandibles — which may be related to an adaptation to this ecological niche and further illustrate a case of convergent evolution with some branchiopod taxa. 

These results suggest that the bivalved carapace could have been a basal trait for all Mandibulata or may even have had an earlier origin if this and the bivalved carapace of the Isoxyiidae were found to be homologous. 

Homologies between arthropod carapaces, bivalved or not, and structures such as radiodont shields, non-crustaceomorph univalved carapaces (e.g. Burgessia, Naraoia) and head shields (e.g. fuxianhuiids, habeliids, nauplius) are still quite poorly understood. We will need to find more examples to fully flesh out a comprehensive evolutionary analysis on this trait. 

Besides, new data and morphological revisions on key bivalved arthropods could reshape the present phylogenetic analyses. Nonetheless, Cambrian bivalved arthropods certainly show a high ecological and taxonomic disparity, that is increasingly contributing to the understanding of the evolution of early arthropods and the Cambrian period as a whole.

Top Image by the talented Danielle Dufault @MesozoicMuse. Composite Bivalved Cambrian Arthropods by Alejandro Izquierdo-López. 

Illustration: Interpretative cladogram based on a consensus tree from a Bayesian analysis using a Markov k model on a morphological dataset with 90 taxa and 213 characters. There is some interpretation here. Numbers next to nodes are posterior probabilities. The yellow box indicates the new monophyletic group to which Fibulacaris belongs. The green box highlights the group Hymenocarina.

Reference link: A Burgess Shale mandibulate arthropod with a pygidium: a case of convergent evolution. https://onlinelibrary.wiley.com/doi/abs/10.1002/spp2.1366

Wednesday, 23 June 2021

PAKUCARIS APATIS: A PAC-MAN-LIKE-CRAB OF THE GODDESS OF DECEIT

Pakucaris apatis. Illustration by Danielle Dufault, ROM
Meet Pakucaris apatis — the Pac-Man-like Crab of the Goddess of Deceit Apate — from the heart of the Canadian Rockies.

This fresh look at evolutionary trends during the Cambrian Explosion landed in my inbox — straight off the press from its June 15, 2021 publication in Papers in Palaeontology. 

In it, Alejandro Izquierdo-López and Jean-Bernard Caron untangle the evolutionary mysteries of Cambrian bivalved arthropods — a polyphyletic group of carapace-bearing arthropods that includes stem euarthropods, stem mandibulates and crustaceans. 

They describe Pakucaris apatis gen. et sp. nov., a new stem mandibulate bivalved arthropod from the middle Cambrian, Wuliuan Stage, Burgess Shale at Marble Canyon, Kootenay National Park, British Columbia, Canada. 

This new half a billion-year-old Burgess Shale mandibulate arthropod is the first we are seeing with a pygidium — an exciting case of convergent evolution. 

In Pakucaris, the pygidium — the plate-like region formed by the fusion of posterior body segments — has limbs similar to the preceding thorax/trunk. In this case, it convergently evolved between trilobites, mollisoniids and Pakucaris apatis — though Kylinxia also had a pygidium. 

Pakucaris apatis, a new Cambrian bivalved arthropod
Although similar structures appear in crustaceans, this is the first time we see a pygidium in a mandibulate (crustaceans + myriapods). What are we seeing in these Cambrian arthropods? 

The authors note that the number of segments in the thorax and pygidium of Pakucaris apatis increase at the same rate. 

If this occurs — as it does in trilobites — then the rate of segment generation in the pygidium must have exactly matched the rate of segment release. 

In our new friend, Pakucaris apatis only a few specimens have ever been found, so we have only two morphotypes of this wee arthropod from 11.6–26.6 mm long, which differ mainly in their size and number of segments — possibly reflecting sexual dimorphism (the differences between male and female of a species) or different anamorphic stages. 

Most specimens are around ~1 cm long but a single specimen is ~3 cm long. Given the limited number of specimens, we cannot yet speculate if we are seeing differences between males and females or post-embryonic growth and moulting stages within the species as seen in proturans and millipedes. Either possibility could be the case. We will hopefully find more of these lovelies within the Burgess Shale and elsewhere as a base of comparison.

Pakucaris apatis Alejandro Izquierdo @trichodes
The carapace is a dorsal crest that extends anteriorly into a small recurved rostrum and two anterolateral processes. 

Pakucaris also have some very interesting filiform structures at their head. These likely originate before the eyes and could be related to the labrum complex. The labrum is that flat extension of the head (below the clypeus), we see covering the mandibles of arthropods. Unlike other mouthparts, the labrum is a single, fused plate — though it originally was—and embryonically is—two structures.

The filiform structures we see in Pakucaris pop up in many arthropods, and their evolution provides an interesting puzzle.

Around 20% of the posterior-most body segments and limbs are covered by a large spine-bearing shield. The head bears a pair of eyes, a possible pair of unsegmented appendicular projections and two pairs of segmented appendages. 

The thorax is multisegmented, homonomous, with weakly sclerotized segments bearing biramous limbs, composed of a stenopodous endopod with c. 20 podomeres and a paddle-shaped exopod. 

Pakucaris is interpreted as a nektobenthic suspension feeder. Bayesian phylogenetic analysis implies a position within Hymenocarina as stem mandibulates. 

The posterior shield is regarded as a pygidium and represents a case of morphofunctional convergent evolution between mandibulates, artiopodans and mollisoniids. 

Trilobite Anatomy for Comparison
What is most interesting about Pakucaris apatis is it adds to a growing number of pygidium-bearing arthropods, potentially hinting at a common developmental pattern across early arthropod evolution. 

Many of our Cambrian arthropod friends faced similar living conditions and challenges — and adapted to them in similar means. Is this what we are seeing in Pakucaris? Maybe. 

Pakucaris does have a rather fetching posterior shield, which may be analogous to a trilobite pygidium — the plate-like fused segments used for protection and sometimes enrolment. Arthropods have evolved this feature multiple times convergently. And many crustaceans technically go through a pygidium phase — the oddity there being retaining it into adulthood.

This study not only increases our understanding of the early evolution of mandibulates but also illustrates a unique case of early evolutionary convergence during the Cambrian Explosion.

The name Pakucaris apatis means Pac-Man-like crab of the goddess of deceit Apate. Maryam A., the collection managers at the Royal Ontario Museum suggested it after noting the resemblance to the videogame character. She was a huge contribution to the team pulling this paper together.

Bivalved Cambrian Arthropods / Alejandro Izquierdo
Pakucaris belongs to a group of Cambrian arthropods termed bivalved arthropods. These have a carapace that covers their cephalothorax, in many cases, the only structure preserved. Exceptional preservation has allowed us to know more about these animals, albeit often only the hard parts of them.

Overall, Pakucaris shows us how different Cambrian bivalved arthropods can be — making our current phylogenies more difficult to clarify — and presents different features (frontal filaments, pygidium) which may be important as we look to understand early arthropod evolution.

Their paper was made possible by the University of Toronto and Royal Ontario Museum along with la Asociación de Becarios de la Caixa — funding research that expands our knowledge of nature. So far Pakucaris is classified in Hymenocarina — stem-crustaceans or mandibulates with bivalved carapaces — joining other Cambrian arthropods like Waptia fieldensis — but there is still much we do not know about this group and additional research — and research funding — will help us solve these mysteries.

Photos / Illustrations: Alejandro Izquierdo, University of Toronto. Art by Danielle Dufault, Palaeo-Scientific Ilustrator, Research Assistant at the Royal Ontario Museum, Host of Animalogic

References: A Burgess Shale mandibulate arthropod with a pygidium: a case of convergent evolution. https://onlinelibrary.wiley.com/doi/10.1002/spp2.1366


Tuesday, 22 June 2021

MEET ACICULOLENUS ASKEWI: A NEW UPPER CAMBRIAN TRILOBITE

A new species of trilobite from the upper Cambrian McKay Group was introduced in March of 2020: Aciculolenus askewi.  The species is named after Don Askew, an avid fossil hunter of Upper Cambrian trilobites from Cranbrook, British Columbia, Canada, who has discovered several new species in the East Kootenays. 

Don was the first to brave the treacherous cliffs up the waterfall on the west side of the ravine below Tanglefoot mountain. That climb led to his discovery of one of the most prolific outcrops in the McKay Group with some of the most exciting and best-preserved trilobites from the region. 

The faunal set are similar to those found at site one — the first of the trilobite outcrops discovered by Chris New and Chris Jenkins — an hours hike through grizzly bear country.

The specimens found at the top of the waterfall are not in calcite wafers, as they are elsewhere, instead, these exceptionally preserved specimens are found complete with a thin coating of matrix that must be prepped down to the shell beneath. 

Askew was also the skill preparator called upon to tease out the details from the 'gut trilobite' recently published from the region. In all, this area has produced more than 60 new species — many found by Askew — and not all of which have been published yet.

I caught up with Don last summer on a trip to the region. He was gracious in openly sharing his knowledge and a complete mountain goat in the field — a good man that Askew. 

Not surprising then that Brian Chatterton would do him the honour of naming this new species after him. 

Chatterton, Professor Emeritus at the University of Alberta, is an invertebrate palaeontologist with a great sense of humour and a particular love of trilobites. Even so, his published works span a myriad of groups including conodonts, machaeridians, sponges, brachiopods, corals, cephalopods, bivalves, trace fossils — to fishes, birds and dinosaurs.

Brian Chatterton has been visiting the East Kootenay region for many years. In 1998, he and Rolf Ludvigsen published the pivotal work on the "calcified trilobites" we had begun hearing about in the late 1990s. There were tales of blue trilobites in calcified layers guarded by a resident Grizzly. This was years before logging roads had reached this pocket of paleontological goodness and hiking in — bear or no bear — was a daunting task. 

In his Cambridge University Press paper, Chatterton describes the well-preserved fauna of largely articulated trilobites from three new localities in the Bull River Valley. 

The Dream Team at Fossil Site #15, East Kootenays, August 2, 2020
All the trilobites from these localities are from the lower or middle part of the Wujiajiania lyndasmithae Subzone of the Elvinia Zone, lower Jiangshanian, in the McKay Group. 

Access is via a bumpy ride on logging roads 20 km northeast of Fort Steele that includes fording a river (for those blessed with large tires and a high wheelbase) and culminating in a hot, dusty hike and death-defying traipse down 35-degree slopes to the localities.

Two new species were proposed with types from these localities: Aciculolenus askewi and Cliffia nicoleae

The trilobite (and agnostid) fauna from these localities includes at least 20 species that read like a who's who of East Kootenay palaeontology: 

Aciculolenus askewi n. sp., Agnostotes orientalis (Kobayashi, 1935), Cernuolimbus ludvigseni Chatterton and Gibb, 2016, Cliffia nicoleae n. sp., Elvinia roemeri (Shumard, 1861), Grandagnostus? species 1 of Chatterton and Gibb, 2016, Eugonocare? phillipi Chatterton and Gibb, 2016, Eugonocare? sp. A, Housia vacuna (Walcott, 1912), Irvingella convexa (Kobayashi, 1935), Irvingella flohri Resser, 1942, Irvingella species B Chatterton and Gibb, 2016, Olenaspella chrisnewi Chatterton and Gibb, 2016, Proceratopyge canadensis (Chatterton and Ludvigsen, 1998), Proceratopyge rectispinata (Troedsson, 1937), Pseudagnostus cf. P. josepha (Hall, 1863), Pseudagnostus securiger (Lake, 1906), Pseudeugonocare bispinatum (Kobayashi, 1962), Pterocephalia sp., and Wujiajiania lyndasmithae Chatterton and Gibb, 2016.

Chris New, pleased as punch atop Upper Cambrian Exposures
It has been the collaborative efforts of Guy Santucci, Chris New, Chris Jenkins, Don Askew and Stacey Gibb that has helped open up the region — including finding and identifying many new species or firsts including Pseudagnostus securiger, a widespread early Jiangshanian species not been previously recorded from southeastern British Columbia. 

Other interesting invertebrate fossils from these localities include brachiopods, rare trace fossils, a complete silica sponge (Hyalospongea), and a dendroid graptolite. 

The species we find here are more diverse than those from other localities of the same age in the region — and enjoy much better preservation. 

The birth of new species into our scientific nomenclature takes time and the gathering of enough material to justify a new species name.

Fortunately for Labiostria gibbae, specimens had been found of this rare species had been documented from the upper part of Wujiajiania lyndasmithae Subzone — slightly younger in age. 

Combined with an earlier discovery, they provided adequate type material to propose the new species — Labiostria gibbae — a species that honours Stacey Gibb and which will likely prove useful for biostratigraphy.

Reference: https://www.cambridge.org/core/journals/journal-of-paleontology/article/abs/midfurongian-trilobites-and-agnostids-from-the-wujiajiania-lyndasmithae-subzone-of-the-elvinia-zone-mckay-group-southeastern-british-columbia-canada/E8DBC8BD635863E840715122C05BB14A#

Photo One: Aciculolenus askewi by Chris Jenkins, Cranbrook, British Columbia
Photo Two: L to R: Dan Bowden, Guy Santucci, Chris Jenkins, Dan Askew and John Fam at Fossil Site #15, East Kootenay Region, British Columbia, Canada, August 2, 2020.
Photo Three: Chris New pleased as punch atop of Upper Cambrian Exposures in the East Kootenay Region, British Columbia, Canada

Monday, 21 June 2021

GUT TRILOBITE: TAGMOSIS IN AGLASPIDID ARTHROPODS

Orygmaspis (Parabolinoides) contracta with gut structure
This specimen lovely chocolate brown trilobite specimen is Orygmaspis (Parabolinoides) contracta — one of the most exciting trilobites to come out of the McKay Group in the East Kootenay Region of British Columbia, Canada.

And what is most exciting about this specimen is that there is clear preservation of some of the gut structures preserving this trilobite's last meal.

Documentation of non- or weakly biomineralizing animals that lived during the Furongian is essential for a comprehensive understanding of the diversification of metazoans during the early Palaeozoic. 

Biomineralization, biologically controlled mineralization, occurs when crystal morphology, growth, composition, and location is completely controlled by the cellular processes of a specific organism. Examples include the shells of invertebrates, such as molluscs and brachiopods. The soft bits of those same animals tend to rot or be scavenged long before mineralization or fossilization can occur — hence, we find less of them.

So, not surprisingly, the fossil record of soft-bodied metazoans is particularly scarce for this critical time interval. To date, the fossils we do have are relatively rare and scattered at a dozen or so localities worldwide. 

Location and stratigraphy of the Fossil Locality
This is one of the reasons that the soft gut structures from this Orygmaspis contracta trilobite are particularly exciting. 

This specimen was found in Upper Cambrian exposures in the Clay Creek section at the top of the left fork of the ravine below Tanglefoot Mountain, 20 km northeast of Fort Steele. 

It was the keen eyes of Chris Jenkins who noticed the interesting structures worthy of exploration.

Lerosey-Aubril along with colleagues, Patterson, Gibb and Chatterton, published a great study on this trilobite in Gondwana Research, February 2017. 

Their work looked at this new occurrence of exceptional preservation in Furongian (Jiangshanian) strata of the McKay Group near Cranbrook, British Columbia, Canada. Their study followed up on the work of Chatterton et al. studying trilobites with phosphatised guts in this same 10-m-thick interval. 

Lerosey-Aubril et al.'s paper looked at two stratigraphically higher horizons with soft-tissue preservation. One yielded a ctenophore and an aglaspidid arthropod, the other a trilobite with a phosphatised gut belonging to a different species than the previously described specimens. 

Undetermined ctenophore
The ctenophore represents the first Furongian record of the phylum and the first reported occurrence of Burgess Shale-type preservation in the upper Cambrian of Laurentia. 

The aglaspidid belongs to a new species of Glypharthrus, and is atypical in having twelve trunk tergites and an anteriorly narrow ‘tailspine’. These features suggest that the tailspine of aglaspidids evolved from the fusion of a twelfth trunk segment with the telson. 

They also confirm the vicissicaudatan affinities of these extinct arthropods. Compositional analyses suggest that aglaspidid cuticle was essentially organic with a thin biomineralised (apatite) outer layer. 

Macro imagery of the trilobite reveals previously unknown gut features — medial fusion of digestive glands — possibly related to enhanced capabilities for digestion, storage, or the assimilation of food. 

These new fossils show that conditions conducive to soft-tissue preservation repeatedly developed in the outer shelf environment represented by the Furongian strata near Cranbrook. Future exploration of the c. 600-m-thick, mudstone-dominated upper part of the section is ongoing by Chris New, Chris Jenkins and Don Askey. There work and collaboration will likely result in more continued discoveries of exceptional fossils.

Glypharthrus magnoculus sp.
The specimen you see here was expertly prepped by Don Askew of Cranbrook, British Columbia. It now resides in collections at the Royal BC Museum.

Photo One: Orygmaspis (Parabolinoides) contracta (Trilobita) from the Jiangshanian (Furongian) part of the McKay Group, Clay Creek section, near Cranbrook, British Columbia, Canada. A–D, specimen RBCM.EH2016.031.0001.001, complete dorsal exoskeleton preserved dorsum-down and showing ventral features, such as the in situ hypostome and phosphatised digestive structures. 

A, general view, specimen immersed under ethanol; B, detail of the digestive structures, specimen under ethanol; C, same as B, electron micrograph; D, same as B and C, interpretative drawing with digestive tract in blue-purple and digestive glands in pink. 

Abbreviations: Dc 1 and 2, cephalic digestive glands 1 and 2, Dt1 and 5, thoracic digestive glands 1 and 5, hyp, hypostome, L2, glabellar lobe 2, LO, occipital lobe, T1 and 5, thoracic segments 1 and 5. Scale bars represent 2 mm (A) and 1 mm (B–D). For interpretation of the references to the colours in this figure legend, you'll want to read the full article in the link below. 

Photo Two:  Undetermined ctenophore from the Jiangshanian (Furongian) part of the McKay Group, Clay Creek section, near Cranbrook, British Columbia, Canada. A, B, specimen UA 14333, flattened body fragment with oral-aboral axis oriented parallel to bedding; specimen photographed immersed under dilute ethanol with presumed oral region facing to the bottom. A, general view. B, detailed view showing comb rows and ctene. Scale bars represent 1 cm (A) and 5 mm (B). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)  

Photo Three: Glypharthrus magnoculus sp. nov. from the Jiangshanian (Furongian) part of the McKay Group, Clay Creek section, near Cranbrook, British Columbia, Canada. A–H, holotype, UA 14332, almost complete dorsal exoskeleton; photographs (A–C) and electron micrographs (D, backscattered; E–H, secondary) of the specimen in dorsal view with anterior facing to the top. A, B, general view in normal (A) and inverted (B) colours; C, D, detail of posterior trunk region, showing T12 and its contacts with T11 and the spiniform telson (arrows); the core of the fossil is made of a clay mineral and was initially entirely covered by an apatitic thin layer (white areas on D); E, left eye; F, right posterolateral glabellar lobe; G, rounded tubercles on right posterior border of cephalon; H, triangular tubercles pointing backwards (bottom right corner) on trunk axial region. Scale bars represent 5 mm (A, B), 1 mm (C, D), 500 μm (E, F), and 100 μm (G, H).

Link to the paper: https://www.researchgate.net/publication/309549546_Exceptionally-preserved_late_Cambrian_fossils_from_the_McKay_Group_British_Columbia_Canada_and_the_evolution_of_tagmosis_in_aglaspidid_arthropods

Saturday, 19 June 2021

ORYGMASPIS: ASAPHID TRILOBITE

This calcified beauty is Orygmaspis (Parabolinoides) spinula (Westrop, 1986) an Upper Cambrian trilobite from Furongian strata of the McKay Group near Tanglefoot Mountain in the East Kootenay Region of British Columbia, Canada. 

Orygmaspis is a genus of asaphid trilobite with an inverted egg-shaped outline, a wide headshield, small eyes, long genal spines, 12 spined thorax segments and a small, short tail shield, with four pairs of spines. 

Asaphida is comprised of six superfamilies found as marine fossils that date from the Middle Cambrian through to the Ordovician — Anomocaroidea, Asaphoidea, Cyclopygoidea, Dikelocephaloidea, Remopleuridoidea and Trinucleioidea. It was here, in the Ordovician, that five of the six lineages met their end along with 60% of all marine life at the time. They did leave us with some wonderful examples of their form and adaptations. 

The stubby eyed Asaphids evolved to give us Asaphus kowalewskii with delightfully long eyestalks. These specialized protrusions would have given that lovely species a much better field of view in which to hunt Ordovician seas — and avoid becoming the hunted.

Only the hardy Superfamily Trinucleiodea pushed through. They were to meet their end in the final days of the Silurian where yet another cataclysmic event wiped out much of the life on Earth, including the last remains of Asaphida (Fortey & Chatterton, 1988).

The outline of the exoskeleton Orygmaspis is inverted egg-shaped, with a parabolic headshield — or cephalon less than twice as wide as long. Picture a 2-D egg where the head is wider than the tail.

The glabella, the well-defined central raised area excluding the backward occipital ring, is ¾× as wide as long, moderately convex, truncate-tapering, with 3 pairs of shallow to obsolete lateral furrows. 

The occipital ring is well defined. The distance between the glabella and the border (or preglabellar field) is ±¼× as long as the glabella. This fellow had small to medium-sized eyes, 12-20% of the length of the cephalon. These were positioned between the front and the middle of the glabella and about ⅓ as far out as the glabella is wide. 

The remaining parts of the cephalon, the fixed and free cheeks — or fixigenae and librigenae — are relatively flat. The fracture lines or sutures — that separate the librigenae from the fixigenae in moulting — are divergent just in front of the eyes. These become parallel near the border furrow and strongly convergent at the margin. 

From the back of the eyes, the sutures bend out, then in, diverging outward and backward at approximately 45°, cutting the posterior margin well within the inner bend of the spine — or opisthoparian sutures. 

The thorax or articulating middle part of the body has 12 segments. The anteriormost segment gradually narrows into a sideward directed point, while further to the back the spines are directed outward and the spine is of increasing length up until the ninth spine, while the spine on the tenth segment is abruptly smaller, and 11 and 12 even more so. 

This fellow has a wee pygidium or tail shield that is only about ⅓× as wide as the cephalon. It is narrowly transverse about 2× wider than long. Its axis is slightly wider than the pleural fields to each side, and has up to 4 axial rings and a terminal and almost reaches the margin. Up to 4 pleural segments with obsolete interpleural grooves and shallow pleural furrows. The posterior margin has 3 or 4 pairs of spines, getting smaller further to the back. 

References:

Chatterton, Brian D. E.; Gibb, Stacey (2016). Furongian (Upper Cambrian) Trilobites from the McKay Group, Bull River Valley, Near Cranbrook, Southeastern British Columbia, Canada; Issue 35 of Palaeontographica Canadiana; ISBN: 978-1-897095-79-9

Moore, R.C. (1959). Arthropoda I - Arthropoda General Features, Proarthropoda, Euarthropoda General Features, Trilobitomorpha. Treatise on Invertebrate Paleontology. Part O. Boulder, Colorado/Lawrence, Kansas: Geological Society of America/University of Kansas Press. pp. O272–O273. ISBN 0-8137-3015-5.

Thursday, 17 June 2021

GENTLE GENTOO PENGUINS

These black, white and grey cuties — looking very smart in their natural colouring akin to formal wear — are gentoo penguins.

They are foraging predators — dining on crustaceans, fish and squid in the cold nearshore waters of the Antarctic Peninsula, Falkland Islands, South Georgia and Sandwich Islands.

South Georgia, the South Sandwich Islands and the Falklands are inhospitable British Overseas Territories in the southern Atlantic Ocean.

The first scientific description of these romantic seabirds was done by Johann Reinhold Forster in 1781. He used the Falkland Islands population for both the type specimen and locality. These diminutive penguins are in the genus Pygoscelis, and are most closely related to their penguin cousins — the Adélie and Chinstraps. 

The gentoo penguin is one of three species in the genus Pygoscelis. Mitochondrial and nuclear DNA evidence suggests the genus split from other penguins around 38 million years ago, about 2 million years after the ancestors of the genus Aptenodytes

In turn, the Adelie penguins split off from the other members of the genus around 19 million years ago, and the chinstrap and Gentoo finally diverged around 14 million years ago.

Very fetching Gentoo penguins
Two subspecies of this penguin are recognised: Pygoscelis papua papua (the subantarctic Gentoo) and the smaller Pygoscelis papua ellsworthi (the Antarctic Gentoo). 

We will likely need to reclassify the gentle Gentoos into a species complex of four morphologically similar but separate species: the northern gentoo penguin (P. papua sensu stricto), the southern gentoo penguin (P. ellsworthi), the eastern gentoo penguin (P. taeniata), and the newly-described South Georgia gentoo penguin (P. poncetii).

We find breeding colonies of gentoo penguins on ice-free surfaces either directly on the shoreline or far inland. 

They prefer shallow coastal areas and often nest between tufts of grass. In South Georgia, breeding colonies are 2 km inland. 

In colonies farther inland, where the penguins nest in grassy areas, they shift location slightly every year because the grass will become trampled over time.

Gentoos breed on many sub-Antarctic islands. The main colonies are on the Falkland Islands, South Georgia and the South Sandwich Islands, and Kerguelen Islands; smaller colonies are found on Macquarie Island, Heard Islands, Crozet Islands, South Shetland Islands, and the Antarctic Peninsula. 

Their breeding populations number well over 600,000 birds. Once a breeding pair decide that their romance is a go, they stay together for life. 

These lovelies breed monogamously and infidelity is frowned upon. Punishment is banishment from the colony — strict but these birds know how to draw a firm line in the pebbles. 

Nests are usually made from a roughly circular pile of stones and can be quite large — up to 20 cm (7.9 in) high and 25 cm (9.8 in) in diameter. The chosen rocks are prized and jealously guarded. 

Just who owned which pebble is the subject of many noisy debates — some escalating to nasty physical altercations between disagreeing parties. "That rock is mine. Mine!" 

The pebbles are especially prized by the females, to the point that a male penguin can woo his lady love and secure a lifetimes' devotion by proffering a particularly choice stone — not unlike some human females.

Wednesday, 16 June 2021

TRIASSIC FOSSILS OF SVALBARD

Ice, Snow, Reindeer & Ichthyosaurs — Svalbard is just what I imagine my version of Valhalla to be like, without all the mead, murder and mayhem. 

Svalbard is a Norwegian archipelago between mainland Norway and the North Pole. 

One of the world’s northernmost inhabited areas, it is known for its rugged, remote terrain of glaciers and frozen tundra sheltering polar bears, reindeer and Arctic fox. 

The Northern Lights or Nordlys are visible during winter, and summer brings the Midnight sun — sunlight 24 hours a day.

The Botneheia Formation is made up of dark grey, laminated shales coarsening upwards to laminated siltstones and sandstones. South of the type area, the formation shows several (up to four) coarsening-upward units. 

The formation is named for Botneheia Mountain, a mountain in Nordenskiöld Land at Spitsbergen, Svalbard. It has a height of 522 m.a.s.l., and is located south of Sassenfjorden, east of the valley of De Geerdalen. 

I was asked recently if folk head out in the torrential rain or ice and snow to fossil collect. I would generally say yes for those where the potential prize always outweighs the weather. For Svalbard, it is a resounding yes. 

You have to remove the snow cover — or ice if you are impatient or unlucky — to get to the outcrops here. It is well worth the effort. Beneath the icy cover, you find lovely ammonoids and bivalves. 

Tastier still, ichthyosaur remains are found here. We had been expecting to, but it was not until the early 2000s that the first bones were found after a whole lot of looking.

Two specimens have of ichthyosaur have been recovered. They comprise part of the trunk and the caudal vertebral column respectively. 

Some features, such as the very high and narrow caudal and posterior thoracic neural spines, the relatively elongate posterior thoracic vertebrae and the long and slender haemapophyses indicate that they probably represent a member of the family Toretocnemidae. 

Numerous ichthyosaur finds are known from the underlying Lower Triassic Vikinghøgda Formation and the overlying Middle to Upper Triassic Tschermakfjellet Formation, the new specimens help to close a huge gap in the fossil record of the Triassic ichthyosaurs from Svalbard. There is a resident research group working on the Triassic ichthyosaur fauna, the Spitsbergen Mesozoic Research Group. 

Lucky for them, they often find the fossil remains fully articulated — the bones having retained their spatial relationship to one another. 

Most of their finds are of the tail sections of primitive Triassic ichthyosaurs. In later ichthyosaurs, the tail vertebrae bend steeply downwards and have more of a fish-like look. 

In these primitive ancestors, the tail looks more eel-like — bending slightly so that the spines on the vertebrae form more of the tail. 

Maisch, Michael W. and Blomeier, Dierk published on these finds back in 2009: Neues Jahrbuch für Geologie und Paläontologie - Abhandlungen Band 254 Heft 3 (2009), p. 379 - 384. Nov 1, 2009.

Svalbard was so remote that there were no First Nation settlements. It is certainly possible an earlier people came through these islands, but they did not leave any trace of their travels. 

The first documented travellers to explore Spitsbergen arrived in 1795 as part of a hunting expedition. They included people from the arctic town of Hammerfest in Norway's far north. They were an excellent choice as they were used to barren, inhospitable lands and sailed to discover more. 

We know them as the Coast Sámi — a hearty, rugged people probably best known in history for their chieftain, Ottar. He left Hammerfest in the 9th century to visit then join King Alfred the Great's court in a newly forming England. 

Expeditions to the remote islands of Svalbard continued into the early 1800s and finally, a settlement was eked out of the cold landscape and slowly expanded to the rest of the century. While today the islands are called Svalbard, I would have named them for the Norwegian word for remote — fjernkontroll.

This marvellous block is filled with Aristoptychites (syn = Arctoptychites) euglyphus (Mojsisovics, 1886) and Daonella sp., oyster-like clams or bivalves from the Middle Triassic, Ladinian, rugged windswept outcrops at the top of the Daonella Shales, Botneheia Formation, Spitzbergen, Edgeøya and Barentsøya, eastern Svalbard, Norway. 

Daonella and Monotis are important species for our understanding of biostratigraphy in the Triassic and are useful as Index fossils. 

Index fossils are fossils used to define and identify geologic periods (or faunal stages). To be truly useful, they need to have a short vertical range, wide geographic distribution and rapid evolutionary development.

Daonellids preferred soft, soupy substrates and we tend to find them in massive shell beds. Generally, if you find one, you find a whole bunch cemented together in coquina. The lovely block you see here is in the collections of the deeply awesome John Fam. 

Monday, 14 June 2021

PS STORIES: CALL FOR SUBMISSIONS

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Sunday, 13 June 2021

LANDMANNALAUGAR: AURORA BOREALIS

The Northern Lights over a sea of wildflowers in the marsh near Landmannalaugar, part of the Fjallabak Nature Reserve in the Highlands of Iceland.

Landmannalaugar is at the northern tip of the Laugavegur hiking trail that leads through natural geothermal hot springs and an austere yet poetically beautiful landscape. 

Here, you can see the Northern Lights play through the darkness of a night sky without light pollution and bask in the raw geology of this rugged land.

The Fjallabak region takes its name from the numerous wild and rugged mountains with deeply incised valleys, which are found there. 

The topography of the Torfajokull, a central volcano found within the Fjallabak Nature Reserve, is a direct result of the region being the largest rhyolite area in Iceland and the largest geothermal area (after Grimsvotn in Vatnajokull).

The Torfajokull central volcano is an active volcanic system but is now in a declining fumarolic stage as exemplified by numerous fumaroles and hot springs. The hot pools at Landmannalaugar are but one of many manifestations of geothermal activity in the area, which also tends to alter the minerals in the rocks, causing the beautiful colour variations from red and yellow to blue and green, a good example being Brennisteinsalda. Geologists believe that the Torfajokull central volcano is a caldera, the rim being Haalda, Suðurnamur, Norður-Barmur, Torfajokull, Kaldaklofsfjoll and Ljosartungur.

The bedrock of the Fjallabak Nature Reserve dates back 8-10 million years. At that time the area was on the Reykjanes – Langjokull ridge rift zone. 

The volcano has been most productive during the last 2 million years, that is during the last Ice Age Interglacial rhyolite lava (Brandsgil) and sub-glacial rhyolite (erupted under ice/water, examples being Blahnukur and Brennisteinsalda are characteristic formations in the area. 

To the north of the Torfajokull region, sub-glacial volcanic activity produced the hyaloclastites (Moberg) mountains, such as Lodmundur and Mogilshofdar.

Earlier this year, on March 19, 2021, a volcanic eruption started in the Geldingadalir valley at the Fagradalsfjall mountain on the Reykjanes peninsula, South-West Iceland. The volcano is situated approximately 30 km from the country’s capital city, Reykjavík. The eruption is ongoing and the landscape in the valley and its surrounding area is constantly changing as a result.

Prior to the eruptive display earlier this year, volcanic activity over the past 10.000 years has been restricted to a few northeast-southwest fissures, the most recent one, the Veidivotn fissure from 1480, formed Laugahraun (by the hut at Landmannalaugar), Namshraun, Nordurnamshraun, Ljotipollur and other craters which extend 30 km, further to the north Eruptions in the area tend to be explosive and occur every 500 – 800 years, previous known eruptions being around AD 150 and 900.

Saturday, 12 June 2021

HALENDID: ICELANDIC HIGHLANDS

Glaciers, mountains, active volcanoes — Iceland has it all. 

Sitting at the junction of the North Atlantic and Arctic Oceans is the ruggedly beautiful island of Iceland. It is Europe's second-largest island after Great Britain. 

Geologically, Iceland is part of the Mid-Atlantic Ridge — a wee bit of the oceanic crust sitting just above a mantle plume, hence all the showy volcanic eruptions and lava flows.

The interior of Iceland is usually referred to as the central highlands or as the locals call it — Halendid — which roughly translates to Highlands in Icelandic. It is considered one of the last great wilderness areas in all of Europe, covering nearly 40,000 square kilometres. Truly one of the last untamed regions on earth. Halendid contains high concentrations of waterfalls, volcanoes, glaciers, and rivers. Large expanses of black sand, lava fields, and fragile vegetation are found throughout the region.

Still, one of the features that make this region so unique are the rivers. These rivers carry glacial runoff and sediment from the interior of the island to the ocean. Along the way, this mix of minerals and water produces dramatic colours, complex systems, and vibrant patterns.

Thursday, 10 June 2021

AMMONITE TIME PIECE: INDEX FOSSILS

Ammonites 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 of rock to match up to specific geologic time periods, rather like the way we use tree rings to date trees.

Wednesday, 9 June 2021

GORGONS: APEX PREDATORS OF THE PERMIAN

The Mighty Gorgons — Apex Predators of the Permian. 

Back in the Paleozoic, some 540 million years ago, life in the seas was teaming with life but life on life amounted to a bit of moss and some low fungi. 

Cut to 240 million years later, the vertebrate animals evolved and a huge spectrum of variety was living on land. 

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 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.
If you fancy a read, check out more geeky goodness over on the ARCHEA blog at https://fossilhuntress.blogspot.com/
If you like podcasts, check out the Fossil Huntress — Palaeo Sommelier Podcast at https://anchor.fm/fossil-huntress
Fossil Huntress Geeky Goodness on YouTube:
Photo: National Geographic