Sunday, 26 December 2021

AWKWARD AND AWESOME: DIMORPHODON

This remarkable fellow is Dimorphodon — a genus of medium-sized pterosaur from the Early Jurassic. He is another favourite of mine for his charming awkwardness.

You can see this fellow's interesting teeth within his big, bulky skull. Dimorphodon had two distinct types of teeth in their jaws — an oddity amongst reptiles — and also proportionally short wings for their overall size. 

Just look at him. What an amazing beast. We understand their anatomy quite well today, but can you imagine being the first to study their fossils and try to make sense of them. 

The first fossil remains now attributed to Dimorphodon were found in England by fossil collector Mary Anning, at Lyme Regis in Dorset, the United Kingdom in December 1828. While she faced many challenges in her life, she was blessed to live in one of the richest areas in Britain for finding fossils. 

She walked the beaches way back in the early 1800s of what would become the Jurassic Coast UNESCO World Heritage Site. The Jurassic Coast holds some of the most interesting fossils ever found — particularly within the strata of the Blue Lias which date back to the Hettangian-Sinemurian. It is one of the world’s most famous fossil sites. Millions come to explore the eroding coastline looking for treasures that provide delight and inspiration to young and old.

These fossil treasures provide us with tremendous insights into our world 185 million years ago when amazing animals like Dimorphodon ruled the skies. 

Mary's specimen was acquired by William Buckland and reported in a meeting of the Geological Society on 5 February 1829. Six years later, in 1835, William Clift and William John Broderip built upon the work by Buckland to publish in the Transactions of the Geological Society, describing and naming the fossil as a new species. 

As was the case with most early pterosaur finds, Buckland classified the remains in the genus Pterodactylus, coining the new species Pterodactylus macronyx. The specific name is derived from Greek makros, "large" and onyx, "claw", in reference to the large claws of the hand. The specimen, presently NHMUK PV R 1034, consisted of a partial and disarticulated skeleton on a slab — notably lacking the skull. Buckland in 1835 also assigned a piece of the jaw from the collection of Elizabeth Philpot to P. macronyx

Later, the many putative species assigned to Pterodactylus had become so anatomically diverse that they began to be broken into separate genera.

In 1858, Richard Owen reported finding two new specimens, NHMUK PV OR 41212 and NHMUK PV R 1035, again partial skeletons but this time including the skulls. Having found the skull to be very different from that of Pterodactylus, Owen assigned Pterodactylus macronyx its own genus, which he named Dimorphodon

His first report contained no description and the name remained a nomen nudum. In 1859, however, a subsequent publication by Owen provided a description. After several studies highlighting aspects of Dimorphodon's anatomy, Owen finally made NHMUK PV R 1034 the holotype in 1874  — 185 million years after cruising our skies the Dimorphodon had finally fully arrived.

Saturday, 25 December 2021

GOD JUL: TRILACINOCERAS NORVEGICUM

Trilacinoceras norvegicum
A lovely example of Trilacinoceras norvegicum (Sweet, 1958), a nektonic carnivorous cephalopod from Ordovician outcrops on Helgö Island, Hovindsholm, Helgøya, Lake Mjosa, Norway.

This has been a site of human habitation for more than 5,000 years. Vikings, kings, traders, farmers —  and geologists have walked these fields.

To give that timeframe a bit of context, that's about the age of Skara Brae, the Neolithic settlement in Orkney, Scotland — and older than Stonehenge which clocks in at 3000 BC to 2000 BC and the Great Pyramids — built around 2560 BC.

For my friend, Gale Bishop, that's about 469 km west or a good 7-hour drive from your ancestral home in Ask, just north of Bergen and just south of Knarvik where many of my relatives live — Hei du!

The fossils found here are part of the Engervik Member, Elnes Formation, Aseri, and date back to the Middle Ordovician, 463.5 - 460.9 million years ago. W. C. Sweet did fossil fieldwork here in the 1950s and published a paper on the Middle Ordovician of the Oslo Region, Norway 10. Nautiloid Cephalopods. Norsk Geologisk Tidsskrift 38:1-178.

Deservedly, Sweetoceras boreale is named for him and is one of the most delightful species names of all time. In the 1960s, Yochelson picked up where Sweet left off, continuing the survey of the Middle Ordovician of the Oslo region. I chose this Trilacinoceras for a holiday post because their curly tops remind me of a wee Norwegian gnome, or Nisse from the Norse niðsi, a dear little relative. My Swedish relatives call them Tomte, a throwback to Saint Birgitta of Sweden in the 1300s.

Helgøya is an island in Mjøsa located in the Ringsaker municipality of Hedmark county, Norway. It was formerly a part of the Nes municipality. 

Long before that, it was the ruling centre for the Kings in Hedmark, where bold men and women held great blót celebrations to Odin and planned raids and expansion into Europe and Russia — roughly A.D. 793 — the beginning of the Viking Age.

Today, it is lush and green and easy to explore — or fish. Mjøsa is Norway's largest lake, as well as one of the deepest lakes in Norway and in Europe. 

Battles have been fought on its waters and its depths hold interesting archaeological and paleontological secrets. They also hold a goodly amount of large and tasty trout, pike, perch, burbot and graylings.

Helgøya is the largest freshwater island in Norway at 18.3 km². The island is delightful to explore and home to 32 farms. One of the most beautiful of these is the Hovinsholm manor. You can visit the farm in both summer and winter — both equally beautiful — and enjoy a café, workshop or their Christmas market. They have lush gardens and some very friendly horses you can pet — or spoil with apples, as you do. The property is massive at 2012 acres, divided into grain, potatoes and forest. It has been home to kings and court. It was a monastery in the Middle Ages from the 5th to the 15th century. Today, Tolle Hoel Slotnæs and his wife, Charlotte Holberg Sveinsen own and run the manor with their three daughters.

Hovinsholm, Helgøya, Lake Mjosa, Norway
Helgøya means holy island, in Norwegian. There is a lovely double meaning here and such layered history. The manor, in its various iterations, has been on this site since the 1500s. They had their own Christian manor church until 1612.

On the southern tip of the island, there is an old pagan temple to the Norse Gods, Thor, Frigg, Loki, Hod, Heimdall, Tyr, and Baldur.

Here, farmers of the area would gather at four blót sacrifices a year that followed the seasons — one for each of the winter solstice, spring equinox, summer solstice and autumn equinox. Animals would be sacrificed, their blood splattered on altars, walls and folk around them. Toasts were made. The first was in honour of Thor or Odin, “to the king and victory.” 

Odin, although nominally chief of the gods, was more the god of aristocrats. If a king were toasting, particularly a Danish King, it would be for Odin. If you look at place names in Scandinavia, you'll see him conspicuously absent in favour of Thor, the god of the common man.

When the farmers at Helgøya were shouting Skål, it was likely for Thor. The toasting and drinking continued with cups emptied for Njörd and Freyr and Freyja in the hope of securing a prosperous future. 

Finally, personal pledges (and beer-soaked boasts) would be made to undertake great exploits, Valknut — to die well in battle — and finally to kinsmen laid to rest now drinking with the gods in Valhalla. Weapons, jewellery and tools were thrown into the lake as offerings.

If they were gathering for Jol (Old Norse), Jul (Norwegian) or the Yule blót, they'd also make a large sun wheel (picture a circle with a cross in the middle), carve it up with runes, set it on fire and roll it down a hill. 

It was quite a celebration with the festivities going on for three days and nights. With the formalities over, people did as people do  — drink, sing, boast, play games and find someone to bed down with — Gods be good.

Thor and Odin are still going strong nearly 1,000 years after the end of the Viking Age. You'd think that the old Nordic religion — the belief in the Norse gods — disappeared with the introduction of Christianity. That is not the case. There are still folk in Denmark (Odin-lovers) and Norway (Thor's their guy) who follow the old Norse religion and worship its ancient gods — right down to the splatter.

If you visit Norway at Christmas, Jul (Yule), you'll find much more of the pagan than the Christian in the festivities. King Haakon, old Haakon the Good, Hákon Góði or Håkon den Gode,  moved the Winter Solstice or Yule, Jul, Jol blót over to match up with the Christian holiday on December 25th in his attempts to introduce Christianity in the 10th century. Both traditions are still celebrated but without an overtly religious tone.

Old traditions run deep, animals are still sacrificed (but without all the splatter), bread is baked, houses cleaned, beer is abundant and fires warmth the hearth.

After all the drinking, toasting and feasting at the Jul blót, leftover food was not cleaned up but left overnight for the little relatives. Though shy, Nisse like a good feast and failing to offer them their tithe brings ill-fortune.

But we started this journey together admiring a lovely (and oddly festive) Ordovician cephalopod. Go on, picture him in red and white with a little beard. If you fancy a visit to the Ordovician outcrops, you can find them at Nes-Hamar, Norway. 60.0° N, 11.2° E: paleo-coordinates 33.7° S, 10.3° W. Look for gastropods (five known species) and cephalopods (at least 15 species).

If you'd like to visit the burial mound of Haakon the Good, you'll want to head to Seim, Hordaland, about 10 km north of Knarvik. Good 'ol Haakon may have tried to bring Christianity to Norway but he died full Viking — taking an arrow at the Battle of Fitjar. Many of my rellies live in Knarvik. 

We have enjoyed many a sunny afternoon feasting at the Håkonarspelet summer festivals and exploring Haakon's burial mound at Håkonhaugen in Seim.

If you're more of the manor type, you can stop by Hovinsholm gård, Helgøyvegen 850, 2350 Nes på Hedmarken, Norway. 

If you're curious and want to see the farmstead, head on over to: https://www.skafferiet.no/about. 

If you need to square things up with Odin, you're on your own.

E. L. Yochelson. 1963. The Middle Ordovician of the Oslo Region, Norway. 15. Monoplacophora and Gastropoda. Norsk Geologisk Tidsskrift 43 (2):133-213.

Friday, 24 December 2021

ICE, SNOW, REINDEER AND ICHTHYOSAURS: SVALBARD

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

This Norwegian archipelago sits 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. 

It is also known for reindeer. The lovelies you see here are all females as the males lose their antlers in the winter. So Rudolf and the rest of Santa's crew who pull his sleigh for him would have all been females as they are pictured with antlers. They are also shown flying across the sky, so the science gets a bit creative.

The Northern Lights or Nordlys are visible during winter, and summer brings the Midnight Sun — sunlight 24 hours a day. Norway or Norge is one of the very few locations where sunset merges into the sunrise, with no darkness in between, creating a soft, captivating twilight in which to view the world. 

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 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. 

Svalbard, Norway
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. The first Triassic ichthyosaurs from Svalbard were found in the early 20th century. Now there are quite a few Triassic and Jurassic ichthyosaur species from this archipelago.

Two ichthyosaur specimens have been recovered that are of particular interest. 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. 

Ichthyosaur Bones
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, Norway (Norge)
Svalbard was so remote that there were no Inuit or 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 islands. While today the islands are called Svalbard, I would have named them for the Norwegian word for remote — fjernkontroll.

Aristoptychites euglyphus and Daonella sp.
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. 

Learning Languages

The Sámi languages (/ˈsɑːmi/ SAH-mee), Sami or Saami, are a group of Uralic languages spoken by the Sámi people in Northern Europe in parts of northern Finland, Norway, Sweden, and extreme northwestern Russia. Of the world's languages, I find them the most difficult for my mind and tongue to wrap around. The Uralic languages will be familiar to you as Hungarian (Magyar nyelv), Finnish and Estonian. 

Since my Sámi is terrible, I will share a few words of Norwegian that may come in handy if you visit Svalbard and have a hankering for their tasty fossils or fossiler. To say, ice, snow, reindeer and ichthyosaurs in Norwegian, you would say: is, snø, reinsdyr og ikthyosaurer

To say, "hello, where can I find fossils?" Use, "Hei, hvor kan jeg finne fossiler?" An expression you may not need but circumstances being what they are, "That is a big polar bear," is "Det er en stor isbjørn." A solid follow-up would be, "nice bear, run..." as "Fin bjørn, løp..." Good luck with that.

Wishing you and yours the very best of the holidays however you celebrate. 

Thursday, 23 December 2021

DINOFLAGELLATES: TEENSY OCEAN STARS

This showy Christmas Cracker is a Dinoflagellate

The showy royal blue Christmas cracker looking fellow you see here is a dinoflagellate. 

Bioluminescent dinoflagellates are a type of plankton — teensy marine organisms that make the seaways shimmer as you swim through them or the tide crashes them against the shore. 

The first modern dinoflagellate was described by Baker in 1753, the first species was formally named by Muller in 1773. 

The first fossil forms were described by Ehrenberg in the 1830s from Cretaceous outcrops. More dinoflagellates have lived, died and gone extinct than there are living today. We know them mainly from fossil dinocysts dating back to the Triassic. They are one of the most primitive of the eukaryotic group with a fossil record that may extend into the Precambrian. They combine primitive characteristics of prokaryotes and advanced eukaryotic features.

The luciferase found in dinoflagellates is related to the green chemical chlorophyll found in plants. Their twinkling lights are brief, each containing about 100 million photons that shine for only a tenth of a second. While each individual flicker is here and gone in the wink of an eye, en masse they are breathtaking. I have spent several wondrous evenings scuba diving amongst these glittering denizens off our shores. What you know about light above the surface does not hold true for the light you see as bioluminescence. Its energy and luminosity come from a chemical reaction. 

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

The light you see is produced by a compound called Luciferin. It is the shiny, showy bit in this chemical show. Luciferase acts as an enzyme, the substance that acts as a catalyst controlling the rate of chemical reactions, allowing the luciferin to release energy as it is oxidized. 

The colour of the light depends on the chemical structures of the chemicals. There are more than a dozen known chemical luminescent systems, indicating that bioluminescence evolved independently in different groups of organisms.

Coelenterazine is the type of luciferin we find in shrimp, fish and jellyfish. Dinoflagellates and krill share another class of unique luciferins, while ostracods or firefleas and some fish have a completely different luciferin — but all produce lights of various colours to great effect.  

Tuesday, 21 December 2021

AIOLOCERAS OF MADAGASCAR

Aioloceras besairiei (Collingnon, 1949)
A stunning example of the internal suturing with calcite infill in this sliced Aioloceras besairiei (Collingnon, 1949) ammonite from the Upper Cretaceous (Lower Albian) Boeny region of Madagascar. 

This island country is 400 kilometres off the coast of East Africa in the Indian Ocean and a wonderful place to explore off the beaten track.

Madagascar has some of the most spectacular of all the fossil specimens I have ever seen. This beauty is no exception. The shell has a generally small umbilicus, arched to acute venter, and typically at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, usually disappearing on the outer whorls. I had originally had this specimen marked as a Cleoniceras besairiei, except Cleoniceras and Grycia are not present in Madagascar. 

This lovely, seen in cross-section, is now far from home and in the collection of a wonderful friend. It is an especially lovely example of the ammonite, Aioloceras besairiei, making it a beudanticeratinae. Cleoniceras and Grycia are the boreal genera. If you'd like to see (or argue) the rationale on the name, consider reading Riccardi and Medina's riveting work from back in 2002, or Collingnon from 1949.

The beauty you see here measures in at a whopping 22 cm, so quite a handful. This specimen is from the youngest or uppermost subdivision of the Lower Cretaceous. I'd originally thought this locality was older, but dating reveals it to be from the Lower Albian, so approximately 113.0 ± 1.0 Ma to 100.5 ± 0.9 Ma.

Aioloceras are found in the Cretaceous of Madagascar at geo coordinates 16.5° S, 45.9° E: paleo-coordinates 40.5° S, 29.3° E.; and in four localities in South Africa: at locality 36, near the Mzinene River at 28.0° S, 32.3° E: paleo-coordinates 48.6° S, 7.6° E. 

We find them near the Mziene River, at a second locality north of Hluhluwe where the Mzinene Formation overlies the Aptian-Albian Makatini Formation at 28.0° S, 32.3° E: paleo-coordinates 48.6° S, 7.6° E; and at Haughton Z18, on the Pongola River in the Albian III, Tegoceras mosense beds at 27.3° S, 32.2° E: paleo-coordinates 48.0° S, 7.8° E.

If you happen to be trekking to Madagascar, know that it's big. It’s 592,800 square kilometres (or  226,917 square miles), making it the fourth-largest island on the planet — bigger than Spain, Thailand, Sweden and Germany. The island has an interesting geologic history.

Although there has been a geological survey, which was active extending back well into French colonial times, in the non-French-speaking world our geological understanding of the island is still a bit of a mystery. 

Plate tectonic theory had its beginnings in 1915 when Alfred Wegener proposed his theory of "continental drift." 

Wegener proposed that the continents ploughed through the crust of ocean basins, which would explain why the outlines of many coastlines (like South America and Africa) look like they fit together like a puzzle. Half a century after Wegener there is still no agreement as to whether in continental reconstructions Madagascar should be placed adjacent to the Tanzanian coast to the north (e.g., McElhinny and Embleton,1976), against the Mozambique-Natal coast (Flores 1970), or basically left where it is (Kent 1974, Nairn 1978).

There have been few attempts apart from McKinley’s (1960) comparison of the Karoo succession of southwestern Tanzania with that of Madagascar to follow the famous geological precept of “going to sea.” One critical reason is that although there may be a bibliography of several thousand items dealing with Madagascan geology as Besairie (1971) claims, they are items not generally available to the general public. The vital information gained of the geology of the offshore area by post-World War II petroleum exploration has remained largely proprietary. 

Without this data to draw upon, our understanding remains incomplete. I don't actually mind a bit of a mystery here. It is interesting to speculate on how these geologic puzzle pieces fit together and wait for the big reveal. Still, we have good old Besairie from his 1971, Geologie de Madagascar, and a later précis (Besairie, 1973).

We do know that Madagascar was carved off from the African-South American landmass early on. The prehistoric breakup of the supercontinent Gondwana separated the Madagascar–Antarctica–India landmass from the Africa–South America landmass around 135 million years ago. Madagascar later split from India about 88 million years ago, during the Late Cretaceous, so the native plants and animals on the island evolved in relative isolation. 

It is a green and lush island country with more than its fair share of excellent fossil exposures. Along the length of the eastern coast runs a narrow and steep escarpment containing much of the island's remaining tropical lowland forest. If you could look beneath this lush canopy, you'd see rocks of the Precambrian age stretching from the east coast all the way to the centre of the island. The western edge is made up of sedimentary rock from the Carboniferous to the Quaternary.

Red-Tailed Lemurs, Waiwai & Hedgehog
Madagascar is a biodiversity hotspot. Just as Darwin's finches on the Galápagos were isolated, evolving into distinct species (hello, adaptive radiation), over 90% of the wildlife from Madagascar is found nowhere else. 

The island's diverse ecosystems, like so many on this planet, are threatened by Earth's most deadly species, homo sapien sapiens. 

We arrived back in 490 CE and have been chopping down trees and eating our way through the island's tastier populations ever since. Still, they have cuties like this Red-Tailed Lemur. Awe, right?

Today, beautiful outcrops of wonderfully preserved fossil marine fauna hold appeal for me. The material you see from Madagascar is distinctive — and prolific.

Culturally, you'll see a French influence permeating the language, architecture and legal process. There is a part of me that pictures these lovely Lemurs chatting away in French. "Ah, la vache! Regarde le beau fossile, Hérissonne!"

We see the French influence because good 'ol France invaded sleepy Madagascar back in 1883, during the first Franco-Hova War. Malagasy (the local Madagascarian residents) were enlisted as troops, fighting for France in World War I.  During the Second World War, the island was the site of the Battle of Madagascar between the Vichy government and the British. By then, the Malagasy had had quite enough of colonization and after many hiccuping attempts, reached full independence in 1960. Colonization had ended but the tourist barrage had just begun. You can't stop progress.

If you're interested in learning more about this species, check out the Treatise on Invertebrate Paleontology, Part L (Ammonoidea). R.C. Moore (ed). Geological Soc of America and Univ. Kansas Press (1957), p L394. Or head over to look at the 2002 paper from Riccardi and Medina. 2002. Riccardi, A., C. & Medina, F., A. The Beudanticeratinae and Cleoniceratinae (Ammonitina) from the Lower Albian of Patagonia in Revue de Paléobiologie - 21(1) - Muséum d’Histoire Naturelle de la ville de Genève, p 313-314 (=Aioloceras besairiei (COLLIGNON, 1949). You have Bertrand Matrion to thank for the naming correction. Good to have friends in geeky places!

Collignon, M., 1933, Fossiles cenomaniens d’Antmahavelona (Province d’ Analalave, Madagascar), Ann. Geol. Serv. Min. Madagascar, III, 1934 Les Cephalopods du Trias inferieur de Madagascar, Ann. Paleont. XXII 3 and 4, XXII 1.

Besairie, H., 1971, Geologie de Madagascar, 1. Les terrains sedimentaires, Ann. Geol. Madagascar, 35, p. 463.

J. Boast A. and E. M. Nairn collaborated on a chapter in An Outline of the Geology of Madagascar, that is very readable and cites most of the available geologic research papers. It is an excellent place to begin a paleo exploration of the island.

If you happen to parle français, check out: Madagascar ammonites: http://www.ammonites.fr/Geo/Madagascar.htm

Monday, 20 December 2021

CRINOIDS: BEAUTIES OF ECHINODERMATA

Uintacrinus socialis from Utah, USA
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. 

If you look closely at the detail here you can see a stunning example of Upper Cretaceous, Santonian age, Uintacrinus socialis — named by O.C. Marsh for the Uinta Mountains of Utah nearly 150 years ago.  

These lovelies are best known from the Smoky Hills Niobrara Formation of central Kansas.

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. 

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.

Thursday, 16 December 2021

PROSAUROLOPHUS MAXIMUS

Reconstruction of Prosaurolophus maximus
Prosaurolophus maximus was a large-headed duckbill dinosaur, or hadrosaurid, in the ornithischian family Hadrosauridae.

The most complete Prosaurolophus maximus specimen had a massive skull an impressive 0.9 metres (3.0 ft) long that graced a skeleton about 8.5 metres (28 ft) long. 

He had a small, stout, triangular crest in front of his eyes. The sides of the crest are concave, forming depressions. 

The crest grew isometrically — without changing in proportion — throughout the lifetime of each individual, leading one to wonder if Prosaurolophus had had a soft tissue display structure such as inflatable nasal sacs. We see this feature in hooded seals, Cystophora cristata, who live in the central and western North Atlantic today. Prosaurolophus maximus may have used their inflatable nasal sac for a display to warn a predator or to entice the ladies, attracting the attention of a female.

When this good looking fellow was originally described by Brown, Prosaurolophus maximus was known only from a skull and jaw. Half of the skull was badly weathered at the time of examination, and the level of the parietal was distorted and crushed upwards to the side. You can imagine that these deformations in preservation created some grief in the final description.

The different bones of the skull are easily defined with the exception of the parietal and nasal bones. Brown found that the skull of the already described genus Saurolophus was very similar overall, just smaller than the skull of Prosaurolophus maximus. The unique feature of a shortened frontal in lambeosaurines is also found in Prosaurolophus maximus, and the other horned hadrosaurines Brachylophosaurus, Maiasaura, and Saurolophus. Although they lack a shorter frontal, the genera Edmontosaurus and Shantungosaurus share an elongated dentary structure.

Prosaurolophus maximus, Ottawa Museum of Nature
Patches of preserved skin are known from two juvenile specimens, TMP 1998.50.1 and TMP 2016.37.1; these pertain to the ventral extremity of the ninth through fourteenth dorsal ribs, the caudal margin of the scapular blade, and the pelvic region. 

Small basement scales (scales that make up the majority of the skin surface), 3–7 millimetres (0.12–0.28 in) in diameter, are preserved on these patches - this is similar to the condition seen in other saurolophine hadrosaurs.

More uniquely, feature scales (larger, less numerous scales which are interspersed within the basement scales) around 5 millimetres (0.20 in) wide and 29 millimetres (1.1 in) long are found interspersed in the smaller scales in the patches from the ribs and scapula (they are absent from the pelvic patches). 

Similar scales are known from the tail of the related Saurolophus angustirostris (on which they have been speculated to indicate pattern), and it is considered likely adult Prosaurolophus would've retained the feature scales on their flanks like the juveniles.

Image: Three-dimensional reconstruction of Prosaurolophus maximus. Created using the skull reconstructions in the original description as reference. (Fig. 1 and 3 in Brown 1916). According to Lull and Wright (1942), the muzzle was restored too long in its original description. The colours and/or patterns, as with nearly all reconstructions of prehistoric creatures, are speculative. Created & uploaded to Wikipedia by Steveoc 86.

Tuesday, 14 December 2021

AMMOLITE: LOVE, GREED AND GLORY

Ammolite from the Bearpaw Formation
Ammolite is an opal-like organic gemstone found primarily along the eastern slopes of the Rocky Mountains of North America. 

The mining of ammolite is a serious business. I happened upon a locality while in search of fossilized oysters along the St. Mary's River in Alberta. It was one of the few times that I have ever been shot at. 

They sunk the wee boat I was using as a raft to haul my finds but I will give them credit for firing warning shots and not actually trying to hit me. With that, I can safely say that ammolite inspires strong emotions amongst fossil collectors — love, greed and glory. 

It is made of the fossilized shells of ammonites, which in turn are composed primarily of aragonite, the same mineral contained in shell nacre, with a microstructure inherited from the shell. It is one of few biogenic gemstones along with amber and pearl.

The chemical composition of ammolite is variable. Aside from aragonite, it may include a mix of calcite, silica, pyrite or wee bits and pieces of other minerals. The shell itself may contain a number of trace elements based on the chemical composition of the original sediments where it was fossilized and chemical goodies carried in from groundwater. Most anything can be found in the mix, but primarily we see aluminium, barium, chromium, copper, iron, magnesium, manganese, strontium, titanium, and vanadium. 

Its crystallography is orthorhombic, a seven-sided crystal system. Its hardness is 3.5–4.5, and its specific gravity is 2.60–2.85. The refractive index of Canadian material (as measured via sodium light, 589.3 nm) is as follows: α 1.522; β 1.672–1.673; γ 1.676–1.679; biaxial negative. Under ultraviolet light, ammolite may fluoresce a mustard yellow.

Ammolite comes from the fossil shells of the Upper Cretaceous disk-shaped ammonites Placenticeras meeki and Placenticeras intercalare, and to a lesser degree, the cylindrical baculite, Baculites compressus. The ammonites that form our Alberta ammolite inhabited a prehistoric, inland subtropical sea that bordered the Rocky Mountains — the Cretaceous Western Interior Seaway. 

As the cephalopods died, they sank to the bottom and were buried by layers of bentonitic mud that eventually became shale. Many gem-quality ammonites are found within siderite concretions. These sediments preserved the aragonite of the shells, preventing them from converting to calcite.

Ammolite: Colourful Microstructure of Aragonite
An iridescent opal-like play of colour is shown in fine specimens in shades of yellow, orange, red, green and gold. 

The iridescence is due to the microstructure of the aragonite: unlike most other gems, whose colours come from light absorption, the iridescent colour of ammolite comes from interference with the light that rebounds from stacked layers of thin platelets that make up the aragonite. 

The thicker the layers, the more reds and greens are produced; the thinner the layers, the more blues and violets predominate. Reds and greens are the most commonly seen colours, owing to the greater fragility of the finer layers responsible for the blues. 

When freshly quarried, these colours are not especially dramatic; the material requires polishing and other treatments to reveal the specimen's full-colour potential.

Ammolite itself is quite thin, generally 0.5–0.8 millimetres (0.02–0.03 inches) thick. This thin coating covers a matrix typically made up of grey to brown shale, chalky clay, or limestone. Truly, when you find these ammonites in the field, they do not look like much. They are perhaps a nice shape but often matte grey and unappealing until prepared.  

Frost shattering of these specimens is common. If left exposed to the elements the thin ammolite tends to crack and flake. Prolonged exposure to sunlight can also lead to bleaching of the generally intense colouration. The cracking results in a tessellated appearance, sometimes described as a "dragon skin" or referred to as a stained glass window pattern. 

Ammolite mined from deeper deposits may be entirely smooth or with a rippled surface. Occasionally a complete ammonite shell is recovered with its structure well-preserved: fine, convoluted lines delineate the shell chambers, and the overall shape is suggestive of a nautilus. While these shells may be as large as 90 centimetres (35.5 inches) in diameter, the iridescent ammonites — as opposed to the pyritized variety — are typically much smaller. Most fossilized shells have had their aragonite pseudomorphously replaced by calcite or pyrite, making the presence of ammolite particularly uncommon.

In 1981, ammolite was given official gemstone status by the World Jewellery Confederation (CIBJO), the same year commercial mining of ammolite began. It was designated the official gemstone of the City of Lethbridge, Alberta in 2007.

Ammolite is also known as aapoak — Kainah for "small, crawling stone" — gem ammonite, calcentine, and Korite. The latter is a Trade name given to the gemstone by the Alberta-based mining company Korite. Roughly half of all ammolite deposits are contained within the Kainah (Kainaiwa) reserve, and its inhabitants play a major role in ammolite mining. Marcel Charbonneau and his business partner Mike Berisoff were the first to create commercial doublets of the gem in 1967. They went on to form Ammolite Minerals Ltd.

Monday, 13 December 2021

BELEMNITES: SQUID-LIKE CEPHALOPODS

Lower Jurassic Belemnites, Photo: Georg Laki
Belemnitida is an extinct order of squid-like cephalopods that swam our ancient seas from the Late Triassic to Late Cretaceous. 

Unlike squid, belemnites had an internal skeleton that made up the cone and it is this hard part that we often find fossilized. 

The parts are, from arms to tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard.  

When you find these as fossils, it is not intuitive as to what kind of animal they came from. This is the internal hard part of a rather soft, squishy squid-like fellow. 

Because the softer bits are often scavenged and decay, we rarely see them fossilized. Instead, we get what looks like a pointy selection of cigar-shaped goodies that are all that is left of these marine cephalopods. 

We find this fossil in many places around the world. Some friends shared where they have personally found them which I thought might be of interest to you. Arno Martini has found them in northern California, Anne Glenn finds them in Wyoming, Marco Valentin has an enviable collection from Hannover, Misburg, Germany, Juanjo Ugalde Robledo finds them in La Rioja, Spain, Barbara Hnb finds them in Normandy, Patrick Buster finds them in the Navesink Formation of New Jersey, Kim Pervis shared a monograph on Mississippian Belemnites by Rousseau. 

Georg Laki has collected many of their number in the Early Jurassic (Sinemurian/Pliensbachian) of South Luxembourg at Gasperich. I included a photo of Georg's belemnites (with permission) here for you to enjoy. He has a lovely collection that shows the variety of these fossils. 

Anatomy of a Belemnite Fossil

Other notable finds are from Scott Carpenter and his daughter who collect them on the Jurassic Coast, Gabriel Santos who collects them in Peniche, Portugal and Rossi Franco shared a belemnite he found in the building materials used to construct the Bank of Italy in Genoa. 

There are also some wonderfully preserved plates of multiple Jurassic belemnites from Mistelgau, Germany you may want to take a boo at. Imagine slate grey to honey brown Youngibelus and Paxillosus clusters on a beige matrix. Quite stunning. 

I have found them around British Columbia, as has Lloyd Rempel, including at Harrison Lake, British Columbia, Canada. 

Wednesday, 8 December 2021

ORTHOCONE: STRAIGHT-SHELLED NAUTILOIDS

Orthocone Nautiloid Fossil
An orthocone is an unusually long, straight shell of a nautiloid cephalopod. You have likely seen them from Ontario or Morocco. These straight-shelled nautiloids rules our seas during the Ordovician, nothing else was even close in size to them. 

To put that into context, they would have been more than two times longer than the tallest person you know. 

During the 18th and 19th centuries, all shells of this type were named Orthoceras, creating a wastebasket taxon, but it is now known that many groups of nautiloids developed or retained this type of shell.

An orthocone can be thought of as a nautilus but with a pencil-straight, uncoiled shell. You have likely seen living nautilus in the sea if you are very lucky or on social media, if your curiosity has you streaming cephalopod posts. Living nautilus are chunky and coiled with a wee squid-like body living within their shells that they use for protection and the air within for buoyancy to move through the water. Their ancestors were not dissimilar. For a long while, we thought that these marine lovelies represented the most primitive form of nautiloid, but we now know that the earliest nautiloids had shells that were slightly curved. 

An orthoconic form evolved several times amongst cephalopods. Amongst nautiloid cephalopods, we 
see this in the primitive ellesmerocerids, the endocerids — apex predators of the Ordovician who dined on trilobites, molluscs and brachiopods, in the generally straight-shelled actinocerids, the orthoceratoids (perhaps the last unexplored wilderness in the Cephalopoda).

Orthocone Fossil
We see this form again in the rather smallish order bactritids (relatively speaking within the vast array of the Class Cephalopoda).

These lovely straight-shelled fossils are found in Late Cambrian to Late Triassic outcrops but they were most common in the early Paleozoic. Revivals of the orthocone design later occurred in other cephalopod groups, notably baculitid ammonites in the Cretaceous Period. 

Orthocone nautiloids range in size from wee little fellas less than 25 mm (1 in) to a massive 5.2 metres or 17 feet long in the case of the giant endocerids of the Ordovician. Never underestimate just how large a cephalopod can get. If our oceans remain fertile, I expect we'd see one larger than a city block one day.


Saturday, 4 December 2021

DRIFTWOOD CANYON FOSSIL BEDS / KUNGAX

White Eared Puffbird, Nystalus chacuru
Driftwood Canyon Provincial Park 

Driftwood Canyon Provincial Park covers 23 hectares of the Bulkley River Valley, on the east side of Driftwood Creek, a tributary of the Bulkley River, 10 km northeast of the town of Smithers in northern British Columbia. 

Wet'suwet'en First Nation

The parklands are part of the asserted traditional territory of the Wet'suwet'en First Nation which includes lands around the Bulkley River, Burns Lake, Broman Lake, and François Lake in the northwestern Central Interior of British Columbia. 

The Wetʼsuwetʼen are part of the Dakelh or Carrier First Nation, and in combination with the Babine First Nation are referred to as the Western Carrier. They speak Witsuwitʼen, a dialect of the Babine-Witsuwitʼen language which, like its sister language Carrier, is a member of the Athabaskan family.

Their oral history or kungax recounts a time when their ancestral village, Dizkle or Dzilke, once stood upstream from the Bulkley Canyon. This cluster of cedar houses on both sides of the river was said to be abandoned because of an omen of impending disaster. The exact location of the village has been lost. The neighbouring Gitxsan people of the Hazelton area have a similar tale, though the village in their version is referred to as Dimlahamid or Temlahan. Their house groups include the Gilseyhu or Big Frog Clan, the Laksilyu or Small Frog Clan, the Tsayu or Beaver Clan, the Gitdumden or Wolf and Bear Clan and the Laksamshu or Fireweed and Owl Clan.

The park was created in 1967 by the donation of the land by the late Gordon Harvey (1913–1976) to protect fossil beds on the east side of Driftwood Creek. The beds were discovered around the beginning of the 20th century. 

Driftwood Canyon Fossil Beds

Driftwood Canyon is recognized as one of the world’s most significant fossil beds. It provides park users with a fascinating opportunity to understand the area’s evolutionary processes of both geology and biology. We have found plant, fish and insect fossil here that include Dawn Redwood, alder, fossil salmon, wasps, water striders and vertebrate material. Bird feathers are infrequently collected from the shales; however, two bird body fossils have been found here.

In 1968, a bird body fossil was collected in the Eocene shales of the Ootsa Lake Group in Driftwood Canyon Provincial Park by Pat Petley of Kamloops. Pat Petley donated the specimen in 2000 to the Thompson Rivers University (TRU) palaeontology collections. This fossil bird specimen is tentatively identified as the puffbird, Piciformes Bucconidae, of the genus Primobucco.

Primobucco is an extinct genus of bird placed in its own family, Primobucconidae. The type species, Primobucco mcgrewi, lived during the Lower Eocene of North America. It was initially described by American paleo-ornithologist Pierce Brodkorb in 1970, from a fossil right-wing, and thought to be an early puffbird. However, the discovery of a further 12 fossils in 2010 indicate that it is instead an early type of roller.

Related fossils from the European Messel deposits have been assigned to the two species P. perneri and P. frugilegus. Two specimens of P. frugilegus have been found with seeds in the area of their digestive tract, which suggests that these birds were more omnivorous than the exclusively predaceous modern rollers. The Driftwood specimen has never been thoroughly studied. If there is a grad student out there looking for a worthy thesis, head on down to the Thompson Rivers University where you'll find the specimen on display.

Another fossil bird, complete with feathers, was collected at Driftwood Canyon in 1970, This one was found by Margret and Albrecht Klöckner who were travelling from Germany. Theirs is a well-travelled specimen, having visited many sites in BC as they toured around, then to Germany and finally back to British Columbia when it was repatriated and donated to the Royal British Columbia Museum in Victoria. I'm not sure if it is still on display or back in collections, but it was lovingly displayed back in 2008. There is a new grad student, Alexis, looking at Eocene bird feathers down at the RBCM, so perhaps it is once again doing the rounds. 

This second bird fossil is of a long-legged water bird and has been tentatively identified by Dr. Gareth Dyke of the University of Southampton as possibly from the order Charadriiformes, a diverse order of small to medium-ish water birds that include 350 species of gulls, plovers, sandpipers, terns, snipes, and waders. Hopefully, we'll hear more on this find in the future.

What To Know Before You Go

If you fancy a visit to Driftwood Canyon Park, the park is accessible from Driftwood Road from Provincial Highway 16. You are welcome to view and photograph the fossils found here but collecting is strictly forbidden. 

Driftwood Canyon is recognized as one of the world’s most significant fossil beds. It provides park users with a fascinating opportunity to understand the area’s evolutionary processes of both geology and biology. The day-use area is open from May 15 to September 2. There is a short, wheelchair-accessible interpretative trail that leads from the parking are to the fossil beds. Pets are welcome on leash. Signs along the trail provide information on fossils and local history. 

Below a cliff face at the end of the trail is a viewing area that has interpretive information and viewing area overlooking Driftwood Creek.

This park proudly operated by Mark and Anais Drydyk
Email: kermodeparks@gmail.com / Tel: 1 250 877-1482 or 1 250 877-1782

Driftwood Canyon Provincial Park Brochure: 
https://bcparks.ca/explore/parkpgs/driftwood_cyn/driftwood-canyon-brochure.pdf?v=1638723136455


Wednesday, 1 December 2021

GOOSE / NAXAK

What's good for the goose is good for the gander. A goose is a bird of any of several waterfowl species in the family Anatidae. 

They can fly 40 mph and you'll notice that in the sky they choose the highly efficient V form as it gives them a 71% increased flight range. Smart those geese. 

A male goose is called a gander and a group of geese are charmingly called a gaggle. We use geese for the plural of male, female or a mix of both. The females are referred to as goose, as in Mother Goose from your childhood stories.

These social birds are very loyal and will follow you around like puppies if you happen to raise one from a wee gosling. And no matter which of the many geese you see as wee goslings, they are all charmingly fluffy and cute.

Geese fossils have been found ranging from 10 to 12 million years ago, so a relatively recent addition to our species list. We have found proto-geese fossils in Gargano, one of the most scenic but overlooked parts of the southern Italian region of Puglia in central Italy. This massive relative of our modern geese stood one and a half metres tall and was likely flightless, unlike modern geese.

The family Anatidae comprises the genera Anser — the grey geese and white geese — and Branta —the black geese. Some other birds, mostly related to the shelducks, have goose as part of their names which can muddle things a bit. More distantly related members of the family Anatidae are swans, most of which are larger than true geese, and ducks, which are significantly smaller.

The word goose is a direct descendant of the Proto-Indo-European root, ghans. In the Germanic languages, the root gave Old English gōs with the plural gēs and gandres — becoming our Modern English goose, geese, gander, and gosling, respectively. The Frisian's use goes, gies and guoske. In New High German, Gans, Gänse, and Ganter, and Old Norse gās.

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, na̱x̱aḵ is used to say goose. 

Around the world, we refer to these birds as: Lithuanian: žąsìs, Irish: gé (goose, from Old Irish géiss), Latin: anser, Spanish: ganso, Ancient Greek: χήν (khēn), Dutch: gans, Albanian: gatë (heron), Sanskrit haṃsa and haṃsī ("gander" and "goose", also the words for male and female swans), Finnish: hanhi, Avestan zāō, Polish: gęś, Romanian: gâscă / gânsac, Ukrainian: гуска / гусак (huska / husak), Russian: гусыня / гусь (gusyna / gus), Czech: husa, and Persian: غاز‎ (ghāz). 

By any name, geese are majestic birds. They are long lived at around 20 years for some species and spend their days eating seeds, nuts, plants and berries. Once fattened up, they have been on our menu for a very long time. They grace the wilderness around the globe and are fond of our parks, golf courses and are surprisingly comfortable in major cities. And while they are social and friendly, a threatened goose will chase you and take wee nips of your bottom if they take issue with your presence. You go, goose!

Tuesday, 30 November 2021

PALEONTOLOGY LITHOGRAPH

Paleontology — A lovely faded lithograph from A History Of The Earth And Animated Nature By Oliver Gold Smith.

I love the old lithographs. They transport me back in time to the beginnings of the study of the various realms of nature. 

Lithography was invented around 1796 in Germany by an otherwise unknown Bavarian playwright, Alois Senefelder, who accidentally discovered that he could duplicate his scripts by writing them in greasy crayon on slabs of limestone and then printing them with rolled-on ink.

A History of the Earth and Animated Nature was printed in the traditional method used by Senefelder. It is a fascinating work of natural history. It was first published in 1774 in eight volumes, these volumes brought together a history of the earth with a description of its many weird and wonderful species and geographical features. 

Oliver Gold Smith was an Irish novelist, poet and journalist as well as the author of many works on natural history. He is now best known for his 1766 novel, The Vicar of Wakefield., a widely read 18th-century novel sharing the life and woes of Dr. Charles Primrose. Oliver Gold Smith spelt the title of his work, Paleontology, though the British spelling is Palaeontology — hence our Canadian use of the same.

Sunday, 28 November 2021

OSTRACODERMS TO ANGLERFISH

The festive lassie you see here is an Anglerfish. They always look to be celebrating a birthday of some kind, albeit solo. This party is happening deep in our oceans and for those that join in, I hope they like it rough.

The wee candle you see on her forehead is a photophore, a tiny bit of luminous dorsal spine. Many of our sea dwellers have these candle-like bits illuminating the depths. You may have noticed them glowing around the eyes of many of our cephalopod friends. 

These light organs can be a simple grouping of photogenic cells or more complex with light reflectors, lenses, colour filters able to adjust the intensity or angular distribution of the light they produce. Some species have adapted their photophores to avoid being eaten, in others, it's an invitation to lunch.

In anglerfish' world, this swaying light is dead sexy. It's an adaptation used to attract prey and mates alike.

Deep in the murky depths of the Atlantic and Antarctic oceans, hopeful female anglerfish light up their sexy lures. When a male latches onto this tasty bit of flesh, he fuses himself totally. He might be one of several potential mates. She's not picky, just hungry. Lure. Feed. Mate. Repeat.

A friend asked if anglerfish mate for life. Well, yes.... yes, indeed they do.

Mating is a tough business down in the depths. Her body absorbs all the yummy nutrients of his body over time until all that's left are his testes. While unusual, it is only one of many weird and whacky ways our fishy friends communicate, entice, hunt and creatively survive and thrive. The deepest, darkest part of the ocean isn't empty — its hungry.

The evolution of fish began about 530 million years ago with the first fish lineages belonging to the Agnatha, a superclass of jawless fish. We still see them in our waters as cyclostomes but have lost the conodonts and ostracoderms to the annals of time. Like all vertebrates, fish have bilateral symmetry; when divided down the middle or central axis, each half is the same. Organisms with bilateral symmetry are generally more agile, making finding a mate, hunting or avoiding being hunted a whole lot easier.

When we envision fish, we generally picture large eyes, gills, a well-developed mouth. The earliest animals that we classify as fish appeared as soft-bodied chordates who lacked a true spine. While they were spineless, they did have notochords, a cartilaginous skeletal rod that gave them more dexterity than the cold-blooded invertebrates who shared those ancient seas and evolved without a backbone. 

Fish would continue to evolve throughout the Paleozoic, diversifying into a wide range of forms. Several forms of Paleozoic fish developed external armour that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many species, including sharks, became formidable marine predators rather than just the prey of arthropods.

Fish in general respire using gills, are most often covered with bony scales and propel themselves using fins. There are two main types of fins, median fins and paired fins. The median fins include the caudal fin or tail fin, the dorsal fin, and the anal fin. Now there may be more than one dorsal, and one anal fin in some fishes.

The paired fins include the pectoral fins and the pelvic fins. And these paired fins are connected to, and supported by, pectoral and pelvic girdles, at the shoulder and hip; in the same way, our arms and legs are connected to and supported by, pectoral and pelvic girdles. This arrangement is something we inherited from the ancestors we share with fish. They are homologous structures.

When we speak of early vertebrates, we are often talking about fish. Fish is a term we use a lot in our everyday lives but taxonomically it is not all that useful. When we say, fish we generally mean an ectothermic, aquatic vertebrate with gills and fins.

Fortunately, many of our fishy friends have ended up in the fossil record. We may see some of the soft bits from time to time, as in the lovely fossil fish found in concretion in Brazil, but we often see fish skeletons. Vertebrates with hard skeletons had a much better chance of being preserved. 

Eohiodon Fish, McAbee Fossil Beds
In British Columbia, we have lovely two-dimensional Eocene fossil fish well-represented from the Allenby of Princeton and the McAbee Fossil Beds. 

We have the Tiktaalik roseae, a large freshwater fish, from 375 million-year-old Devonian deposits on Ellesmere Island in Canada's Arctic. Tiktaalik is a wonderfully bizarre creature with a flat, almost reptilian head but also fins, scales and gills. We have other wonders from this time. 

Canada also boasts spectacular antiarch placoderms, Bothriolepsis, found in the Upper Devonian shales of Miguasha in Quebec.

There are fragments of bone-like tissues from as early as the Late Cambrian with the oldest fossils that are truly recognizable as fishes come from the Middle Ordovician from North America, South America and Australia. At the time, South America and Australia were part of a supercontinent called Gondwana. North America was part of another supercontinent called Laurentia and the two were separated by deep oceans.

These two supercontinents and others that were also present were partially covered by shallow equatorial seas and the continents themselves were barren and rocky. Land plants didn't evolve until later in the Silurian Period. In these shallow equatorial seas, a large diverse and widespread group of armoured, jawless fishes evolved: the Pteraspidomorphi. The first of our three groups of ostracoderms. The Pteraspidomorphi are divided into three major groups: the Astraspida, Arandaspida and the Heterostraci.

The oldest and most primitive pteraspidomorphs were the Astraspida and the Arandaspida. You'll notice that all three of these taxon names contain 'aspid', which means shield. This is because these early fishes — and many of the Pteraspidomorphi — possessed large plates of dermal bone at the anterior end of their bodies. This dermal armour was very common in early vertebrates, but it was lost in their descendants. 

Arandaspida is represented by two well-known genera: Sacabampaspis, from South America and Arandaspis from Australia. Arandaspis have large, simple, dorsal and ventral head shields. Their bodies were fusiform, which means they were shaped sort of like a spindle, fat in the middle and tapering at both ends. Picture a sausage that is a bit wider near the centre with a crisp outer shell.

If you're a keen bean to see an anglerfish that recently washed up on the shores of Newport Beach this past May, hit this link: https://www.theguardian.com/us-news/2021/may/11/deep-sea-anglerfish-california-beach-finding-nemo. Kudos for my colleague, Giovanni, bringing this gloriously horrific lovely to my attention. 

Saturday, 27 November 2021

BIOLUMINESCENCE: CHEMICAL POETRY

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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