SEA ANEMONES: CNIDARIA

These colourful beauties are sea anemones. They are familiar inhabitants of rocky shores and coral reefs around the world — with some of their brethren found at very low depths in our oceans. They are one of the wonderful examples of the diversity that radiated out of the Cambrian Explosion.

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, sea anemones are known as 'mis'ma̱t̕sa. 

These beautiful predatory animals are a common site in tide pools all along the Pacific Coast. They form a large part of many special memories of exploring the tide pools along Storey's Beach on the east side of Vancouver Island as a child. 

Touching their soft tentacles is hypnotic and highly entertaining but our human skin is coated in oils and bacteria that may damage these delicate organisms. 

We sometimes see them turn up in First Nation's art — particularly in association with Kumugwe' or the Copper-Maker, Chief of the undersea world and the one to thank for the rising and ebbing of the tides.

At first glance, they look like beautiful and delicate marine flowers. If you have discovered them in tidepools, you will know that they retract or pull into themselves with the lightest touch. These would-be flowers are predatory marine animals of the order Actiniaria that have graced our oceans for over half a billion years. 

They are named after anemones — Anemonastrum, a genus of flowering plants in the family Ranunculaceae — because of their colourful flower-like appearance. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Hexacorallia. 

As cnidarians, sea anemones are related to corals, jellyfish, tube-dwelling anemones, and Hydra. Jellyfish have a complex life cycle that includes both sexual and asexual phases, with the medusa being the sexual stage in most instances. 

A typical sea anemone is a single polyp attached to a hard surface by its base, but some species live in soft sediment and a few float near the surface of the water. The polyp has a columnar trunk topped by an oral disc with a ring of sticky tentacles that fold in towards its central mouth. If they have stung and paralyzed a tasty snack, it is pulled towards the gaping mouth to be consumed. 

The tentacles can be retracted or pulled back inside the body cavity or stretched out and expanded to catch passing prey. They are armed with cnidocytes or stinging cells. In many species, nourishment comes from a symbiotic relationship with single-celled dinoflagellates — zooxanthellae or with green algae, zoochlorellae, that live within the cells. Some species of sea anemone live in association with hermit crabs, small fish or other animals to their mutual benefit.

Most actinarians are sessile — that is, they live attached to rocks or other substrates and do not move, or move only very slowly by contractions of the pedal disk. 

A number of anemones burrow into sand, and a few can even swim short distances, by bending the column back and forth or by "flapping" their tentacles. In all, there are about 1000 species of sea anemone in the world's oceans — including those who live amongst the mythic sea lions that form the posts and beams of Kumugwe''s undersea home.

Sea anemones breed by releasing sperm and eggs through their mouth into the surrounding ocean. The fertilized eggs develop into wee planula larvae that live as tiny planktonic bits floating in the sea. Eventually, they settle on the seafloor and develop directly into juvenile polyps. Sea anemones can also breed asexually. They do this by breaking in half or into smaller pieces that regenerate into polyps.

We sometimes see these beauties kept in saltwater aquariums. I can understand the appeal but it comes with a price. The global trade in marine ornamentals threatens our lovely sea anemone populations. 

Most Actiniaria do not form hard parts that can be recognized as fossils, but a few fossils of sea anemones have been found. The bag-like — almost sea cucumber-like — Mackenzia, from the Middle Cambrian, Stephen Formation in the Canadian Rockies of British Columbia and Alberta, is the oldest fossil identified as a sea anemone. These ancient sea anemones attached themselves to hard surfaces, such as brachiopod shells in a similar fashion to their modern sessile cousins. 

Mackenzia costalis, Walcott 1911

Fourteen specimens of Mackenzia costalis are known from the Greater Phyllopod bed, where they make up less than <0.1% of the fossil community. Mackenzia was originally described by Charles Walcott in 1911 — but as a holothurian echinoderm, which was a reasonable assumption at the time. Once additional specimens had been found and studied, Mackenzia costalis was reclassified as a cnidarian and the great grandparent of our modern sea anemones.

Some fossil sea anemones have also been found from the Lower Cambrian of China. The new find lends support to genetic data that suggests anthozoans — anemones, corals, octocorals and their kin — were one the first Cnidarian groups to diversify. We will likely find more of these rare fossils over time and perhaps get a better view of their long lineage.

Photo: Charles Doolittle Walcott - Charles D. Walcott: Middle Cambrian Holothurians and Medusae. Smithsonian Miscellaneous Collections Volume 57, Number 3 (Publication 2011). City of Washington. Published by the Smithsonian Institution. June 13, 1911. 

References:  

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

 Durham, J. W. (1974). "Systematic Position of Eldonia ludwigi Walcott". Journal of Paleontology. 48 (4): 750–755. JSTOR 1303225.

Conway Morris, S. (1993). "Ediacaran-like fossils in Cambrian Burgess Shale–type faunas of North America". Palaeontology. 36 (31–0239): 593–635.

THE CALL OF THE WILD: ANTARCTIC FUR SEALS

This little cutie is an Antarctic fur seal pup. He and his Mamma belong to the species Arctocephalus gazella — pinnipeds that live in dense colonies alongside King Penguins. 

These two call the South Georgia islands home, as do 95% of the world's fur seal population.  

Though a wee pup, he can already recognize her voice from all the other lovely Mammas in his busy, noisy colony. Little ones left on the rocky shores while their mother is out hunting will raise their heads and listen for their mother's voice. They can distinguish its vocal pitch over the loud calls of all the other busy Mammas and penguins of the colony. If you look closely, you can see his wee little ears. Antarctic fur seals, unlike some other seal species, have visible ears.  

Seal pups stay with their mother, relying on her lactation milk to help them fatten up and grow healthy and strong. For the first four months of their lives, their mother will feed them on her rich milk, then head out to sea to forage for food. 

Once she is back, she will call out to him and then give him a good sniff upon their reunion, the final confirmation for both parties that the right match has been made. The interaction between mother and pup is tender and heartbreakingly sweet to watch. She only gives birth to one pup (two is rare) each October to December. Pups are born with a sheen of fur and grow their waterproof fur during their first months of life. 

When this little fellow grows up, he will dine on fish, birds (including his penguin pals), squid and krill. Krill are small crustaceans of the order Euphausiacea that look like tiny shrimp. They look similar and are both crustaceans but shrimp hail from the suborder Natantia, order Decapoda and their hearts are located in their heads.

Krill live in all the world's oceans and sadly for them, they make a handy and tasty snack. They form an important part of the oceanic food chain. The krill feed on phytoplankton and zooplankton and then larger animals feed on the krill. 

Krill is Norwegian for small fry of fish. And they are small, indeed — but also tasty, nutritious and easy to catch. Once this little pinniped pup is out hunting on his own, krill will make up the majority of his adult diet. He will need our help to make sure he gets a steady supply. Krill are one of the casualties of ocean acidification from climate change. Hopefully, we will do better so they can, too.

PLAYFUL WATERBABIES: PORPOISE

Dall's Porpoise

These delightfully friendly and super smart fellows are Dall's porpoise. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, a blowhole is known as a ka̱'was, whether on a dolphin (porpoise) or whale and a porpoise is known as a k̓ulut̕a. 

In the Pacific Northwest, we see many of their kind — the shy, blunt-nosed harbour porpoise, the social and herd-minded Pacific white-sided dolphin and the showy and social Dall's porpoise.  

Of these, the Dall's porpoise is a particular favourite. These speedy muscular black and white showboats like to ride the bow waves of passing boats — something they clearly enjoy and a thrill for everyone on board the vessel. If you slow down, they will often whisk away, but give them a chance to race you and they may stay with you all afternoon. 

Harbour porpoises are the complete opposite. You are much more likely to see their solid black bodies and wee fin skimming through the waves across the bay as they try to avoid you entirely. Harbour porpoise prefer quiet sheltered shorelines, often exploring solo or in small groups of two or three. 

We sometimes see these lovely marine mammals represented in the art of the First Nations in the Pacific Northwest, particularly along the coast of British Columbia. You will know them from their rather rectangular artistic depiction with a pronounced snout and lacking teeth (though they have them) used to portray killer whales or orca. 

As a group, even considering the shy Harbour porpoise, these marine mammals are social and playful. Humpback whales are fond of them and you will sometimes see them hanging out altogether in the bays and inlets or near the shore. 

They are quite vocal, making lots of distinctive and interesting noises in the water. They squeak, squawk and use body language — leaping from the water while snapping their jaws and slapping their tails on the surface. They love to blow bubbles, will swim right up to you for a kiss and cuddle. 

Each individual has a signature sound, a whistle that is uniquely their own. They use these whistles to tell one of their friends and family members from another.

Porpoise are marine mammals that live in our world's oceans. If it is salty and cold, you can be pretty sure they are there. They breathe air at the surface, similar to humans, using their lungs and inhaling and exhaling through a blowhole at the top of their heads instead of through their snouts. 

TRACKING WHALES WITH BARNACLES

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

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

Barnacles are in the infraclass Cirripedia in the class Maxillopoda. They are marine arthropods related to crabs and lobsters. 

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, barnacles are known as k̕wit̕a̱'a and broken barnacle shells are known as t̕sut̕su'ma. Unless scraped off, barnacles live on one single sturdy object for their entire lives — 8 to 20 years — while chowing down on tasty snacks like plankton and algae they absorb from the surrounding water.

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

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

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

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

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

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

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

Barnacles have few predators. Their one nemesis is the whelk. It seems that catching a lifetime's ride on a passing whale would have extended their ability to feed on plankton in a variety of settings whelk-free and likely live longer than they might have cemented to something closer to the seafloor.

HUMPBACK WHALES: MEGAPTERA NOVAENGLIAE

Look deep into the knowing eye of this magnificent one. He is a Humpback whale, Megaptera novaeangliae, a species of baleen whale for whom I hold a special place in my heart. 

Baleens are toothless whales who feed on plankton and other wee oceanic tasties that they consume through their baleens, a specialised filter of flexible keratin plates that frame their mouth and fit within their robust jaws.

Baleen whales, the mysticetes, split from toothed whales, the Odontoceti, around 34 million years ago. The split allowed our toothless friends to enjoy a new feeding niche and make their way in a sea with limited food resources. There are fifteen species of baleen whales who inhabit all major oceans. Their number include our humbacks, grays, right whales and the massive blue whale. Their territory runs as a wide band running from the Antarctic ice edge to 81°N latitude. These filter feeders

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, whales are known as g̱wa̱'ya̱m. Both the California grey and the Humpback whale live on the coast. Only a small number of individuals in First Nation society had the right to harpoon a whale. It was generally only the Chief who was bestowed this great honour. Humpback whales like to feed close to shore and enter the local inlets. Around Vancouver Island and along the coast of British Columbia, this made them a welcome food source as the long days of winter passed into Spring.

Humpback whales are rorquals, members of the Balaenopteridae family that includes the blue, fin, Bryde's, sei and minke whales. The rorquals are believed to have diverged from the other families of the suborder Mysticeti during the middle Miocene. 

While cetaceans were historically thought to have descended from mesonychids— which would place them outside the order Artiodactyla— molecular evidence supports them as a clade of even-toed ungulates — our dear Artiodactyla. 

It is one of the larger rorqual species, with adults ranging in length from 12–16 m (39–52 ft) and weighing around 25–30 metric tons (28–33 short tons). The humpback has a distinctive body shape, with long pectoral fins and a knobbly head. It is known for breaching and other distinctive surface behaviours, making it popular with whale watchers.

Both male and female humpback whales vocalize, but only males produce the long, loud, complex "song" for which the species is famous. Males produce a complex soulful song lasting 10 to 20 minutes, which they repeat for hours at a time. I imagine Gregorian Monks vocalizing their chant with each individual melody strengthening and complimenting that of their peers. All the males in a group produce the same song, which differed in each season. Its purpose is not clear, though it may help induce estrus in females and bonding amongst the males.

Humpback Whale, Megaptera novaeangliae

Found in oceans and seas around the world, humpback whales typically migrate up to 25,000 km (16,000 mi) each year. 

They feed in polar waters and migrate to tropical or subtropical waters to breed and give birth, fasting and living off their fat reserves. Their diet consists mostly of krill and small fish. 

Humpbacks have a diverse repertoire of feeding methods, including the bubble net technique.

Humpbacks are a friendly species that interact with other cetaceans such as bottlenose dolphins. They are also friendly and oddly protective of humans. You may recall hearing about an incident off the Cook Islands a few years back. In September of 2017, Nan Hauser was snorkeling and ran into a tiger shark. Two adult humpback whales rushed to her aid, blocking the shark from reaching her and pushing her back towards the shore. We could learn a thing or two from their kindness. We have not been as good to them as they have been to us.

Like other large whales, the humpback was a tasty and profitable target for the whaling industry. My grandfather and uncle participated in that industry out of Coal Harbour on northern Vancouver Island back in the 1950s. 

Six whaling stations operated on the coast of British Columbia between 1905 and 1976. Two of these stations were located at Haida Gwaii, one at Rose Harbour and the other at Naden Harbour. Over 9,400 large whales were taken from the waters around Haida Gwaii. The catch included blue whales, fin whales, sei whales, humpback whales, sperm whales and right whales. In the early years of the century, primarily humpback whales were taken. In later years, fin whales and sperm whales dominated the catch. 

Whales were hunted off South Moresby in Haida Gwaii, on the north side of Holberg Inlet in the Quatsino Sound region. It was the norm at the time and a way to make a living, especially for those who had hoped to work in the local coal mine but lost their employment when it shut down. 

While my First Nations relatives hunted whales in small numbers, my Norwegian relatives participated in the hunt on such a scale that it nearly led to the extinction of our lovely Humpbacks before the process was banned back in the 1960s. The Coal Harbour Whaling Station closed in 1967. Once it had closed, my grandfather Einar Eikanger took to fishing and my uncle Harry lost his life when he slipped and fell over the side of the boat. He was crushed between the hull and a Humpback in rough seas. The Gods will have their sacrifice.

Humpback populations have partially recovered to build their population up to 80,000 animals worldwide since the 1960s but entanglement in fishing gear, collisions with ships, and noise pollution continue to negatively impact the species. So be kind if you see them. Turn your engine off and see if you can hear their soulful cries echoing in the water.

I did up a video on Humpback Whales over on YouTube so you could see them in all their majesty. Here is the link: https://youtu.be/_Vbta7kQNoM

CONLINOCERAS TARRANTENSE

Previously Calycoceras Tarrantense, this ammonite is now called Conlinoceras tarrantense after J.P. Conlin, a famous early 20th-century fossil collector from Texas, USA.

Ammonite expert Bill Cobban used this collection to describe many Texas Cretaceous ammonites species including this species from Tarrant County, Arlington, Texas.

He was a surveyor by training and kept incredibly detailed notes on the context of his fossils.

Conlin donated his collection to the USGS and we have learned much by studying it along with other specimens from the Lone Star State. Almost a quarter of Texas is covered by Cretaceous strata, much of it fossiliferous. If we stepped back 95 million years, the world and what we now call Texas was a very different place.

95 million years ago, during the Late Cretaceous, a shallow seaway separated North America into separate eastern and western landmasses. We have a pretty complete picture in the fossil record of the western groups of species but relatively little in comparison to their cohorts in the east.

At the time this fellow was swimming our ancient seas, he was sharing the Earth with carnivorous dinosaurs, duck-billed dinosaurs, mammals, crocodilians, turtles, a variety of amphibians, prehistoric bony fish, oddly prolific sea cucumbers, various invertebrates and plants. Many of these sites are just being written up now and contain new species just being discovered.

During the Late Cretaceous Period, a shallow seaway separated North America into separate eastern and western landmasses. The Woodbine Formation in Texas preserves a rare fossil record of this time for the east, but many of these fossils are isolated and incomplete, making interpretations more difficult. Preliminary excavations at the Arlington Archosaur Site (AAS) are providing hints at a more complete ecosystem, preserving similar patterns of change to what we see in the west.

The Arlington Archosaur site contains an extraordinary diversity, abundance, and quality of fossil material, preserving one of the most complete terrestrial ecosystems known for this time period and area.

These outcrops and the fossils they contain have a lot to tell us about Late Cretaceous life in the east. Over 2200 individual specimens have been found belonging to numerous groups including carnivorous dinosaurs, duck-billed dinosaurs, crocodilians, turtles, mammals, amphibians, sharks, bony fish, invertebrates, and plants.

Many of the fossils found here represent brand new species and studying these fossils will help to establish the geographic and environmental forces that shaped Cretaceous ecosystems in North America by providing a necessary comparison to the fossil record of the west.

VOAY ROBUSTUS

This big beastie is Voay robustus. You likely met him first as Crocodylus‭ (‬C.‭ ‬robustus‭) from his original naming by Grandidier and Vaillant in‭ 1872. 

Looking more closely at his remains revealed that he is nearer in design to the dwarf crocodile Osteolaemus. 

The type series cannot be identified, but the original description includes details consistent with known specimens that almost certainly pertain to the same species. 

It had a prominent triangular ‘horn’ on the posterolateral corner of each squamosal; near-exclusion of the nasals from the external naris; constricted supratemporal fenestral rims; a dorsoventrally deep snout; a constricted external mandibular fenestra in which the surangular–angular suture emerges from the posterior rather than posteroventral margin; and robust limb and limb-girdle elements. 

It shares with Osteolaemus, and with several extinct crocodylids from the Neogene of Africa, a depressed surface of the pterygoid around the internal choana forming a choanal ‘neck’. It cannot be referred to as Crocodylus and a new praenomen, Voay, was established for its reception. 

In 2007, Christopher‭ ‬A.‭ ‬Brochu created a new genus, Voay, and this fellow became Voay robustus. Christopher published his work in the Zoological Journal of the Linnean Society in Volume 150, Issue 4, August 2007, Pages 835-863. Voay lived into the Holocene of Madagasgar, perhaps meeting some of our relatives 2,000 years ago. Voay was replaced by Crocodylus niloticus in Madagascar as they moved into the niche left by Voay's ultimate demise. 

https://doi.org/10.1111/j.1096-3642.2007.00315.x

WHALER

 

INKY BEAUTY: AMMONITE OF PONGO DE MANSERICHE

This inky beauty is Prolyelliceras ulrichi (Knechtel, 1947) a fast-moving nektonic carnivorous ammonite from Cretaceous lithified, black, carbonaceous limestone outcrops in the Pongo de Manseriche gorge in northwest Peru. 

If you look closely, you can see that this specimen shows a pathology, a slight deviation to the side of the siphonal of the ammonite. We see Prolyelliceras from the Albian to Middle Albian from five localities in Peru.

The canyons of the Amazon River system in the eastern ranges of the Andes of Peru are known by the Indian name pongo. 

The most famous of these is the Pongo de Manseriche, cut by the Marañon River through the eastern range of the Andes, where it emerges from the cordillera into the flat terrane of the Amazon Basin. The fossil exposures here are best explored by boat. The reality of the collecting is similar to the imagined. I was chatting with Betty Franklin, VIPS, about this. They float along and pick up amazing specimen after amazing specimen. When the water rises, the ammonites are aided in their erosion out of the cliffs.  

The Pongo de Manseriche lies nearly 500 miles upstream from Iquitos, and consequently nearly 3,000 miles above the mouth of the Amazon River. It is situated in the heart of the montaña, in a vast region the ownership of which has long been in dispute between Peru and Ecuador, but over which neither country exercises any police or other governmental control. There is an ancient tradition of the indigenous people of the vicinity that one of their gods descended the Marañón and another ascended the Amazon to communicate with him. Together they opened the pass called the Pongo de Manseriche.

Reference: M. M. Knechtel. 1947. Cephalopoda. In: Mesozoic fossils of the Peruvian Andes, Johns Hopkins University Studies in Geology 15:81-139

W. J. Kennedy and H. C. Klinger. 2008. Cretaceous faunas from Zululand and Natal, South Africa. The ammonite subfamily Lyelliceratinae Spath, 1921. African Natural History 4:57-111. The beauty you see here is in the collection of the deeply awesome José Juárez Ruiz.

FOSSILIZED SEA URCHIN: AM'DA'MA

This lovely little biscuit is a Holectypus sea urchin from 120 million-year-old deposits from the Lagniro Formation of Madagascar.

The specimen you see here is in the collections of my beautiful friend Ileana. She and I were blessed to meet in China many years ago and formed an unbreakable bond that happens so few times in one's life. 

Holectypus are a genus of extinct echinoids related to modern sea urchins and sand dollars. They were abundant from the Jurassic to the Cretaceous (between 200 million and 65.5 million years ago).

This specimen is typical of Holectypus with his delicate five-star pattern adorning a slightly rounded test and flattened bottom. The specimen has been polished and was harvested both for its scientific and aesthetic value. 

I have many wonderful memories of collecting their modern cousins that live on the north end of Vancouver Island and along the beaches of Balaklava Island. In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, sea urchins are known as a̱m'da̱'ma and it is this name that I hear in my head when I think of them.

In echinoids, the skeleton is almost always made up of tightly interlocking plates that form a rigid structure or test — in contrast with the more flexible skeletal arrangements of starfish, brittle stars, and sea cucumbers. Test shapes range from nearly globular, as in some sea urchins, to highly flattened, as in sand dollars. 

Sea Urchin Detail

Living echinoids are covered with spines, which are movable and anchored in sockets in the test. These spines may be long and prominent, as in typical sea urchins and most have lovely raised patterns on their surface. 

In sand dollars and heart urchins, however, the spines are very short and form an almost felt-like covering. The mouth of most echinoids is provided with five hard teeth arranged in a circle, forming an apparatus known as Aristotle’s lantern.

Echinoids are classified by the symmetry of the test, the number and arrangement of plate rows making up the test, and the number and arrangement of respiratory pore rows called petals. Echinoids are divided into two subgroups: regular echinoids, with nearly perfect pentameral (five-part) symmetry; and irregular echinoids with altered symmetry.

Because most echinoids have rigid tests, their ability to fossilize is greater than that of more delicate echinoderms such as starfish, and they are common fossils in many deposits. The oldest echinoids belong to an extinct regular taxon called the Echinocystitoidea. 

They first appeared in the fossil record in the Late Ordovician. Cidaroids or pencil urchins appear in the Mississippian (Early Carboniferous) and were the only echinoids to survive the mass extinction at the Permo-Triassic boundary. Echinoids did not become particularly diverse until well after the Permo-Triassic mass extinction event, evolving the diverse forms we find them in today. 

True sea urchins first appear in the Late Triassic, cassiduloids in the Jurassic, and spatangoids or heart urchins in the Cretaceous. Sand dollars, a common and diverse group today, do not make an appearance in the fossil record until the Paleocene. They remain one of my favourite echinoderms and stand tall amongst the most pleasing of the invertebrates.

AMMONITE TRACE FOSSIL

This is a particularly fetching trace fossil of an ammonite.

Trace fossils or ichnofossils are burrows, footprints, tracks or even faeces left behind by plants and animals that lived long ago. 

Animals may have scurried across a muddy exposure or sea bottom, perhaps eaten a tasty meal then pooped it out — leaving behind clues to how they lived, what they ate and what the environment was like at the time. These are wonderfully informative clues to our ancient world.

OPABINIA REGALIS

Opabinia regalis is an extinct stem-group arthropod found in the Greater Phyllopod Bed, Middle Cambrian Burgess Shale Lagerstätte of British Columbia, Canada. 

These marine arthropods flourished from 505 million years ago to 487 million years ago.

Charles Doolittle Walcott found nine partially complete fossils of Opabinia regalis and a few of what he classified as Opabinia media, that he published in 1912. 

The bizarre arthropod's name is derived from the Opabin pass between Mount Hungabee and Mount Biddle, southeast of Lake O'Hara, British Columbia, Canada. 

In 1966–1967, Harry B. Whittington found a rather good specimen which he published in 1975. He provided a detailed description based on a very thorough dissection of some specimens and photographs of these specimens lit from a variety of angles. Harry was a very thorough fellow.

But he was still ridiculed. Opabinia looked so strange that the audience at the first presentation of Whittington's analysis laughed.

Earth's ancient seas teemed with new life 541 - 485 Million Years Ago. The Cambrian Explosion had arrived. Weird and wonderful life forms like Hallucigenia and Anomalocaris are found in the fossil record giving us a peek at ancient life half a billion years ago.

THE DUDLEY BUG: CALYMENE BLUMENBACHII

A lovely rolled trilobite, Calymene blumenbachii,  from outcrops in the UK. This wee beauty is in the collections of the deeply awesome Theresa Paul Spink Dunn — or perhaps in her daughter Layla's collections as she is quite the budding palaeontologist. This Silurian beauty is from the Homerian, Wenlock Series, Wrens Nest, Dudley, UK.

Calymene blumenbachii, sometimes erroneously spelled blumenbachi, is a species of trilobite found in the limestone quarries of the Wren's Nest in Dudley, England.

Nicknamed the Dudley Bug or Dudley Locust by an 18th-century quarryman, it became a symbol of the town and featured on the Dudley County Borough Council coat-of-arms. Calymene blumenbachii is commonly found in Silurian rocks (422.5-427.5 million years ago) and is thought to have lived in the shallow waters of the Silurian, in low energy reefs.

This particular species of Calymene — a fairly common genus in the Ordovician-Silurian — is unique to the Wenlock series in England and comes from the Wenlock Limestone Formation in Much Wenlock and the Wren's Nest in Dudley. These sites seem to yield trilobites more readily than any other areas on the Wenlock Edge, and the rock here is dark grey as opposed to yellowish or whitish as it appears on other parts of the Edge, just a few miles away, in Church Stretton and elsewhere. This suggests local changes in the environment in which the rock was deposited. The Wenlock Edge quarry is closed now to further collecting but may be open to future research projects. We shall have to see.

PIKAIA GRACILIENS: MIDDLE CAMBRIAN GRACE

Pikaia graciliens is an extinct, primative chordate animals from the Middle Cambrian Burgess Shale Lagerstätte of British Columbia, Canada. 

These lovelies swam by moving their bodies in a series of zigzag curves similar to the movement of eels, all the while filtering particles from the water.

Although primitive, Pikaia shows the essential prerequisites for vertebrates. When alive, Pikaia was a compressed, leaf-shaped animal with an expanded tail fin; the flattened body is divided into pairs of segmented muscle blocks, seen as faint vertical lines. 

The muscles lie on either side of a flexible structure resembling a rod that runs from the tip of the head to the tip of the tail. It swam by throwing its body into a series of S-shaped undulating movements that mimicked the movement of eels. Fish inherited this same swimming movement, but they generally have stiffer backbones so it does not quite have the same visual effect. 

Pikaia was likely a slow swimmer since it lacked the fast-twitch fibres that we associate with rapid swimming in modern chordates. Still, even that form of movement in the Middle Cambrian is impressive in terms of mobility and design.

Conway Morris and Caron (2012) published an exhaustive description based on more than one hundred known fossil specimens. Through their deeper look at this primitive marine mystery, they discovered new and unexpected characteristics that they recognized as primitive features of the first chordate animals. On the basis of these findings, they constructed a new scenario for chordate evolution. 

Subsequently, Mallatt and Holland reconsidered Conway Morris and Caron's description and concluded that many of the newly recognized characters are unique, already-divergent specializations that would not be helpful for establishing Pikaia as a basal chordate.

PTEROSAURS: SOARING ANCIENT SKIES

If you could travel through time and go back to observe our ancient skies, you would see massive pterosaurs — huge, winged flying reptiles of the extinct order Pterosauria — cruising along with you. 

They soared our skies during most of the Mesozoic — from the late Triassic to the end of the Cretaceous (228 to 66 million years ago). 

By the end of the Cretaceous, they had grown to giants and one of their brethren, Quetzalcoatlus, a member of the family Azhdarchidae, boasts being the largest known flying animal that ever lived. 

They were the earliest vertebrates known to have evolved powered flight. Their wings were formed by a membrane of skin, muscle, and other tissues stretching from the ankles to a dramatically lengthened fourth finger.

PISTA DE BAILE JURÁSICA

This busy slate grey dinosaur trackway from the Iberian Peninsula looks more like a dance floor than the thoroughfare it is. 

The numerous theropod dinosaur tracks — with a few enormous sauropod tracks thrown in for good measure — cover the entire surface. 

The local soil has a bit of rusty iron ore in it that highlights each print nicely when the soil is blown into the depressions the tracks left. 

The dinosaurs crossed this muddy area en masse sometime back in the Jurassic.

The Iberian Peninsula is the westernmost of the three major southern European peninsulas — the Iberian, Italian, and Balkan. It is bordered on the southeast and east by the Mediterranean Sea, and on the north, west, and southwest by the Atlantic Ocean. The Pyrenees mountains are situated along the northeast edge of the peninsula, where it adjoins the rest of Europe. Its southern tip is very close to the northwest coast of Africa, separated from it by the Strait of Gibraltar and the Mediterranean Sea.

The Iberian Peninsula contains rocks of every geological period from the Ediacaran to the recent, and almost every kind of rock is represented. To date, there are 127 localities of theropod fossil finds ranging from the Callovian-Oxfordian — Middle-Upper Jurassic — to the Maastrichtian (Upper Cretaceous), with most of the localities concentrated in the Kimmeridgian-Tithonian interval and the Barremian and Campanian stages. The stratigraphic distribution is interesting and suggests the existence of ecological and/or taphonomic biases and palaeogeographical events that warrant additional time and attention.

As well as theropods, we also find their plant-eating brethren. This was the part of the world where the last of the hadrosaurs, the duck-billed dinosaurs, lived then disappeared in the Latest Cretaceous K/T extinction event 65.5 million years ago.

The core of the Iberian Peninsula is made up of a Hercynian cratonic block known as the Iberian Massif. On the northeast, this is bounded by the Pyrenean fold belt, and on the southeast, it is bounded by the Baetic System. These twofold chains are part of the Alpine belt. To the west, the peninsula is delimited by the continental boundary formed by the magma-poor opening of the Atlantic Ocean. The Hercynian Foldbelt is mostly buried by Mesozoic and Tertiary cover rocks to the east but nevertheless outcrops through the Sistema Ibérico and the Catalan Mediterranean System. The photo you see here is care of the awesome Pedro Marrecas from Lisbon, Portugal. Hola, Pista de baile jurásica!

Pereda-Suberbiola, Xabier; Canudo, José Ignacio; Company, Julio; Cruzado-Caballero, Penélope; Ruiz-Omenaca, José Ignacio. "Hadrosauroid dinosaurs from the latest Cretaceous of the Iberian Peninsula" Journal of Vertebrate Paleontology 29(3): 946-951, 12 de septiembre de 2009.

Pereda-Suberbiola, Xabier; Canudo, José Ignacio; Cruzado-Caballero, Penélope; Barco, José Luis; López-Martínez, Nieves; Oms, Oriol; Ruíz-Omenaca, José Ignacio. Comptes Rendus Palevol 8(6): 559-572 septiembre de 2009.

SNOWY TREE CRICKET: CHIRPING THERMOMETERS

About 250 million years ago, our once silent world became a cacophony of diverse animal sounds. 

One of the most lyrical of those voices to join the Earth's chorus were the true crickets. We can count them as some of the earliest musicians on the planet. 

This group evolved and contributed to the nocturnal circumambience of our planet a full 150 million years before our human ancestors would have heard them for the very first time. It is their long lineage that I am mindful of when I am out for an evening stroll and hear their pleasing serenade.

If you find yourself out in the woods and are wondering what the temperature might be, you need only slip closer to the nearest stand of deciduous trees to follow the musical sounds of the wee Snowy Tree Cricket, Oecanthus Fultoni, part of the order orthoptera.

Snowy Tree Crickets and their cousins double as thermometers and wee garden predators, dining on aphids and other wee beasties. Weather conditions, both hot and cold, alter the speed at which they rub the base of their wings together and consequently regulate their rate of chirping.

Listen closely for their tell-tale high pitch triple chirp sound in the early evening. Being in Canada, our crickets chirp in Celsius. To figure out the temperature, we simply count the number of chirps over a seven-second period and add five to learn the local temperature.

If did not happen to bring your calculator and you are still operating in old-school Fahrenheit, you can use this handy conversion — double the temperature in Celsius, add 32 you'll get the approximate temperature in Fahrenheit. And if you are not all that interested in the temperature, enjoy their pleasing serenade as you take your early evening stroll. They've been working on this number for millions of years. 

Daniel Otte from the Academy of Natural Sciences in Philadelphia did up a wonderful piece on the evolution of cricket songs. If you’re a keen bean & want to learn more, I'll attach the journal article for you. https://doi.org/10.2307/3503559. https://www.jstor.org/stable/3503559

DIMORPHODON: TWO TOOTH PTERODACTYLUS

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, 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.

MAMMUTUS PRIMIGENIUS: WOOLLY MAMMOTH

This fellow is Mammutus primigenius a Woolly Mammoth from the Pleistocene of Siberia, Russia. 

Mammoths have a wonderful display of mammoth teeth, the diagnostic flat enamel plates and the equally distinct pointy cusped molars of the mastodons. He was a true elephant, unlike his less robust cousins, the mastodons. Mammoths were bigger — both in girth and height — weighing in at a max of 13 tonnes. 

They are closely related to Asian elephants and were about the size of the African elephants you see roaming the grasslands of Africa today.

If you stood beside him and reached way up, you might be able to touch his tusks but likely not reach up to his mouth or even his eyes. He would have had a shaggy coat of light or dark coloured hair with long outer hair strands covering a dense thick undercoat. His oil glands would have worked overtime to secrete oils, giving him natural waterproofing.

Some of the hair strands we have recovered are more than a meter in length. These behemoth proboscideans boasted long, curved tusks, little ears, short tails and grazed on leaves, shrubs and grasses that would have been work to get at as much of the northern hemisphere was covered in ice and snow during his reign. It is often the teeth of mammoths like those you see in the photo here that we see displayed. 

Their molar teeth were large and have always struck me as looking like ink plates from a printing press. If they are allowed to dry out in collection, they fall apart into discreet plates that can be mistaken for mineralized or calcified rock and not the bits and pieces of mammoth molars that they indeed are. Their large surface area was perfect for grinding down the low nutrient, but for the most part, plentiful grasses that sustained them.

Mammoth Tusk, Wrangel Island, Chukotka Okrug, Russia

How did they use their tusks? Likely for displays of strength, protecting their delicate trunks, digging up ground vegetation and in dry riverbeds, digging holes to get at the precious life-giving water. 

It's a genius design, really. A bit like having a plough on the front of your skull. In the photo here you can see a tusk washed clean in a creek bed on Wrangel Island.

Their size offered protection against other predators once the mammoth was full grown. Sadly for the juveniles, they offered tasty prey to big cats like Homotherium who roamed those ancient grasslands alongside them.

They roamed widely in the Pliocene to Holocene, roaming much of Africa, Europe, Asia and North America. We see them first some 150,000 years ago from remains in Russia then expanding out from Spain to Alaska. They enjoyed a very long lifespan of 60-80 — up to 20 years longer than a mastodon and longer than modern elephants. 

They enjoyed the prime position as the Apex predator of the megafauna, then declined — partially because of the environment and food resources and partially because of their co-existence with humans. In places where the fossil record shows a preference for hunting smaller prey, humans and megafauna do better together. We see this in places like the Indian Subcontinent where primates and rodents made the menu more often than the large megafauna who roamed there. We also see this in present-day Africa, where the last of the large and lovely megafauna show remarkable resilience in the face of human co-existence.  

The woolly mammoths from the Ukrainian-Russian plains died out 15,000 years ago. This population was followed by woolly mammoths from St. Paul Island in Alaska who died out 5,600 years ago — and quite surprisingly, at least to me, the last mammoth died just 4,000 years ago in the frosty ice on the small island of Wrangel in the Arctic Ocean — their final days spent scratching out a dwindling existence of genetic mutations, howling winds, rain-darkened hills and subsistence on tough grasses grown in thin soil. 

Further reading: Laura Arppe, Juha A. Karhu, Sergey Vartanyan, Dorothée G. Drucker, Heli Etu-Sihvola, Hervé Bocherens. Thriving or surviving? The isotopic record of the Wrangel Island woolly mammoth population. Quaternary Science Reviews, 2019; 222: 105884 DOI: 10.1016/j.quascirev.2019.105884

COELACANTHS: LIVING FOSSILS

Coelacanths are members of a now-rare order of fish, the Coelacanthiformes, that includes two extant species in the genus Latimeria: the West Indian Ocean coelacanth — Latimeria chalumnae — primarily found near the Comoro Islands off the east coast of Africa and the Indonesian coelacanth — Latimeria menadoensis. 

The name originates from the Permian genus Coelacanthus, which means hollow spine and was published by Swiss-born American biologist and geologist Jean Louis Rodolphe Agassiz in 1839. 

The type species Coelacanthus granulatus was described from the Late Permian, Wuchiapingian of Kupferschiefer of Germany and England. Coelacanthus is primarily known from Late Permian and Early Triassic deposits in Europe and Canada, although the referred species C. welleri, known from Iowa, is of Late Devonian, Famennian age. They survived the Permian–Triassic extinction event, and one species, C. banffensis, is known from the Early Triassic.

Coelacanths belong to the subclass Actinistia, a group of lobed-finned fish related to lungfish and certain extinct Devonian fish such as osteolepiforms, porolepiforms, rhizodonts, and Panderichthys. The oldest known coelacanth fossils are over 410 million years old. Coelacanths were thought to have become extinct in the Late Cretaceous, around 66 million years ago, but were rediscovered in 1938 off the coast of South Africa.

Coelacanths follow the oldest-known living lineage of Sarcopterygii, lobe-finned fish and tetrapods, which makes them are more closely related to lungfish and tetrapods — which includes amphibians, reptiles, birds and mammals — than to ray-finned fish. They are found along the coastline of Indonesia and in the Indian Ocean. The West Indian Ocean coelacanth is a critically endangered species.

The coelacanth was long considered a living fossil because scientists thought it was the sole remaining member of a taxon otherwise known only from fossils, with no close relations alive, and that it evolved into roughly its current form approximately 400 million years ago. Several more recent studies have shown that coelacanth body shapes are much more diverse than previously thought.

CHELICERATA: EURYPTERIDS, SPIDERS AND HORSESHOE CRABS

Sanctacaris uncata

This lovely is Sanctacaris uncata — a wonderful example of Chelicerata.

We first see them emerge in our ancient oceans in the Middle Cambrian, 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 Burgess Shale, British Columbia, Canada. 

Sanctacaris is proof positive that chelicerates, although rare, were present in the Middle Cambrian sea. Even at this early stage of evolution, Sanctacaris had the number and type of head appendages found in modified form in the 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 were long 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 with 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.

HORSESHOE CRABS: WINNING THE SLOW RACE OF TIME

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

CRUZIANA TRILOBITE AND ANCIENT FOSSIL TRACKWAYS

Trilobite and Sea Scorpion Fossil Trackways

This is a very interesting block with wee trace fossil trackways from our Mississippian seas some 359.2 million to 318.1 million years ago. 

It shows a nice combination of Cruziana fossil trilobite trackway and eurypterid (sea scorpion) or horseshoe crab trackway on the same matrix. 

When we use the term Cruziana, we are not referring to the trilobite species, but to the particular shape and form of the trackway. 

In this case, elongate, bilaterally symmetrical burrows preserved along the bedding plane with repeated striations that are mostly oblique to the long dimension. I like to picture a teeny, tiny painter or sculpture with a small putty knife making angled cuts along a line or a wave motion to create a small curved line. Very showy skate skiing is another good visual. Sadly, neither is the case. While a Cruziana trace fossil is most often associated with trilobites, it can be made by other arthropods. 

When we see trace fossils — preserved tracks or other signs of behaviour from our marine friends living on the seafloor — they are generally from their furrowing, resting, emerging, walking or striding. They provide a glimpse of how these ancient sea creatures moved about to make a living. 

Trilobite and Sea Scorpion Fossil Trackways

This busy 4 1/2" x 3 1/2" x 1 1/4" block hails from the Tar Springs Formation in Perry County, Indiana, USA, and is in the collections of the deeply awesome David Appleton.

The Tar Springs Formation is recognized on the surface from southwestern Orange County to the Ohio River and is known in the subsurface from central Martin County southwestward (Gray, 1970, 1986).

In Indiana, the Tar Springs Formation is primarily shale, but it also contains scattered thin beds of limestone and massive local lenses of sandstone that on outcrop are differentiated as the Tick Ridge Sandstone Member (Gray, 1986). The formation ranges in thickness from about 70 ft (21 m) to more than 150 ft (46 m) in central Posey County and in southwestern Gibson County (Droste and Keller, 1995). Commonly sandstone predominates in those areas where the Tar Springs is as much as 150 ft (46 m) thick (Droste and Keller, 1995).

TRILOBITES: DARLINGS OF THE FOSSIL RECORD

Trilobites are the darlings of most fossil collectors. These diverse beauties are an extinct group of marine arthropods that first appeared in the Early Cambrian. 

They left many beautifully preserved examples of their three-lobed exoskeletons in the fossil record.

Trilobites — in all their many wonderful forms — lived in our ancient oceans for more than 270 million years. The last of their lineage went extinct at the end of the Permian, 252 million years ago. 

EURYPTERIDS: ANCIENT MARINE ARTHROPODS

More commonly known as sea scorpions, the now-extinct eurypterids were arthropods that lived during the Paleozoic. 

We saw the first of their brethren during the Ordovician and the last of them during the End-Permian Mass Extinction Event. 

In between, they thrived and irradiated out to every niche within our ancient seas and many later forms survived and thrived in both brackish and freshwater. 

The group Arthropoda includes invertebrate animals with exoskeletons, segmented bodies, and paired joint appendages. Eurypterids had six sets of appendages. You can clearly see the segmented body on this cutie, which is one of the defining characteristics of arthropods. The first set was modified into pinchers which are used for feeding. The largest appendage visible in this fossil is a broad paddle that E. tetragonophthalmus used to swim.

This first eurypterid, Eurypterus remipes, was discovered in New York in 1818. It is an iconic fossil for this region and was chosen as the state's official fossil in 1984. An excellent choice as most of the productive eurypterid-bearing outcrops are within the state's boundaries. Most of the fossils we find from them, whether body fossils or trace fossils are from fossil sites in North America and Europe This is because the group lived primarily in the waters around and within the ancient supercontinent of Euramerica. 

Only a handful of eurypterid groups spread beyond the confines of Euramerica and a few genera, such as Adelophthalmus — the longest-lived of all known eurypterid genera — and the giant predatory Pterygotus, achieved a cosmopolitan distribution so we find their fossil remains worldwide today. 

Interestingly, the type species, Pterygotus anglicus, was first through to be the remains of a massive fish by Swiss naturalist Louis Agassiz who described it in 1839 — hence the poorly chosen name Pterygotus, which translates to winged fish. He did catch that embarrassing error five years later, but the name remains for all time.

PIRANIA: MIDDLE CAMBRIAN SPONGE

Pirania is an extinct genus of sea sponge from the Middle Cambrian Burgess Shale in the Canadian Rockies of British Columbia and the Ordovician Fezouata Formation of Morocco. 

We have sea sponges living in our oceans today. Sea Sponges are some of the simplest multicellular organisms alive. They do not have brains, digestive, circulatory or nervous systems and, once rooted, do not move. 

Sponge species are numerous and diverse. There are 8,550 living sponge species in the phylum Porifera, which is comprised of four distinct classes. 

Demospongiae is the most diverse, containing 76.2% of all living sponges. Desmospongiae form complex bodies with monoaxon or tetraxon spicules. They can live in both marine and freshwater.

Hexactinellida, the rare glass sponges; Calcarea which contains all the calcareous sponges; and, Homoscleromorpha, the rarest and simplest class with 117 species. Homoscleromorpha has only recently been recognized so perhaps we will find more examples as we explore the world's oceans.

They are very skilled at filtering water and can pass more than 20,000 times their volume through their systems in a single day. They greatly aid in the water quality of coral reef ecosystems, filtering bacteria along with the water they process. They also aid with carbon, nitrogen and phosphorus as they filter it through their bodies and put it back into the ecosystem via their excrement.

Pirania is named after Mount St. Piran, near the Bow River Valley, Banff National Park, Alberta, Canada. It was first described by Charles Doolittle Walcott in 1920 from 128 fossil specimens found within the Greater Phyllopod bed, the most famous fossil-bearing member of the 508 million-year-old Burgess Shale Fossil Lagerstätte in the Canadian Rockies of British Columbia. The type locality has exceptional preservation of soft-bodied animals from the Middle Cambrian.

ANCIENT MARINE REPTILES: ICHTHYOSAURS

During the early Triassic period, ichthyosaurs evolved from a group of unidentified land reptiles that returned to the sea. 

They were particularly abundant in the later Triassic and early Jurassic periods before being replaced as the premier aquatic predator by another marine reptilian group, the Plesiosauria, in the later Jurassic and Cretaceous periods.

They thrived during much of the Mesozoic era; based on fossil evidence, they first appeared around 250 million years ago and at least one species survived until about 90 million years ago into the Late Cretaceous.

While they resembled fish and dolphins, ichthyosaurs were large marine reptiles belonging to the order known as Ichthyosauria or Ichthyopterygia. In 2018, Benjamin Kear and his team were able to study ichthyosaur remains at the molecular level, Their findings suggest ichthyosaurs had skin and blubber quite similar to our modern dolphins.

While ichthyosaurs evolved from land-dwelling, lung-breathing reptiles, they returned to our ancient seas and evolved into the fish-shaped creatures we find in the fossil record today.

Their limbs fully transformed into flippers, sometimes containing a very large number of digits and phalanges. Their flippers tell us they were entirely aquatic as they were not well-designed for use on land. And it was their flippers that first gave us the clue that they gave birth to live young; a find later confirmed by fossil embryo and wee baby ichy finds.