HEXACORALLIA

Hexacorallia is a subclass of Anthozoa comprising approximately 4,300 species of aquatic organisms formed of polyps, generally with six-fold symmetry. Their temporal range is from the Fortunian to the Holocene. The subclass includes all of the stony corals, most of which are colonial and reef-forming, as well as all sea anemones, and zoanthids, arranged within five extant orders.

The hexacorallia are distinguished from another subclass of Anthozoa, Octocorallia, in having six or fewer axes of symmetry in their body structure; the tentacles are simple and unbranched and normally number more than eight. These organisms are formed of individual soft polyps which in some species live in colonies and can secrete a calcite skeleton. As with all Cnidarians, these organisms have a complex life cycle including a motile planktonic phase and a later characteristic sessile phase. Hexacorallia also includes the significant extinct order of rugose corals.

AURELIA AURITA: MOON DANCERS

Moon Jelly Fish / Aurelia Aurita

Aurelia aurita (also called the common jellyfish, moon jellyfish, moon jelly or saucer jelly) is a widely studied species of the genus, Aurelia. All species in the genus are closely related, and it is difficult to identify Aurelia medusae without genetic sampling; most of what follows applies equally to all species of the genus.

The genus Aurelia is found throughout most of the world's oceans, from the tropics to as far north as latitude 70° north and as far south as 40° south. The species Aurelia aurita is found along the eastern Atlantic coast of Northern Europe and the western Atlantic coast of North America in New England and Eastern Canada. In general, Aurelia is an inshore genus that can be found in estuaries and harbours.

The genus Aurelia is found throughout most of the world's oceans, from the tropics to as far north as latitude 70° north and as far south as 40° south. The species Aurelia aurita is found along the eastern Atlantic coast of Northern Europe and the western Atlantic coast of North America in New England and Eastern Canada. In general, Aurelia is an inshore genus that can be found in estuaries and harbours.

OH MAXIMUS: ISOTELUS REX

This lovely big fella is Isotelus rex from Churchill, Manitoba, Canada. He was found along the Hudson Bay and is the largest complete trilobite ever found. Isotelus is a genus of asaphid trilobites, an extinct group of arthropods, from the middle and upper Ordovician

Discovered by a paleo dream team, including the deeply awesome, Dave Rudkin, assistant curator of paleobiology at the Royal Ontario Museum, along with Robert Elias (Project Lead), University of Manitoba, Graham Young (Project Lead), associate curator of geology at the Manitoba Museum of Man and Nature (and adjunct professor at the University of Manitoba) and Edward Dobrzanski, Manitoba Museum during a long-term field project in 1998-1999.

The specimen measures in at a whopping 28 inches in length and is 70 percent larger than the previous record holder and warranted a new species name. The image here shows one of several replicas (casts), not the actual holotype specimen which is on exhibit at the Manitoba Museum.

There is a second complete specimen (430 mm in length) of Isotelus rex in the collections of the Geological Survey of Canada (GSC 85292 - a designated paratype). As with many such projects, financial contributions make field work and research possible. A nod to the Natural Sciences and Engineering Research Council of Canada, the University of Manitoba, the Manitoba Museum Foundation nd the Royal Ontario Museum Foundation.

Kudos as well to field crew, David Wright, Curtis Moffat and Janis Klapecki. You arrived four hundred and forty-five million years too late for sunscreen and tropical weather.

In the prophetic words of Eddard Stark, "Winter is Coming." And so it did to the Canadian prairies. Thank you to everyone involved for enduring the frozen cold, wind, rains and hail of northern Manitoba. For those who haven't had the pleasure, dear Manitoba gets blasted by cold Arctic high-pressure that drops it to a frigid -47.2 Celsius. That's a sweet, sweet -52 with wind chill.

Paper: Rudkin, D.A.; Young, G.A.; Elias, R.J.; Dobrzanski, E.P. (2003). "The World's biggest Trilobite: Isotelus rex new species from the Upper Ordovician of northern Manitoba, Canada". Palaeontology. 70 (1): 99–112. doi:10.1666/0022-3360(2003)077<0099:twbtir>2.0.CO;2. ISSN 0022-3360.

Photo credit: Mike Beauregard from Nunavut, Canada. Cast of Isotelus rex. Churchill Manitoba. 2 foot long replica housed at the University of Manitoba. Original specimen is in the Manitoba Museum. The original specimen was recovered the intertidal zone of Hudson Bay.

OREGON PALEONTOLOGY

Driving down the Oregon coast, you see large basalt sentinels left stranded on the beaches. The surf rubs at them slowly eroding a story that extends into our geologic past.

The rugged landscape of Oregon was shaped over millions of years. Fire, floods, earthquakes and volcanic eruptions —  driven by the collision of an oceanic and continental plate — each had a hand in helping to shape this beautiful part of the world. The ground here has been moving and shifting on a steady northeast direction for several hundred million years and continues today.

Oregon's geologic record extends back to the Devonian. Oregon had been mostly submerged hidden beneath the depths of an ancient ocean. The centre of the state boasts the oldest rocks. Near Suplee, Oregon snuggled up against the Malheur National Forest you can find Devonian limestones with a lovely of shallow-water marine invertebrates. Look for corals and brachiopod who made a living in Devonian seas far from where they rest today.

In the Carboniferous period, a series of volcanic archipelagos formed in Oregon. The islands enjoyed a warm, wet, terrestrial environments. Think of the Mississipi today. Fossils in Oregon's oldest floral assemblage, dating to the Late Carboniferous, were built on a lagoon ecosystem. The fossil fauna here include horsetails, ferns, scale trees, and conifer tree seeds. Formations of similar age also include shallow-water invertebrates telling us that Oregon's volcanic islands were surrounded by coral reefs.

Oregon remained mostly submerged until the Paleocene. Oregon was covered by seaways and volcanic islands during the Mesozoic. We find marine plants, invertebrates, ichthyosaurs, pterosaurs, and traces such as invertebrate burrows.

During the Cenozoic, Oregon's climate gradually cooled and eventually yielded the environments now found in the state. The era's fossils include marine and terrestrial plants, invertebrates, fish, amphibians, turtles, birds, mammals, and traces such as eggs and animal tracks.

Sediment records show that Oregon remained mostly submerged until the Paleocene period. The state's earliest fossil record includes plants, corals, and conodonts.

Oregon was covered by seaways and volcanic islands during the Mesozoic era. Fossils from this period include marine plants, invertebrates, ichthyosaurs, pterosaurs, and traces such as invertebrate burrows.

During the Cenozoic, Oregon's climate gradually cooled and eventually yielded the environments now found in the state. The era's fossils include marine and terrestrial plants, invertebrates, fish, amphibians, turtles, birds, mammals, and traces such as eggs and animal tracks.

Reference: https://www.oregongeology.org/pubs/ims/ims-028/index.htm

CROCUTA CROCUTA

Female Spotted Hyena / Sub-Saharan Africa

This lovely lady is a spotted hyena. While she looks like a large dog, she shares more similarities with our large cats, lions and tigers.

Like all her kin, she's a wonderful hunter either with her pack or out solo. While portrayed as scavengers, those who've seen them in the wild know that she's a good little hunter and not a picky eater. Hyenas snack on a varied selection of birds, lizards, snakes, fish and insects over their long lives. Most live about 25 years and are quite social animals. They live in large groups called clans, some up to 75-80 individuals. They eat larger game as well, often hunting with their clan packs to take down zebra, antelope, wildebeest and even young hippos.

Spotted hyenas are mammals in the Family Hyaenidae. They roam the tropical grasslands, woodlands and savanna of Africa. The females are the larger of the species, weighing up to 82 kg and growing up to 2 metres long and are the leaders of the group. Each clan is led by one alpha female who rules the roost and still takes time out to have one ot cubs a year. They are the original working moms.

PALEO PARENTING: NOTHOSAURS

In Sauropterygia, a diverse group of Mesozoic marine reptiles, fossil evidence of viviparity (live‐bearing) only exists for Pachypleurosauria and Plesiosauria, and was assumed to also be the case for nothosaurs.

Previous studies have successfully applied an extant squamate model to sauropterygian life‐history traits. In extant squamates, oviparity and viviparity are associated with differences in life‐history trait combinations.

A paper released in March 2019, in the journal Palaeontology, sheds light on this view. Griebeler et al. have establish growth curves for Nothosaurus specimens based on their humeral histology.

They analyzed life‐history traits derived from these curves and compared inferred traits to those of modern squamates and pachypleurosaurs to assess their reproduction mode.

Their data shows birth to adult size ratios (i.e. birth size divided by the mother's size) provides a good estimate of clutch sizes in extant squamates and in viviparous extinct marine reptiles, but these ratios cannot discriminate viviparous and oviparous squamates.

Thus, large ratios do not indicate viviparity in fossil taxa to which the extant squamate model is applicable.

Applying differences in birth size, age at maturation, and maximum longevity that are observed between extant viviparous and oviparous squamates to our Nothosaurus sample, they identified 7 out of 24 specimens as being potentially viviparous.

Conversely, they suggested oviparity for many nothosaurs but also for many pachypleurosaur samples.

Under the assumption that the entire clade Pachypleurosauria was viviparous, the majority of nothosaurs would also have been viviparous as they comprised trait combinations similar to those seen in pachypleurosaurs.

Overall, this suggests that within nothosaurs and pachypleurosaurs both reproduction modes existed in different taxa.

TAKING IN THE VIEW

We soak up the breathtaking views after a long morning's paddle. The east and south sides of our route are bound by the imposing white peaks of the Cariboo Mountains, the northern boundary of the Interior wet belt, rising up across the Rocky Mountain Trench, and the Isaac Formation, the oldest of seven formations that make up the Cariboo Group.

Some 270 million years ago, the rock that would become the Cariboo Mountains and form the lakes and valleys of Bowron was far out in the Pacific Ocean, down near the equator. With tectonic shifting, these rocks drifted north-eastward, riding their continental plate, until they collided with and joined the Cordillera in what is now British Columbia. Continued pressure and volcanic activity helped create the tremendous slopes of the Cariboo Range we see today with repeated bouts of glaciation during the Pleistocene carving their final shape. Warm and dry with bellies filled full of soup and crisps, we head back out to explore more of nature's bounty.

GIDDY UP AND GO

ODE TO OECANTHUS

Out in the woods and wondering what the temperature is? Slip down to the nearest stand of deciduous trees to search for 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, affect the speed at which they rub the base of their wings together and consequently regulate their rate of chirping. Listen for their tell-tale high pitch triple chirp sound in the early evening. Being in Canada, our crickets chirp in Celsius. Simply count the number of chirps over a seven second period and add five to learn your local temperature.

If didn't bring your calculator with you into the woods and you're still operating in old-skool Fahrenheit, ie. those in the United States, the Bahamas, Belize, the Cayman Islands and Liberia can use this handy conversion. Double the temperature in Celsius, add 32 you'll get the approximate temperature in Fahrenheit.

IMPERIUM IN IMPERIO

FEMALE MACROCONCH

This sweet beauty with lovely colouring is a Hoploscaphites nebrascensis (Owen, 1852) macroconch. This is the female form of the ammonite that has a larger shell than the male, or microconch.

Hoploscaphites nebrascensis is an upper Maastrichtian species and index fossil. It marks the top of ammonite zonation for the Western Interior. This species has been recorded from Fox Hills Formation in North and South Dakota as well as the Pierre Shale in southeastern South Dakota and northeastern Nebraska.

It is unknown from Montana, Wyoming, and Colorado due to the deposition of coeval terrestrial units. It has possibly been recorded in glacial deposits in Saskatchewan and northern North Dakota, but that is hearsay. Outside the Western Interior, this species has been found in Maryland and possibly Texas in the Discoscaphites Conrad zone. This lovely one is in the collection of the deeply awesome (and enviable) José Juárez Ruiz. A big thank you to Joshua DrSlattmaster J Slattery for his insights on this species.

BERLIN-ICHTHYOSAUR STATE PARK

URSUS CURIOUS

A young Black Bear cub, Ursus americanus, checking out the view from a tree branch. His mamma is likely very near by as they keep an eye on the cubs, helping to feed, dry and protect them from danger.

Full grown, this fuzzy fellow will be able to run 48 kilometres or 30 miles an hour. They like to swim and hunt for fish, berries and roots. They will also dine on insects, deer, moose and whatever they can scavenge in the forest. 

We are blessed to have them living amongst us today on the rugged west coast of British Columbia. 

In the Kwak'wala language of the Kwakiutl First Nations of the Pacific Northwest, this little cutie is t̕ła'yi — a lovely, playful black bear.

ANCIENT TOMB

DEVONIAN FISH PODOLIA, UKRAINE

A Devonian fish mortality plate showing all lower shields of Zenaspis podolica (Lankester, 1869) and Stensiopelta pustulata (and potentially Victoraspis longicornualis) from Lower Devonian deposits of Podolia, Ukraine.

Zenaspis is an extinct genus of jawless fish which thrived during the early Devonian. Being jawless, Zenaspis was probably a bottom feeder, snicking on debris from the seafloor.

The lovely 420 million-year-old plate you see here is from Podolia or Podilia, a historic region in Eastern Europe, located in the west-central and south-western parts of Ukraine, in northeastern Moldova. Podolia is the only region in Ukraine where Lower Devonian remains of ichthyofauna can be found near the surface.

For the past 150 years, vertebrate fossils have been found in more than 90 localities situated in outcrops along banks of the Dniester River and its northern tributaries, and in sandstone quarries. At present, the faunal list of Early Devonian agnathans and fishes from Podolia number 72 species, including 8 Thelodonti, 39 Heterostraci, 19 Osteostraci, 4 Placodermi, 1 Acanthodii, and 1 Holocephali (Voichyshyn 2001a, modified).

In Podolia, Lower Devonian redbeds strata (the Old Red Formation or Dniester Series) are up to 1800 m thick and range from Lochkovian to Eifelian in age (Narbutas 1984; Drygant 2000, 2003). In their lower part (Ustechko and Khmeleva members of the Dniester Series) they consist of multicoloured, mainly red, fine-grained cross-bedding massive quartz sandstones and siltstones with seams of argillites (Drygant 2000).

We also see fossils of Zenaspis in the early Devonian of Western Europe. Both Zenaspis pagei and Zenaspis poweri can be found up to 25 centimetres long in Devonian outcrops of Scotland.

Reference: Voichyshyn, V. 2006. New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica 51 (1): 131–142. Photo care of the awesome Fossilero Fisherman.

STONE CARRIAGE

DEVONIAN FISH

NEMRUT ADIYAMAN

Nemrut, Adıyaman / Turkey

SILURIAN BEAUTIES

The impressive homeotype specimen of a Eurypterus lacustris duo hails from Late Silurian deposits of New York. These lovelies are now housed in UCMP Berkeley's paleontological collections.

About two dozen families of eurypterids “sea scorpions” are known from the fossil record. Although these ancient predators have a superficial similarity, including a defensive needle-like spike or telson at their tail end, they are not true scorpions.

They are an extinct group of arthropods related to spiders, ticks, mites and other extant creepy crawlies.

Eurypterids hunted fish in the muddy bottoms of warm shallow seas before moving on to hunting grounds in fresh and brackish water during the latter part of their reign.

They declined in numbers and diversity until becoming extinct during the Permian–Triassic extinction event (or sometime shortly before) 251.9 million years ago.

As to the oldest and youngest of the order, we can look to the Stylonurina. Members of the suborder are collectively and informally known as "stylonurine eurypterids" or "stylonurines". They are known from deposits primarily in Europe and North America, but also in Siberia.

Compared to the suborder, Eurypterina, the stylonurines were comparatively rare and retained their posterior prosomal appendages for walking. Despite their rarity, the stylonurines have the longest temporal range of the two suborders. The suborder contains some of the oldest known eurypterids, such as Brachyopterus, from the Middle Ordovician as well as the youngest known eurypterids, from the Late Permian.

They remained rare throughout the Ordovician and Silurian, though the radiation of the mycteropoids (a group of large sweep-feeding forms) in the Late Devonian and Carboniferous is the last major radiation of the eurypterids before their extinction in the Permian.

FERGUSONITES HENDERSONAE

Fergusonites hendersonae (Longridge, 2008)

Meet Fergusonites hendersonae, a Late Hettangian (Early Jurassic) ammonite from the Taseko Lakes area of British Columbia, Canadian Rockies.

I had the very great honour of having this fellow, a new species of nektonic carnivorous ammonite, named after me by paleontologist Louse Longridge from the University of British Columbia. I'd met Louise as an undergrad and was pleased as punch to hear that she would be continuing the research by Dr. Howard Tipper.

We did several trips over the years up to the Taseko Lake area of the Rockies joined by many wonderful researchers from Vancouver Island Palaeontological Society and Vancouver Paleontological Society, as well as the University of British Columbia. Both Dan Bowen and John Fam were instrumental in planning those expeditions. We endured elevation sickness, rain, snow, grizzly bears and very chilly nights (we were sleeping right next to a glacier at one point) but were rewarded by the enthusiastic crew, helicopter rides (which really cut down the hiking time) excellent specimens and stunningly beautiful country. We were also blessed with excellent access as the area is closed to collecting except with a permit.

Reference: PaleoDB 157367 M. Clapham GSC C-208992, Section A 09, Castle Pass Angulata - Jurassic 1 - Canada, Longridge et al. (2008)

Full reference: L. M. Longridge, P. L. Smith, and H. W. Tipper. 2008. Late Hettangian (Early Jurassic) ammonites from Taseko Lakes, British Columbia, Canada. Palaeontology 51:367-404

PaleoDB taxon number: 297415; Cephalopoda - Ammonoidea - Juraphyllitidae; Fergusonites hendersonae Longridge et al. 2008 (ammonite); Average measurements (in mm): shell width 9.88, shell diameter 28.2; Age range: 201.6 to 196.5 Ma. Locality info: British Columbia, Canada (51.1° N, 123.0° W: paleo coordinates 22.1° N, 66.1° W)

ICHTHYOSAUR VERTEBRAE

Ichthyosaur vertebrae, Berlin-Ichthyosaur State Park

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

The first researcher to recognize the Nevada fossil specimens as ichthyosaurs was Siemon W. Muller of Stanford University. He had the work of Sir Richard Owen to build on from the 1840s. That being said, there are very few contenders for a species that boasts vertebrae over a foot wide and weighing in at almost 10 kg or 21 lbs. Muller contacted the University of California Museum of Paleontology at Berkeley. Surface collecting by locals continued at the site but no major excavation was planned.

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

Back in the 1950s, these large marine reptiles were rumoured to be "marine monsters," as the concept of an ichthyosaur was not well understood by the local townsfolk. Excitement soon hit West Union Canyon as the quarry began to reveal the sheer size of these mighty beasts. In the end, the ichthyosaur bones were left in situ to better understand how they were laid down over 200 million years ago.

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

In 1957, the site was incorporated into the State Park System and Berlin-Ichthyosaur State Park was born. The park Twenty years later, in 1977, the population of Nevada weighed in and the Legislature designated Shonisaurus popularis as the State Fossil of Nevada.

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

PHYLLOCERAS VELLEDAE

Lovely defined sutures on this rather involute, high-whorled hoplitid ammonite from the middle part of the Lower Albian in the Mahajanga Province, northwestern Madagascar.

While this large island off the southeast coast of Africa is known more for exotic lemurs, rainforests & beaches, it also boasts some of the world's loveliest fossils.

This specimen is from a quarry near the top of an escarpment, 3 km to the west of the village of Ambatolafia (coordinates: Lat. 16.330 23.600 S, Long. 46.120 10.20 E).

Judging from plate tectonic reconstruction (Stampfli & Borel, 2002), the area was located in middle latitudes within the tropical-subtropical climatic zone at palaeo-latitudes of 40E45.S in the late Early Cretaceous of the early Albian.

This specimen of Phylloceras velledae (Michelin) has a shell with a small umbilicus, arched, acute venter, and at some growth stage, falcoid ribs that spring in pairs from umbilical tubercles, disappearing on the outer whorls.

EXQUISITE EROSION: TIME & TIDE

OUR CAMBRIAN PAST

Wanneria dunnae / Eager Formation

There is so much more to Canada than meets the eye. Deep in the ground beneath our feet is window into our past. It speaks of ancient oceans, continents on the move, powerful forces upthrusting whole coastlines and creating mountains.

And through that window, on the west side of the Kootenay River at its confluence with the St. Mary's, we find some of the oldest fossils in Canada.

This specimen of Wanneria dunnae is from the Lower Cambrian Eager Formation of British Columbia and is typical of the group.

He's from the Rifle Range outcrop near Cranbrook. The site is just a shade older than the Burgess Shale, Middle Cambrian deposits though the species found here are much less varied. Trilobites were amongst the earliest fossils with hard skeletons. While they are extinct today, they were the dominant life form at the beginning of the Cambrian.

Back in the late 1990's and early 2000's, it was a glorious place for fossil collecting. I have many beautifully preserved Wanneria and abundant Olellenus from here along with a few rare and treasured Tuzoia.

The shale matrix lends itself to amazing preservation. This specimen of Wanneria is a big fellow. Five inches long and four inches wide. Wanneria are slightly less common here than Olenellus. Olenellus are slightly smaller in size with a large, semi-circular head, a body of 15 segments and a long spine on the 15th segment with a wee tail. You find a mixture of complete specimens and head impressions from years of perfectly preserved molts.

The Wanneria are their bruising cousins by comparison with their large heads lacking conspicuous furrows and a robust body without an expanded third segment.

As luck would have it, the plate he is in split him right down the centre. Bless the hardness of shale for preservation and it's sheer irony for willfully cracking exactly where you least desire it.

What is missing in this photograph is any detail around the specimen's eyes. Trilobite eyes were compound like those found in modern crustaceans and insects.

The eyes of these earliest trilobites are not well known. They were built in such a way that the visual surface dropped away and was lost during molting or after death throwing a wrench in studying them.

We may learn more from the Burgess Shale and the lovely soft mud that was the foundation of their preservation.

FUSED RIBS: TURTLES

Turtle ribs fuse together with some of their vertebrae so they have to pump air in and out of the lungs with their leg muscles instead?

Another unusual feature in turtles is their limb girdles (pectoral and pelvic) have come to lie 'within' their rib cage, a feature that allows some turtles to pull its limbs inside the shell for protection. Sea turtles didn't develop this behaviour (or ability) and do not retract into their shells like other turtles.

Turtle shells are different from the armoured “shells” we see on dinosaurs like the ankylosaurs. Turtles are covered by a special bony or cartilaginous shell developed from their ribs that acts as a shield. It is fundamentally different from the armour seen on our other vertebrate pals. Turtle armour is made of dermal bone and endochondral bones of the vertebrae and rib cage.

Armadillos have armour formed by plates of dermal bone covered in relatively small, overlapping epidermal scales called "scutes," composed of bone with a covering of horn. In crocodiles, their exoskeletons form their armour. It is made of protective dermal and epidermal components that begin as rete Malpighii: a single layer of short, cylindrical cells that lose their nuclei over time as they transform into a horny layer.

Depending on the species and age of the turtle, turtles eat all kinds of food including seagrass, seaweed, crabs, jellyfish, and shrimp,. That tasty diet shows up in the composition of their armour as they have oodles of great nutrients to work with. The lovely example you see here is from the Oxford Museum collections.

MAMMOTH HOT SPRINGS

Mammoth Hot Springs Yellowstone National Park

SILURIAN SEA SCORPION

The impressive homeotype specimen of a Eurypterus lacustris duo hails from Late Silurian deposits of New York. These lovelies are now housed in UCMP Berkeley's paleontological collections.

About two dozen families of eurypterids “sea scorpions” are known from the fossil record. Although these ancient predators have a superficial similarity, including a defensive needle-like spike or telson at their tail end, they are not true scorpions.

They are an extinct group of arthropods related to spiders, ticks, mites and other extant creepy crawlies.

Eurypterids hunted fish in the muddy bottoms of warm shallow seas before moving on to hunting grounds in fresh and brackish water during the latter part of their reign.They declined in numbers and diversity until becoming extinct during the Permian–Triassic extinction event (or sometime shortly before) 251.9 million years ago. As to the oldest and youngest of the order, we can look to the Stylonurina. Members of the suborder are collectively and informally known as "stylonurine eurypterids" or "stylonurines". They are known from deposits primarily in Europe and North America, but also in Siberia.

Compared to the suborder, Eurypterina, the stylonurines were comparatively rare and retained their posterior prosomal appendages for walking. Despite their rarity, the stylonurines have the longest temporal range of the two suborders. The suborder contains some of the oldest known eurypterids, such as Brachyopterus, from the Middle Ordovician as well as the youngest known eurypterids, from the Late Permian. They remained rare throughout the Ordovician and Silurian, though the radiation of the mycteropoids (a group of large sweep-feeding forms) in the Late Devonian and Carboniferous is the last major radiation of the eurypterids before their extinction in the Permian.

PERFECTLY ROLLED TRILOBITE

GASTROPODS

Gastropods, or univalves, are the largest and most successful class of molluscs. They started as exclusively marine but have adapted well and now their rank spends more time in freshwater than in salty marine environments.

Many are marine, but two-thirds of all living species live in freshwater or on land. Their entry into the fossil record goes all the way back to the Cambrian.

Slugs and snails, abalones, limpets, cowries, conches, top shells, whelks, and sea slugs are all gastropods. They are the second-largest class of animals with over 60,000–75,000 known living species.

The gastropods are originally sea-floor predators, though they have evolved to live happily in many other habitats. Many lines living today evolved in the Mesozoic. The first gastropods were exclusively marine and appeared in the Upper Cambrian (Chippewaella, Strepsodiscus).

By the Ordovician, gastropods were a varied group present in a variety of aquatic habitats. Commonly, fossil gastropods from the rocks of the early Palaeozoic era are too poorly preserved for accurate identification. Still, the Silurian genus Poleumita contains fifteen identified species.

Most of the gastropods of the Palaeozoic era belong to primitive groups, a few of which still survive today. By the Carboniferous, many of the shapes we see in living gastropods can be matched in the fossil record, but despite these similarities in appearance the majority of these older forms are not directly related to living forms. It was during the Mesozoic era that the ancestors of many of the living gastropods evolved.

In Mesozoic rocks, gastropods are more common as fossils and their shells often very well preserved. While not all gastropods have shells, the ones that do fossilize more easily and consequently, we know a lot more about them. We find them in fossil beds from both freshwater and marine environments, in ancient building materials and as modern guests of our gardens.

FOSSIL TURTLE

Fossil Turtle. Photo credit: Luis Lima. Lisbon Museum Collection