GONDWANA: EVOLUTION OF A SUPERCONTINENT

The ancient supercontinent of Gondwana, as we think of it, came into being about 500 million years ago. We refer to that time as the Ediacaran, the time of the beginnings of multicellular organisms. These were exotic and primitive beasties, interesting segmented worms, rounded jellyfish-like organisms, enigmatic tubular and sea-pen-like beauties.

Gondwana split into the landmasses we know today about 180 million years ago. Not lost, just reformed as Africa, South America, Australia, Antarctica, the Indian subcontinent and the Arabian Peninsula. Gondwana joined with other landmasses to become Pangea by about 300 million years ago, before morphing again into Laurasia. By the middle of the Eocene, some fifty-five million years ago, only Australia, Antarctica and South America remained as they straddled the South Pole.

Free of ice and the giant marine and flying reptiles, a new line-up of mammals, flightless birds, crocodiles, snakes and turtles thrived in the warm, wet climate, rapidly adapting and dominating the forests, oceans and skies. New and fanciful creatures, the monotremes, marsupials and placentals explored and took root in the Gondwanan forests as conifers gave way to broad-leaved trees in an ever changing landscape.

CHENGJIANG LOBOPODIAN

A rather nice Onychodictyon ferox (lobopod) from the Chengjiang Biota, Lower Cambrian, Yunnan, China. The Lobopodians, or Velvet Worms, are small marine and terrestrial animals averaging about 70 mm in length. All recent forms of these wee beasties are terrestrial. Most of the fossil Lobopodians are marine and closely resemble Aysheaia from the Burgess Shale. Collection of Marc R. Hänsel.

SKØKKENMØDDINGER

Many First Nations sites were inhabited continually for centuries. These sites were both home, providing continuity and community and also formed a spiritual connection to the landscape.

The day to day activities of each of these communities would much like our own. Babies were born, meals were served and life followed a natural cycle.

As coastal societies lived their lives they also left their mark. Sometimes through totems and carvings but almost always through discarded shells and scraps of bone from their food. These refuse heaps contain a wealth of information about how that community lived, what they ate and what environmental conditions looked like over time. This physical history provides a wonderful resource for archaeologists in search of botanical material, artifacts, broken cooking implements and my personal favourite, mollusc shells.

These wonderfully informative heaps of the local gastronomic record provide a wealth of information. Especially those formed from enormous mounds of bivalves and clams. We call these middens. Left over time, these unwanted dinner scraps transform through a process of preservation.

The Danish term køkkenmøddinger (plural) was first used by Japetus Steenstrup, a Danish zoologist and biologist, to describe shell heaps and continues to be used by some researchers. I still prefer middens, but to each his own. Time and pressure leach the calcium carbonate, CaCO3, from the surrounding marine shells and help “embalm” bone and antler artifacts that would otherwise decay. Useful this, as antler makes for a fine sewing tool when worked into a needle. A bone that has had some time to harden through this natural embalming process makes for a fine needle indeed. Much of what we know around the modification of natural objects into tools comes from this preservation.

Calcium carbonate is a chemical compound that shares the typical properties of other carbonates. In prepping fossil specimens embedded in limestone, it is useful to know that limestone, itself a carbonate sedimentary rock, reacts with stronger acids, releasing carbon dioxide: CaCO3(s) + 2HCl(aq) → CaCl2(aq) + CO2(g) + H2O(l).

Calcium carbonate reacts with water saturated with carbon dioxide to form the soluble calcium bicarbonate. Bone already contains calcium carbonate, as well as calcium phosphate, Ca2, but it is also made of protein, cells and living tissue.

Decaying bone acts as a sort of natural sponge that wicks in the calcium carbonate displaced from the shells. As protein decays inside the bone, it is replaced by the incoming calcium carbonate, making the bone harder and more durable.

The shells, beautiful in their own right, make the surrounding soil more alkaline, helping to preserve the bone and turning the dinner scraps into exquisite scientific specimens for future generations.

TYLOSTOMA TUMIDUM

This lovely big fellow is Tylostoma tumidum, an epifaunal grazing Lower Cretaceous Gastropod from white, micritic, coarsely nodular limestone deposits of the Goodland Formation at White Settlement west of Fort Worth, Texas, USA. (171.6 to 58.7 Ma).

The bedding here is massive with some thin clay beds. The macro fossil found here include the ammonite, Oxytropidoceras acutocarinatum, pelecypods such as Protocardia, Pinna and Lima wacoensis along with heart-shaped urchins in abundance and lovely gastropods such as this beauty, Tylostoma tumidum. This specimen shows the wear and tear of erosion common at the site.

Tylostoma have thick, smooth shells with a moderately elevated spire. Their aperture is ovato-lunate with the lips meeting above at a sharp angle. The outer lip is furnished internally, running the whole length and ending with a nice thickened edge. This chunky specimen is about 3 inches tip to tip.

ANCIENT PLANKTON HUNTER

Pentremites sp. / Hardin County, Kentucky

This wee lovely Blastoid is Pentremites sp. from Mississippian deposits in Hardin County, Kentucky. This little fellow represents a specimen from the peak of their diversity in the Mississippian.

Blastoids are an extinct type of stemmed or stalked suspension feeding echinoderms, sometimes referred to as "sea buds."

They made a living feeding on planktonic organisms that inhabited our ancient seas from shelf to basin. Their lineage dates back to the Ordovician and died out at the end of the Permian, about 250 million years ago. This little guy measures 10mm top to bottom and 5mm at his widest.

TRAGOPHYLLOCERAS LOSCOMBI

Tragophylloceras loscombi / Dorset Coast

A very interesting Tragophylloceras loscombi (134 mm with the peristome / 41 mm) from Lower Pliensbachian deposits near the coastal village of Seatown near Charmouth on the Dorset coast of the UK.

This lovely specimen is in the collection of the deeply awesome José Juárez Ruiz. He was amongst the many belemnite guards and ammonite shells of this lovely collection spot. Both beautiful in and of itself and highly prized for its fossil finds along the silty mudstone cliffs and fossiliferous boulders.

This fellow like to live in the offshore, deep subtidal shelves of our ancient seas around 189 to 183 million years ago.

He was a nektonic carnivore, an active swimmer cruising our ancient seas looking for tasty daily sustenance. Ammonites belong to the class of animals called mollusks. More specifically they are cephalopods and first appeared in the lower Devonian Period. Cephalopods were an abundant and diverse group during the Paleozoic Era.

Varying in size from millimeters to meters across, these elegant marine dwellers are prized as both works of art and index fossils helping us better understand and date strata. Cousins in the Class Cephalopoda, meaning "head-footed," ammonites are closely related to modern squid, cuttlefish and octopus with complex eye structures and advanced swimming abilities. They used these evolutionary benefits to their advantage, making them successful marine predators cruising our ancient oceans expertly capturing prey with their tentacles.

PLATRYACHELLA: DEVONIAN BRACHIOPOD

Platryachella sp. / Devonian Brachiopod

This fellow is Platyrachella sp. a brachiopod from Middle Devonian deposits of the renamed the Little Cedar Formation, Cedar Valley Group (probably out of the Solon Member) near Benton County, deep in the agricultural belt of east-central Iowa.

Driving through Benton you see long, gently rolling slopes, farms of corn and soybean growing in deep black soil.

Benton also has three very productive quarries that produce limestone, gravel and clay for industrial uses. While the quarries focus on the commercial aspects of the many varieties of limestone produced there, they also boasts some very nice macro fossils like the brachiopod specimen you see here. While brachiopods share some similarities with their molluscan friends they are in a phylum all their own. Clams or bivalves are molluscs, the second-largest phylum of invertebrates with about 85,000 extant species.

Brachiopods are small marine shellfish that are not so common today but back in the Palaeozoic they were plentiful the world over. The two valves that make up a brachiopods shell are of different sizes and if you look closely you'll see that the hinge runs top and bottom  -- versus left and right like a clam.

Brachiopods have been with us a long time. Their lineage dates back to the Cambrian with over 12,000 fossil species and 350 living species sorted between 6,000 genera. There are two major groups of brachiopods, articulate with toothed hinges and simple open and closing muscles to manipulate their shells and inarticulate brachiopods with untoothed hinges and a more complex set of muscles used to control the brachial supports used to open and close their shells. This specimen is 7cm long and about 2.5cm deep

OLIGOCENE FOSSIL WHALE VERTEBRAE

Oligocene Fossil Whale vertebrae from Majestic Beach, Olympic Peninsula, Washington State, USA.

These lovely water worn specimens are difficult to ID to species with certainty but may be from an early baleen whale. Found amongst the beach pebbles on the Olympic Peninsula, they are likely cetacean and very likely baleen as this area is home to some of the earliest baleen whales in the Pacific Northwest.

In 1993, a 27-million-year-old specimen was discovered in deposits nearby that represents a new species of early baleen whale. It is especially interesting as it is from a stage in the group’s evolutionary history when baleen whales transitioned from having teeth to filtering food with baleen bristles.

Visiting researcher Carlos Mauricio Peredo studied the fossil whale remains, publishing his research to solidify Sitsqwayk (pronounced sits-quake) cornishorum, in the annals of science history.

The earliest baleen whales clearly had teeth, and clearly still used them. Modern baleen whales have no teeth, and have instead evolved baleen plates for filter feeding. So when did this evolutionary change occur and what factors might have caused it?

Traditionally, paleontologists have sought answers about the evolution of baleen whales by turning to two extinct groups: the aetiocetids and the eomysticetids. The aetiocetids are small baleen whales that still have teeth, but they are very small, and it remains uncertain whether or not they used their teeth.

In contrast, the eomysticetids are about the size of an adult Minke Whale and seem to have been much more akin to modern baleen whales; though it’s not certain if they had baleen. Baleen typically does not preserve in the fossil record being soft tissue; generally only hard tissue, bones & teeth, are fossilized.

OLIGOCENE FOSSIL BEAVER

This may be the cutest fossil skull you'll see all day. This is Microtheriomys brevirhinus, an adorable teeny, 19 mm, fossil beaver skull from the John Day Formation in Oregon. Awe, right?

Paleontologists Dr William Korth of Rochester Institute of Vertebrate Paleontology and Dr Joshua Samuels of John Day Fossil Beds National Monument were chuffed to find a treasure trove of new fossil species during field work this past year building on the knowledge from previous finds. They have described four new genera and ten new species of prehistoric rodents that lived in what is now Oregon during the Oligocene -- 30- 22 million years ago.

The newly-discovered genera include this wee fellow, the early beaver, Microtheriomys brevirhinus, a dwarf tree squirrel, Miosciurus covensis, a primitive pocket mouse, Bursagnathus aterosseusm the birch mouse Plesiosminthus fremdi, an early relative of beavers, Allotypomys pictus along with bits and pieces of Proapeomys condoni; Apeomys whistleri; Neoadjidaumo arctozophus, Proheteromys latidens & Trogomys oregonensis.

Of these ten new species, four represent completely new genera: Allotypomys, Microtheriomys, Proapeomys, and Bursagnathus. It's a bit like winning the paleo lottery.

“This study fills some substantial gaps in our knowledge of past faunas, specifically smaller mammals,” said Dr Samuels, who is a co-author of the paper published in the Annals of Carnegie Museum. “Some of the new species are really interesting in their own right, and will ultimately help improve our understanding of the evolution of beavers and pocket mice.”

CHOCOLATE CHIP SEA STAR

Protoeaster nodosus / Chocolate Chip Sea Star

If you're lucky enough to swim in the warm, shallow waters of the Indo-Pacific region, you may encounter one of the most charming of all the sea stars, the Protoeaster nodosus.

These beauties are commonly known as Horned Sea Stars or, my personal favorite, Chocolate Chip Sea Stars.

They are part of the class Asteroidea (starfish or sea stars) one of the most diverse groups within the phylum Echinodermata and have a lengthy lineage in the fossil record stretching all the way back to the Triassic. These echinoderms make a living on near-shore sandy bottoms or lurk in the sea grass meadows of some of our most beautiful waters.

Chocolate Chip Sea Stars live in the waters off the Philippine Sea, off the coast of Australia and New Guinea. Their range extends to the Marshall Islands through central and southeastern Polynesia, past Easter Island and all the way up to Hawaii. Pretty much pick any of the top contenders for a warm, tropical vacation and they've beat you to it!

This species of sea star have black rows of "horns" or "spines" meant to scare off predators. A noble deterrent for his fishy friends but I find this signature decoration rather fetching. These fellows like to graze on choice corals and sponges. They are also happy to make a meal of snails and bitter sea urchin when these ambrosial treats are presented. And they are social, both to mate, gathering in groups to aid in fertilization and acting as soft cover for shrimp, wee brittle stars and juvenile leatherjackets or filefish, who tuck in and enjoy the protective cover of those dark nodes.

BALANG: TUZOIA SINENSIS

Tuzoia sinensis (Pan, 1957) / York Yuxi Wang Collection

A large extinct bivalved arthropod, Tuzoia sinesis (Pan, 1957) from Cambrian deposits of the Balang Formation. The Balang outcrops in beautiful Paiwu, northwestern Hunan Province in southern China. The site is intermediate in age between the Lower Cambrian Chengjiang fauna of Yunnan and the Lower to Middle Cambrian, Kaili Lagerstätten of Guizhou in southwestern China.

This specimen was collected earlier this week. It is one of many new and exciting arthropods to come from the site.

Balang has a low diversity of trilobites and many soft-bodied fossils similar in preservation to Canada's Burgess Shale. Some of the most interesting finds include the first discovery of anomalocaridid appendages (Appendage-F-type) from China along with the early arthropod Leanchoiliids with his atypical frontal appendages (and questionable phylogenetic placement) and the soft-shelled trilobite-like arthropod, Naraoiidae.

While the site is not as well-studied as the Chengjiang and Kaili Lagerstätten, it looks very promising. The exceptionally well-preserved fauna includes algae, sponges, chancelloriids, cnidarians, worms, molluscs, brachiopods, trilobites and a few non-mineralized arthropods. It is an exciting time for Cambrian paleontology. The Balang provides an intriguing new window into our ancient seas and the profound diversification of life that flourished there.

SAUROPTERYGIAN MANDIBLE

Libonectes atlasense / Andy Chua Collection

A beautifully preserved mandible of an Libonectes atlasense, an elasmosaurid plesiosaur from early Turonian, Upper Cretaceous,  deposits of the Akrabou Formation near Asfla Village, Goulmima, Errachidia Province in eastern central Morocco.

The collecting area is in the region of Drâa-Tafilalet. You may know Errachidia as Ksar Souk. It was renamed My Rachid, in honor of Moroccan royal family. Libonectes is an genus of sauropterygian reptile belonging to the plesiosaurs. Specimens have been found in the Britton Formation of Texas and the Akrabou Formation of Morocco. Sauropterygian reptiles were a diverse taxon of extinct aquatic reptiles that arose from terrestrial ancestors just after the Permian extinction event. They flourished during the Triassic then all but the Plesiosaurs became extinct at the end of the Triassic -- with Plesiosaurs dying out at the end of the Cretaceous.

LAMPLIT DINOSAUR TRACKS

Ankylosaur Trackway / Tumbler Ridge

A detailed view of the Dinosaur Trackway near Wolverine River, Tumbler Ridge, northeastern British Columbia.

The tracks are filled with water to reflect the lamplight, making them both beautiful and easier to view.

There are three types of footprints found in the Tumbler Ridge GeoPark. At the Wolverine River Tracksite there are theropods (at least four different sizes) and ankylosaurs. Also found in the area are ornithopod tracks from herbivorous dinosaurs with their nice wide tracks. You'll recognize them by their short-wide prints with three blunt toes. There are rare wee hand prints associated with some of those tracks if you look closely.