Tuesday, 17 September 2019
While the crustacean cuticle has been the subject of study for over 250 years (Reaumur, 1712, in Drach, 1939), the focus of that early work has been the process of moulting.
Because crabs and other crustaceans have a hard outer shell (the exoskeleton) that does not grow, they must shed their shells through a process called moulting. Just as we outgrow our shoes, crabs outgrow their shells.
In 1984, Roer and Dillaman took a whole new approach, instead looking at the exoskeleton as a mineralized tissue. The integument of decapod crustaceans consists of an outer epicuticle, an exocuticle, an endocuticle and an inner membranous layer underlain by the hypodermis. The outer three layers of the cuticle are calcified.
The mineral is in the form of calcite crystals and amorphous calcium carbonate. In the epicuticle, the mineral is in the form of spherulitic calcite islands surrounded by the lipid-protein matrix. In the exo- and endo-cuticles the calcite crystal aggregates are interspersed with chitin-protein fibres which are organized in lamellae. In some species, the organization of the mineral mirrors that of the organic fibres, but such is not the case in certain cuticular regions in the xanthid crabs.
Control of crystal organization is a complex phenomenon unrelated to the gross morphology of the matrix. Since the cuticle is periodically moulted to allow for growth, this necessitates a bidirectional movement of calcium into the cuticle during post-moult and out during premolt resorption of the cuticle.
These movements are accomplished by active transport affected by a Ca-ATPase and Na/Ca exchange mechanism. The epi- and exo-cuticular layers of the new cuticle are elaborated during pre-moult but do not calcify until the old cuticle is shed. This phenomenon also occurs in vitro in the cuticle devoid of living tissue and implies an alteration of the nucleating sites of the cuticle in the course of the moult.
We're still learning about the relationship between the mineral and the organic components of the cuticle, both regarding the determination of crystal morphology and about nucleation. While the Portunidae offers some knowledge of the mechanisms and pathways for calcium movement, we know nothing concerning the transport of carbonate. These latter areas of investigation will prove fertile ground for future work; work which will provide information not only on the physiology of Crustacea but also on the basic principles of mineralization. The bidirectional nature of mineral transport and the sharp temporal transitions in the nucleating ability of the cuticular matrix provide ideal systems in which to study these aspects of calcification.
Torrey Nyborg, Francisco J. Vega and Harry F. Filkorn, Boletín de la Sociedad Geológica Mexicana, Vol. 61, No. 2, Número especial XI Congreso Nacional de Paleontología, Juriquilla 2009 (2009), pp. 203-209. Coahuila paleo coordinates:25°32′26″N 100°57′2″W
Monday, 16 September 2019
They are fossil relics, the sole surviving species of the order Amiiformes. Although bowfins are highly evolved, they are often referred to as primitive fishes and living fossils as they retain many of the morphologic characteristics of their ancestors.
This specimen was found in Lower Cretaceous outcrops of the Santana Formation in the Araripe Basin UNESCO Global Geopark of northeastern Brazil. Collection of David Murphy
Sunday, 15 September 2019
So which lucky ducks evolved one? Warm-blooded birds and mammals can claim those bragging rights. They're joined by our cold-blooded, ectothermic friends, the fish, amphibians and reptiles. All these lovelies share this characteristic.
And whether they now live at sea or on land, all of these lineages evolved from a marine organism somewhere down the line, then went on to develop a notochord and spinal column. Notochords are flexible rods that run down the length of chordates and vertebrates. They are handy adaptations for muscle attachment, helping with signalling and coordinating the development of the embryonic stage. The cells from the notochord play a key role in the development of the central nervous system and the formation of motor neurons and sensory cells. Alas, we often take our evolution for granted.
Let's take a moment to appreciate just how marvellous this evolutionary gift is and what it allows us to do. Your backbone gives your body structure, holds up that heavy skull of yours and connects your tasty brain to your body and organs. Eating, walking, fishing, hunting, your morning yoga class, are all made possible because of this adaptation. Pick pretty near anything you love to do and it is only possible because of your blessed spine.
And it sets us apart from our invertebrate friends.
While seventy thousand may seem like a large number, it represents less than three to five percent of all described animal species. The rest is made up of the whopping 97%'ers, our dear invertebrates who include the arthropods (insects, arachnids, crustaceans, and myriapods), mollusks (our dear chitons, snails, bivalves, squid, and octopus), annelids (the often misunderstood earthworms and leeches), and cnidarians (our beautiful hydras, jellyfish, sea anemones, and corals). You'll notice that many of our invertebrate friends occur as tasty snacks. Having a backbone provides a supreme advantage to your placement in the food chain. Not always, as you may include fish and game on your menu. But generally, having a backbone means you're more likely to be holding the menu versus being listed as an appetizer. So, enjoy your Sunday 'downward dog' and thank your backbone for the magical gift it is.
Saturday, 14 September 2019
These columns tell a story of the cooling and freezing of the lava flows that formed them. As lava at the surface cools and freezes, it also shrinks as its molecules rearrange themselves into a solid structure. This happens much more quickly at the surface where the lava comes in contact with moist, cool air. As the basalt cools and shrinks, pressure increases in intensity and cracks begin to form. A way to dissipate this huge stress is to crack at an angle of 120 degrees, the angle that gives us a hexagon.
We see this beautifully illustrated at the Giant's Causeway in Ireland. Here, highly fluid molten basalt intruded through chalk beds which later cooled, contracted and cracked into hexagonal columns, creating a surreal visual against a dark and stormy Irish Sea.
Friday, 13 September 2019
The carapace is deeply grooved with conspicuous wart-like tubercles; anterolateral margin, between the base of the exorbital tooth and cervical groove, smooth, without tubercles or denticles.
The teeth on the lower orbital margin in the cluster. Carpus of cheliped distinctly granulated on the upper surface and with a conspicuous row of granules along the anterior margin. Though missing here, the merus of second and third pereiopods are almost cylindrical. (Türkay 1995). This specimen was collected and is the collection of the deeply awesome Takashi Ito of Japan
These early fishes and many of the Pteraspidomorphi possessed large plates of dermal bone at the anterior end of their bodies. This dermal armour was very common in early vertebrates, but it was lost in their descendants. Arandaspida is represented by two well-known genera: Sacabampaspis, from South America and Arandaspis from Australia. Arandaspis have large, simple, dorsal and ventral head shields. Their bodies were fusiform, which means they were shaped sort of like a spindle, fat in the middle and tapering at both ends. Picture a sausage that is a bit wider near the centre with a crisp outer shell. Image: Tamura (http://spinops.blogspot.com) - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19460450
Thursday, 12 September 2019
Tuesday, 10 September 2019
They were mammals and looked like large rodents. They were also quite small by whale standards, reaching about four-feet in length. They ate meat, sometimes fish and are the ancestors of whales, porpoises and dolphins.
The only real clue of their connection to our aquatic friends is the shape of their skulls. Pakicetus had a long skull and an ear bone that is unique to whales. Oddly, they also had ankle bones that share characteristics with some of our even-toed mammals. They lived along the shores of a large shallow sea known as the Tethys. Although rare, there are several examples of mammals heading back to a life at sea. Photo: Kevin Guertin from Ottawa, Ontario, Canada - DSCF1201, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=36657302
Monday, 9 September 2019
|Northumberland Fm, Upper Cretaceous Nanaimo Group|
Thee Upper Cretaceous Nanaimo Group of southwest British Columbia is a >4 km-thick succession consisting mostly of deep marine siliciclastics deposited directly on the Insular Superterrane. As such, this succession has been the focus of several paleomagnetic, isotope geochemistry, paleontology, and sedimentology studies in attempts to elucidate the tectonic history and paleolatitude of the Insular Superterrane and associated entities during the critical time of Nanaimo Group deposition, 90 to 65 million years ago. The upper two-thirds of the succession is continuously and well exposed on Denman and Hornby islands and represents the best example of this part of the succession in the northern half of what we consider the single Nanaimo Basin. A concretion found on the beach at Denman, eroding out of the grey shales of the Upper Cretaceous Nanaimo Group
Sunday, 8 September 2019
|Nootka Sound, Photo: Dan Bowen|
The area is known for its exceptional natural beauty and bounty of beautifully preserved decapod fossil specimens. The formation is named for the Hesquiaht people of the Nuu-chah-nulth, of Nootka Sound.
Saturday, 7 September 2019
During the upper Cretaceous, between ~90 to 65 Ma, sediments derived from the Coast Belt to the east and the Cascades to the southeast poured seaward to the west and northwest into what was the large ancestral Georgia Basin. This major forearc basin was situated between Vancouver Island and the mainland of British Columbia.
The Nanaimo Group as a whole represents largely coarse-grained units deposited in deep-sea fan systems. In this environment, deeper channels continuously cut through successive shale and sandstone bodies. The channels funnelled density currents into the basin, while also building levee deposits. Turbidity currents travelled down the channels, and also overtopped the levees spilling across backslope areas. The sequential sediment formations, from significantly coarse-grained sandstones and conglomerates to fine silts and shale units of the Nanaimo Group, are considered to be partly due to eustacy, but more significantly related to relative sea-level changes induced by regional tectonics in an active forearc setting.
The Northumberland Fm consists of a massive, dark-grey mudstone which is locally interlaminated and interbedded with siltstone and fine-grained sandstone. There are abundant calcium carbonate concretions, parallel and current ripple laminations, clastic dikes and folded layers due to slumping. In the Gulf Islands to the south, this formation has been found to contain abundant and diverse foraminifera indicating marine paleodepths of 150-1200 m.
The more resistive Geoffrey Fm consists of thick-bedded sandstone and conglomerate. It is highly channelized, and some sandstone has exposed parallel and ripple laminations. The Spray Fm exposed on the east end of the island is a massive olive-grey mudstone with interlaminations of sandstone.
Furthest to the east, the youngest exposures on Hornby Island are from the Gabriola Fm, which outcrops on the eastern peninsula. This is again a thick-bedded and channelized sequence of conglomerates and massive sandstone with minor mudstone interbeds. South, in the Gulf Islands, this formation has contained ammonites, gastropods and pelecypods. Paleowater-depth from foraminiferal assemblages has been set at 200 m.
Katnick, D.C. and P.S. Mustard (2001): Geology of Denman and Hornby Islands, British Columbia (NTS 92F/7E, 10); British Columbia Geological Survey Branch, Geoscience Map 2001-3.
England, T.D.J. and R. N. Hiscott (1991): Upper Nanaimo Group and younger strata, outer Gulf Islands, southwestern British Columbia: in Current Research, Part E; Geological Survey of Canada, Paper 91-1E, p. 117-125.
Friday, 6 September 2019
Since that time, a shocking half a billion years ago, our seas have played host to an astonishing array of species. If I'd visited our Earth back in the Cambrian, I would have bet good money that our watery planet's future was in the seas not on the land. But that 's not the case. Quite surprisingly, it is our humble rock and soil who now boast more species. Five times that of those living in the oceans. I know, shocking but true. Our oceans certainly had the running start on both numbers and diversity of species. But it is our fungi, our flowering plants, mindblowing variety of insects, trees, bees and fleas that make up the bulk of Earth's species these days.
It is something I'm interested in learning more about as it does not make good sense to me. 80 percent of Earth's species live on land today. About 15 percent call our oceans home and another 5% or so live in freshwater. Why more species live on land than in the ocean has puzzled others as well. Robert May, a zoologist at the University of Oxford, mulls this very question in an article from 1994 titled, “Biological Diversity: Differences between Land and Sea.” He continued with his research and published "The future of biological diversity in a crowded world," in Current Science, Vol. 82, No. 11 (10 June 2002), pp. 1325-1331.
Here he questions how well we know the plants, animals and micro-organisms with which we share this beautiful planet. His focus in the paper was to question how many species are there and how fast are some going extinct? You'll be interested to know that his best guess in 2002 was somewhere between 1.7 to 1.8 million. That's a considerable increase from Carl Linneaus' work back in 1758, the Swedish botanist, zoologist, and physician took a stab at the same question and came up with an estimate of about 9,000 species. While his numbers were off by a long margin, he did give us the binomial nomenclature system we use for naming organisms, so he still gets a hall pass.
May is a boy about town. His work is referenced everywhere. You may enjoy an article by the Atlantic from 2017 that delves into the topic for the lay audience with an eye to popularized reading. May, R. (2002). The future of biological diversity in a crowded world. Current Science, 82(11), 1325-1331. Retrieved from http://www.jstor.org/stable/24105996 / The Atlantic article: https://www.theatlantic.com/science/archive/2017/07/why-are-there-so-many-more-species-on-land-than-in-the-sea/533247/
Thursday, 5 September 2019
"Ichthyosaurs are interesting because they have many traits in common with dolphins, but are not at all closely related to those sea-dwelling mammals," says research co-author Mary Schweitzer, professor of biological sciences at NC State with a joint appointment at the North Carolina Museum of Natural Sciences and visiting professor at Lund University. "We aren't exactly sure of their biology either. They have many features in common with living marine reptiles like sea turtles, but we know from the fossil record that they gave live birth, which is associated with warm-bloodedness. This study reveals some of those biological mysteries."
We find their fossil remains in outcrops spanning from the mid-Cretaceous to the earliest Triassic. As we look through the fossils, we see a slow evolution in body design moving towards that enjoyed by dolphins and tuna by the Upper Triassic, albeit with a more narrower, more pointed snout.
Johan Lindgren, Associate Professor at Sweden's Lund University and lead author of a paper, describing the work, worked with twenty-one other ichthyosaur researchers to analyze the 180 million-year-old specimen, Stenopterygius, from outcrops in the Holzmaden quarry in Germany.
"Both the body outline and remnants of internal organs are clearly visible," says Lindgren. "Remarkably, the fossil is so well-preserved that it is possible to observe individual cellular layers within its skin." Researchers identified cell-like microstructures containing pigment organelles on the surface of the fossil. This ancient skin revealed a feature we recognized from marine dwelling animals, the ability to change colour, providing camouflage from potential predators. They also found traces of what might have been the animal's liver. When they put some of the tissue through chemical analysis, it was consistent with what we'd look for in adipose tissue or blubber. Not surprising as dolphins today use blubber for buoyancy and to help thermally insulate for thermal regulation in cold seas. might find in a vertebrate that uses blubber as a means of maintaining body temperatures independent of ambient conditions.
Today, blubber is an important part of the anatomy of seals, whales and walruses. It covers the core of their bodies, storing energy, insulating them from cold seas and provide extra buoyancy. While they do not have blubber on their fins, flippers and flukes. Not all marine animals need blubber. Our cold-blooded marine friends: sharks, crabs, fish, are able to let their body temperatures dropdown to very chilly levels, some as low as 36 degrees Fahrenheit. They have a few tricks up their sleeves to make this happen. Sharks have evolved specialized physiology to keep their metabolic rate high and their hearts are able to contract in the icy depths because of a special protein. These adaptations allow sharks to enjoy a wide range of habitats and follow their food from warm tropical seas to the icy waters of the North Pacific.
Johan Lindgren, Peter Sjövall, Volker Thiel, Wenxia Zheng, Shosuke Ito, Kazumasa Wakamatsu, Rolf Hauff, Benjamin P. Kear, Anders Engdahl, Carl Alwmark, Mats E. Eriksson, Martin Jarenmark, Sven Sachs, Per E. Ahlberg, Federica Marone, Takeo Kuriyama, Ola Gustafsson, Per Malmberg, Aurélien Thomen, Irene Rodríguez-Meizoso, Per Uvdal, Makoto Ojika, Mary H. Schweitzer. Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur. Nature, 2018; DOI: 10.1038/s41586-018-0775-x
North Carolina State University. (2018, December 5). Soft tissue shows Jurassic ichthyosaur was warm-blooded, had blubber and camouflage. ScienceDaily. Retrieved September 7, 2019, from www.sciencedaily.com/releases/2018/12/181205134118.htm
Wednesday, 4 September 2019
The wee candle you see on her forehead is a photophore, a tiny bit of luminous dorsal spine. In anglerfish' world, it's dead sexy. It's an adaptation used to attract prey and mates alike.
Deep in the murky depths of the Atlantic and Antarctic oceans, hopeful female anglerfish light up their sexy lures. When a male latches onto this tasty bit of flesh, he fuses himself totally. He might be one of several potential mates. She's not picky, just hungry. Lure. Feed. Mate. Repeat.
A friend asked if anglerfish mate for life. Well, yes.... yes, indeed they do.
Mating is a tough business down in the depths. Her body absorbs his over time until all that's left are his testes. While unusual, it is only one of many weird and whacky ways our fishy friends communicate, entice, hunt and creatively survive and thrive.
The evolution of fish began about 530 million years ago with the first fish lineages belonged to the Agnatha, a superclass of jawless fish. We still see them in our waters as cyclostomes but have lost the conodonts and ostracoderms to the annals of time. Like all vertebrates, fish have bilateral symmetry; when divided down the middle or central axis, each half is the same. Organisms with bilateral symmetry are generally more agile, making finding a mate, hunting or avoiding being hunted a whole lot easier.
When we envision fish, we generally picture large eyes, gills, a well-developed mouth. The earliest animals that we classify as fish appeared as soft-bodied chordates who lacked a true spine. While they were spineless, they did have notochords, a cartilaginous skeletal rod that gave them more dexterity than the cold-blooded invertebrates who shared those ancient seas and evolved without a backbone. Fish would continue to evolve throughout the Paleozoic, diversifying into a wide range of forms. Several forms of Paleozoic fish developed external armour that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many species, including sharks, became formidable marine predators rather than just the prey of arthropods.
Fishes in general respire using gills, are most often covered with bony scales and propel themselves using fins. There are two main types of fins, median fins and paired fins. The median fins include the caudal fin or tail fin, the dorsal fin, and the anal fin. Now there may be more than one dorsal, and one anal fin in some fishes.
The paired fins include the pectoral fins and the pelvic fins. And these paired fins are connected to, and supported by, pectoral and pelvic girdles, at the shoulder and hip; in the same way, our arms and legs are connected to and supported by, pectoral and pelvic girdles. This arrangement is something we inherited from the ancestors we share with fishes. They are homologous structures.
When we speak of early vertebrates, we're often talking about fishes. Fish is a term we use a lot in our everyday lives but taxonomically it is not all that useful. When we say, 'fish' we generally mean an ectothermic, aquatic vertebrate with gills and fins.
Fortunately, many of our fishy friends have ended up in the fossil record. We may see some of the soft bits from time to time, as in the lovely fossil fish found in concretion in Brazil, but we often see fish skeletons. Vertebrates with hard skeletons had a much better chance of being preserved. In British Columbia, we have lovely two-dimensional Eocene fossil fish well-represented from the Allenby of Princeton and the McAbee Fossil Beds. We have the Tiktaalik roseae, a large freshwater fish, from 375 million-year-old Devonian deposits on Ellesmere Island in Canada's Arctic. Tiktaalik is a wonderfully bizarre creature with a flat, almost reptilian head but also fins, scales and gills. We have other wonders from this time. There are also spectacular antiarch placoderms, Bothriolepsis, found in the Upper Devonian shales of Miguasha in Quebec.
There are fragments of bone-like tissues from as early as the Late Cambrian with the oldest fossils that are truly recognizable as fishes come from the Middle Ordovician from North America, South America and Australia. At the time, South America and Australia were part of a supercontinent called Gondwana. North America was part of another supercontinent called Laurentia and the two were separated by deep oceans.
These two supercontinents and others that were also present were partially covered by shallow equatorial seas and the continents themselves were barren and rocky. Land plants didn't evolve until later in the Silurian Period. In these shallow equatorial seas, a large diverse and widespread group of armoured, jawless fishes evolved: the Pteraspidomorphi. The first of our three groups of ostracoderms. The Pteraspidomorphi are divided into three major groups: the Astraspida, Arandaspida and the Heterostraci.
The oldest and most primitive pteraspidomorphs were the Astraspida and the Arandaspida. You'll notice that all three of these taxon names contain 'aspid', which means shield. This is because these early fishes and many of the Pteraspidomorphi possessed large plates of dermal bone at the anterior end of their bodies. This dermal armour was very common in early vertebrates, but it was lost in their descendants. Arandaspida is represented by two well-known genera: Sacabampaspis, from South America and Arandaspis from Australia. Arandaspis have large, simple, dorsal and ventral head shields. Their bodies were fusiform, which means they were shaped sort of like a spindle, fat in the middle and tapering at both ends. Picture a sausage that is a bit wider near the centre with a crisp outer shell.
Tuesday, 3 September 2019
- Haikouichthys ercaicunensis
- Myllokunmingia fengjiaoa
- Zhongjianichthys rostratus
A friend of mine, Eldon Grupp from the USA, found an 18 mm specimen on a mortality slab of Haikouella from Chengjiang. Apparently, no one had noticed it before shipping. Not surprising as Zhongjianichthys are easy to overlook. I've asked him if I can get a photo of that mortality plate to share with you. It's quite stunning. Haikouella, of course, are not vertebrates, but advanced craniate chordates. The specimen in question, however, was a vertebrate. Eldon has assigned this specimen to genus Zhongjianichthys based on its eel-like characteristics and its large eyes located behind the anterior or rostral lobe instead of within it. Even so, family affiliation is uncertain.
Monday, 2 September 2019
Both of these lovelies from the order Sirenia went from terrestrial to marine, taking to the water in search of more prosperous pastures, as it were.
They are the extant and extinct forms of the oddball manatees and dugongs. They inhabit rivers and shallow coastal waters, making the best use of their fusiform bodies that lack dorsal fins and hind limbs. I've been thinking about them in the context of some of the primitive armoured fish we find in the Chengjiang biota of China, specifically those primitive species that were also fusiform.
We find dugongs today in waters near northern Australia and parts of the Indian and Pacific Oceans. They favour locations where seagrass, their food of choice, grows plentiful and they eat it roots and all. While seagrass low in fibre, high in nitrogen and easily digestible is preferred, dugongs will also dine on lower grade seagrass, algae and invertebrates should the opportunity arise. They've been known to eat jellyfish, sea squirts and shellfish over the course of their long lives. Some of the oldest dugongs have been known to live 70+ years, which is another statistic I find surprising. They are large, passive, have poor eyesight and look pretty tasty floating in the water; a defenceless floating buffet. Their population is in decline but yet they live on.
Sunday, 1 September 2019
Our dear penguins, seals, sea lions, walruses, whales, crocodiles and sea turtles were once entirely terrestrial. Some dipped a toe or two into freshwater ponds, but make no mistake, they were terrestrial. Each of these animals had ancestors that tried out the sea and decided to stay. They evolved and employed a variety of adaptations to meet their new saltwater challenges. Some adapted legs as fins, others became more streamlined, and still, others developed specialized organs to extract dissolved oxygen from the water through their skin or gills. The permutations are endless.
Returning to the sea comes with a whole host of benefits but some serious challenges as well. Life at sea is very different from life on land. Water is denser than air, impacting how an animal moves, sees and hears. More importantly, it impacts an air-breathing animal's movement on a pretty frequent basis. If you need air and haven't evolved gills, you need to surface frequently. Keeping your body temperature at a homeostatic level is also a challenge as water conducts heat much better than air. Even with all of these challenges, the lure of additional food sources and freedom of movement kept those who tried the sea in the sea and they evolved accordingly.
This is an interesting article from Alicia Ault writing for the Smithsonian who interviewed Nick Pysenson and Neil Kelley about some of their research that touches on this area. They published a paper on it in the journal Science back in 2015.
Here's the link: https://science.sciencemag.org/content/348/6232/aaa3716
And Ault's work is definitely worth a read: https://www.smithsonianmag.com/smithsonian-institution/take-deep-dive-reasons-land-animals-moved-seas-180955007/
Saturday, 31 August 2019
|Armoured Agnatha / Photo: Fossilero Fisher|
Victoraspis longicornualis was named by Anders Carlsson and Henning Bloom back in 2008. The new osteostracan genus and species were described based on material from Rakovets' present-day Ukraine. This new taxon shares characteristics with the two genera Stensiopelta (Denison, 1951) and Zychaspis (Javier, 1985).
Agnatha is a superclass of vertebrates. This fellow looks quite different from our modern Agnatha, who include lamprey and hagfish. Ironically, hagfish are vertebrates who do not have vertebrae. Sometime in their evolution they lost them as they adapted to their environment.
Ref: Carlsson, A. & Blom, H. Paläont. Z. (2008) 82: 314. https://doi.org/10.1007/BF02988898
Friday, 30 August 2019
The Geology of Yorkshire in northern England shows a very close relationship between the major topographical areas and the geological period in which their rocks were formed. The rocks of the Pennine chain of hills in the west are of Carboniferous origin whilst those of the central vale is Permo-Triassic.
The North York Moors in the north-east of the county are Jurassic in age while the Yorkshire Wolds to the south east are Cretaceous chalk uplands. The plain of Holderness and the Humberhead levels both owe their present form to the Quaternary ice ages. The strata become gradually younger from west to east. Much of Yorkshire presents heavily glaciated scenery as few places escaped the direct or indirect impact of the great ice sheets as they first advanced and then retreated during the last ice age. This beauty is in the collection of the deeply awesome Harry Tabiner.
Thursday, 29 August 2019
The Puntledge Elasmosaur discovery led to the expansion of the local museum, the excavation site became a provincial heritage site and many, many teaching programs and guided tours have transpired since.
This is a far cry from other similar finds. You may remember an earlier find by Edward Drinker Cope. His 1868 discovery from outcrops in Kansas was originally described with the head incorrectly attached to the tail. Oops. It wasn't long before his archrival, one Othniel Charles March pointed it out quite publically. These were less gentle times and those two gents had a rivalry so underhanded and so public it is famously called, "the Bone Wars." The Courtenay and District Museum, the community surrounding it and allied organizations like the Vancouver Island Palaeontological Society, have a lot to be proud of. Their outreach and educational programs have inspired young and old alike.
Wednesday, 28 August 2019
Pine Pass is part of the Pardonet Formation. Just a short hike from the road we were able to easily find the abundant outcroppings of the paper clam, Monotis subcircularis, perfectly preserved and cemented in this strata from the Late Triassic. Because of their widespread distribution and very high species turnover rates, they make for excellent biochronological macrofossils, helping us to correlate biological events through time.
Tuesday, 27 August 2019
It is one of the best local sites in the province to experience a fossil dig first-hand. It's an easy 4-hour drive from Vancouver and easily done as a rather longish day trip. I headed up there this past weekend with some wonderful enthusiastic crew. The site was designated a Provincial Heritage Site under British Columbia's Heritage Conservation Act in July of 2012. The site was reopened to public tours and viewing this summer with plans to build out a visitor's centre and educational programs in the future.
We were greeted on the day by two wonderful hosts from the Bonaparte Band, Gayle Pierro and Leroy Antoine. Both were very welcoming and informative, sharing the lay of the land, a bit of their history with the workings and offering us a guided tour. From the road, it is a short drive up to the first staging area that houses visitor parking and a public washroom. The first Site Information station is a short stroll away and includes a tent with a table and maps showing plans for the site. Here, Gayle walked us through the vision for McAbee and showed us a selection of some of the species found here. We were asked to stop back on the way down and fill out a survey that asked about our experience and provide feedback that will help shape what McAbee is to become. A short hike up the hill towards the hoodoos leads to another staging area. Here, Leroy was our host and guide. He shared a bit more about the geology of the area and showed us specimens found over the summer.
As McAbee is a Heritage Site, their only request was that we stay within the marked area and trails and keep ourselves safe. Here safe means hydrated, shaded from the sun and avoiding both the resident rattlesnakes and cacti. McAbee offers an excellent opportunity for education and outreach both for locals and the larger community. It was very enjoyable to see the reactions of those visiting the site as they took in the wonderful diversity of fossil species and learning about the local history from our hosts.
The Province is committed to providing access to the site to scientists and the lay public. The direction on what happens next at McAbee is being driven by the Heritage Branch in consultation with members of the Shuswap Nation and Bonaparte Band. Bonaparte's traditional territory is located within the Shuswap Nation. Local members of the Bonaparte Band are Secwepemc. They would like to share the spiritual significance of the area from a Secwepemc First Nation perspective and see McAbee as an indigenous tourism destination. So it looks like it will be paleontology, archaeology with a cultural focus to add spice. In any case, fossil viewing, and hopefully supervised collecting will continue with oversight to ensure significant fossil finds make their way to science.
It would be good to see McAbee take a page out of the Courtney and District Museum's playbook. You'll recall that it was the Puntledge Elasmosaur that sparked the expansion of that museum and inspired a whole host of outreach and educational programs. The Courtenay Museum has been offering paid guided tours to the elasmosaur heritage site for over a dozen years. They are members of the British Columbia Paleontological Alliance (BCPA), a union of professional and amateur paleontological organizations working to advance the science of paleontology in the province by fostering public awareness, scientific collecting and education, and by promoting communication among all those interested in fossils. Within that context, the Courtenay Museum are bound both by the BCPA constitution and bylaws, and of course, the laws around fossil collecting in British Columbia.
One of the sister sites to McAbee, the Driftwood Canyon Provincial Park Fossil Beds, offers an honours system for their site. Visitors may handle and view fossils but are asked to not take them home. Both Driftwood Canyon and McAbee are part of an arc of Eocene lakebed sites that extend from Smithers in the north, down to the fossil site of Republic Washington, in the south. The grouping includes the fossil sites of Driftwood Canyon, Quilchena, Allenby, Tranquille, McAbee, Princeton and Republic. Each of these localities provides important clues to our ancient climate.
The fossils range in age from Early to Middle Eocene. McAbee had a more temperate climate, slightly cooler and wetter than other Eocene sites to the south at Princeton, British Columbia, Republic in north-central Washington, in the Swauk Formation near Skykomish and the Chuckanut Formation of northern Washington state. The McAbee fossil beds consist of 30 metres of fossiliferous shale in the Eocene Kamloops Group.
The fossils are preserved here as impressions and carbonaceous films. We see gymnosperm (16 species); a variety of conifers (14 species to my knowledge); two species of ginkgo, a large variety of angiosperm (67 species); a variety of insects and fish remains, the rare feather and a boatload of mashed deciduous material. Nuts and cupules are also found from the dicotyledonous Fagus and Ulmus and members of the Betulaceae, including Betula and Alnus.
We see many species that look very similar to those growing in the Pacific Northwest today. Specifically, cypress, dawn redwood, fir, spruce, pine, larch, hemlock, alder, birch, dogwood, beech, sassafras, cottonwood, maple, elm and grape. If we look at the pollen data, we see over a hundred highly probable species from the site. Though rare, McAbee has also produced spiders, birds (and lovely individual feathers) along with multiple specimens of the freshwater crayfish, Aenigmastacus crandalli.
For insects, we see dragonflies, damselflies, cockroaches, termites, earwigs, aphids, leafhoppers, spittlebugs, lacewings, a variety of beetles, gnats, ants, hornets, stick insects, water striders, weevils, wasps and March flies. The insects are particularly well-preserved. Missing are the tropical Sabal (palm), seen at Princeton and the impressive Ensete (banana) and Zamiaceae (cycad) found at Eocene sites in Republic and Chuckanut, Washington.
McAbee is located just east of Cache Creek, just north of and visible from Highway 1/97. 14.5 km to be exact and exactly the distance you need to drink one large coffee and then need a washroom. You'll be pleased to know they have installed one at the site. McAbee is a site for hiking boots, hand, head and eye protection. They have a few resident rattlesnakes and prickly cacti to keep you on your toes. Keep yourself safe and well-hydrated.
As you drive up, you'll see telltale hoodoos on the ridge to let you know you've reached the right spot. If you have a GPS, pop in these coordinates and you're on your way. 50°47.831′N 121°8.469′W.
Monday, 26 August 2019
Hornby is a glorious place to collect. The island is beautiful in its own right and the fossils from here often keep some of their original shell or nacre which makes them quite fetching.
This fellow is found amongst gastropods, shark teeth, fossil crabs, baculites and other bivalve fossils. A new species of pterosaur (flying reptile) Gwawinapterus beardi was found on the same beach site and named after Graham Beard, a local collector, author and great friend.
Like most of the fossils found at this locality, the specimen was found in concretions rolled smooth by time and tide. The concretions you find on the beach are generally round or oval in shape and are made up of hard, compacted sedimentary rock. If you are lucky, when you split them you see a fossil hidden within. The main topographic feature on Hornby Island is an arcuate mountain consisting of the resistant cliff-forming Geoffrey formation. Near Shingle Spit about half a mile from the coast is Mt. Geoffrey 920-foot peak; from there the mountain gradually drops in elevation to the southeast and to the north. It consists of a structurally simple 700-foot conglomerate homocline striking N 20° W and dipping to the northeast at a shallow angle of about 6°. The apex of the arcuate mountain belt points to the southwest.
Behind the mountain and almost enclosed by it is the fertile, green Strachan Valley. On the large peninsula which extends in a southeast direction from the north of the island towards St. John’s Point, the Hornby Formation outcrops forming the cliffs on the east side of Tribune Bay. The highest of these is about 200 feet. The argillaceous Lambert and Spray formations form the subdued lowlands of the island.
The coast of Hornby is probably a rising shoreline, as indicated by the almost perpendicular cliffs along its periphery. A hundred (100) foot cliffs of Lambert shale extends from Shingle Spit to Phipps Point, while from the latter to Boulder Point, the cliffs are not as steep and are covered in many places by vegetation.
Sunday, 25 August 2019
This specimen is now housed in the Courtenay and District Museum on Vancouver Island, British Columbia. He's tagged as a mosasaur, but the court is still out (and will need more study) to see if we are looking at a Tylosaurus.
Saturday, 24 August 2019
There are two main groups of Hadrosaurs, crested and non-crested. The bony crest on the top of the head of the hadrosaurs was hollow and attached to the nasal passages. It is thought that the hollow crest was used to make different sounds. These sounds may have signalled distress or been the mating calls used to attract mates.
This beautiful specimen graces the back galleries of the Courtenay and District Museum on Vancouver Island, British Columbia, Canada. This fellow has kissing cousins over in the state of New Jersey where this species is the official state fossil. The first of his kind was found by John Estaugh Hopkins in New Jersey back in 1838.
Friday, 23 August 2019
The Green River Formation is particularly abundant in beautifully preserved fossil fish, eleven species of reptiles including a 13.5ft crocodile, an armadillo-like mammal, Brachianodon westorum, bats, birds and other freshwater aquatic goodies.
Thursday, 22 August 2019
This fellow (or at least his skull) is on display at the Natural History Museum in Madrid, Spain. For now, he is the only known genus of this species of bipedal predator.
The skull is quite unusual. Initially, it has a very marine reptile feel (but make no mistake this guy is clearly a terrestrial theropod). Once you look closer you see his bull-like horns (from whence he gets his name) that imply battle between rivals for the best meal, sexual partner and to be the one who leads the herd.
Wednesday, 21 August 2019
Here, great wine is produced and consumed along with a huge variety of seafood, figs, olives, capers and Limoncello in the wee restaurants and bars along the Via Colombo that look out onto the Gulf of Genoa. Inspired by the praise of Dante, Petrarch and Boccaccio, I had the great pleasure to venture there years ago, prior to the huge slides that plagued the Cinque Terre. I ate one of my finest meals, a pasta made from squid ink, one evening I was there. Drawn to the picturesque beauty of the Liguria region, ancient vineyards and the irresistible "photo a moment" scenery, we travelled from village-to-village, all along the Cinque Terre.
Liguria remains one of the wildest parts of the Ligurian littoral east of Genoa. The coastline is home to incredibly complex and exciting geology. It is composed of the Maritime Alps in the west and the Ligurian "nappies," continental margin ophiolites, of the Apennines in the east.
Along the coast, the north-northwest convergence of the Alpine orogeny gives way to the active east-northeast convergence along the Apennines. All of this tasty geology can be observed while walking from town to town from Riomaggiore through Manarola, Corniglia and Vernazza. We stayed in Monterosso al Mare during our visit, meeting up with friends and then visiting them in their home city of Milan. If one is lucky enough to be invited as a guest, the geology of the Via dell Amore is true to its namesake and well worth the trip.
Tuesday, 20 August 2019
|Collection of José Juárez Ruiz. The specimen is 202 mm.|
Balearites, with their planispiral shell (conch) and compressed whorls, is an extinct ancyloceratin genus ammonite in the family Crioceratitidae, suborder Ancyloceratina.
We find fossils of this genera in Romania, Slovakia, Austria, France, Spain, Switzerland, Hungary, Italy, Russia, Bulgaria and Morocco. This specimen is in the collection of José Juárez Ruiz and is roughly 202 mm. If you find this lovely interesting, you'll enjoy reading more on this genus and others in Arkell, W. J. et al., 1957. Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L, Mollusca 4. 1957.
Monday, 19 August 2019
You can see the nice ceratitic suture pattern on this specimen with his smooth lobes and frilly saddles. The sutures would have increased the strength of the shell and allowed Ceratites (de Haan, 1825) to dive deeper, bearing the additional pressure of the sea in search of food.
Ammonite shells are made up predominantly of calcium carbonate in the form of aragonite and proteinaceous organic matrix or conchiolin arranged in layers: a thin outer prismatic layer, a nacreous layer and an inner lining of prismatic habitat. While their outer shells are generally aragonite, aptychus are distinct as they are composed of calcite.
The aptychus we see here, hard anatomical structures or curved shelly plates now understood to be part of the body of an ammonite, are often referred to as beaks. If you look closely at this specimen, you can see the beak of the ammonite, that wee pointed piece, near the centre.
These ammonites lived in open shallow, to subtidal and basinal environments some 247 to 221 million years ago. We've found them, thus far, in just over forty collections from nearly ninety fossil deposits around the globe. Fossils of species have been found in the Triassic of Austria, Canada, China, France, Germany, Hungary, India, Israel, Italy, Pakistan, Poland, Russia, Thailand, Turkey and the United States.
The parent taxon is Ceratitinae according to E. T. Tozer 1981. That's our own Tim Tozer, one of the great knights-errant of the Triassic timescale. It was Tim Tozer and Norm Silberling who published one the classic milestones of the Triassic timescale, "Biostratigraphic Classification of the Marine Triassic in North America, Geological Society of America, Special Paper 110." The Global Triassic: Bulletin 41 from the New Mexico Museum of Natural History and Science by Lucas and Spielmann honours them in their work. Collection of Ange Mirabet, Strasbourg, France.
Sunday, 18 August 2019
There are lovely brachiopods, including the spiriferids Striipirifer and Eospirifer, the strophomenids Leptaena, Coolinia and Amphistrophia. We also see the orthids represented by Mendacella (formerly Dalejina) and Resserella.
They shales also house a stunning assortment of our echinoderm friends with their radial symmetry. We see cystoids, crinoids, asterozoans and edrioasteroids. The diversity of the crinoids is especially spectacular. We see the camerates Macrostylocrinus, Dimerocrinites, Saccocrinus and Eucalyptocrinites. Cladids are represented by the elegant and long-stemmed Dendrocrinus, with his lengthy anal sac and branched, non-pinnulate arms. Disparids occur as the wee Homocrinus, recumbent calceocrinids (Calceocrinus) and the coiled, Crinobrachiatus with his coiled bilateral symmetry.
We also see the flexible crinoids represented by Asaphocrinus, Icthyocrinus and Lecanocrinus. Gracing many of the beds is the rhombiferan cystoid Caryocrinites scattered in bits and pieces and on rarer occasions fully intact, sometimes with rooted specimens associated with bryozoan thickets. The edrioasteroid Hemicystites occurs in select layers referred to as the Homocrinus Beds. These beds record a history from when the area that is now New York State was located south of the equator and covered by an ancient shallow sea.
The Lewiston Member of the Rochester Shale were first studied by James Hall in the 1850-60's. Many great paleontologists have contributed to our understanding of their place in geologic and paleontological history, including Eugene Ringueberg's work from 1884-88; Frank Springer's studies from 1914-22 and Carlton E. Brett (along with his students, Denis Tetreault, James Eckert and Wendy Taylor) in the 1970-90's.
While the site became famous back in the 1820s, it is because of these latter paleontologists that I came to know about the site and appreciate the full breadth of fauna. Collection of Felix Collantes. If you are interested in the diversity of fauna from this area, I highly recommend the 1999 publication by Taylor and Brett referenced below. It's a definitive work.
Reference: Taylor and Brett 1999: Middle Silurian Rochester Shale of Western New York, USA, and Southern Ontario, Canada
Saturday, 17 August 2019
These Atlantic Puffins are one of the most famous of all the seabirds and form the largest colony in Southern Britain. They live about 25 years making a living in our cold seas dining on herring, hake and sand eels. Some have been known to live to almost 40 years of age. They are good little swimmers as you might expect, but surprisingly they are great flyers, too! They are hindered by short wings, which makes flight challenging but still possible with effort. Once they get some speed on board, they can fly up to 88 km an hour.
Their sexy orange beaks (dead sexy, right?) shifts from a dull grey to bright orange when it is time to attract a mate. While not strictly monogamous, most Puffin choose the same mate year upon year producing adorable chicks or pufflings (awe) from their mating efforts. Female Puffins produce one single white egg which the parents take turns to incubate over a course of about six weeks. They dutiful parents share the honour of feeding the wee pufflings five to eight times a day until the chick is ready to fly. Towards the end of July, the fledgling Puffins begin to venture from the safety of their parents and dry land. Once they take to the seas, mom and dad are released from duty and the newest members of the colony are left to hunt and survive on their own.
Friday, 16 August 2019
Agriotherium is one of the largest of the mighty carnivores that lived in Europe back in the Pleistocene. They weighed as much as 900 kilos (almost 2,000 lbs) and grew up to 2.5 meters tall. These ancient bears roamed prehistoric Italy amid a humid and temperate climate, competing for food resources with some of our ancestors as they only becoming extinct 2.6 million years ago.
Thursday, 15 August 2019
Anahoplites is now included in the subfamily Anahoplitinae and separated from the Hoplitinae where it was placed in the older in the 1957 edition of the Treatise on Invertebrate Paleontology, Part L (Ammonoidea). Genera of the Hoplitinae tend to be more robust, with broader whorls and stronger ribs.
Anahoplites is found in Cretaceous (Middle to the late Albian) deposits from England, through Europe, all the way to the Transcaspian Oblast region in Russia to the east of the Caspian Sea. The Aube department, named after the local river, is the type locality of the Albian stage (d'ORBIGNY, 1842). Two formations are recognised in the clay facies (the "Gault" auct.) of the stratotype, the Argiles tégulines de Courcelles (82 m), overlain by the Marnes de Brienne (43 m). The boundary between the two formations is well-defined at the top of an indurated bed and readily identifiable in the field.
Anahoplites is found in Cretaceous (Middle to the late Albian) deposits from England, through Europe, all the way to the Transcaspian Oblast region in Russia to the east of the Caspian Sea. The Aube department, named after the local river, is the type locality of the Albian stage (d'ORBIGNY, 1842). Two formations are recognised in the clay facies (the "Gault" auct.) of the stratotype, the Argiles tégulines de Courcelles (82 m), overlain by the Marnes de Brienne (43 m). The boundary between the two formations is well-defined at the top of an indurated bed and readily identifiable in the field.
This involute (113 mm) specimen shows evidence of cohabitation by some of his marine peers. We see two different bryozoa, an oyster and some serpulids making a living and leaving trace fossils on his flat sides. This specimen was prepared with potase by José Juárez Ruiz of Spain.
Wednesday, 14 August 2019
If you look closely at this specimen, you can see the remarkable 3-D and soft-bodied preservation. This fish specimen reminds me of the ray-finned fossil fish you see in carbonate concretion from Lower Cretaceous deposits in the Santana Formation, Brazil.
Eusthenopteron would have shared our ancient seas with the first ammonites and primitive sharks, along with well-established fauna including the trilobites, brachiopods, coral reefs and a whole host of interesting arthropods.
Miguasha National Park / Parc National de Miguasha, is a protected area near Carleton-sur-Mer on the Gaspé Peninsula along the south side of the Saint Lawrence River to the east of the Matapedia Valley in Quebec, Canada. It was created in 1985 by the Government of Quebec and designated as a World Heritage Site in 1999 in honour of paleontological significance for Devonian fish, flower and spore fossils.
These fossils represent five of the six main fossil fish groups recorded from the Devonian (370 million years ago) including specimens of the lobe-finned fish and tetrapods. We see the placoderms, armoured prehistoric fish, in their heyday, dominating almost every known aquatic environment. The Devonian is known as the 'Age of Fishes,' but it could have equally been called the 'Age of Spores,' as this was a time of significant adaptive radiation of terrestrial biota and free-sporing vascular plants. Immense forests carpeted the continents and we see the first of the plant groups evolving leaves, true roots and seeds.
The site was discovered in 1842 by a local geologist and medical doctor, Abraham Gesner. He shared much of his collection with both the British Museum and Royal Scottish Museum for further study. Other names for this site are the Miguasha Fossil Site, the Bay of Escuminac Fossil Site, the Upper Devonian Escuminac Formation, and the Hugh-Miller Cliffs. It is also sometimes referred to on fossil specimens as 'Scaumenac Bay' or 'Scaumenac Bay P.Q. Photo credit to the deeply awesome John Fam
Tuesday, 13 August 2019
Porpoceras (Buchman, 1911) is genus of ammonite that lived during the early and middle Toarcian stage of the early Jurassic. We see members of this genus from the uppermost part of Serpentinum Zone to Variabilis Subzone. These beauties are found in Europe, Asia, North America and South America.
Ammonites belonging to this genus have evolute shells, with compressed to depressed whorl section. Flanks were slightly convex and venter has been low. The whorl section is sub-rectangular. The rib are pronounced and somewhat fibulate on inner whorls (just wee nodes here) and tuberculate to spined on the ventrolateral shoulder.
It differs from Peronoceras by not having a compressed whorl section and regular nodes or fibulation. Catacoeloceras is also similar, but it has regular ventrolateral tubercules and is missing the classic nodes or fibulation of his cousins.
This specimen hails from southern France near the Rhône, one of the major rivers of Europe. It has twice the average water level of the Loire and is fed by the Rhône Glacier in the Swiss Alps at the far eastern end of the Swiss canton of Valais then passes through Lake Geneva before running through southeastern France. This 10 cm specimen was prepared by the supremely talented José Juárez Ruiz
Monday, 12 August 2019
That's right, a Fish Wash. You'd be hard pressed to find a terrestrial Molly Maid with two opposable thumbs as studious and hardworking as this wee marine beauty. You'll find them each day cleaning and snacking on a host of parasites. As many as twenty to thirty shrimp gather together to assemble a highly-efficient marine cleaning station. They're even open to partnerships and mergers, partnering up with Cleaner Wrasse, or cleaner fish, for larger, high-end clients.
Spotted cleaner shrimp are about 2.5 cm long and have a delightful transparent body with telltale white and brown spots. Their legs, or chelae, are striped in purple, white and red. They live about 24 metres (or 79 ft) down on the sea floor in many of our planet's most beautiful waters. Aside from the Caribbean, they also enjoy setting up shop in the Bahamas, southern Florida and live as far south as Panama and Columbia.They are carnivorous crustaceans in the family, Palaemonidae.
This quiet marine mogul is turning out to be one of the ocean's top entrepreneurs. Keeping its host and diet clean and green, the spotted shrimp hooks up with the locals, in this case, local sea anemones and sets up a fish wash. Picture a car wash but without the noise and teenage boys. The signage posted is the shrimps' natural coloring which attracts fish from around the reefs.
Wash on, wash off.
Once within reach, the shrimp cleans the surface of the fish, giving the fish a buff and the shrimp its daily feed. This is good news for the shrimp, especially this time of year as they breed and brood their eggs in summer. After hatching, the larvae pass through many (sadly, tasty) planktonic stages before setting up a fish wash of their own. Once they are older, they gain some protection from being eaten by their clients by a special signalling system that essentially shouts, "just here cooperation not as food." Here's to Periclimenes for keeping up the family business.
Sunday, 11 August 2019
And what a specimen it is! The spectacularly preserved fruit was found in 2018 and measures 6-1/2" round. Here you can see both the part and counterpart in fine detail. Doug Miller of Green River Stone sent copies to me this morning and a copy to the deeply awesome Kirk Johnson, resident paleontologist over at the Smithsonian Institute, to confirm the ID.
There is another spectacular specimen from Fossil Butte National Monument. They shared photos of a Nelumbo just yesterday. Nelumbo is a genus of aquatic plants in the order Proteales found living in freshwater ponds. You'll recognize them as the emblem of India, Vietnam and many wellness centres.
Interestingly, these lovelies can thermoregulate, producing heat. Nelumbo use the alternative oxidase pathway (AOX) to exchange electrons. Instead of using the typical cytochrome complex pathway most plants use to power mitochondria, they instead use their cyanide-resistant alternative. This is perhaps to generate a wee bit more scent in their blooms and attract more pollinators. The use of this thermogenic feature would have also allowed thermo-sensitive pollinators to seek out the plants at night and possibly use the cover of darkness to linger and mate.
So they functioned a bit little like a romantic evening meeting spot for lovers and a wee bit like the scent diffuser in your home. This lovely has an old lineage with fossil species in Eurasia and North America going back to the Cretaceous and represented in the Paleogene and Neogene. Photo: Doug Miller of Green River Stone / Lotus Image: Sarah-Anne Juliette McCarthy / Foliage Image: J.M.Garg - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=7249919
Saturday, 10 August 2019
|Apodoceras / Stonebarrow Fossils|
Apoderoceras has been found in the Lower Jurassic of Argentina, Hungary, Italy, Portugal, and most of North-West and central Europe, including as this one is, the United Kingdom. This specimen was found on the beaches of Charmouth in West Dorset.
Neither Apoderoceras nor Bifericeras donovani are strictly index fossils for the Taylori subzone, the index being Phricodoceras taylori. Note that Bifericeras is typical of the earlier Oxynotum Zone, and ‘Bifericeras’ donovani is doubtfully attributable to the genus. The International Commission on Stratigraphy (ICS) has assigned the First Appearance Datum of genus Apoderoceras and of Bifericeras donovani the defining biological marker for the start of the Pliensbachian Stage of the Jurassic, 190.8 ± 1.0 million years ago.
Apoderoceras, Family Coeloceratidae, appears out of nowhere in the basal Pliensbachian and dominates the ammonite faunas of NW Europe. It is superficially similar to the earlier Eteoderoceras, Family Eoderoceratidae, of the Raricostatum Zone, but on close inspection can be seen to be quite different. It is therefore an ‘invader’ and its ancestry is cryptic.
The Pacific ammonite Andicoeloceras, known from Chile, appears quite closely related and may be ancestral, but the time correlation of Pacific and NW European ammonite faunas is challenging. Even if Andicoeloceras is ancestral to Apoderoceras, no other preceding ammonites attributable to Coeloceratidae are known. We may yet find clues in the Lias of Canada. Apoderoceras remains present in NW Europe throughout the Taylori Subzone, showing endemic evolution. It becomes progressively more inflated during this interval of time, the adult ribs more distant, and there is evidence that the diameter of the macroconch evolved to become larger. At the end of the Taylori Subzone, Apoderoceras disappeared as suddenly as it appeared in the region, and ammonite faunas of the remaining Jamesoni Zone are dominated by the Platypleuroceras–Uptonia lineage, generally assigned (though erroneously) to the Family Polymorphitidae.
In the NW European Taylori Subzone, Apoderoceras is accompanied (as well as by the Eoderoceratid, B. donovani, which is only documented from the Yorkshire coast, although there are known examples from Northern Ireland) by the oxycones Radstockiceras (quite common) and Oxynoticeras (very rare), the late Schlotheimid, Phricoderoceras (uncommon) Note: P. taylori is a microconch, and P. lamellosum, the macroconch), and the Eoderoceratid, Tetraspidoceras (very rare). The lovely large specimen (macroconch) of Apoderoceras pictured here is likely a female. Her larger body perfected for egg production.
Friday, 9 August 2019
The genus Deinotherium could reach a height of over 3.5 meters. Its structure and size are similar to those of the present-day elephant. Deinotherium first appeared approximately 17 million years ago and became extinct relatively recently, just 1.6 million years ago.
One of the distinguishing features of Deinotherium is their curved tusks inserted only in the jaw. One of the tusks from this fellow, on display at the Museo Nacional De Ciencias Naturales in Madrid, Spain, while incomplete, was preserved rather nicely and shows the detail of where the tusk meets the jaw.
Thursday, 8 August 2019
The megatheria were large terrestrial sloths belonging to the group, Xenarthra. These herbivores inhabited large areas of land on the American continent. Their powerful skeleton enabled them to stand on their hind legs to reach leaves high in the trees, a huge advantage given the calories needed to be consumed each day to maintain their large size.
Avocados were one of the food preferences of our dear Giant ground sloths. They ate then pooped them out, spreading the pits far and wide. The next time you enjoy avocado toast, thank this large beastie. One of his ancestors may have had a hand (or butt) in your meal.
In 1788, Bru assembled the skeleton as you see it here. It is exhibited at the Museo Nacional De Ciencias Naturales in Madrid, Spain, in its original configuration for historic value. If you look closely, you'll see it is not anatomically correct. But all good paleontology is teamwork. Based upon the drawings of Juan Bautista Bru, George Cuvier used this specimen to describe the species for the very first time.