Sunday, 28 June 2020
CRASPEDITES OF RUSSIA
Saturday, 27 June 2020
AMMONITES OF THE VOLGA REGION
The Heteromorph, Jaubertites (Audouliceras) renauxianum |
These magnificent Jaubertites (Audouliceras) renauxianum heteromorph ammonites are often composites — built with exceptional artful skill from various partial specimens.
We sometimes see them cut in two symmetrical parts and glued into a matrix then doctored up a bit for sale. The practice is frowned upon both scientifically and commercially but continues as does the demand for these exceptional specimens. This beauty is in the collection of José Juárez Ruiz and is complete with some minor restorations. I love these chunky Jaubertites and particularly appreciate the beautiful oil in water colouring in the nacre.
The second photo here shows a lovely busy block of ammonites with Deshayesites volgensis (Sasonova, 1958), and Aconeceras (Sinzovia) trautscholdi (Sinzow. 1870) from Lower Cretaceous, Aptian, (120 - 112 MYA), deposits in the v. Shilovka, Ulyanovsk Region of Russia. This beauty is in the collections of Emil Black. While Emil has counselled me that there are some fundamental challenges with the interpretation of these faunal groups, I will share what is available from the current literature.
Aptian deposits near the Volga River between Ul'yanovsk and Saratov have been studied for more than a century. The area produces some of the most beautiful and sought after ammonite specimens in the world. I've never had the pleasure of collecting in this region but follow the literature and local collectors with enthusiastic interest. Looking at the specimens from here, I'm sure you can appreciate why.
Deshayesites volgensis & Aconeceras trautscholdi |
But Deshayesitidae are not the only specimens found here. The vast array of heteromorphic ammonites — the Ancyloceratidae, inhabitants of relatively deep basins, has made it possible to propose a new scheme of ammonoid zonation in the lower Aptian epipelagic deposits of the Russian plate.
Many of the identified ancyloceratids were established here for the first time. The analysis of coexisting deshayesitids and heteromorphs enables a correlation of stratigraphic schemes for the monomorphic Deshayesitidae and heteromorphic Ancyloceratidae.
The described generic taxa and species are Volgoceratoides I. Michailova et Baraboshkin, gen. nov., V. schilovkensis I. Michailova et Baraboshkin, sp. nov., Koeneniceras I. Michailova et Baraboshkin, gen. nov., K. tenuiplicatum (von Koenen, 1902), K. rareplicatum I. Michailova et Baraboshkin, sp. nov.
In some sections of the Saratov Volga area, specifically in the central part of the Russian Platform, we find both offshore and nearshore lithofacies of the epicontinental Middle Russian Sea. Here we see simultaneous changes in ammonite and belemnite successions that speak to an environmental shift. The significant influence of anoxic events on faunal turnovers in marine communities is well-established. However, many studies are focused on the impact of anoxic conditions on benthic organisms, not on the hunter-gatherers living higher up in the sea column and food chain. For this reason, coeval changes in pelagic cephalopod assemblages remain relatively poorly studied and marginally understood.
Belemnites, represented by the late members of the family Oxyteuthididae, are common in the interval directly preceding the anoxic event, but totally disappear with the onset of the black shale deposition. We see a reduction in the shell size of the Deshayesites ammonites across the mudstone – black shale boundary (maximum shell diameter of adults reduces from ∼20 cm to 7–8 cm).
Some other ammonites become numerous (Sinzovia) within the black shale interval or show the first occurrence in it (Koeneniceras and Volgoceratoides). The diminishing of Deshayesites shell size during the early Aptian OAE may have been caused by palaeoenvironmental factors such as progressive warming and regional input of brackish water.
The significant influence of anoxic events on faunal turnovers in marine communities is well-established. However, many studies are focused on the impact of anoxic conditions on benthic organisms, not on the hunter-gatherers living higher up in the sea column. This means that coeval changes in pelagic cephalopod assemblages remain relatively poorly understood.
Photo: Jaubertites (Audouliceras) renauxianum (d'Orbigny, 1842) collection of José Juárez Ruiz.
Photo: Deshayesites volgensis (Sasonova, 1958), and Aconeceras (Sinzovia) trautscholdi (Sinzow. 1870) collections of Emil Black. The diameter on the Deshayesites shown here is 70 mm.
Rogov, Mikhail & Shchepetova, Elena & Ippolitov, Alexei & Seltser, Vladimir & Mironenko, Aleksandr & Pokrovsky, Boris & Desai, Bhawanisingh. (2019). Response of cephalopod communities on abrupt environmental changes during the early Aptian OAE1a in the Middle Russian Sea. Cretaceous Research. 10.1016/j.cretres.2019.01.007.
E. Yu. Baraboshkin and I. A. Mikhailova. New Stratigraphic Scheme of the Lower Aptian in the Volga River Middle Courses. Stratigraphy arid Geological Correlation, Vol 10, No 6, 2002, pp 603-626 Translated from Stratigrafiy a Geologicheskaya Korrelyatsiya, Vol 10, No 6, 2002, pp 82-105
Friday, 26 June 2020
HETTANGIAN: TETHYAN AFFINITY
Thursday, 25 June 2020
EXPLORING THE GSC COLLECTIONS
Wednesday, 24 June 2020
NORTH AMERICAN MIDDLE TRIASSIC AMMONOIDS
Tuesday, 23 June 2020
NAPPING KOALA
Monday, 22 June 2020
POKEY TACHYCLOSSIDAE
Echidnas are sometimes called spiny anteaters and belong in the family Tachyglossidae (Gill, 1872). They are monotremes, an order of egg-laying mammals.
There are four species of echidnas living today. They, along with the platypus, are the only living mammals who lay eggs and the only surviving members of the order Monotremata.
Superficially, they resemble the anteaters of South America and other spiny mammals like porcupines and adorable hedgehogs. They are usually a mix of brown, black and cream in colour. While rare, there have been several reported cases of albino echidnas, their eyes pink and their spines white. Echidnas have long, slender snouts that act as both nose and mouth for these cuties. The Giant Echidna we see in the fossil record had beaks more than double this size.
Like the platypus, they are equipped with electro sensors, but while the platypus has 40,000 electroreceptors on its bill, the long-beaked echidna has only 2,000. The short-beaked echidna, which lives in a drier environment, has no more than 400 at the tip of its snout.
Echidnas evolved between 20 and 50 million years ago, descending from a platypus-like monotreme. Their ancestors were aquatic, but echidnas have adapted to life on land. Today, they weigh in at about 7 kg today but back in the Pleistocene, they were much larger. The Giant Echnida, Megalibwilia ramsayi was about 10% larger at 10 kg and Zaglossus hacketti was a whopping 30 kg.
Fossil remains are relatively rare and sadly, incomplete, but they tell us potentially two other species of Echidna thriving in the Pleistocene. We also find Robust Echidna, Zaglossus robustus, in slightly older Miocene aged outcrops in a goldmine in Australia. The Giant Echnida's we find in the fossil record are relatives of the Long-Beaked Echidnas who live in New Guinea today.
Sunday, 21 June 2020
INUKSUK: STONE SENTINELS
These rocky sentinels stand as helpful reference markers for navigation.
Translated from Inuktitut, the word inuksuk means that which acts in the capacity of a human, combining inuk or person and suk, to substitute.
Saturday, 20 June 2020
KEUPPIA: UNCOVERING OCTOBRACHIA
Wednesday, 17 June 2020
FOSSIL PEARLS
A simple search will show you a vast array of pearls being used for their ornamental value in cultures from all over the world. I suppose the best answer to why they are appealing is just that they are.
If you make your way to Paris, France and happen to visit the Louvre's Persian Gallery, do take a boo at one of the oldest pearl necklaces in existence — the Susa necklace. It hails from a 2,400-year-old tomb of long lost Syrian Queen. It is a showy piece with three rows of 72 pearls per strand strung upon a bronze wire.
A queen who truly knew how to accessorize.
I imagine her putting the final touches of her outfit together, donning the pearls and making an entrance to wow the elite of ancient Damascus. The workmanship is superb, intermixing pure gold to offset the lustre of the pearls. It is precious and ancient, crafted one to two hundred years before Christ. Perhaps a gift from an Egyptian Pharaoh or from one of the Sumerians, Eblaites, Akkadians, Assyrians, Hittites, Hurrians, Mitanni, Amorites or Babylonian dignitaries who sued for peace but brought war instead.
Questions, good questions, but questions without answers. So, what can we say of pearls? We do know what they are and it is not glamorous. Pearls form in shelled molluscs when a wee bit of sand or some other irritant gets trapped inside the shell, injuring the flesh. As a defensive and self-healing tactic, the mollusc wraps it in layer upon layer of mother-of-pearl — that glorious shiny nacre that forms pearls.
They come in all shapes and sizes from minute to a massive 32 kilograms or 70 pounds. While a wide variety of our mollusc friends respond to injury or irritation by coating the offending intruder with nacre, there are only a few who make the truly gem-y pearls. These are the marine pearl oysters, Pteriidae and a few freshwater mussels. Aside from Pteriidae and freshwater mussels, we sometimes find less gem-y pearls inside conchs, scallops, clams, abalone, giant clams and large marine gastropods.
Pearls are made up mostly of the carbonate mineral aragonite, a polymorphous mineral — same chemical formula but different crystal structure — to calcite and vaterite, sometimes called mu-calcium carbonate. These polymorphous carbonates are a bit like Mexican food where it is the same ingredients mixed in different ways. Visually, they are easy to tell apart — vaterite has a hexagonal crystal system, calcite is trigonal and aragonite is orthorhombic.
As pearls fossilize, the aragonite usually gets replaced by calcite, though sometimes by vaterite or another mineral. When we are very lucky, that aragonite is preserved with its nacreous lustre — that shimmery mother-of-pearl we know and love.
Molluscs have likely been making pearls since they first evolved 530 million years ago. The oldest known fossil pearls found to date, however, are 230-210 million years old.
This was the time when our world's landmass was concentrated into the C-shaped supercontinent of Pangaea and the first dinosaurs were calling it home. In the giant ancient ocean of Panthalassa, ecosystems were recovering from the high carbon dioxide levels that fueled the Permian extinction. Death begets life. With 95% of marine life wiped out, new species evolved to fill each niche.
While this is where we found the oldest pearl on record, I suspect we will one day find one much older and hopefully with its lovely great-great grandmother-of-pearl intact.
Monday, 15 June 2020
IS THAT YOU, MAMMA?
When this little fellow grows up, he'll dine on fish, birds (including his penguin pals), squid and krill. Krill are small crustaceans of the order Euphausiacea that look like tiny shrimp. They look similar and are both crustaceans but shrimp hail from the suborder Natantia, order Decapoda and their hearts are located in their heads. I know, right?
Sunday, 14 June 2020
PUFFIN ENJOYING A SNICK
These are pelagic seabirds that feed primarily by diving in the water. They breed in large colonies on coastal cliffs or offshore islands, nesting in crevices among rocks or in burrows in the soil. Two species, the tufted puffin and horned puffin are found in the North Pacific Ocean, while the Atlantic puffin is found in the North Atlantic Ocean. This lovely fellow, with his distinctive colouring, is an Atlantic Puffin or "Sea Parrot" from Skomer Island near Pembrokeshire in the southwest of Wales. Wales is bordered by Camarthenshire to the east and Ceredigion to the northeast with the sea bordering everything else. It is a fine place to do some birding if it's seabirds you're after.
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.
The oldest alcid fossil is Hydrotherikornis from Oregon dating to the Late Eocene while fossils of Aethia and Uria go back to the Late Miocene. Molecular clocks have been used to suggest an origin in the Pacific in the Paleocene. Fossils from North Carolina were originally thought to have been of two Fratercula species but were later reassigned to one Fratercula, the tufted puffin, and a Cerorhinca species. Another extinct species, Dow's puffin, Fratercula dowi, was found on the Channel Islands of California until the Late Pleistocene or early Holocene.
The Fraterculini are thought to have originated in the Pacific primarily because of their greater diversity there; there is only one extant species in the Atlantic, compared to two in the Pacific. The Fraterculini fossil record in the Pacific extends at least as far back as the middle Miocene, with three fossil species of Cerorhinca, and material tentatively referred to that genus, in the middle Miocene to late Pliocene of southern California and northern Mexico.
Although there no records from the Miocene in the Atlantic, a re-examination of the North Carolina material indicated that the diversity of puffins in the early Pliocene was as great in the Atlantic as it is in the Pacific today. This diversity was achieved through influxes of puffins from the Pacific; the later loss of species was due to major oceanographic changes in the late Pliocene due to closure of the Panamanian Seaway and the onset of severe glacial cycles in the North Atlantic.
Friday, 12 June 2020
OLENELLUS OF THE EAGER FORMATION
Olenellus are a genus of trilobites — extinct arthropods — common in but restricted to Early Cambrian rocks some 542 million to 521 million years old and thus a useful guide fossil for the Early Cambrian. Olenellus had a well-developed head, large and crescentic eyes, and a poorly developed, small tail. The fellow you see had a bit of his tail crushed as he turned to stone.
This specimen of Olenellus 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.
Thursday, 11 June 2020
PORTUNOID CRAB
Tuesday, 9 June 2020
THE ELEPHANT BIRDS OF MADAGASCAR
Aepyornis skeleton, Monnier, 1913 |
Riding the movements of the Earth's crust, Madagascar, along with India, first split from Africa and South America and then from Australia and Antarctica, and started heading north. India eventually smashed into Asia — forming the Himalayas in the process — but Madagascar broke away from India and was marooned in the Indian Ocean. Madagascar has been on its own for the past 88 million years.
Elephant birds are members of the extinct ratite family Aepyornithidae, made up of large to enormous flightless birds that once lived on the island of Madagascar. A ratite is any of a diverse group of flightless and mostly large and long-legged birds of the infraclass Palaeognathae.
Elephant birds became extinct, around 1000–1200 CE, as a result of human hunting. Elephant birds comprised the genera Mullerornis, Vorombe and Aepyornis. While they were in close geographical proximity to the ostrich, their closest living relatives are the much smaller nocturnal Kiwi — found only in New Zealand — suggesting that ratites did not diversify by vicariance during the breakup of Gondwana but instead evolved from ancestors that dispersed more recently by flying.
Elephant birds were endemic to Madagascar. Phylogenetic, genetic, and fossil evidence all suggest that the elephant bird, along with the ostrich, arrived in Madagascar and India when these landmasses were still connected to Australia and Antarctica via a land bridge.
When India and Madagascar split, the elephant bird wound up surviving on Madagascar, while the ostrich was carried north with India and was eventually introduced to Eurasia when India collided with the continent. The presence of the elephant bird on Madagascar can be chalked up to vicariance; it was living on Madagascar land already when Madagascar broke off from India. Most of the species on Madagascar today seem to be descended from individuals that dispersed from Africa long after Madagascar was established as a separate island.
Photo: Aepyornis skeleton. Quaternary of Madagascar by Monnier, 1913 by Monnier - http://digimorph.org/specimens/Aepyornis_maximus/Aepyornis.phtml digimorph.org, Public Domain, https://commons.wikimedia.org/w/index.php?curid=79655
Image: Size of Aepyornis maximus (centre, in purple) compared to a human, an ostrich (second from right, in maroon), and some non-avian theropod dinosaurs. Grid spacings are 1.0 m by Matt Martyniuk.
Cooper, A., Lalueza-Fox, C., Anderson, S., Rambaut, A., Austin, J., and Ward, R. (2001). Complete mitochondrial genome sequences of two extinct moas clarify ratite evolution. Nature 409:704-707.
Goodman, S. M., and Benstead, J. P. (2005). Updated estimates of biotic diversity and endemism for Madagascar. Oryx 39(1):73-77.
Evolution Berkeley: https://evolution.berkeley.edu/evolibrary/news/091001_madagascar
Vences, M., Wollenberg, K. C., Vieites, D. R., and Lees, D. C. (2009). Madagascar as a model region of species diversification. Trends in Ecology and Evolution 24(8):456-465.
Monday, 8 June 2020
URSUS CURIOUS: TLA'YI
The animals are known for their ability to spray a liquid with a strong, unpleasant smell. Generally, the aroma from a skunk is enough of a deterrent to keep curiosity at bay. Not in this case.
Bear cubs are known for being playful and altogether too curious. Born in January, they usually stick pretty close to Mamma for the first two years of their lives but sometimes an intriguing opportunity for discovery will cross their path and entice them to slip away just for a few minutes to check it out. Yearlings are usually quite skittish, spending their time hidden up in trees. By the end of the summer, they grow into confident little bears. The karma gods were good to this wee one. Nobody was skunked in this quest for exploration, though not for lack of trying.
Sunday, 7 June 2020
ELEPHANT SHREW
These small, quadrupedal, insectivorous mammals strongly resemble rodents or opossums with their scaly tails, elongated snouts, and rather longish legs.
They live in the desert and temperate grasslands of southern Africa. The Elephant shrew is considered "Living Fossils" as their distinctive morphology has not changed all that much in the past 30 million years. They ought to have been named Elephant Bunny shrew. They move through the world like wee baby elephant-bunnies, snuffling on all fours and hopping about looking for tasty snacks. They have a preference for seeds, fruit, termites and berries. They know how to live well, taking a siesta each afternoon when the sun gets high in the sky.
Thursday, 4 June 2020
BASILEMYS FORELIMB
Basilemys is an extinct genus of early terrestrial or land turtles belonging to the family Nanhsiungchelyideae. They had a carapace similar in shape to aquatic turtles but limps and beak closer to terrestrial herbivores.
Today, these lovelies live in the Hell Creek floodplains munching on bits of grass and swamp plants. They are ectotherms, cold-blooded, reptiles and amniotes — they breathed air and did not lay eggs underwater but came to shore similar to modern turtles. They are known from Cretaceous deposits in North America and Asia. We've got some lovely examples from the Horseshoe Canyon Formation in Alberta and the Sustut Basin in northern British Columbia. Fossil remains of Basilemys have also been found in Saskatchewan, China, Kazakhstan, Mexico, Mongolia, the United States in California, Colorado, Montana, New Mexico, North Dakota, South Dakota, Texas, Utah, Wyoming and Uzbekistan from 144 collections and 152 occurrences. Photo credit: Joe Sertich
Wednesday, 3 June 2020
BASILEMYS: FRESHWATER TURTLE
You'll recall we've found Basilemys in the Sustut Basin of northern British Columbia. These two finds allow us to make some correlations on what was happening during the Upper Cretaceous in BC and Alberta.
The species Mallon and Brinkman wrote up is intermediate in age between the Campanian forms B. variolosa and B. gaffneyi and the upper Maastrichtian forms B. sinuosa and B. praeclara. It is also intermediate in its morphology, possessing a unique suite of both plesiomorphic — divided extragulars — and derived, square epiplastral beak, pygal wider than long, traits.
The Horseshoe Canyon specimen also boasts an autapomorphic square cervical scale. Phylogenetic analysis assuming parsimony recovers B. morrinensis in a polytomy with B. variolosa and B. gaffneyi, outside the clade formed by the upper Maastrichtian forms B. sinuosa and B. praeclara. The holotype of Basilemys morrinensis provides the first evidence that this genus reached a fairly large size, sometimes over a meter in length in the Horseshoe Canyon Formation, so not as small as previously thought based on less complete shell material.
Although Basilemys is usually regarded as terrestrial based on its skull and limb morphology, this specimen has a shell with a low profile — a derived hydrodynamic feature usually indicative of an aquatic mode of life.
The Horseshoe Canyon specimen was found with well-preserved fossils of Equisetum or horsetail. The Basilemys from Sustut was also found in association with plant fossils. So, aquatic, yes. But swampy freshwater aquatic. Or perhaps wet woods and the peripheries of water bodies — lakes, rivers, ponds. We know horsetails prefer a moist location and it appears our dear Basilymys did also.
Image One: Basilemys morrinensis, CMN 57059, shell, in A, dorsal, B, ventral, C, right lateral, and D, anterior views. Photo: Donald B. Brinkman
Image Two: Depositional context of CMN 57059. Segmented stalks of Equisetum cf. E. perlaevigatum (marked by arrowheads) found associated with shell. B, CMN 57059 as it was originally uncovered in the field (CMN negative #61554). Scale bar equals 8 cm (A). Photo: Donald B. Brinkman
Mallon, J. C., and D. B. Brinkman. 2018. Basilemys morrinensis, a new species of nanhsiungchelyid turtle from the Horseshoe Canyon Formation (Upper Cretaceous) of Alberta, Canada. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1431922.