Tuesday, 30 November 2021

PALEONTOLOGY LITHOGRAPH

Paleontology — A lovely faded lithograph from A History Of The Earth And Animated Nature By Oliver Gold Smith.

I love the old lithographs. They transport me back in time to the beginnings of the study of the various realms of nature. 

Lithography was invented around 1796 in Germany by an otherwise unknown Bavarian playwright, Alois Senefelder, who accidentally discovered that he could duplicate his scripts by writing them in greasy crayon on slabs of limestone and then printing them with rolled-on ink.

A History of the Earth and Animated Nature was printed in the traditional method used by Senefelder. It is a fascinating work of natural history. It was first published in 1774 in eight volumes, these volumes brought together a history of the earth with a description of its many weird and wonderful species and geographical features. 

Oliver Gold Smith was an Irish novelist, poet and journalist as well as the author of many works on natural history. He is now best known for his 1766 novel, The Vicar of Wakefield., a widely read 18th-century novel sharing the life and woes of Dr. Charles Primrose. Oliver Gold Smith spelt the title of his work, Paleontology, though the British spelling is Palaeontology — hence our Canadian use of the same.

Sunday, 28 November 2021

OSTRACODERMS TO ANGLERFISH

The festive lassie you see here is an Anglerfish. They always look to be celebrating a birthday of some kind, albeit solo. This party is happening deep in our oceans and for those that join in, I hope they like it rough.

The wee candle you see on her forehead is a photophore, a tiny bit of luminous dorsal spine. Many of our sea dwellers have these candle-like bits illuminating the depths. You may have noticed them glowing around the eyes of many of our cephalopod friends. 

These light organs can be a simple grouping of photogenic cells or more complex with light reflectors, lenses, colour filters able to adjust the intensity or angular distribution of the light they produce. Some species have adapted their photophores to avoid being eaten, in others, it's an invitation to lunch.

In anglerfish' world, this swaying light is 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 all the yummy nutrients of his body 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 deepest, darkest part of the ocean isn't empty — its hungry.

The evolution of fish began about 530 million years ago with the first fish lineages belonging 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.

Fish 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 fish. They are homologous structures.

When we speak of early vertebrates, we are often talking about fish. 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. 

Eohiodon Fish, McAbee Fossil Beds
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. 

Canada also boasts 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.

If you're a keen bean to see an anglerfish that recently washed up on the shores of Newport Beach this past May, hit this link: https://www.theguardian.com/us-news/2021/may/11/deep-sea-anglerfish-california-beach-finding-nemo. Kudos for my colleague, Giovanni, bringing this gloriously horrific lovely to my attention. 

Saturday, 27 November 2021

BIOLUMINESCENCE: CHEMICAL POETRY

Light in the oceans? It is chemistry, my friends. 

In the inky blackness of the deep sea, more than 90% of the animals are luminescent. It is quite a startling number but makes good sense when you think of the edge bioluminescence provides. 

The ability to generate light helps umpteen animals find mates, attracts prey and avoid predation. Handy stuff, light. 

What you know about light above the surface does not hold true for the light you see as bioluminescence. Its energy and luminosity come from a chemical reaction. 

In a luminescent reaction, two types of chemicals — luciferin and luciferase — combine together. Together, they produce cold light — light that generates less than 20% thermal radiation or heat. 

The light you see is produced by a compound called Luciferin. It is the shiny, showy bit in this chemical show. Luciferase acts as an enzyme, the substance that acts as a catalyst controlling the rate of chemical reactions, allowing the luciferin to release energy as it is oxidized. The colour of the light depends on the chemical structures of the chemicals. There are more than a dozen known chemical luminescent systems, meaning that bioluminescence evolved independently in different groups of organisms.

Coelenterazine is the type of luciferin we find in shrimp, fish and jellyfish. Dinoflagellates and krill share another class of unique luciferins, while ostracods or firefleas and some fish have a completely different luciferin. 

The luciferase found in dinoflagellates is related to the green chemical chlorophyll found in plants. Bioluminescent dinoflagellates are a type of plankton — teensy marine organisms that make the seaways shimmer like the Milky Way as you swim through them. 

Their twinkling lights are brief, each containing about 100 million photons that shine for a tenth of a second. While each individual flicker is here and gone in the wink of an eye, en masse they are awe-inspiring. I have spent many wondrous evenings scuba diving amongst these glittering denizens off our shores. 

Cotylorhiza Tuberculata Jellyfish
In this close up of a Cotylorhiza Tuberculata Jellyfish, you can see the luminosity of her blue and white tentacles. The occurrence of identical luciferins for different types of organisms may suggest a dietary source for some groups strengthening the adage, you are what you eat, or perhaps you glow how you eat

Bacteria and fireflies have unique luminescent chemistries. Fireflies light up when oxygen combines with calcium, adenosine triphosphate (ATP) and luciferin in the presence of luciferase. 

For bacteria, the world stage of luminosity is quite small — and a bit gormless. Just how much light they emit and when is a free-for-all. Not so for the rest of our bioluminescent friends who have very precise control over when they shine and just how bright. 

Bioluminescence comes in a variety of colours, from blue through red. The colour is based on the chemistry, which involves a substrate molecule called luciferin, the source of energy that goes into light, and an enzyme called luciferase or photoprotein. 

Most of this lighting up of our world happens on land or in saltwater. There are almost no bioluminescent organisms native to freshwater.

In terrestrial plants and animals — fireflies, beetles and fungi like this Ghost Fungus, Omphalotus nidiformis, a gilled basidiomycete mushroom — we commonly find green, yellow, and sometimes red. 

In the ocean, bioluminescence is mostly blue-green or green. You would think that blues and green would not show up all that well in our seas but, surprisingly, they do. While sound travels better through saltwater than air, it is the reverse for light. 

Various colours of light do not transmit equally through saltwater. Once we move deeper than the top layer of the ocean warmed by the sun and brimming with nutrients, the epipelagic zone, and move deeper through the mesopelagic, deeper and deeper still to the bathypelagic, frigid abyssalpelagic and finally the deep trenches of the icy pressure and all but inhospitable hadalpelagic, less and less light — until no light — gets through.

It is the twilight of the mesopelagic, 200 - 1000 metres below the surface, that is the sweet spot for most of our bioluminescent friends. Here, only very faint sunlight gets through. The water pressure is higher than at the surface but still lacks the crushing intensity of the lower zones. It is here that bioluminescence becomes a real advantage — good real estate and the showmanship of light pays gold.

We know that the deeper you go in our oceans, less and less sunlight gets through, so if the purpose of bioluminescence is to provide a signal that is noticed by prey, potential mates and predators alike, it is important that the light moves through the seawater, and not be absorbed or scattered — and this plays out in the colours evolved to be seen here. 

If you have spent any time underwater, you will know that blue-green light transmits best through seawater. The deeper you go, the colours fade. Gone are the reds and yellows until everything looks brown or blue-green. Because of this, it is no surprise that blue-green is the most common colouring of bioluminescence in our oceans. 

There are some exceptions to the blue-green/green colour rule — minuscule planktonic polychaete worms, Tomopteris helgolandica, emit yellow light, and deep-sea fish Malacosteus niger in the family Stomiidae, the barbeled dragonfishes, produce both red and blue. 

Malacosteus niger's unique adaptation of producing red bioluminescence is only found in two other deep-sea dwelling creatures, Aristostomias and Pachystomias

This rare form of bioluminescence can reach up to 700 nm in the deep-sea and cannot be perceived by green and blue bioluminescent organisms — granting M. niger a considerable advantage while hunting at depth.

The red light may function as an invisible searchlight of sorts because most animals in the ocean cannot see red light, while the eyes of M. niger are red-sensitive. It is much easier to find and eat something that cannot see you, particularly if it is lit up like a tasty red holiday snack.

Reference: https://latzlab.ucsd.edu/bioluminescence/

Friday, 26 November 2021

OH, MEDUSA: JELLYFISH. A HALF BILLION YEARS IN THE MAKING

Mesmerizing, delicate and seemingly impossible — this lovely luminescent denizen of the sea has been living in our oceans for more than half a billion years.

Jellyfish are found all over the world, from surface waters to our deepest seas — and they are old. They are some of the oldest animals in the fossil record.

Jellyfish are not fish at all. These gossamer wonders evolved millions of years before true fish.

Jellyfish and sea jellies are the informal common names given to the medusa-phase or adult phase of certain gelatinous members of the subphylum Medusozoa, a major part of the phylum Cnidaria — more closely related to anemones and corals.

The oldest conulariid scyphozoans appeared between 635 and 577 mya in the Neoproterozoic of the Lantian Formation in China. Others are found in the youngest Ediacaran rocks of the Tamengo Formation of Brazil, c. 505 mya, through to the Triassic. Cubozoans and hydrozoans appeared in the Cambrian of the Marjum Formation in Utah, USA, c. 540 mya.

I have seen all sorts of their brethren growing up on the west coast of Canada in tide pools, washed up on the beach and swam amongst thousands of Moon Jellyfish while scuba diving in the Salish Sea. Their pulsating movements are marvellous.  

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, jellyfish are known as ǥaǥisama.

The dreamy blue and purple ǥaǥisama you see here is but one of a large variety of colours and designs. Jellyfish come in bright yellow, orange, clear with pink spots and are often luminescent.


Wednesday, 24 November 2021

TEYLERS OF THE NETHERLANDS

Exceptional fossil starfish Helianthaster preserved in minute detail in pyrite from the Devonian of Bundenbach, Germany.

Helianthaster rhenanus was first described in 1862 by Roemer, based on fossils found in the Bundenbach area in Germany, dating back to the lower Devonian. 

Helianthaster was variously attributed to Asteroidea, Ophiuroidea or to another group (Auluroidea ), but only recently this echinoderm and its close relatives (Helianthasteridae ) have been attributed with some certainty to Asteroidea (Blake, 2009). 

Other very similar starfish were the North Americans Arkonaster (Middle Devonian) and Lepidasterella ( Carboniferousmedium), the latter with 24 arms.

This animal, similar to modern starfish, had a diameter that could exceed 15 centimetres with extended arms. Helianthaster had 14 - 16 arms, elongated and thin, with an aboral surface with granular ossifications. The mouth was wide and composed of rather large oral plates; there were thorns on the adambulacrali, while the central disc was composed of small ossicles.

A study of the type specimen was examined with the use of X- rays. The result was images that seem to confirm the presence of large semicircular muscle flanges along the middle of the arms (Südkamp, ​​2011).

The second image you see here is a specimen from the Teylers Museum in Haarlem, the oldest museum in the Netherlands established in 1778. 

We have a cloth merchant turned banker to thank for both the building and this specimen. And, in a way, the beginnings of nomenclature. Pieter Teyler van der Hulst left us this legacy including many of the museum's specimens and the nest egg that would allow its expansion to the glory we enjoy today. 

Pieter lived next to George Clifford III, the financier of Swedish naturalist Carlo Linnaeus. Pieter's funds aided George in funding Linnaneus' work. In a bit of full circle scientific poetry, it was those dollars and this work that gave us the naming system that allowed us to attach a scientific name to this very specimen through Carl's binomial nomenclature. 

In taxonomy, binomial nomenclature ("two-term naming system"), or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name (which may be shortened to just "binomial"), a binomen, binominal name or a scientific name; more informally it is also historically called a Latin name. So, for this lovely specimen, Helianthaster rhenanus is this specimen's Latin name.

In his will, Pieter Teyler decided that his collection and part of his fortune should be used to create a foundation for their promotion, the Teylers Stichting (Teyler foundation). 

Teyler's legacy to the city of Haarlem was divided into two societies Teylers Eerste Genootschap (Dutch: Teyler's First Society ) or 'Godgeleerd Genootschap' ( Theological Society ), aimed at the study of religion, and the Teylers Tweede Genootschap ( Second Society ), dedicated to physics, poetry, history, drawing and numismatics.

The executors of Teyler's wishes, the first directors of Teylers Stichting, decided to establish a centre for study and education. Books, scientific instruments, drawings, fossils and minerals, would be housed under one roof. 

The concept was based on a revolutionary ideal derived from the Enlightenment: people could discover the world independently, without coercion from the church or the state. The example that guided the founders in creating the Teyler Museum was the Mouseion of classical antiquity: a "temple for the muses of the arts and sciences" which would also be a meeting place for scholars and host various collections.

This was a time when science and religion were still intermixed but beginning to divide into separate camps. The world was at war, expeditions were undertaken to secure new lands and trade routes—and the slave trade was slowly being abolished. In 1778, Russia controlled Alaska and would not sell to the USA, a country two years old in 1778, for another eighty-nine years in 1867.  

Here are some of the world events that happened in 1778, the year this museum was founded to give all of this a bit more context:

  • January 18 – Third voyage of James Cook: Captain James Cook, with ships HMS Resolution and HMS Discovery, first views Oahu then Kauai in the Hawaiian Islands of the Pacific Ocean, which he names the Sandwich Islands.
  • February 5 – South Carolina becomes the first state to ratify the Articles of Confederation. General John Cadwalader shoots and seriously wounds Major General Thomas Conway in a duel after a dispute between the two officers over Conway's continued criticism of General George Washington's leadership of the Continental Army.[1]
  • February 6 – American Revolutionary War – In Paris, the Treaty of Alliance and the Treaty of Amity and Commerce are signed by the United States and France, signalling official French recognition of the new republic.
  • February 23 – American Revolutionary War – Friedrich Wilhelm von Steuben arrives at Valley Forge, Pennsylvania and begins to train the American troops.
  • March 6–October 24 – Captain Cook explores and maps the Pacific Northwest coast of North America, from Cape Foulweather (Oregon) to the Bering Strait.
  • March 10 – American Revolutionary War – George Washington approves the dishonourable discharge of Lieutenant Frederick Gotthold Enslin, for "attempting to commit sodomy, with John Monhort a soldier."
  • July 10 – Louis XVI of France declares war on the Kingdom of Great Britain.
  • July 27 – American Revolutionary War – First Battle of Ushant – British and French fleets fight to a standoff.
  • August 3 – The La Scala Opera House opens in Milan, with the première of Antonio Salieri's Europa riconosciuta.
Many more things happened, of course. Folk were born, fell in love, died—and some left legacies that we still enjoy to this day. 

Photo two by Ghedoghedo, CC BY-SA 4.0.

Tuesday, 23 November 2021

BACK IN THE USSR: KEPPLERITES

This glorious chocolate block contains the creamy grey ammonite Kepplerites gowerianus (Sowerby 1827) with a few invertebrate friends, including two brachiopods: Ivanoviella sp., Zeilleria sp. and the deep brown gastropod Bathrotomaria sp. There is also a wee bit of petrified wood on the backside.

These beauties hail from Jurassic, Lower Callovian outcrops in the Quarry of Kursk Magnetic Anomaly (51.25361,37.66944), Kursk region, Russia. Diameter ammonite 70мм. 

In the mid-1980s, during the expansion and development of one of the quarries, an unusual geological formation was found. This area had been part of the seafloor around an ancient island surrounded by Jurassic Seas. 

The outcrops of this geological formation turned out to be very rich in marine fossil fauna. This ammonite block was found there years ago by the deeply awesome Emil Black. 

In more recent years, the site has been closed to fossil collecting and is in use solely for the processing and extraction of iron ore deposits. Kursk Oblast is one of Russia's major producers of iron ore. The area of the Kursk Magnetic Anomaly has one of the richest iron-ore deposits in the world. Rare Earth minerals and base metals also occur in commercial quantities in several locations. Refractory loam, mineral sands, and chalk are quarried and processed in the region. 

The Kursk Magnetic Anomaly Quarry is not far from the Sekmenevsk Formation or Sekmenevska Svita in Russian, a Cretaceous (Albian to Cenomanian) terrestrial geologic formation where Pterosaur fossils have been found in the sandstones. 

If you head there for a visit, be sure to check out the Sekmenevska Svita and Oblast's artesian-well water — most refreshing!

Monday, 22 November 2021

EUSTHENOPTERON OF MIGUASHA

Eusthenopteron is a genus of prehistoric sarcopterygian (lobe-finned fish) with a close relationship to our dear tetrapods.

The fellow you see here was a fish but with aspirations to be so much more

Eusthenopteron gets his name from the Greek. I cannot think of this genus without picturing the Marvel Universe character Thanos, the genocidal warlord from Titan. While Eusthenopteron were ambitious they were not crazy kill half the Universe ambitious. Instead, they deserve the brouhaha surrounding them because they were the beginnings of an evolutionary push to move from water onto land. 

Their name derives from two Greek stems — eustheno or strength and pteron or wing — thus strongly developed fins. Early depictions of Eusthenopteron show them emerging onto land but this is a bit of fancy. They were strictly aquatic animals. 

Eusthenopteron is known from several species that lived during the Late Devonian, 385 million years ago, and was first described by J. F. Whiteaves in 1881, as part of a large collection of fishes from Miguasha, Quebec. 

While specimens like E. watsoni are very rare, Eusthenopteron fossils are a dime a dozen. More than 2,000 specimens have been collected from the outcrops at Miguasha, one of which was the object of intense study and several papers from the 1940s through to the 1990s by paleoichthyologist Erik Jarvik.

Photo: By Ghedoghedo - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=6683693

Sunday, 21 November 2021

MIGUASHA BOTHRIOLEPIS CANADENSIS

Bothriolepis canadensis
A stunning replica of Bothriolepis canadensis from Upper Devonian (Frasnian), Escuminac formation, Parc de Miguasha, Baie des Chaleurs, Gaspé, Québec, Canada.

Bothriolepis was found and originally described by geologist Abraham Gesner in 1842 as "a tortoise with fossil foot-marks." He was wrong, of course, but these placoderm fish in the order Antiarchi do bear a superficial resemblance to turtles.

For nearly two centuries, the Late Devonian Miguasha biota from eastern Canada has offered up a near-complete brackish water community — 20 species of lower vertebrates — anaspids, osteostra-cans, placoderms, acanthodians, actinopterygians and sarcopterygians — a limited invertebrate assemblage, and terrestrial plants and arthropods — scorpions and millipedes.

Originally interpreted as a freshwater lacustrine environment, recent paleontological, taphonomic, sedimentological and geochemical evidence corroborates a brackish estuarine setting. 

Over 18,000 fish specimens have been recovered from the rock lain down in these brackish waters. They show various modes of fossilization, including uncompressed material and soft-tissue preservation. 

Most vertebrates are known from numerous, complete, articulated specimens. Exceptionally well-preserved larval and juvenile specimens have been identified for fourteen out of the twenty species of fishes, allowing growth studies. 

Numerous horizons within the Escuminac Formation are now interpreted as either Konservat or Konzentrat–Lagerstätten. 

The fine replica above was purchased at the Musée d'Histoire Naturelle, Miguasha (MHNM) and is in the collection of the deeply awesome — and well-travelled — John Fam, Vice-Chair of the Vancouver Paleontological Society.

Great Canadian Lagerstätten 4. The Devonian Miguasha Biota (Québec): UNESCO World Heritage Site and a Time Capsule in the Early History of Vertebrates, Richard Cloutier, Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 allée des Ursulines, Rimouski, QC, Canada, G5L 3A1, richard_cloutier@uqar.ca, http://dx.doi.org/10.12789/geocanj.2013.40.008

Image: Restoration of the upper and underside of B. canadensis. By Unknown author - Popular Science Monthly Volume 82, Public Domain, https://commons.wikimedia.org/w/index.php?curid=20672589

Wednesday, 17 November 2021

UPPER CRETACEOUS TOOTHED BIRDS IN SOUTH AMERICA

70-Million-Year-Old Toothed Enantiornithes Bird Beak
Teeth and jaws, beaks and claws — all species adapt and change over time based on survival. One of the key features of being alive is needing to eat. Depending on what is on the menu, we adapt accordingly. 

I had been thinking about this from a very mammal-centric perspective, but it is true for all animals — birds included.

When we think of our feathered friends, we think of beaks and feathers. True, birds descend from the mighty lineage of dinosaurs, but our experience of them is of their modern forms. 

This modern viewpoint of their characteristics makes beaks with teeth seemingly more fantasy than reality — except this has not always been the case. 70 million years ago, birds flying our Cretaceous skies in what would become South America, Europe and Asia had teeth embedded in their beaks.

The discovery of polyphyodonty and dental replacement in toothed stem birds dates back to the nineteenth century. Marsh reported replacement teeth inside resorption pits in the Late Cretaceous Hesperornis and Ichthyornis.

Enantiornithine Birds & Cladogram
The birds that inhabit the current biomes do not have teeth, but the primitive birds found as fossils in the Upper Cretaceous of Brazil certainly did. 

These ancient relatives to our modern fauna had teeth embedded in their jaw-beaks, clawed fingers and a long tail. 

Both these ancient birds and their modern cousins are descended from the dinosaurs, more specifically the Maniraptora, that clade of coelurosaurian dinosaurs characterized by long arms and three-fingered hands — reduced or fused in some lineages — and semi-lunate or half-moon shaped bone in their wrists you will know as the carpus. 

As with all the dinosaurs in this clad, they had teeth and lots of them.

William Nava, head of the Marília Museum of Paleontology, São Paulo, Brazil, uncovered an outcrop in the city of Presidente Prudente with abundant fossilized bird bones. 

Bird bones are a rare thing as they are delicate, often scavenged before burial and hollow, making them poor candidates for preservation. While bird bones preserved as fossils are generally rare, this was not the case at William's Quarry. The site was a smorgasbord of bones from a number of primitive bird species that lived at the end of the Cretaceous. 

The birds belong to the group of Enantiornithes who looked very much like our modern birds on the outside, but internally they had clawed fingers on each wing and teeth which they replaced in a similar fashion to most reptiles. 

Two other sites have exceptionally preserved Enantiornithes bones. Since most Enantiornithes bones are fragmentary, some species are only known from a piece of a single bone. We are luckier at some sites than others. Almost all complete, fully articulated fossil specimens with soft tissue preserved were known from Las Hoyas in Cuenca, Spain and the Jehol group in Liaoning, China. But the fossil outcrops in the Adamantina Formation, Bauru Group of Brazil can now be added to that very short list.  

If you fancy a read, check out their publication, Dental replacement in Mesozoic birds: evidence from newly discovered Brazilian enantiornithines.” The team included Yun-Hsin Wu and Luis M. Chiappe of the Natural History Museum of Los Angeles County, David J. Bottjer of the University of Southern California, William Nava from the Marília Museum of Paleontology, and Agustín G. Martinelli from the Vertebrate Paleontology Section of the Bernardino Rivadavia Argentine Museum of Natural Sciences.

Publication link: https://www.nature.com/articles/s41598-021-98335-8

Images: Photographs of the enantiornithine specimens MPM-90, MPM-373, and MPM-351, and a simplified cladogram highlighting the stem avian taxa discussed in this study. MPM-373: (a) dorsal view; (b) right lateral view; (c) left lateral view. MPM-90: (d) dorsal view; (e) right lateral view. MPM-351: (f) left lateral view. En external nares, Fp frontal process. With an embedded illustration of a reconstruction of Sinornis santensis by McBlackneck. There is some mice type used so feel free to click the image to see if full size.

The studied specimens consist of two sets of premaxillae (MPM-90 and MPM-373) and an incomplete left dentary (MPM-351) exquisitely preserved in three dimensions. These specimens are housed at the Museu de Paleontologia de Marília (MPM), São Paulo State, Brazil.

Tuesday, 16 November 2021

YOU ARE WHAT YOU EAT... OR CAN DIGEST


The old adage, you are what you eat, might be best amended to you are what you can digest. 

For all the mammals, you and I included, we need the amylase gene (AMY). It codes for a starch-digesting enzyme needed to break down the vegetation we eat. 

Humans, dogs and mice have record numbers of the amylase gene. The AMY gene copy number increases in mammal populations where starch-based foods are more abundant. Think toast and jam versus raw chicken.

A good example of this is seen when we compare wolves living in the wild to dogs from agricultural societies. Dogs split off the lineage from wolves around 30,000–40,000 years ago. 

Domesticated dogs have extra copies of amylase and other genes involved in starch digestion that contribute to an increased ability to thrive on a starch-rich diet, allowing Fido to make the most of those table scraps. Similar to humans, some dog breeds produce amylase in their saliva, a clear marker of a high starch diet. So do mice, rats, and pigs, as expected as they live in concert with humans. Curiously, so do some New World monkeys, boars, deer mice, woodrats, and giant African pouched rats. 

More like cats and less like other omnivores, dogs can only produce bile acid with taurine and they cannot produce vitamin D, which they obtain from animal flesh. Also, more like cats, dogs require arginine to maintain their nitrogen balance. These nutritional requirements place dogs halfway between carnivores and omnivores.

The amount of AMY and starch in the diet varies among subspecies, and sometimes even amongst geographically distinct populations of the same species. I was at a talk recently given by Alaskan wolf researchers who shared that two individual packs of wolves separated by less than a kilometre ate vastly different diets. This had me thinking about what we eat and it is mostly driven by what is on offer. 

Diet impacts our genetics and this, in turn, allows the fittest to eat, digest and survive. While wolves win the carnivore contest, they will still eat opportunistically and that includes vegetation when other food is scarce. Would they evolve similar levels of AMY as humans, dogs and mice? Maybe if their diets evolved to be similar. Likely. The choice would be that or starvation.

The evolution of amylase in other domesticated or human commensal mammals remains an alluring area of inquiry.

Reference: 

Amylase in Dietary Food Preferences in Mammals: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516957/

Monday, 15 November 2021

BLADDER-BEARERS: HOODED SEALS

If you frequent the eastern coast of North America north of Maine to the western tip of Europe, along the coast of Norway near Svalbard you may have glimpsed one of their chubby, dark silver-grey and white residents. 

Hooded seals, Cystophora cristata, are large phocid seals in the family Phocidae, who live in some of the chilliest places on Earth, from 47° to 80° N in latitude. 

These skilled divers are mainly concentrated around Bear Island, Norway, Iceland, and northeast Greenland. 

In rare cases, we find them in the icy waters in Siberia. They usually dive depths of 600 m (1,968 ft) in search of fishy treats but can go as deep as 1000 m (3,280 ft) when needed. That is deep into the cold, dark depths of our oceans. Sunlight entering the sea may travel as deep as 1,000 m (3,280 ft) under the right conditions, but there is rarely any significant light beyond 200 meters (656 ft). This is the dark zone and the place we find our bioluminescent friends. 

Hooded seals have a sparse fossil record. One of the first fossils found was a Pliocene specimen from Anvers, Belgium discovered in 1876. In 1983 a paper was published claiming there were some fossils found in North America thought to be from Cystophora cristata. Of the three accounts, the most creditable discovery was from a sewer excavation in Maine, the northeasternmost U.S. state, known for its rocky coastline, maritime history and nature areas like the granite and spruce islands of Acadia National Park. A scapula and humeri were found among other bones and thought to date to the post-Pleistocene. 

Of two other accounts, one was later reassigned to another species and the other left unsolved. (Folkow, et al., 2008; Kovacs and Lavigne, 1986; Ray, 1983)

The seals are typically silver-grey or white in colour, with black spots that vary in size covering most of the body. 

Hooded seal pups are known as, Blue-backs as their coats are blue-grey on the back with whitish bellies, though this coat is shed after 14 months of age when the pups moult.

FIRST NATION, INUIT, METIS, MI'KMAQ L'NU

In the Kwak̓wala language of the Kwakiutl or Kwakwaka'wakw, speakers of Kwak'wala, of the Pacific Northwest, seal are known as migwat — and fur seals are known as x̱a'wa.

Hooded seals live primarily on drifting pack ice and in deep water in the Arctic Ocean and North Atlantic. Although some drift away to warmer regions during the year their best survival rate is in colder climates. They can be found on four distinct areas with pack ice: near Jan Mayen Island, northeast of Iceland; off Labrador and northeastern Newfoundland; the Gulf of St. Lawrence; and the Davis Strait, off midwestern Greenland. 

The province of Newfoundland and Labrador is home to the Inuit, the Innu, the Mi'kmaq L'nu and the Southern Inuit of NunatuKavut, formerly the Labrador Inuit-Metis. The Hooded Seals that visit their traditional territory were a welcome source of food and clothing. In Mi'kmaw, the language spoken in Mi'kma'ki, the territory of the Mi'kmaq L'nu, the word for seal is waspu.

HOODED SEAL HABITAT

Males are localized around areas of complex seabeds, such as Baffin Bay, Davis Strait, and the Flemish Cap. Females concentrate their habitat efforts primarily on shelf areas, such as the Labrador Shelf. 

Females reach the age of sexual maturity between two and nine years old and it is estimated that most females give birth to their first young at around five years of age. Males reach sexual maturity a little later around four to six years old but often do not mate until much later. Females give birth to one young at a time through March and April. The gestation period is 240 to 250 days. 

Blue-back, Hooded Seal Pup
During this time the fetus, unlike those of other seals, sheds its lanugo — a covering of fine soft hair that is replaced by thicker pelage — in the uterus. 

These young are precocious and at birth are able to move about and swim with ease. They are independent and left to fend for themselves immediately after they have been weaned.

Hooded seals are known to be a highly migratory species that often wander long distances, as far west as Alaska and as far south as the Canary Islands and Guadeloupe. 

Prior to the mid-1990s, hooded seal sightings in Maine and the east Atlantic were rare but began increasing in the mid-1990s. From January 1997 to December 1999, a total of 84 recorded sightings of hooded seals occurred in the Gulf of Maine, one in France and one in Portugal. 

From 1996 to 2006, five strandings and sightings were noted near the Spanish coasts in the Mediterranean Sea. There is no scientific explanation for the increase in sightings and range of the hooded seal.

Cystophora means "bladder-bearer" in Greek and pays homage to this species' inflatable bladder septum on the heads of adult males. The bladder hangs between the eyes and down over the upper lip in a deflated state. 

The hooded seal can inflate a large balloon-like sac from one of its nostrils. This is done by shutting one nostril valve and inflating a membrane, which then protrudes from the other nostril. 

I was thinking of Hooded seals when contemplating the nasal bladders of Prosaurolophus maximum, large-headed duckbill dinosaurs, or hadrosaurid, in the ornithischian family Hadrosauridae. Perhaps both species used these bladders in a similar manner — to warn predators and attract mates.

Hooded seals are known for their uniquely elastic nasal cavity located at the top of their head, also known as the hood. Only males possess this display-worthy nasal sac, which they begin to develop around the age of four. The hood begins to inflate as the seal makes its initial breath prior to going underwater. It then begins to repetitively deflate and inflate as the seal is swimming. 

The purpose of this is acoustic signalling. It occurs when the seal feels threatened and attempt to ward off hostile species when competing for resources such as food and shelter. It also serves to communicate their health and superior status to both other males and females they are attempting to attract. 

In sexually mature males, a pinkish balloon-like nasal membrane comes out of the left nostril to further aid it in attracting a mate. This membrane, when shaken, is able to produce various sounds and calls depending on whether the seal is underwater or on land. Most of these acoustic signals are used in an acoustic situation (about 79%), while about 12% of the signals are used for sexual purposes.

References: Ray, C. 1983. Hooded Seal, Cystophora cristata: Supposed Fossil Records in North America. American Society of Mammalogists, Vol. 64 No. 3: 509-512; Cystophora cristata, Hooded Seal", 2007; "Seal Conservation Society", 2001; Kovacs and Lavigne, 1986.

Mi'kmaq Online Dictionary: https://www.mikmaqonline.org/servlet/dictionaryFrameSet.html?method=showCategory&arg0=animal

Saturday, 13 November 2021

ECHIDNA: MONOTREMES

This little chocolate nugget with his impressive claws is an Echidna. They are curious egg-laying mammals from Australia and Papua New Guinea. 

They have spines like hedgehogs and they are sometimes called spiny anteaters because they feed on ants, termites, earthworms and other burrowing prey with their long, tube-like tiny mouths, toothless jaws and sticky tongue. 

Their spines are golden brown to black for the most part, although a few albino echidnas have been found with pink eyes and white spines. These solitary mammals have mammary glands — and lay eggs.

To help them search for their prey in the soil, Echidnas are equipped with electroreceptors in their beaks which is similar to platypuses and this is not a coincidence. 

Even though echidnas are land animals, they evolved from amphibious ancestors similar to platypuses. They now have strong limbs and claws for digging and just by looking at them, it would be hard to figure out that their ancestors were not fully land animals. 

There is even more to it because mammals evolved from fish that have swim bladders homologous with lungs. They evolved these swim bladders because the ancestors of all fish, except cartilaginous fish, lived either in a shallow aquatic environment, periodically drying lake or swampy water, poor in oxygen. 

Fish evolved into amphibians and conquered land. These amphibious animals evolved the ability to lay eggs in a dry environment and eventually evolved into monotreme mammals which at first were land animals but they adapted to an amphibious lifestyle again, like platypuses. 

Echidnas made another full circle by evolving adaptations to land habitat and abandoned the aquatic habitat again.

Echidnas and platypus are the only egg-laying mammals, known as monotremes. These spiky cuties live about 15-16 years in the wild but have been reported to live as long as 50 years under the right conditions. If you see one in the wild, you can determine the sex by size (of the adults) with males being 25% larger than the females on average. Fully grown a female can weigh up to 4.5 kilograms (9.9 lbs) and a male can weigh up to 6 kilograms (13.2 lbs). 

Friday, 12 November 2021

APATOSAURUS: PLANT-EATING GIANTS

Apatosaurus, one of the largest animals to ever live
Apatosaurus was one of the largest animals to ever live on our planet. Picture this fellow at over 22 metres (75 feet) long and over 22,679 kg (50,000 lbs). 

That's about two-and-a-half times as long as a London bus and two-and-a-half times as heavy as a Tyrannosaurus rex

Given their large size, these big boys did not have to worry about most predators. It would take a posse of large apex predators like the large carnosaurian theropod dinosaur Allosaurus to take down a full-grown Apatosaurus

Their young would be vulnerable and their eggs even more so, but my money would be on the large Apatosaurus defending the smaller members of their family groups against these risks.

This sauropod had a really long neck and whip-like tail and a teeny, tiny head. These massive beasts liked to dine on vegetation and foliage at the tops of the tree canopies.

Othniel Charles Marsh (of Cope & Marsh fame) first described the Apatosaurus in 1877, giving it the name Apatosaurus ajax. There are two recognized species of Apatosaurus, the Apatosaurus ajax (the type species) and Apatosaurus louisae who lived in North America during the Late Jurassic — 152 million years ago.