Mary Anning, ‘the greatest fossilist the world ever knew’.

Duria Antiquior famous watercolor by the geologist Henry de la Beche based on fossils found by Mary Anning. From Wikimedia Commons.

By the 19th century, the study of the Earth became central to the economic and cultural life of Great Britain. Women were free to take part in collecting fossils and mineral specimens, and they were allowed to attend lectures but they were barred from membership in scientific societies. England was ruled by an elite, and of course, these scholarly activities only occurred within the upper echelon of British society. Notwithstanding, the most famous fossilist of the 19th century was a women of a low social station: Mary Anning.

Mary Anning was born on Lyme Regis on May 21, 1799. Her father was a carpenter and an amateur fossil collector who died when Mary was eleven. He trained Mary and her brother Joseph in how to look and clean fossils. After the death of her father, Mary and Joseph used those skills to search fossils that they sold as “curiosities”. The source of those fossils was the coastal cliffs around Lyme Regis, part of a geological formation known as the Blue Lias.

The shore of Lyme Bay where Mary Anning did most of her collecting.

Invertebrate fossils, like ammonoids or belemnites, were the most common findings. But when Mary was 12, her brother Joseph found a skull protruding from a cliff and few month later, Mary found the rest of the skeleton. They sold it for £23. Later, in 1819, the skeleton was purchased by Charles Koenig of the British Museum of London who suggested the name “Ichthyosaur” for the fossil.

In 1819 the Annings were in considerable financial difficulties. They were rescued by the generosity of Thomas James Birch (1768–1829), who arranged for the sale of his personal collection, largely purchased from the Annings, in Bullock’s Museum in London.  The auction took place in May 1820, during which George Cuvier bought several pieces for the Muséum National d’Histoire Naturelle.

Mary Anning’s sketch of belemnites. From original manuscripts held at the Natural History Museum, London. © The Natural History Museum, London

On December 10, 1823, she discovered the first complete Plesiosaur skeleton at Lyme Regis in Dorset. The fossil was acquired by the Duke of Buckingham. Noticed about the discovery, George Cuvier wrote to William Conybeare suggesting that the find was a fake produced by combining fossil bones from different animals. William Buckland and Conybeare sent a letter to Cuvier including anatomical details, an engraving of the specimen and a sketch made by Mary Morland (Buckland’s wife) based on Mary Anning’s own drawings and they convinced Cuvier that this specimen was a genuine find. From that moment, Cuvier treated Mary Anning as a legitimate and respectable fossil collector and cited her name in his publications.

Autograph letter about the discovery of plesiosaurus, by Mary Anning. From original manuscripts held at the Natural History Museum, London. © The Natural History Museum, London

By the age of 27, Mary was the owner of a little shop: Anning’s Fossil Depot. Many scientist and fossil collectors from around the globe went to Mary´s shop. She was friend of Henry De la Beche, the first director of the Geological Survey of Great Britain, who knew Mary since they were both children and lived in Lyme Regis. De la Beche was a great supporter of Mary’s work. She also corresponded with Charles Lyell, William Buckland and Mary Morland, Adam Sedgwick and Sir Roderick Murchison.
It’s fairly to say that Mary felt secure in the world of men, and a despite her religious beliefs, she was an early feminist. In an essay in her notebook, titled Woman!, Mary writes:  “And what is a woman? Was she not made of the same flesh and blood as lordly Man? Yes, and was destined doubtless, to become his friend, his helpmate on his pilgrimage but surely not his slave…”

A) Mary Anning (1799- 1847) B) William Buckland (1784- 1856)

On December of 1828, Mary found the first pterosaur skeleton outside Germany. William Buckland made the announcement of Mary’s discovery in the Geological Society of London and named Pterodactylus macronyx in allusion to its large claws. The skull of Anning’s specimen had not been discovered, but Buckland thought that the fragment of jaw in the collection of the Philpot sisters of Lyme belonged to a pterosaur.
In 1829,  Mary Anning discovered Squaloraja polyspondyle, a fish. Unfortunately, the specimen was lost in the destruction of the Bristol Museum by a German bombing raid in November, 1940.
From her correspondence is clear that Mary learned anatomy by dissecting modern organisms. In a letter to J.S. Miller of the Bristol Museum, dated 20 January 1830, she wrote: “…I have dissected a Ray since I received your letter, and I do not think it the same genus, the Vertebrae alone would constitute it a different genus being so unlike any fish vertebrae they are so closely anchylosed that they look like one bone but being dislocated at two places show that each thin line is a separate vertebrae with the ends flat…”. 

Sketch of Mary Anning by Henry De la Beche.

Mary Anning, ‘the greatest fossilist the world ever knew’, died of breast cancer on 9 March, 1847, at the age of 47. She was buried in the cemetery of St. Michaels. In the last decade of her life, Mary received  three accolades. The first was an annuity of £25, in return for her many contributions to the science of geology. The second was in 1846, when the geologists of the Geological Society of London organized a further subscription for her. The third accolade was her election, in July 1846, as the first Honorary Member of the new Dorset County Museum in Dorchester.

After her death, Henry de la Beche, Director of the Geological Survey and President of the Geological Society of London, wrote a very affectionate obituary published in the Quarterly Journal of the Geological Society on February 14, 1848, the only case of a non Fellow who received that honour.

Mary Anning’s Window, St. Michael’s Church. From Wikimedia Commons.

In February 1850 Mary was honoured by the unveiling of a new window in the parish church at Lyme, funded through another subscription among the Fellows of the Geological Society of London, with the following inscription: “This window is sacred to the memory of Mary Anning of this parish, who died 9 March AD 1847 and is erected by the vicar and some members of the Geological Society of London in commemoration of her usefulness in furthering the science of geology, as also of her benevolence of heart and integrity of life.”

In 1865, Charles Dickens wrote an article about Mary Anning’s life in his literary magazine “All the Year Round”, where emphasised the difficulties she had overcome: “Her history shows what humble people may do, if they have just purpose and courage enough, toward promoting the cause of science. The inscription under her memorial window commemorates “her usefulness in furthering the science of geology” (it was not a science when she began to discover, and so helped to make it one), “and also her benevolence of heart and integrity of life.” The carpenter’s daughter has won a name for herself, and has deserved to win it.”

References:

Buckland, Adelene: Novel Science : Fiction and the Invention of Nineteenth-Century Geology, University of Chicago Press, 2013.

BUREK, C. V. & HIGGS, B. (eds) The Role of Women in the History of Geology. Geological Society, London, Special Publications, 281, 1–8. DOI: 10.1144/SP281.1.

Davis, Larry E. (2012) “Mary Anning: Princess of Palaeontology and Geological Lioness,”The Compass: Earth Science Journal of Sigma Gamma Epsilon: Vol. 84: Iss. 1, Article 8.

Hugh Torrens, Mary Anning (1799-1847) of Lyme; ‘The Greatest Fossilist the World Ever Knew’, The British Journal for the History of Science Vol. 28, No. 3 (Sep., 1995), pp. 257-284. Published by: Cambridge University Press.

De la Beche, H., 1848a. Obituary notices. Quarterly Journal of the Geological Society of London, v. 4: xxiv–xxv.

Dickens, C., 1865. Mary Anning, the fossil finder. All the Year Round, 13 (Feb 11): 60–63.

 

 

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Lessons from the past: Paleobotany and Climate Change

 

From 1984–2012, extensive greening has occurred in the tundra of Western Alaska, the northern coast of Canada, and the tundra of Quebec and Labrador. Credits: NASA’s Goddard Space Flight Center/Cindy Starr.

For the last 540 million years, Earth’s climate has oscillated between three basic states: Icehouse, Greenhouse (subdivided into Cool and Warm states), and Hothouse. The “Hothouse” condition is relatively short-lived and is consequence from the release of anomalously large inputs of CO2 into the atmosphere during the formation of Large Igneous Provinces (LIPs), when atmospheric CO2 concentrations may rise above 16 times (4,800 ppmv), while the “Icehouse” is characterized by polar ice, with alternating glacial–interglacial episodes in response to orbital forcing. The ‘Cool Greenhouse” displays  some polar ice and alpine glaciers,  with global average temperatures between 21° and 24°C. Finally, the ‘Warm Greenhouse’ lacks of any polar ice, and global average temperatures might have ranged from 24° to 30°C.

Reconstructions of Earth’s history have considerably improved our knowledge of episodes of rapid emissions of greenhouse gases and abrupt warming. Several episodes of global climate change were similar in magnitude to the anthropogenically forced climate change that has occurred during the past century. Consequently, the development of different proxy measures of paleoenvironmental parameters has received growing attention in recent years. Paleobotany, the study of fossil plants in deep geological time, offers key insights into vegetation responses to past global change, including suitable analogs for Earth’s climatic future.

Monthly average atmospheric carbon dioxide concentration at Mauna Loa Observatory, Hawaii.

The main forces of climatic change on a global scale are solar forcing, atmospheric composition, plate tectonics, Earth’s biota, and of course, us. Human activity is a major driver of the dynamics of Earth system. Until the Industrial Revolution, the average global CO2 levels fluctuated between about 170 ppm and 280 ppm. But with the beginning of the Industrial Era, that number risen above 300 ppm, currently averaging an increase of more than 2 ppm per year. The average monthly level of CO2 in the atmosphere on last April exceeded the 410 ppm for first time in history. Thus we could hit an average of 500 ppm within the next 45 years, a number that have been unprecedented for the past 50–100+ million years according to fossil plant-based CO2 estimates. Therefore, the closest analog for today conditions is the Eocene, meaning greater similarities in continental configuration, ecosystem structure and function, and global carbon cycling.

Some of the best-studied intervals of global change in the fossil plant record include the Triassic–Jurassic boundary, 201.36 ± 0.17 Mya; the PETM, 56 Mya; and the Eocene–Oligocene boundary, 33.9 Mya.The first two events represent rapid greenhouse gas–induced global warming episodes; the last coincides with the initiation of the Antarctic ice sheet and global cooling leading to our current icehouse.

Time line of plant evolution (From McElwain, 2018)

During the PETM, compositional shifts in terrestrial vegetation were marked but transient in temperate latitudes and long-lived in the tropics. The PETM is characterized by the release of 5 billion tons of CO2 into the atmosphere, while temperatures increased by 5 – 8°C. High temperatures and likely increased aridity in the North American temperate biomes resulted in geologically rapid compositional changes as local mixed deciduous and evergreen forest taxa (such as Taxodium) decreased in relative abundance. These suggest that global warming has a marked effect on the composition of terrestrial plant communities that is driven predominantly by migration rather than extinction. However, it’s difficult to draw parallels with Anthropocene warming and vegetation responses because they are occurring at a minimum of 20 times faster than any past warming episode in Earth’s history.

In the early Eocene (56 to 49 Mya), a time of peak sustained global warmth, the Arctic Ocean was ice free, with a mosaic of mixed deciduous, evergreen (Picea, Pinus), and swamp forests, and with high densities of the aquatic fern Azolla. The Azolla bloom reduced the carbon dioxide from the atmosphere to 650 ppm, reducing temperatures and setting the stage for our current icehouse Earth. The eventual demise of Azolla in the Arctic Ocean is attributed to reduced runoff and a slight salinity increase.

The modern fern Azolla filiculoides (From Wikipedia)

The Earth’s poles have warmed and will continue to warm at a faster rate than the average planetary warming, because the heat is readily transported poleward by oceans and the atmosphere due to positive feedback effects involving snow cover, albedo, vegetation, soot, and algal cover in the Arctic and Antarctic. This phenomenon is known as “polar amplification”.

Recent studies about the greening of the Arctic indicates that increasing shrubiness has likely already had an unexpected negative impact on herbivore populations, such as caribou, by decreasing browse quality. Thus, it is important to predict how short-term temporal trends in Arctic vegetation change will continue under CO2-induced global warming. The paleobotanical record of high Arctic floras may provide broad insight into these questions.

References:

Jennifer C. McElwain, Paleobotany and Global Change: Important Lessons for Species to Biomes from Vegetation Responses to Past Global Change, Annual Review of Plant Biology  (2018), DOI: 10.1146/annurev-arplant-042817-040405

 

Ichthyornis and the evolution of the avian skull.

 

Ichthyornis skull

Birds originated from a theropod lineage more than 150 million years ago. By the Early Cretaceous, they diversified, evolving into a number of groups of varying anatomy and ecology. Much of birds anatomical variety is related to their skulls and in particulary with their beaks.

Discovered in 1870 by Benjamin Franklin Mudge, a professor from Kansas State Agricultural College and good friend of Othniel Charles Marsh, Ichthyornis, which means‭ ‘‬fish bird‭’‭, was a small early ornithuromorph from the Late Cretaceous of North America. Ornithuromorphs, include Gansus, Patagopteryx, Yixianornis, and Apsaravis, which form a grade on the line to Ornithurae, a derived subgroup that includes modern birds and their closest fossil relatives.

 

3D reconstruction of the skull of I. dispar (From Field et al., 2018)

The skull of I. dispar shows a transitional point in the evolutionary history of birds. The upper margin of the beak is concave in profile, a derived condition shared with living birds. The fused, toothless premaxillae have a terminal hook, and occupy the anterior quarter of the rostrum. Neurovascular foramina indicate the presence of a highly keratinized region of rhamphotheca called the premaxillary nail. The maxilla is plesiomorphically long. The dentition is extensive in both upper and lower jaws. A sulcus on the rostral half of the maxilla suggests a broad naso-maxillary contact and a correspondingly broad postnarial bar. The palatine is narrow and elongate, unlike that of Archaeopteryx and more stemward theropods. The quadrate exhibits two rounded capitular condyles that fit into cotyles on the prootic and squamosal bones to form a mobile joint with the cranium. The arrangement of the rostrum, jugal, and quadratojugal, the mobile suspensorium and the narrow, linear palatine all indicate that I. dispar possessed a fully functional avian cranial kinetic system.

The endocranial cavity appears essentially modern in sagittal section. The forebrain was enlarged and posteroventrally rotated while the optic lobes were inflated and laterally shifted, as in living birds. The squamosal exhibits an archaic, deinonychosaur-like morphology. The zygomatic process is deep and triangular in lateral view. The nuchal crest extends from the midline of the skull onto the zygomatic process, forming the upper edge of the squamosal bone, as in non-avialan theropods.

Darwin’s letter to Marsh (Yale Peabody Museum Archives)

Since its discovery, Ichthyornis has been viewed as a classical example of evolution, due to the combination of an advanced postcranial morphology and retention of toothed jaws. In a letter, dated August 31, 1880, Charles Darwin thanks Marsh for a copy of his monograph Odontornithes, which reported two contrasting bird genera: Hesperornis, which was about 1.8 metres tall, and Ichthyornis, which had an average wingspan of about 60 centimetres. In his letter, Darwin wrote: “I received some time ago your very kind note of July 28th, & yesterday the magnificent volume. I have looked with renewed admiration at the plates, & will soon read the text. Your work on these old birds & on the many fossil animals of N. America has afforded the best support to the theory of evolution, which has appeared within the last 20 years.”

 

References:

Daniel J. Field, Michael Hanson, David Burnham, Laura E. Wilson, Kristopher Super, Dana Ehret, Jun A. Ebersole & Bhart-Anjan S. Bhullar, Complete Ichthyornis skull illuminates mosaic assembly of the avian head, Nature (2018). nature.com/articles/doi:10.1038/s41586-018-0053-y
Xing Xu, Zhonghe Zhou, Robert Dudley, Susan Mackem, Cheng-Ming Chuong, Gregory M. Erickson, David J. Varricchio, An integrative approach to understanding bird origins, Science, Vol. 346 no. 6215, DOI: 10.1126/science.1253293.