Tilly Edinger and the study of ‘fossil brains’.

 

Tilly Edinger (Photo,Museum of Comparative Zoology, Harvard University, Cambridge, MA)

Tilly Edinger (Photo,Museum of Comparative Zoology, Harvard University, Cambridge, MA)

Johanna Gabriele Ottilie “Tilly” Edinger was born on November 13, 1897 in Frankfurt, Germany. She was the youngest daughter of the eminent neurologist Ludwig Edinger and Dora Goldschmidt.

Edinger’s scientific interests led her to university studies in zoology and, later, in geology and paleontology. She studied at Universities of Heidelberg, Frankfurt, and Munich. In 1921, she received her Ph. D at the University of Frankfurt. When she was preparing her doctoral dissertation about the palate of the Mesozoic marine reptile Nothosaurus, Edinger encountered a skull with a natural brain cast. Her early research was mostly descriptive and she was influenced by the work of Louis Dollo and Friedrich von Huene.  After obtained her degree, she worked as a volunteer at the Geological-Paleontological Institute of the University of Frankfurt, and later as the section head in vertebrate paleontology at the Senckenberg Museum.

During her time at the Museum, she gathered references of several endocranial casts  treated as isolated curiosities  in earlier texts. Using stratigraphy and comparative anatomy, she organized them taxonomically and summarized the inferences that could be drawn from them. Later, in 1929,  she published Die fossilen Gehirne (Fossil Brains), the book that established Edinger’s membership in the German and international paleontological communities.

Endocranial cast (left) and brain of the living hellbender Cryptobranchus alleganiensis used by Romer and Edinger (1942) to document the relationship between the endocranial cast and the soft tissue brain in a living amphibian.

Endocranial cast (left) and brain of the living hellbender Cryptobranchus alleganiensis used by Romer and Edinger (1942) to document the relationship between the endocranial cast and the soft tissue brain in a living amphibian.

When the Nazi Party reached the power in 1933, Edinger continued working at the Museum thanks to protective actions of Rudolf Richter, Director of the Senckenberg Museum, but after the events that followed the infamous “Kristallnacht” (Night of the Broken Glass), her paleontological career in Germany ended abruptly.

Thanks to her pioneering works and the contacts she made from a previous trip to London in 1926, Edinger emigrated to England in May 1939. She started working at the British Museum of Natural History, alternately translating texts and working on her own paleoneurological projects.

In 1940, with the support of Alfred S. Romer, she moved to Massachusetts to take a position at the Harvard Museum of Comparative Zoology. Shortly after, she was the first and only woman who attend the founding meeting of the Society of Vertebrate Paleontology (SVP).

Edinger’s series of horse brains, showing differences in size and external anatomy as well as order of stratigraphic occurrence (Edinger, 1948)

Edinger’s series of horse brains, showing differences in size and external anatomy as well as order of stratigraphic occurrence.

Her second seminal work was written in 1948: “Evolution of the Horse Brain”.  Her work suggested that both brain enlargement and superficially similar patterns of cortical sulcation (surficial folds and grooves) had arisen independently in different orders of mammals (Buchholtz, 2001). 

Her knowledge of neuroanatomy allowed her to extend the range of information recoverable from endocasts. Based on the enlarged optic lobes and cerebellum of Rhamphorhynchus specimens, Edinger was able to predict their sensory dominance of sight and the possession of flight capabilities in pterosaurs.

By the early 1950s, she was not only the major contributor to the field of paleoneurology but also the mentor to a younger generation that was following in her footsteps. She received several honorary doctorates for her achievements, including Wellesley College (1950), the University of Giessen (1957), and the University of Frankfurt  (1964). She was elected president of SVP in 1963.

Tilly Edinger and colleagues at the Museum of Comparative Zoology. Sitting left to right: Tilly Edinger, Harry B. Whittington, Ruth Norton, Alfred S. Romer, Nelda Wright, and Richard van Frank. Standing left to right: Arnold D. Lewis, Ernest E.Williams, Bryan Patterson, Stanley J. Olsen, and Donald Baird. (Photo: David Roberts, from Buchholtz, 2001)

Tilly Edinger and colleagues at the Museum of Comparative Zoology. Sitting left to right: Tilly Edinger, Harry B. Whittington, Ruth Norton, Alfred S. Romer, Nelda Wright, and Richard van Frank. Standing left to right: Arnold D. Lewis, Ernest E.Williams, Bryan Patterson, Stanley J. Olsen, and Donald Baird. (Photo: David Roberts, from Buchholtz, 2001)

Tilly Edinger died in 1967 as the result of a traffic accident. She had 69 years old.  Her last book: “Paleoneurology 1804-1966. An annotated bibliography”, was completed by several of her colleagues and is considered the necessary starting point for any project in paleoneurology

References:

Buchholtz, Emily A.; Seyfarth, Ernst-August (August 2001), “The Study of “Fossil Brains”: Tilly Edinger (1897–1967) and the Beginnings of Paleoneurology”, Bioscience 51 (8)
Susan Turner, Cynthia V. Burek and Richard T. J. Moody, Forgotten women in an extinct saurian (man’s) world, Geological Society, London, Special Publications 2010, v. 343, p. 111-153

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Brief history of the Ocean Acidification through time.

Corals one of the most vulnerable creatures in the ocean. Photo Credit: Katharina Fabricius/Australian Institute of Marine Science

Corals one of the most vulnerable creatures in the ocean. Photo Credit: Katharina Fabricius/Australian Institute of Marine Science

At the end of the nineteenth century Svante Arrhenius and Thomas Chamberlain were among the few scientists that explored the relationship between carbon dioxide concentrations in the atmosphere and global warming. About one third of the carbon dioxide released by anthropogenic activity is absorbed by the oceans. But the CO2 uptake lowers the pH and alters the chemical balance of the oceans. This phenomenon is called ocean acidification, and is occurring at a rate faster than at any time in the last 300 million years (Gillings, 2014; Hönisch et al. 2012). Acidification affects the biogeochemical dynamics of calcium carbonate, organic carbon, nitrogen, and phosphorus in the ocean as well as the seawater chemical will directly impact in a wide range of marine organisms that build shells from calcium carbonate, like planktonic coccolithophores and pteropods and other molluscs,  echinoderms, corals, and coralline algae.

The geologic record of ocean acidification provide valuable insights into potential biotic impacts and time scales of recovery.  Rapid additions of carbon dioxide during extreme events in Earth history, including the end-Permian mass extinction (252 million years ago) and the Paleocene-Eocene Thermal Maximum (PETM, 56 million years ago) may have driven surface waters to undersaturation. But, there’s  no perfect analog for our present crisis, because we are living in an “ice house” that started 34 million years ago  with the growth of ice sheets on Antarctica, and this cases corresponded to events initiated during “hot house” (greenhouse) intervals of Earth history.

Coccolithophores exposed to differing levels of acidity. Adapted by Macmillan Publishers Ltd: Nature Publishing Group, Riebesell, U., et al., Nature 407, 2000.

Coccolithophores exposed to differing levels of acidity. Adapted by Macmillan Publishers Ltd: Nature Publishing Group, Riebesell, U., et al., Nature 407, 2000.

The end-Permian extinction is the most severe biotic crisis in the fossil record, with as much as 95% of the marine animal species and a similarly high proportion of terrestrial plants and animals going extinct . This great crisis ocurred about 252 million years ago (Ma) during an episode of global warming. The cause or causes of the Permian extinction remain a mystery but new data indicates that the extinction had a duration of 60,000 years and may be linked to massive volcanic eruptions from the Siberian Traps. The same study found evidence that 10,000 years before the die-off, the ocean experienced a pulse of light carbon that most likely led to a spike of carbon dioxide in the atmosphere. This could have led to ocean acidification, warmer water temperatures that effectively killed marine life.

The early Aptian Oceanic Anoxic Event (120 million years ago) was an interval of dramatic change in climate and ocean circulation. The cause of this event was the eruption of the Ontong Java Plateau in the western Pacific, wich led to a major increase in atmospheric pCO2 and ocean acidification. This event was characterized by the occurrence of organic-carbon-rich sediments on a global basis along with evidence for warming and dramatic change in nanoplankton assemblages. Several oceanic anoxic events (OAEs) are documented in Cretaceous strata in the Canadian Western Interior Sea.

major changes in plankton assembledge

The Paleocene-Eocene Thermal Maximum (PETM; 55.8 million years ago) was a short-lived (~ 200,000 years) global warming event. Temperatures increased by 5-9°C. It was marked by the largest deep-sea mass extinction among calcareous benthic foraminifera in the last 93 million years. Similarly, planktonic foraminifer communities at low and high latitudes show reductions in diversity. The PETM is also associated with dramatic changes among the calcareous plankton,characterized by the appearance of transient nanoplankton taxa of heavily calcified forms of Rhomboaster spp., Discoaster araneus, and D. anartios as well as Coccolithus bownii, a more delicate form

The current rate of the anthropogenic carbon input  is probably greater than during the PETM, causing a more severe decline in ocean pH and saturation state. Also the biotic consequences of the PETM were fairly minor, while the current rate of species extinction is already 100–1000 times higher than would be considered natural. This underlines the urgency for immediate action on global carbon emission reductions.

References:

Kump, L.R., T.J. Bralower, and A. Ridgwell. 2009. Ocean acidification in deep time. Oceanography 22(4):94–107, http://dx.doi.org/10.5670/oceanog.2009.100

Kroeker, K. J. et al. Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming. Glob. Change Biol. 19, 1884–1896 (2013).

Payne JL, Turchyn AV, Paytan A, Depaolo DJ, Lehrmann DJ, Yu M, Wei J, Calcium isotope constraints on the end-Permian mass extinction, Proc Natl Acad Sci U S A. 2010 May 11;107(19):8543-8. doi: 10.1073/pnas.0914065107. Epub 2010 Apr 26.

Zeebe RE and Zachos JC. 2013 Long-term legacy ofmassive carbon input to the Earth system: Anthropocene versus Eocene. Phil Trans R Soc A 371: 20120006.http://dx.doi.org/10.1098/rsta.2012.0006.

Daniel H. Rothman, Gregory P. Fournier, Katherine L. French, Eric J. Alm, Edward A. Boyle, Changqun Cao, and Roger E. Summons (2014) “Methanogenic burst in the end-Permian carbon cycle,” PNAS doi: 10.1073/pnas.1318106111

Michael R Gillings, Elizabeth L Hagan-Lawson, The cost of living in the Anthropocene,  Earth Perspectives 2014, DOI 10.1186/2194-6434-1-2