Forgotten women of Paleontology: Margaret Benson

Margaret Jane Benson. Portrait in the Archives of Royal Holloway, University of London (RHC PH/282/13) From Fraser & Cleal, 2007

It is a truth universally acknowledged, that women has always work harder than men to gain some recognition. It was true in the 16th, and it’s true now. In “A Room of One’s Own”, Virginia Woolf explores the conflicts that a gifted woman must have felt during the Renaissance through the fictional character of Judith Shakespeare, the sister of William Shakespeare, and cites as obstacles the indifference of most of the world, the profusion of distractions, and the heaping up of various forms of discouragement. But not only in the Elizabethan times. In the Victorian times there was the common assumption that the female brain was too fragile to cope with mathematics, or science in general. In a letter from March 1860, Thomas Henry Huxley wrote to great geologist Charles Lyell FRS: “Five-sixths of women will stop in the doll stage of evolution, to be the stronghold of parsonism, the drag on civilisation, the degradation of every important pursuit in which they mix themselves – intrigues in politics and friponnes in science.”

Margaret Crosfield on a Geologists’ Association fieldtrip to Leith Hill with Professor Lapworth (From Burek and Malpas, 2007).

Women have played  various and extensive roles in the history of geology. Unfortunately, their contribution has not been widely recognised by the public or academic researchers. In the 18th and 19th centuries women’s access to science was limited, and science was usually a ‘hobby’ for intelligent wealthy women. Early female scientists were often born into influential families, like Grace Milne, the eldest child of Louis Falconer and sister of the eminent botanist and palaeontologist, Hugh Falconer; or Mary Lyell, the daughter of the geologist Leonard Horner. They collected fossils and mineral specimens, and were allowed to attend scientific lectures, but they were barred from membership in scientific societies. But by the first half of the 20th century, a third of British palaeobotanists working on Carboniferous plants were women. The most notable were  Margaret Benson, Emily Dix, and Marie Stopes.

Newnham began as a house for five students in Regent Street in Cambridge in 1871

Margaret Benson was born on the 20th October 1859 in London. Between 1878 and 1879, she studied at Newnham College Cambridge. After obtaining her BSc at University College London (UCL) in 1891, she started research on plant embryology.  In 1893, Benson was appointed head of the new Department of Botany at Royal Holloway College, the first woman in the United Kingdom to hold such a senior position in the field of botany. Her palaeobotanical research centred on the anatomy of reproductive structures, especially of Carboniferous pteridosperms and lycophytes. In 1904, she was among the first group of women to be elected as Fellows of the Linnean Society, and in 1912 she was appointed Professor of Botany at the University of London. Her major study on lycophyte fructifications was on the cones of the Sigillaria plant. She also speculated on the relationship between the Palaeozoic arborescent lycophytes and the Recent Isoetes, with the Triassic Pleuromeia as a possible intermediate form. She worked with ferns and cordaites and described a new species, Cordaites felicis. Benson’s work is characterized by careful description. One of her most important theoretical works concerns the phylogenetic significance of the sporangiophore in lycophytes, sphenophytes and ferns. After her retirement in 1922, she was encouraged by D. H. Scott to write up some of her earlier unpublished work on the root anatomy of the early Carboniferous pteridosperm Heterangium. She even continued with fieldwork when she was in her 70s. There is an unpublished manuscript in which she described a new fertile Rhacopteris that she collected from Teilia Quarry in North Wales in 1933. She died on 20th June 1936 at Highgate, Middlesex.

References:

H. E. Fraser and C. J. Cleal, The contribution of British women to Carboniferous palaeobotany during the first half of the 20th century, Geological Society, London, Special Publications, 281, 51-82, 1 January 2007, https://doi.org/10.1144/SP281.4

C. V. Burek (2007). The role of women in geological higher education – Bedford College, London (Catherine Raisin) and Newnham College, Cambridge, UK, Geological Society, London, Special Publications, eds Burek C. V., Higgs B. 281, pp 9–38

 

A brief history of the Spinosaurus.

One of the photographs donate by W. Stromer. Image from the Washington University in St. Louis

Despite its low fossil record, Spinosaurus is one of the most famous dinosaur of all time. This gigantic theropod possessed highly derived cranial and vertebral features sufficiently distinct for it to be designated as the nominal genus of the clade Spinosauridae. In 1910, E. Stromer went to his third paleontological expedition to Egypt. He arrived to Alexandria on November 7. He was initially looking for early mammals and planned visit the area of Bahariya, in the Western Desert, which has sediments from the Cretaceous era. But an expedition to the Western Desert needed the permission by the English and French colonial authorities and of course the Egyptian authorities. Although diplomatic relations with Germany were rapidly deteriorating, Stromer managed to get the permissions. He arrived to the Bahariya Oasis on January 11, 1911. After facing some difficulties during the journey, on January 17 he began to explore the area of Gebel el Dist, and at the bottom of the Bahariya Depression, Stromer found  the remains of four immense and entirely new dinosaurs (Aegyptosaurus, Bahariasaurus, Carcharodontosaurus and Spinosaurus aegyptiacus), along with dozens of other unique specimens. Stromer and Markgraf recovered the right and left dentaries and splenials from the lower jaw; a straight piece of the left maxilla that was described but not drawn; 20 teeth; 2 cervical vertebrae; 7 dorsal (trunk) vertebrae; 3 sacral vertebrae; 1 caudal vertebra; 4 thoracic ribs; and gastralia. This gigantic predator is estimated to have been about 14 m, with unusually long spines on its back that probably formed a large, sail-like structure.

1) Photograph of the right mandibular ramus of the holotype of Spinosaurus aegyptiacus Stromer, 1915 (BSP 1912 VIII 19), in lateral view. 2) Reproduction of Stromer’s (1915, pl. I, fig. 12a) illustration of the right mandibular ramus.

Due to political tensions before and after World War I, many of this fossils were damaged after being inspected by colonial authorities and not arrived to Munich until 1922. The shipping from El Cairo was paid by the Swiss paleontologist Bernhard Peyer (1885-1963), a former student and friend of Stromer. During the World War II, E. Stromer tried to convince Karl Beurlen -a young nazi paleontologist who was in charge of the collection- that he had to move the fossils to a safer place, but Beurlen refused to do it. Unfortunately, on April 24, 1944, a British Royal Air Force raid bombed the museum and incinerated its collections. Only two photographs of the holotype of Spinosaurus aegyptiacus were recovered in in the archives of the Paläontologische Museum in June 2000, after they were donated to the museum by Ernst Stromer’s son, Wolfgang Stromer, in 1995. These photographs provide additional insight into the anatomy of the holotype specimen of Spinosaurus aegyptiacus.

“Illustrations of the vertebrate “sail” bones of Spinosaurus that appeared in one of Stromer’s monographs. From Wikimedia Commons.

In his original monograph, Stromer emphasized the peculiar character of the teeth of this unusual theropod. Because of their morphological convergence with those of crocodilians and other fish-eating reptiles, isolated spinosaurid teeth have frequently been misinterpreted. It appears that Baryonyx-like teeth were collected by Gideon Mantell in Sussex around 1820. Georges Cuvier was the first to publish an illustration of the four teeth from Tilgate Forest. These teeth, however, were generally considered as belonging to crocodilians, and when Richard Owen erected the taxon Suchosaurus cultridens to designate them he placed it among the crocodiles. Even when Owen realized that these teeth were peculiar in many respects and hinted at possible affinities with dinosaurs, he persistently classified Suchosaurus as a crocodilian, an interpretation that was accepted by most subsequent authors.

Although Stromer’s original description of Spinosaurus aegyptiacus was published in 1915, a more complete detailed picture of its anatomy, evolution, and biogeography only begun to emerge in recent decades.

 

References:

HONE, D. W. E. and HOLTZ, T. R. (2017), A Century of Spinosaurs – A Review and Revision of the Spinosauridae with Comments on Their Ecology. Acta Geologica Sinica, 91: 1120–1132. doi: 10.1111/1755-6724.13328

Smith, et al. “NEW INFORMATION REGARDING THE HOLOTYPE OF SPINOSAURUS AEGYPTIACUS STROMER, 1915.” J. Paleont., 80(2), 2006, pp. 400–406

New tetrapod assemblage from the Chañares Formation

Skeletal anatomy of the erpetosuchid pseudosuchian Tarjadia ruthae. From Ezcurra et al., 2017

In the aftermath of the Permo-Triassic mass extinction (~252 Ma), several typical Palaeozoic synapsids and parareptiles were replaced by stem and crown archosaurs (archosauromorphs) and eucynodonts, and the Late Triassic fossil record of South America has been crucial to shed light on their evolutionary histories.

The Chañares Formation is part of the Ischigualasto-Villa Unión Basin, and represents one of the most continuous continental Triassic succesions in South America. Located in Talampaya National Park (La Rioja Province), the Chañares Formation is characterized at its base by a sandstone–siltstone fluvial facies with distinct lower and upper levels. The lower levels are composed of light olive grey fine-grained sandstones with abundant small brown carbonate concretions. The upper levels include fine-grained sandstones and siltstones that yielded a rich tetrapod assemblage composed of kannemeyeriiform dicynodonts, traversodontid and probainognathian cynodonts, proterochampsid stem-archosaurs, stem-crocodylians, and dinosaur precursors.

Volcanism played an important role in the generation and preservation of the Chañares Formation’s exceptional tetrapod fossil record. Recent radioisotopic datings temporally constrained most of the lower half of this unit to the earliest Carnian (236–231 Ma), showing that this assemblage preceded the oldest members of typical Late Triassic archosaur clades that are found in the Ischigualasto Formation. The new assemblage is called here as the Tarjadia Assemblage Zone, while the upper, historically known assemblage is called the Massetognathus–Chanaresuchus Assemblage Zone. This new assemblage sheds light on the link between the Early–Middle Triassic tetrapod assemblages of Africa (for example, Karoo, Ruhuhu and Otiwarongo basins) and those from the Middle–Late Triassic of South America.

The Chañares Formation (© 2012 Idean)

Tarjadia ruthae is characterized by a dorsoventrally thick skull roof ornamented by deep pits and grooves of random arrangement; Y-shaped tuberosity on the dorsal surface of the anterior end of the parietals; marginal dentition with serrations; spine table of the presacral and anterior caudal vertebrae with a transversely concave dorsal surface; a femur with a poorly developed fourth trochanter and a hook-shaped tibial condyle; and thick dorsal osteoderms with a coarse pitted ornamentation. The abundance of the erpetosuchid Tarjadia in the lowermost levels of the Chañares Formation indicates that this pseudosuchian was an important secondary consumer in its ecosystem

The Tarjadia and Massetognathus–Chanaresuchusassemblage zones currently do not share species or low level taxa, indicating a profound faunal replacement involving both primary and secondary consumers. Therefore, the rise of dinosaurs and other archosauromorph clades that diversified worldwide in the Late Triassic was preceded by a phase of relatively rapid changing ecosystems in southwestern Pangaea, including two (Tarjadia and Massetognathus–Chanaresuchus assemblage zones) profound faunal replacements in a time span shorter than 6 Myr (around 236–231 Ma).

References:

Martín D. Ezcurra, Lucas E. Fiorelli, Agustín G. Martinelli, Sebastián Rocher, M. Belén von Baczko, Miguel Ezpeleta, Jeremías R. A. Taborda, E. Martín Hechenleitner, M. Jimena Trotteyn & Julia B. Desojo; Deep faunistic turnovers preceded the rise of dinosaurs in southwestern Pangaea, Nature Ecology & Evolution (2017) doi:10.1038/s41559-017-0305-5

Benton, M. J., Tverdokhlebov, V. P. & Surkov, M. V. Ecosystem remodelling among vertebrates at the Permian–Triassic boundary in Russia. Nature 432, 97–100 (2004).

A Brief Introduction to the Osteology of Viavenator exxoni

Viavenator exxoni, Museo Municipal Argentino Urquiza

The Abelisauridae is the best-known carnivorous dinosaur group from Gondwana. Their fossil remains have been recovered in Argentina, Brazil, Morocco, Niger, Libya, Madagascar, India, and France. These theropods exhibit spectacular cranial ornamentation in the form of horns and spikes and strongly reduced forelimbs and hands. The group was erected by Jose Bonaparte with the description of  Abelisaurus comahuensis, and includes: Carnotaurus sastrei, Aucasaurus garridoi, Ekrixinatosaurus novasi, Skorpiovenator bustingorryi, Eoabelisaurus and Viavenator exxoni. 

The holotype of Viavenator exxoni (MAU-Pv-LI-530) was found in the outcrops of the Bajo de la Carpa Formation (Santonian, Upper Cretaceous), northwestern Patagonia, Argentina. Viavenator series of autapomorphies are: transversely compressed parietal depressions on both sides of the supraoccipital crest; ventral edges of the paraoccipital processes located above the level of the dorsal edge of the occipital condyle; basioccipital-opisthotic complex about two and a half times the width and almost twice the height of the occipital condyle, in posterior view; well-developed crest below the occipital condyle; deeply excavated and sub-circular basisphenoidal recess; basipterygoid processes horizontally placed with respect to the cranial roof and located slightly dorsally to the basal tubera; mid and posterior cervical centra with slightly convex lateral and ventral surfaces; presence of an interspinous accessory articular system in middle and posterior dorsal vertebrae; presence of a pair of pneumatic foramina within the prespinal fossa in anterior caudal vertebrae; distal end of the scapular blade posteriorly curved.

Figure 1. Rendering of the type braincase of Viavenator exxoni (MAU-Pv-LI-530) in dorsal (A,B), and right lateral (C,D) view. Adapted from Carabajal y Filippi, 2017.

Viavenator presents highly-derived postcranial characters, and a relatively plesiomorphic skull in comparison with Carnotaurus and Aucasaurus. Cranial elements of this specimen include the complete neurocranium: frontals, parietals, sphenethmoids, orbitosphenoids, laterosphenoids, prootics, opisthotics, supraoccipital, exoccipitals, basioccipital, parasphenoids and basisphenoids. The plesiomorphic traits of the skull of Viavenator are mainly related with the anatomy of frontals, wich lack osseous prominences such as domes or horns. The dorsal surface of the frontals exhibits an ornamentation that consists of pits and sinuous furrows and ridges, although it is not well-preserved. The  exoccipitals form the lateral and possibly the laterodorsal margins of the foramen magnum, as apparently occurs in Carnotaurus. 

Vertebrae of Viavenator exxoni. Scale bar: 5 cm. From Filippi et al., 2017),

The postcranial skeleton of Viavenator is represented by eight cervical vertebrae (the atlas; seven dorsal vertebrate, four of them articulated; twelve caudal vertebrae); ribs; gastralias; one chevron; scapulocoracoid; ischium foot; and fibulae. The atlas is similar to that of Carnotaurus, though less robust and anteroposteriorly shorter; and there  are not observed prezygapophyseal facets in the neurapophyses, so it is inferred that the proatlas was absent, as also occurs in Carnotaurus and Majungasaurus. The shape of the epipophyses of the cervical region, which are
characterized by anterior and posterior projections, is shared by Viavenator and Carnotaurus, but it is not present in pre-Santonian forms such as Ilokelesia and Skorpiovenator. The derived vertebral characters of Viavenator are linked with an increase in the structural rigidity of the vertebral column, and with an increase in the cursorial abilities of these abelisaurids. This combination of plesiomorphic and derived traits suggests that Viavenator is a transitional form.

 

References:

Filippi, L.S., Méndez, A.H., Gianechini, F.A., Juárez Valieri, Rubé.D., Garrido, A.C., Osteology of Viavenator exxoni (Abelisauridae; Furileusauria) from the Bajo de la Carpa Formation, NW Patagonia, Argentina, Cretaceous Research (2017), doi: 10.1016/j.cretres.2017.07.019.

Leonardo S. Filippi, Ariel H. Méndez, Rubén D. Juárez Valieri and Alberto C. Garrido (2016). «A new brachyrostran with hypertrophied axial structures reveals an unexpected radiation of latest Cretaceous abelisaurids». Cretaceous Research 61: 209-219. doi:10.1016/j.cretres.2015.12.018

Paulina-Carabajal, A., Filippi, L., Neuroanatomy of the abelisaurid theropod Viavenator: The most complete reconstruction of a cranial endocast and inner ear for a South American representative of the clade, Cretaceous Research (2017), doi: 10.1016/j.cretres.2017.06.013