The Banquet In The Belly Of The Beast

Hawkins’ Sydenham Studio. Image from The Crystal Palace Dinosaurs, Steve McCarthy & Mick Gilbert, 1994.

In 1851, Richard Owen used his influence with Prince Albert, Queen Victoria’s husband, to propose the financing of the three-dimensional reconstruction of the first known dinosaurs: Megalosaurus, Iguanodon and Hylaeosaurus, for the closure of the first international exposition in modern European history: the Crystal Palace exhibition, that would be placed in Sydenham Park, south of London, instead of the original site in London’s Hyde Park. Benjamin Waterhouse Hawkins, sculptor and natural history artist, was commissioned to make the full-size replicas of the dinosaurs and other extinct reptiles for Sydenham Park.

Invitation To Victorian New Year’s Eve In the Iguanodon.

On New Year’s Eve of 1853 a banquet was held inside the reconstruction of the Iguanodon, which had not yet been completed, and under the portraits of Cuvier, Buckland, Mantell and Owen the twenty one privileged guests to this unusual inauguration proposed a toast to the glory of the dinosaurs and Queen Victoria. The special invitation to enjoy an eight-course feast was suggested by Hawkins: “Mr Waterhouse Hawkins requests the honour of — at dinner in the mould of the Iguanodon at the Crystal Palace on Saturday evening December the 31st at five o’clock 1853. An answer will oblige.”

The sophisticated menu included soups, fillets of Whiting, roast turkey, ham, raised pigeon pie,  mayonnaise de filets de Sole, pheasants, sweets and desserts, and a great variety of wines. Richard Owen was sat at the head of the table, while Hawkins was at the centre.

The famous banquet in Benjamin Waterhouse Hawkins’ standing Crystal Palace Iguanodon. From Wikipedia Commons.

On January 7, 1854, the Illustrated London News reported the special dinner and published the drawing mady by Benjamin Waterhouse Hawkins. The drawing included a small report with details of the banquet: “The arch in the head of the animal was occupied by Prof R Owen the celebrated Palaeontologist who with Prof Edward Forbes liberally aided Mr Waterhouse Hawkins with counsel and scientific criticism during the whole time occupied by his unique, arduous and successful undertaking. The wider arch at the opposite end was filled by Mr Francis Fuller the Managing Director of the Crystal Palace with Prof Edward Forbes on his right and a musical friend on his left whose delightful singing greatly increased the pleasure of a memorable evening. The two sides contain nine seats each that in centre of left was occupied by Mr Hawkins as host and Chairman, was supported on his right by Mr Joseph Prestwich one of his earliest pupils & constant friend during the previous twenty five years. Mr John Gould FRS was on his left.”

 

References:

A. BUCKLAND, ‘“The Poetry of Science”: Charles Dickens, Geology and Visual and Material Culture in Victorian London’, Victorian Literature and Culture, 35 (2007), 679–94 (p. 680).

Jose Luis Sanz, Starring T. rex!: Dinosaur Mythology and Popular Culture, Indiana University Press, 2002.

MacCarthy, S. (1998). Crystal Palace Dinosaurs: The Story of the World’s First Prehistoric Sculptures (London, 1994), and WJT Mitchell. The Last Dinosaur Book.

Link:
The British Newspaper Archive https://www.britishnewspaperarchive.co.uk/viewer/BL/0001578/18540107/083/0022

Top fossil discoveries of 2021

Australotitan cooperensis. Image credit: Eromanga Natural History Museum, Artist: Vlad Konstantinov.

The pandemic is not over yet. Despite the fast development of effective vaccines against COVID-19, the virus continued to spread and mutate throughout the last year, with Omicron taking central stage in the last two months. Much of the blame is the unequal distribution of vaccines, a phenomeno described by Tedros Adhanom Ghebreyesus as a “catastrophic moral failure”.

But 2021 was not all bad. Cool new papers about ancient DNA, a billion-year-old freshwater protist, mass extinctions, the abundance of Tyrannosaurus rex, the description of two new spinosaurids from the Wessex Formation of the Isle of Wight, the speed of theropods, and the flower revolution, shapped a remarkable year in paleontology. Among the most striking fossil discoveries are:

  • MOZ-Pv 1221, a new giant titanosaur sauropod from the Upper Cretaceous of Argentina.

Image credit; Jose Luis Carballido/CTyS-UNLaM/AFP

This new giant titanosaur sauropod was discovered in 2012 and is the second taxon from Candeleros Formation, in addition to Andesaurus. The new specimen, identified as MOZ-Pv 1221, includes a sequence of anterior and middle caudal vertebrae, consisting of the first 20 mostly articulated caudal vertebrae and haemal arches plus isolated posterior caudals, pelvis and other appendicular elements. The preserved caudal sequence corresponds to approximately the anterior half of the tail. The neural spines of the anterior caudal vertebrae in MOZ-Pv 1221 are transversely wider than anteroposteriorly long. Compared to other giant titanosaurs, the recovered appendicular bones of MOZ-Pv 1221 are larger than any known titanosaur described to date.

  • Ninjatitan zapatai, the earliest known titanosaur.

Anterior caudal vertebra of Ninjatitan zapatai. From Gallina et al., 2021

Ninjatitan lived 140 million years ago and reached 20 meters in length (65 feet). The firs remains were discovered in 2014 by technician Jonatan Aroca. The holotype (MMCh-Pv228) includes an incomplete anterior–middle dorsal vertebra, a middle dorsal centrum, and anterior caudal centra with the base of neural arches preserved, a complete left scapula, a fragmentary distal femur, and a nearly complete left fibula of a single individual. The generic name honors the Argentine paleontologist Sebastián “Ninja” Apesteguía. The species name refers to Mr. Rogelio “Mupi” Zapata, in recognition for his work as a technician of the Museo Municipal Ernesto Bachman. Despite the fragmentary nature of the new taxon, three derived characters of Ninjatitan support its possition within the clade Titanosauria: 1) presence of procoelous anterior caudal centra; 2) pneumatized neural arch of anterior caudal vertebrae; and 3) position of the acromial process near the glenoid level. The position of Ninjatitan, as a basal titanosaur, extends the origin of this clade by at least 10 Myr.

  • Taytalura alcoberi, the father of lizards.

Taytalura alcoberi.Image credit: Jorge Blanco

The holotype (PVSJ 698), dated to be around 231 million years old, was discovered by a team lead by Ricardo Martínez in 2001 in the Ischigualasto Formation. The tiny skull reached only two centimeters in size, but it was well-preserved. Micro-CT scanning of the skull reveals some features shared with sphenodontians, including a tetraradiate squamosal, differing from the triradiate condition of squamates; a medially curved mandibular symphysis, as in early sphenodontians; and a small coronoid. Taytalura is about 11 million years younger than the oldest known lepidosaurs from Europe, and approximately the same age as the first known crown lepidosaurs in South America. The new finding provides strong evidence that stem lepidosaurs were contemporaneous with the first assemblages of crown lepidosaurs.

  • Australotitan cooperensis, the southern titan.

3-D digital restorations of the holotype (EMF102) of the titanosaurian Australotitan cooperensis (From Hocknull et al. 2021).

The Winton Formation, located in the uppemost unit of the Eromanga Basin, provides an important source of information about the Cretaceous of Australia. In the last two decades, four new dinosaurs were recovered in this area, including Australotitan cooperensis, the largest dinosaur ever found in Australia. The holotype (EMF102), discovered in 2005, comprises a partial left scapula, partial left humerus, complete right humerus, right ulna, both pubic bones and ischia, and partial right and left femora. Three aditional specimens were referred to the genus: EMF164, EMF105, and EMF165. The fragmented femur of specimen EMF164 has a length of 2.146 metres (7.04 feet), similar in size to the femora of Futalognkosaurus and Dreadnoughtus.

  • Ypupiara lopai, the first unenlagiine dromaeosaurid species from Brazil.

Right maxilla of DGM 921-R with details of teeth. Scale bar: 10 mm. From Brum et al., 2021.

Ypupiara lopai from the Maastrichtian of the Bauru Group is the first unenlagiine dromaeosaurid species from Brazil. The holotype (DGM 921-R) includes a partial preantorbital portion of a right maxillary, with three teeth in loci, and a partial posterior portion of a right dentary. The generic name means ‘the one who lives in the water’, an allusion to a Tupian myth about an aquatic creature. The specific name honors Alberto Lopa, the holotype’s discoverer. Ypupiara was found between the 40s and 60s in Peirópolis, near Uberaba, and placed in storage at the National Museum of Brazil. Unfortunately, the fossil was lost when the museum was consumed by a fire on 2 September 2018, but photographs of the specimen survived.

  • Mussaurus and the social behaviour of early sauropodomorphs.

Nest with eggs of Mussaurus patagonicus. Image credit: Credit: Diego Pol.

The discovery of 80 individuals of Mussaurus patagonicus, ranging from embryos to fully-grown adults, and more than 100 eggs, provides the earliest evidence of complex social behaviour. The eggs and nests of Mussaurus were found in three distinct horizons in the middle of the Laguna Colorada Formation. X-ray computed tomography reveals that the eggs were arranged in two or three layers within elongate depressions or trenches that appear to have been purposely excavated. The research team lead by Diego Pol calculated the site’s age at 193 million years, predating previous records of social behavior in dinosaurs by at least 40 My. The researchers also suggest that sociality may have influenced the early success and the first global radiation of sauropods.

  • Stegouros elengassen, an armoured dinosaur from Chile.

Skeletal anatomy of the S. elengassen holotype. From Soto-Acuña et al., 2021.

Stegouros elengassen, a new specimen from the Late Cretaceous Dorotea Formation of southern Chile, offers new evidence that contributes to the understanding of the relationships among the ankylosaurs from Gondwana. The holotype (CPAP–3165) was discovered in 2017 at the lower section of the Dorotea Formation. Stegouros lived about 72 to 75 million years ago, and reached 2 meters in lenght (six feet). The generic name is derived from the the Greek word “stego” (roof ) and the Greek word “uros” (tail) in reference to the covered tail. The specific name “elengassen” comes from an armoured beast in the mythology of the Aónik’enk people.

  • ‘Baby Yingliang’

The new specimen ‘Baby Yingliang’. Credit: Lida Xing

The new specimen (YLSNHM01266), nicknamed Baby Yingliang, is preserved curled inside its egg, with the head positioned ventral to the body. The oviraptorid affinity of Baby Yingliang is supported by several characers, including the crenulated ventral margin of premaxilla; the edentulous skull; the U-shaped mandibular symphysis; and the highly arched dentary. The vertebral column is estimated to have 22 presacral vertebrae. The pubis points posteroventrally, similar to that of modern birds, althought it is unclear how much of its orientation is genuine. The almost complete skeleton is ∼23.5 cm in total length. It was found in Shahe Industrial Park in Ganzhou City and acquired by the director of Yingliang Group, Mr Liang Liu. It was stored in Yingliang Stone Nature History Museum until the museum staff discovered it.

References:

Otero A, Carballido JL, Salgado L, Canudo JI, Garrido AC (2021), Report of a giant titanosaur sauropod from the Upper Cretaceous of Neuquén Province, Argentina, Cretaceous Research https://doi.org/10.1016/j.cretres.2021.104754

Pablo Ariel Gallina, Juan Ignacio Canale, & José Luis Carballido (2021).The earliest known titanosaur sauropod dinosaur. Ameghiniana58(1), 35–51 http://dx.doi.org/10.5710/AMGH.20.08.2020.3376

Martínez, R.N., Simões, T.R., Sobral, G. et al. A Triassic stem lepidosaur illuminates the origin of lizard-like reptiles. Nature 597, 235–238 (2021). https://doi.org/10.1038/s41586-021-03834-3

Hocknull SA, Wilkinson M, Lawrence RA, Konstantinov V, Mackenzie S, Mackenzie R. 2021. A new giant sauropod, Australotitan cooperensis gen. et sp. nov., from the mid-Cretaceous of Australia. PeerJ 9:e11317 https://doi.org/10.7717/peerj.11317

Brum, Arthur Souza, Pêgas, Rodrigo Vargas, Bandeira, Kamila Luisa Nogueira, Souza, Lucy Gomes de, Campos, Diogenes de Almeida, & Kellner, Alexander Wilhelm Armin. (2021). A new Unenlagiinae (Theropoda: Dromaeosauridae) from the Late Cretaceous of Brazil. https://doi.org/10.1002/spp2.1375

Pol, D., Mancuso, A.C., Smith, R.M.H. et al. Earliest evidence of herd-living and age segregation amongst dinosaurs. Sci Rep 11, 20023 (2021). https://doi.org/10.1038/s41598-021-99176-1

Soto-Acuña, S., Vargas, A.O., Kaluza, J. et al. Bizarre tail weaponry in a transitional ankylosaur from subantarctic Chile. Nature (2021). https://doi.org/10.1038/s41586-021-04147-1

Waisum Ma et al. (2021). An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures, iScience  DOI: https://doi.org/10.1016/j.isci.2021.103516

 

Christmas on the HMS Beagle

HMS Beagle in the seaways of Tierra del Fuego, painting by Conrad Martens during the voyage of the Beagle. From Wikimedia Commons.

When Charles Darwin arrived to South America, he was only 22 years old. He was part of the second survey expedition of HMS Beagle. By the end of the expedition, Darwin was already earned a name as a geologist and fossil collector. He narrated his experiences in his book “Journal of Researches into the Geology and Natural History of the Various Countries visited by H.M.S. Beagle, under the Command of Captain FitzRoy, R.N. from 1832 to 1836″, published in 1839 and later simply known as “The Voyage of the Beagle”.

On December 24, 1833, Darwin wrote: “Took a long walk on the North side: after ascending some rocks there is a great level plain, which extends in every direction but is divided by vallies. I thought I had seen some desert looking country near B. Bianca; but the land in this neighbourhood so far exceeds it in sterility, that this alone deserves the name of a desert. The plain is composed of gravel with very little vegetation & not a drop of water. In the vallies there is some little, but it is very brackish. It is remarkable that on the surface of this plain there are shells of the same sort which now exist & the muscles even with their usual blue colour. It is therefore certain, that within no great number of centuries all this country has been beneath the sea. Wretched looking as the country is, it supports very many Guanacoes. By great good luck I shot one; it weighed without its entrails &c 170 pounds: so that we shall have fresh meat for all hands on Christmas day.

Portrait of Charles Darwin painted by George Richmond (1840)

At the time, the HMS Beagle was anchored at Port Desire (now Puerto Deseado) in Argentina. Syms Covington, a cabin boy on HMS Beagle who became an assistant to Charles Darwin, also kept a journal of the voyage. In his diary, he wrote: “This Port Desire is much the same as other parts of Patagonia, viz. sandy hills with very bad brackish water, and that obliged to dig for; but some of the valleys are very pleasant: in season there are plenty of wild cherries. They were nearly ripe at this time; I ate some which were rather tart, but tasted pleasant. Birds are not so numerous nor so splendid here as in many other parts of South America, but of course they are less well known. About this part no deer were seen, but immense quantities of guanacos, also lions, foxes, ostriches and aperea or guinea pig. The cliffs are full of fossil shells.”

Geologic map of Patagonia (Darwin, circa 1840). Image credit: Cambridge University Library

At Puerto Deseado, Darwin collected some fossils that were later described by G B Sowerby, and sketched some botanical specimens, like Gavilea patagonica, a foot-high orchid. Darwin also described the presence of porphyries, covered by Tertiary deposits,  in the first geological map of Patagonia. His geological observations and interpretations on the history of life in the continent were included in an essay titled Reflection on reading my geological notes.

Slinging the Monkey, Port Desire, Dec 25 1833. By Conrad Martens. Image credit: Cambridge University Library

On Christmas Day 1833, Darwin wrote: “Christmas. After dining in the Gun-room, the officers & almost every man in the ship went on shore. — The Captain distributed prizes to the best runners, leapers, wrestlers. — These Olympic games were very amusing; it was quite delightful to see with what school-boy eagerness the seamen enjoyed them: old men with long beards & young men without any were playing like so many children. — certainly a much better way of passing Christmas day than the usual one, of every seaman getting as drunk as he possibly can.”

 

References:

Darwin, C. (1840). Journal of Researches into the Geology and Natural History of the Various Countries Visited by HMS Beagle under the Command of Captain Fitzroy, RN from 1832 to 1836. Henry Colburn.

McIntyre, J. (1972). Syms Covington: an associate of Charles Darwin. Journal of the Royal Historical Society of Queensland, 9(3), 87-93.

Aguirre-Urreta, B., Griffin, . M., & Ramos, . V. A. (2009). Darwin’s geological research in Argentina. Revista De La Asociación Geológica Argentina, 64(1), 4-7. https://revista.geologica.org.ar/raga/article/view/1288

Zappettini, E. O., & Mendía, J. (2009). El primer mapa geológico de la Patagonia. Revista de la Asociación Geológica Argentina, 64(1), 55-59.

A dinosaur embryo exquisitely preserved

The new specimen ‘Baby Yingliang’. Credit: Lida Xing

Oviraptorosaurs are a well-defined group of coelurosaurian dinosaurs characterized by short, deep skulls with toothless jaws, pneumatized caudal vertebrae, anteriorly concave pubic shafts, and posteriorly curved ischia. The most basal forms were small, similar to a chicken or a turkey, and like extant birds, they had pennaceous feathers. Their fossil record span much of the Cretaceous of Asia and North America. The most famous dinosaur of this group, Oviraptor, was discovered in 1923 by Roy Chapman Andrews in Mongolia, associated with a nest of what was thought to be Protoceratops eggs. The misconception persisted until 1990s when it was revealed that the eggs actually belonged to Oviraptor, not Protoceratops. Since then, more skeletons of Oviraptor and other oviraptorids like Citipati and Nemegtomaia have been found brooding over their eggs. Oviraptorids also have the best record of embryonic fossils. A new specimen, from the Late Cretaceous Hekou Formation of southern China, represents the most well-preserved dinosaur embryo ever discovered, and exhibits a posture of a late-stage modern bird embryo. This new finding suggests that avian tucking behavior possibly originated among non-avian theropods.

Life reconstruction of the new specimen ‘Baby Yingliang.’ Credit: Lida Xing.

The new specimen (YLSNHM01266), nicknamed Baby Yingliang, is preserved curled inside its egg, with the head positioned ventral to the body. The oviraptorid affinity of Baby Yingliang is supported by several characers, including the crenulated ventral margin of premaxilla; the edentulous skull; the U-shaped mandibular symphysis; and the highly arched dentary. The vertebral column is estimated to have 22 presacral vertebrae. The pubis points posteroventrally, similar to that of modern birds, althought it is unclear how much of its orientation is genuine.
The almost complete skeleton is ∼23.5 cm in total length. It was found in Shahe Industrial Park in Ganzhou City and acquired by the director of Yingliang Group, Mr Liang Liu. It was stored in Yingliang Stone Nature History Museum until the museum staff discovered it.

References:

Waisum Ma et al. (2021). An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures, iScience  DOI: https://doi.org/10.1016/j.isci.2021.103516

Bi, Shundong, et al. (2021). An oviraptorid preserved atop an embryo-bearing egg clutch sheds light on the reproductive biology of non-avialan theropod dinosaurs. Science Bulletin, 66(9), 947-954 https://doi.org/10.1016/j.scib.2020.12.018

 

Introducing Stegouros elengassen

Life reconstruction of Stegouros elengassen. Image credit: Luis Perez Lopez

Ankylosauria is a clade of herbivorous, armored ornithischian dinosaurs subdivided in two major clades: the Ankylosauridae and the Nodosauridae. The most derived members of this group are characterized by shortened skulls, pyramidal squamosal horns, and tail clubs. Fossil evidence of armored dinosaurs from Gondwana is scarce. They were present primarily in Asia and North America. Stegouros elengassen, a new specimen from the Late Cretaceous Dorotea Formation of southern Chile, offers new evidence that contributes to the understanding of the relationships among the ankylosaurs from Gondwana.

Stegouros lived about 72 to 75 million years ago, and reached 2 meters in lenght (six feet). The generic name is derived from the the Greek word “stego” (roof ) and the Greek word “uros”
(tail) in reference to the covered tail. The specific name “elengassen” comes from an armoured
beast in the mythology of the Aónik’enk people.

Skeletal anatomy of the S. elengassen holotype. From Soto-Acuña et al., 2021.

The holotype (CPAP–3165), represented by a nearly complete skeleton, semi-articulated, was discovered in 2017 at the lower section of the Dorotea Formation. The new specimen exhibits an unusual combination of characters. The skull and teeth, are classically Ankylosauria, but the pelvis and slender limb bones resemble Stegosauria. The most striking feature of Stegouros is the short, bizarre tail covered by seven pairs of large osteoderms, that are fused into a flat composite unit resembling a battle axe.

Phylogenetic analyses with five different datasets indicate that Stegouros was closer to Ankylosauria than to Stegosauria. It was grouped with the basal ankylosaurs Kunbarrasaurus (from the late Lower Cretaceous of Australia) and Antarctopelta (from the Late Cretaceous of Antarctica) forming a monophyletic clade that split earliest from all other Ankylosauria. The study, led by Chilean paleontologists, proposes the clade Parankylosauriato include the first ancestor of Stegouros—but not Ankylosaurus—and all descendants of that ancestor (Soto-Acuña et al., 2021).

 

 

References:

Soto-Acuña, S., Vargas, A.O., Kaluza, J. et al. Bizarre tail weaponry in a transitional ankylosaur from subantarctic Chile. Nature (2021). https://doi.org/10.1038/s41586-021-04147-1

The Flower Revolution

The rise of angiosperms was accompanied by massive expansion in biodiversity. From Benton et al., 2021

Angiosperms, or flowering plants, represent almost 90% of all living land plants. The group first appeared in the fossil record during the Early Cretaceous and by the Late Cretaceous, angiosperms came to dominate plant diversity. Charles Darwin’s fascination and frustration with the evolutionary events associated with the origin and early radiation of angiosperms are legendary. On 22 July 1879, in a letter to Joseph Dalton Hooker, Darwin refers to the early evolution of flowering plants as an “abominable mystery”. Since Darwin many new fossils have been found and facilitated the calibration of molecular clock age estimates for various angiosperm clades. Before the Aptian, the only convincing angiosperm megafossils are from the Barremian Las Hoyas flora of Spain and the Yixian flora of northeastern China. By contrast, there is an extensive pre-Aptian pollen record of angiosperms.

Model of the ancestral flower (From Sauquet et al., 2017)

The Angiosperm Terrestrial Revolution (Benton et al., 2021) reshaped the entire terrestrial ecosystem. Flowering plants altered climate and water cycles, and drove a massive expansion in biodiversity of numerous key groups of fungi, insects, arachnids, reptiles, mammals and birds. But angiosperm success lies no only in their possesion of flowers. They have smaller genomes on average than other plants, which lead to small cell sizes in angiosperms with tightly-packed internal structures. Other key innovations like high vein density and densely packed stomata are also related to genome size. Stomata are the controlled pores through which plants exchange gases with their environments, and play a key role in regulating the balance between photosynthetic productivity and water loss through transpiration

Atmospheric CO2 concentrations and paleotemperatures were the major drivers of floristic turnover. Multiple climate proxy records, identified the EECO as the warmest interval of the past 65 million years. During EECO (Eocene Climate Optimum), the warmest interval of the past 65 million years, emerged many angiosperm dominated forest. Today, many organisms depend substantially or entirely on angiosperms for their existence, especially in tropical rain forests. Among them are about 15 000 species of lizards, birds and mammals. 

References:

Benton, Michael J., et al. 2021. The Angiosperm Terrestrial Revolution and the Origins of Modern Biodiversity. New Phytologist. Wiley Online Library https://doi.org/10.1111/nph.17822

Sauquet, H., von Balthazar, M., Magallón, S. et al. The ancestral flower of angiosperms and its early diversification. Nat Commun 8, 16047 (2017). https://doi.org/10.1038/ncomms16047

Halloween special IX: The Hounds of Tindalos and the Ediacaran fauna.

The Hounds of Tindalos, original Arkham House hardcover, 1946.

The Hounds of Tindalos, original Arkham House hardcover, 1946.

Human beings as we know them are merely fractions, infinitesimally small fractions of one enormous whole. Every human being is linked with all the life that has preceded him on this planet. All of his ancestors are parts of him. Only time separates him from his forebears, and time is an illusion and does not exist.” The quote belongs to “The Hounds of Tindalos”, a short story, first published in the March 1929 issue of Weird Tales. The autor was American writer Frank Belknap Long (1901- 1994).  He was one of H. P. Lovecraft’s close friends and contributor to the Cthulhu Mythos.

The Hounds of Tindalos” (also mentioned by Lovecraft in his short story “The Whisperer in Darkness”, 1931) are strange creatures that exist in the angles of time (while human beings descended from the curves of time) in the extremely distant past. They can travel through time and space impelled by hunger or other evil purpose. Although they are represented as hounds, their appearance is a mass of incomprehensible shapes. Geometry is a powerful presence in the story of Frank Belknap Long. Halpin Chalmers, one of the main characters, reveres Einstein as “a priest of transcendental mathematics”, and the hounds could be a representation of fractal forms of life.

Rangeomorph taxa illustrating the characteristic fractal-like branching and diversity of overall form. (a) Charnia masoni, (b) Rangea schneiderhoehni, (c) Hapsidophyllas flexibilis, (d) Fractofusus misrae, (e) Bradgatia sp. Scale bar: (a, e) 2 cm; (b) 1.5 cm; (c) 4 cm; and (d) 3 cm. From Butterfield, 2020

The diversity of shapes in the Ediacara biota (575–542 Ma) include some of the most enigmatic creatures in the fossil record. From discs to fronds, to segmented morphologies at least vaguely comparable with modern animals, alongside bizarre fractal constructions unknown in our modern world. Among them, rangeomorphs, with their fractal body plan, were the first substantially macroscopic organisms.

Rangeomorphs have been traditionally interpreted as sessile organisms that lived in deep- and shallow-marine depositional environments, and were ecologically analogous to sponges or anthozoan cnidarian. They are characterized by a broadly frond-like habit. The arrangement of their branches has been proposed as a basis for distinguishing between taxa. The group dominated the Ediacaran ecosystems and provided key insights into the early evolution of multicellular eukaryotes. But at the the beginning of the Cambrian period, the ecological and geochemical conditions where the rangeomorphs were optimized changed, and their extraordinary body plan was lost forever.

References:

Long, Frank Belknap. “The Hounds of Tindalos” (1929). In Tales of the Cthulhu Mythos (1st ed.)

G.M. Narbonne, The Ediacara Biota: Neoproterozoic origin of animals and their ecosystems, Annual Review of Earth and Planetary Sciences, 33 (2005), pp. 421-442 (1)

D.H. Erwin, M. Laflamme, S.M. Tweedt, E.A. Sperling, D. Pisani, K.J. Peterson, The Cambrian conundrum: early divergence and later ecological success in the early history of animals
Science, 334 (2011), DOI: 10.1126/science.1206375

N.J. Butterfield. Constructional and functional anatomy of Ediacaran rangeomorphs. Geological Magazine (2020) https://doi.org/10.1017/S0016756820000734

 

Mussaurus and the social behaviour of early sauropodomorphs

Mussaurus patagonicus with neonate individuals. Credit: Jorge Gonzalez.

Sauropods were the largest terrestrial vertebrates. Their morphology is easy recognizable: a long, slender neck and a tail at the end of a large body supported by four columnar limbs. They were the first successful group of herbivorous dinosaurs, dominating most terrestrial ecosystems from the Late Triassic to Late Cretaceous. The group evolved from small, gracile, bipedal forms, and the acquisition of giant body size occurred during the Jurassic. The early sauropodomorph Mussaurus patagonicus was originally described from several well-preserved post-hatchling specimens associated with egg remains found at Laguna Colorada Formation (Late Triassic/Early Jurassic) in Argentina. The remains were briefly described by Jose Bonaparte in 1979. Now, the discovery of 80 individuals of Mussaurus patagonicus, ranging from embryos to fully-grown adults, and more than 100 eggs, provides the earliest evidence of complex social behaviour.

Nest with eggs of Mussaurus patagonicus. Image credit: Diego Pol.

The new findings comprise skeletons of six different ontogenetic stages ranging from embryos to adult individuals, that are either fully-articulated or partially disassociated. Their bones show a 0.5 cm-wide phosphatic halo related to the microbial decomposition of soft-tissue, which suggests that the skeletons were buried relatively rapidly at the same time. Histological analysis of the juvenile aggregation suggests a fast growth rate, while the absence of lines of arrested growth (LAGs) in their femora, tibia, humeri, and ribs, combined with their size, indicate that they were possibly members of a single brood. The eggs and nests of Mussaurus were found in three distinct horizons in the middle of the Laguna Colorada Formation. X-ray computed tomography reveals that the eggs were arranged in two or three layers within elongate depressions or trenches that appear to have been purposely excavated.

The research team lead by Diego Pol calculated the site’s age at 193 million years, predating previous records of social behavior in dinosaurs by at least 40 My. The researchers also suggest that sociality may have influenced the early success and the first global radiation of sauropods.

 

References:

Pol, D., Mancuso, A.C., Smith, R.M.H. et al. Earliest evidence of herd-living and age segregation amongst dinosaurs. Sci Rep 11, 20023 (2021). https://doi.org/10.1038/s41598-021-99176-1

Bonaparte, J. F. & Vince, M. E. hallazgo del primer nido de dinosaurios triásicos (Saurischia, Prosauropoda), Triásico Superior de Patagonia, Argentina. Ameghiniana 16, 173–182 (1979).

Volcanism and the Rise of the Dinosaurs

Global paleogeographic setting during the Late Triassic. From X. Fu et al., 2020.

The Carnian Pluvial Episode (CPE), dated to 234–232 Ma, was a time of major turnover in the oceans and on land. It was characterized by global warming, ocean acidification, mega-monsoonal conditions, and a generalised increase in rainfall. In the marine sedimentary basins of the Tethys realm, an abrupt change of carbonate factories and the establishment of anoxic conditions mark the beginning of the climate change. This shift from arid to more humid conditions has been linked to the large-scale volcanism of the Wrangellia large igneous province (LIP). The widespread extinction caused by the CPE was followed by the first substantial diversification of dinosaurs.

Data from Central European Basin, Wessex Basin (United Kingdom), East Greenland (37), Morocco (38), Newark Basin (North America), and the Ischigualasto Basin (Argentina), indicate that increased rainfall resulted in the widespread expansion of the endorheic basins during the CPE. In the Jiyuan Basin, located in the southeast of the Ordos Basin, North China, an expanded Carnian lake succession offers a glimpse into this crucial interval.

 

Some representative palynological genera from the Jiyuan Basin (all scale bars = 20 μm). From Lu, Jing, et al., 2021

During the Early and Middle Triassic, North China was located in eastern Tethys. Later in the Triassic, the North China Plate collided with the South China Plate which resulted in extensive volcanism and the migration of the Ordos Basin depocenter continuously westward. High-resolution chemostratigraphy, palynological and sedimentological data indicate that four pulses of LIP volcanism were likely responsible for the global negative CIEs (carbon isotope excursion) that mark the CPE and drove major environmental changes.

The CPE also marks the first massive appearance of calcareous nannoplankton, while groups, like bryozoans and crinoids, show a sharp decline during this event. On land, palaeobotanical evidence shows a shift of floral associations towards elements more adapted to humid conditions (the palynological record across the CPE suggest at least 3–4 discrete humid pulses). During this interval, several families and orders make their first appearance: bennettitaleans, modern ferns, and conifer families (Pinaceae, Araucariaceae, Cheirolepidaceae), while key herbivorous groups such as dicynodonts and rhynchosaurs, which had represented 50% or more of faunas, disappeared.

Eoraptor lunensis, outcropping from the soil. Valle de la Luna (Moon Valley), Parque Provincial Ischigualasto, Provincia de San Juan, Argentina.

Followed the extinction of rhynchosaurs in most, or all, parts of the world, there was a burst of dinosaurian diversity in the late Carnian, represented by the upper Ischigualasto Formation and coeval units, with mostly carnivorous small- to medium-sized dinosaurs. Then, the long span of the early Norian, from 228.5–218 Ma, during which dicynodonts and sauropodomorph dinosaurs were the major herbivores. Finally, with the disappearance of dicynodonts, sauropodomorph dinosaurs became truly large in the middle and late Norian, from 218 Ma. This was followed by the extinction of basal archosaur groups during the end-Triassic mass extinction, 201 Ma, and the diversification of sauropods, larger theropods, ornithopods, and armoured dinosaurs subsequently, in the Jurassic.

 

References:

Lu, Jing, et al. Volcanically driven lacustrine ecosystem changes during the Carnian Pluvial Episode (Late Triassic), PNAS (2021). doi.org/10.1073/pnas.2109895118

X. Fu et al., A possible link between the Carnian Pluvial Event, global carbon-cycle perturbation, and volcanism: New data from the Qinghai-Tibet Plateau. Global Planet. Change 194, 103300 (2020) doi:10.1016/j.gloplacha.2020.103300

Michael J. Benton et al. The Carnian Pluvial Episode and the origin of dinosaurs, Journal of the Geological Society (2018). DOI: 10.1144/jgs2018-049

The Weissert Event

Paleogeographic map by C.R. Scotese, PALEOMAP project. From Cavalheiro et al., 2021

The continued fragmentation of Pangaea across the Late Jurassic and Early Cretaceous led to large-scale tectonic processes, on both regional and global scale, accompanied by some of the largest volcanic episodes in the history of the Earth, eustatic oscillations of the sea level, potentially heightened levels of anoxia, oceanic stagnation, and sulphur toxicity. The Weissert Event (~133 million years ago), linked with the main magmatic activity of the Parana`-Etendeka large igneous province (LIP), represents one of the most significant paleoceanographic events of the Early Cretaceous. This global perturbation in the C cycle is marked by a positive (+1.5‰) carbon isotope excursion (CIE) observed both in organic and inorganic records.

Global mean surface temperatures (GMSTs) and associated CO2 levels. From Cavalheiro et al., 2021.

A new study analyzed deep sea sediments obtained by the Ocean Drilling Program (ODP) from offshore Antarctica to reconstruct the paleotemperatures. The international team of researchers lead by Liyenne Cavalheiro combinded calcareous nannofossil data and chemostratigraphy, and found that that global temperatures declined by 3.0 °C (±1.7 °C) during the Weissert Event.

Calcareous nannoplankton represent a major component of oceanic phytoplankton. Their calcareous skeletons can be found in fine-grained pelagic sediments in high concentrations and the biomineralization of coccoliths is a globally significant rock-forming process. Additionally, reconstructions of Cretaceous sea-surface temperatures (SSTs) have been revolutionised by the development of the organic palaeothermometer TEX86, based on the distribution of marine archaeal membrane lipids.

 

 

 

References:

Cavalheiro, L., Wagner, T., Steinig, S. et al. Impact of global cooling on Early Cretaceous high pCO2 world during the Weissert Event. Nat Commun 12, 5411 (2021). https://doi.org/10.1038/s41467-021-25706-0

Erba, E., Bartolini, A., & Larson, R. L. (2004). Valanginian Weissert oceanic anoxic event. Geology, 32(2), 149. doi:10.1130/g20008.1 

Holz, M., Mesozoic paleogeography and paleoclimates – a discussion of the diverse greenhouse and hothouse conditions of an alien world, Journal of South American Earth Sciences (2015), doi: 10.1016/j.jsames.2015.01.001