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Cinzia Bottini

Cinzia Bottini is a micropalaeontologist at the University of Milan (Italy), where she studies calcareous nannofossils. In particular, her research focuses on Cretaceous Oceanic Anoxic Events (OAEs) and aims at understanding calcareous nannoplankton response to the extreme climatic and palaeoceanographic conditions that occurred during the OAEs. Her work includes the stratigraphic characterization of pelagic sections as well as multi-proxies based palaeoclimatic and palaeoecological reconstructions. She is one of the two palaeontology science officers for SSP.

The hard part of life: the secrets of biomineralization

Biomineralization is a fascinating natural process by which living organisms produce hierarchical mineral structures with diverse functions. The “secrets” of biomineralization are explored by the scientists since decades but there are still open questions regarding its function, the regulating mechanisms and why and when biomineralization started.This process occurs through self-organization of organic and inorganic molecules and requires specific ambient conditions. It results in highly structured materials with remarkable physical and chemical properties. Examples are the formation of silicates in algae and diatoms, carbonates in invertebrates and phytoplanktonic algae, and calcium phosphates and carbonates in the hard tissues of vertebrates. The crescent number of works dealing with biomineralization highlights the interest of the scientific community which aims at understanding why, under specific circumstances, the process fails. Here I propose a selection of the latest papers published on this topic.

Coronado et al. (2019) published on Nature Communications the work titled “Impact of ocean acidification on crystallographic vital effect of the coral skeleton” where they have assessed crystallographic parameters of bio-aragonite to study the response of the reefbuilding coral Stylophora pistillata to experimental seawater acidification.

Structural features of Stylophora pistillata cultured at different pH conditions (from Coronado et al. 2019)

 

Skeletons formed under high pCO2 conditions show systematic crystallographic changes such as better constrained crystal orientation and anisotropic distortions of bio-aragonite lattice parameters due to increased amount of intracrystalline organic matrix and water content.

 

In the work titled “Terebratulide brachiopod shell biomineralization by mantle epithelial cells” by Roda et al (2019) published in the Journal of Structural Biology the authors wanted to focus on an unknown process in brachiopods: how the mineral is transported from outer mantle epithelium cells to the site of mineralization. So they imaged with TEM and FE-SEM ultrastructural characteristics of outer mantle epithelium cells on Magellania venosa shells to investigate the mineral transport pathways for shell secretion and to assess differences in cellular activity during mineralization.

 

 

Tang et al (2019) published in Nature CommunicationSpiculogenesis and biomineralization in early sponge animals” where they  report an early Cambrian sponge that had weakly biomineralized and hexactine-based siliceous spicules with large axial filaments and high organic proportions. This material, along with Ediacaran microfossils containing putative nonbiomineralized axial filaments, suggests that Precambrian sponges may have had weakly biomineralized spicules or lacked them altogether, hence their poor record. This work provides a new search image for Precambrian sponge fossils, which are critical to resolving the origin of sponge spiculogenesis and biomineralization.

Preservation of organic and biosilica structures in Vasispongia delicata (from Tang et al., 2019)

 

 

The recipe for making shells, spines, and coral skeletons is not only the same across many modern animal lineages, but is ancient—dating back 550 million years—and evolved independently more than once. This is what is presented in”Biomineralization by particle attachment in early animals ” by Pupa et al (2019) published in PNAS . The authors show that when echinoderms, mollusks, and cnidarians started biomineralizing in the Cambrian (more than 500 million years ago) these three phyla started doing it in precisely the same way: using attachment of amorphous nanoparticles.”

Modern and fossil nacre from 3 molluscan classes, exhibiting irregularly shaped nanoparticles (from Pupa et al. 2019)

 

 

Finally, Schoepplera et al (2019) published in PNASCrystal growth kinetics as an architectural constraint on the evolution of molluscan shells” where they  compare the process of ultrastructural morphogenesis of shells from 3 major molluscan classes: A bivalve Unio pictorum, a cephalopod Nautilus pompilius, and a gastropod Haliotis asinina. They demonstrate that the fabrication of these tissues is guided by the organisms by regulating the chemical and physical boundary conditions that control the growth kinetics of the mineral phase. This biomineralization concept is postulated to act as an architectural constraint on the evolution of molluscan shells by defining a morphospace of possible shell ultrastructures that is bounded by the thermodynamics and kinetics of crystal growth.

Structural analysis of the N. pompilius shell using electron microscopy (from Schoepplera et al 2019)

 

The study of biomineral formation is essential to our understanding of the most fundamental processes in evolution and organisms capability to adapt to environmental changes…so let’s keep investigating the “hard part of life”.

Paleontology is sexy! A selection of recent discoveries

The 2019 started with a relatively high number of paleontological discoveries published in highly ranked journals showing that paleontology is sexy indeed! Here you can find a small selection of the most recent ones. The studies in micro- and macropaleontology published earlier this year, provide a large contribution to our understanding of organism evolution and response to peculiar environmental conditions which can be used to predict future ecosystem reactions. Paleontology is therefore not only fascinating but it is a valid instrument for assemble a possible scenario of biotic changes in the future.

 

A gigantic carnivore from the earliest Miocene of Kenya

A relatively young adult of a gigantic carnivore from the early Miocene (ca. 22 million years ago) was discovered at Meswa Bridge, Kenya. The researchers, Borth M. and Stevens N., called the now extinct carnivore Simbakubwa kutokaafrika, Swahili for “big lion from Africa” since this predator would have played a lion-like role. It is the oldest known member in a group of extinct mammals called hyaenodonts, so named due to their dental resemblance to hyenas, even though the groups are also unrelated. The specimen was known from most of its jaw, portions of its skull and parts of its skeleton. It was larger than a modern polar bear, it weighed up to 1,500 kilograms, measured 2.4 meters long from snout to rump and stood 1.2 m tall at its shoulders.The study was published in the Journal of Vertebrate Paleontology  and helps connect some of the evolutionary steps for this group which were near the top of the food chain in theAfrican ecosystems where early apes and monkeys were also evolving. The fossil may also help scientists better understand why these apex predators ultimately did not survive.

  

A modern lion skull (above) compared to the left part of a Simbakubwa kutokaafrika jaw (below) photographed by Matthew Borths. On the right, a rendering of Simbakubwa kutokaafrika (image credits Mauricio Anton).

 

 

Exceptional preservation of mid-Cretaceous marine arthropods and the evolution of novel forms via heterochrony

A new, exceptionally preserved crab from the mid-Cretaceous of Colombia and the United States was discovered by Luque et al. The completeness of the fossil remains shed light on the early disparity of the group and the origins of novel forms.This ancient crab was named Callichimaera perplexa, which means “perplexing beautiful chimera”, and lived during late Cretaceous (ca. 95 to 90 million years ago). The name references the mythical chimera from Greek mythology, which had a lion’s head, a goat’s body and a snake’s tail. The C. perplexa had large unprotected compound eyes, small fusiform body, and leg-like mouthparts suggesting larval trait retention into adulthood via heterochronic development (pedomorphosis), while its large oar-like legs represent the earliest known adaptations in crabs for active swimming. The authors, who published their study in Science Advances, think that these creatures lived in the water, swimming more than crawling  around on land (due to the unusual legs) and were active predators.

                              

A rendering of Callichimaera perplexa (Image credits Oksana Vernygora / University of Alberta). On the right dorsal, frontal, and ocular features in Callichimaera perplexa, from the mid-Cretaceous of Colombia (Luque et al. 2019) .

 

Unlaid egg discovered in an Early Cretaceous bird fossil

A new enantiornithine, Avimaia schweitzerae gen. et sp. nov., from the Lower Cretaceous Xiagou Formation was described by Bailleul et al. The discovery is of great importance since it tetifys the oldest documented case of a common reproductive disorder: called “egg-binding,” where an egg becomes trapped inside a bird. The fossilized bird was in fact found with an unlaid egg two-dimensionally preserved within the abdominothoracic cavity. Ground-sections reveal abnormal eggshell proportions, and multiple eggshell layers best interpreted as a multi-layered egg resulting from prolonged oviductal retention. The find, reported in Nature Communications, belonged to a sparrow-size flyer that lived in northwestern China ca. 110 million years ago. The team has named the bird Avimaia schweitzerae (Avimaia means “mother bird”; and schweitzerae honors paleontologist Mary Schweitzer.)

                                     

A rendering of the female individual Avimaia schweitzerae dead in the water on the left (with an unlaid egg not visible inside its abdomen), represents the fossilized individual discovered in China. Illustration by Michael Rothman. In the center and right side, photograph and line drawing of the holotype of Avimaia schweitzerae, IVPP V25371. a Photograph of the partial skeleton with feather impressions, and the crushed preserved egg between the pubes; b interpretive line drawing, with white arrows indicating the two fragments extracted for microscopic analysis with a super-imposed CT-scan revealing the egg and underlying elements of the right pelvis in dorsal (synsacrum) and medial (ilium) view (from Bailleul et al. 2019).

 

 

A new African Titanosaurian Sauropod Dinosaur from the middle Cretaceous of Southwestern Tanzania

Paleontologists recently discovered a new titanosaurian sauropod – a giant, plant-eating dinosaur – and named it Mnyamawamtuka moyowamkia. A common component in Cretaceous African faunas, titanosaurian sauropods diversified into one of the most specious groups of dinosaurs worldwide and this discovery is helping paleontologists understanding how, where and when the mightiest of land animals evolved. Mnyamawamtuka moyowamkia lived around 100-110 million years ago, during the middle of the Cretaceous and was found in the Mtuka Member of the Galula Formation  (Aptian–Cenomanian) in southwest Tanzania.

Titanosaurs are best known from South America, Tanzania, Egypt, and other parts of the African continent. The new specimen described by Gorscak and O’Connor in PlosOne preserves teeth, elements from all regions of the postcranial axial skeleton, parts of both appendicular girdles, and portions of both limbs including a complete metatarsus. This finding adds a bit more detail to the picture of what ecosystems on continental Africa were like during the Cretaceous.

 

All these findings make you wonder: ‘what else is out there for us to discover?’

Strati 2019

The abstract submission to the third edition of the International Congress on Stratigraphy (STRATI) is now open. The congress will be held in Milano (Italy) from the 2nd to the 5th of July 2019.

STRATI 2019 follows the first edition held in Lisbon (Portugal) in 2013 and the second edition organized in Graz (Austria) in 2015. Several scientific sessions have been proposed covering a wide range of stratigraphic topics. For information and abstract submission go to http://www.strati2019.it

 

Brachiopods in a changing planet: from the past to the future

Between the 10thand 14th of September 2018, the 8thInternational Brachiopod Congress took place in the prestigious venue of the University of Milan, after the previous editions held in Melbourne (Australia) in 2010 and in Nanjing (China) in 2015. It was the first time, since its foundation over 35 years ago, that this important conference was hosted in Italy.


The Congress was attended by 150 participants from universities and research institutes from all over the world (Argentina, Armenia, Austria, Belgium, Canada, China, Czech Republic, Denmark, France, Germany, Hungary, Iran, Israel, Italy, Japan, New Zealand, Poland, Russia, Slovakia, Spain, Sweden, United Kingdom and USA).

 

Brachiopods are a group of marine invertebrates known since the Cambrian, that show a high biodiversity and a dominant role mainly in the Palaeozoic oceans. They are considered one of the best biomineral archive, due to the unique characters of their shells, to understand the evolution of marine calcifiers during climate and environmental changes in the recent and deep geological past.

The topics of the Congress have touched all aspects of the study of brachiopods, from systematics and evolution to biostratigraphy, palaeoecology, palaeobiogeography, up to the biology of recent taxa. Particular emphasis was devoted to research on mass extinctions, biomineralization and geochemistry, as well as new methods of microscopic investigation with the latest equipment in this field.

Interesting talks included new findings on the process of shell formation, and on the steps of its possible diagenetic alteration, and multidisciplinary studies on how brachiopods and their shells respond to ocean acidification both in culturing and natural environment and in the geological record. Advancements in brachiopod research were also testified by new discoveries on their phylogeny and taxonomy, as well as on palaeoecology and taphonomy, and on how they could survive and recover after biotic crises, such as the big ones of the end-Ordovician or the end-Permian, ending up with new approaches in shell geochemical analyses.

The abstract volume of the congress can be downloaded at  http://permian.stratigraphy.org/files/20180828212711700.pdf

 

3D model of the brachiopod species Magellania venosa, made in the frame of the BASE-LiNE EarthProject

 

In addition to the oral and poster scientific sessions and two prestigious plenary lectures, the Congress was preceded and followed by three field trips (Spain, United Kingdom and Sicily), as well as by two mid-congress day excursions only a short distance from Milan (Castell’Arquato and Grigna Mountains). Participants had the possibility to discover the wonderful fossiliferous localities of Italy and Europe.

 

Sometimes released into the background, invertebrate macropalaeontology has a high scientific potential; macrofossils are excellent archives of data which help palaeontologists to understand the lesson from the geological past to interpret our future. The 8thInternational Brachiopod Congress just held in Milan, with its numerous oral and poster presentations, is a clear evidence of that. The brachiopod community has proved to be very active, with a lot of young students and researchers involved in the development of new studies and projects. An example of that is the BASE-LiNE EarthProject, founded by the European community with 21 partners (lead by GEOMAR, Kiel), which produced very innovative multi- and interdisciplinary researches (https://www.baseline-earth.eu/)

 

So…keep an open eye on macropalaeontology latest discoveries!

 

Chair of the Congress: Lucia Angiolini & Renato Posenato

Scientific Committee: Álvarez Martínez F., Angiolini L., Brand U., Carlson S.J., Cusack M., Eisenhauer A., Harper D.A.T., Holmer L., Garcia Joral F., Lüter C., Pérez-Huerta A., Posenato R., Shen S.

Organizing Committee: Crippa G., Brandolese V., Garbelli C., Henkel D., Romanin M., Ye F.

 

This post was written by Gaia Crippa and Lucia Angiolini with revision by Cinzia Bottini

 

Gaia Crippa is a post-doctoral researcher at the University of Milan (Department of Earth Sciences, Italy).

Lucia Angiolini is full professor at the University of Milan (Department of Earth Sciences, Italy).