A newly published study led by scientists from the Field Museum in Chicago (USA) includes descriptions of nine new species of fossil grapes.  The paper, published in the journal “Nature Plants” reveals how the extinction of the non-avian dinosaurs may have permitted grape vines to spread and diversify.  Some of the newly described grape taxa are the oldest found to date in the Western Hemisphere.  The fossils were found in Peru, Panama and Columbia and range in age from sixty million years old to around nineteen million years old.  The seeds range in geological age from the Palaeocene Epoch to the Miocene Epoch.

Fossil grape (photograph top left) with computer model generated from CT fossil scans (top right). Line drawings illustrating the fossil by Pollyanna von Knorring (below). Picture credit: Fabiany Herrera.

Picture credit: Fabiany Herrera

Studying Fossil Grapes

These fossil seeds from Central and South America help to show how the grape family (Vitis) spread in the years following the extinction of the dinosaurs.

Lead author of the paper Fabiany Herrera (assistant curator of palaeobotany at the Field Museum in Chicago), commented:

“These are the oldest grapes ever found in this part of the world, and they’re a few million years younger than the oldest ones ever found on the other side of the planet.  This discovery is important because it shows that after the extinction of the dinosaurs, grapes really started to spread across the world.”

It is rare for fruits to be preserved in the fossil record.  However, seeds are more likely to survive the fossilisation process.  What palaeobotanists know about the evolution of angiosperms has been greatly enhanced by studying seeds and fossil pollen.  The earliest known grape seed fossils were found in India.  They are approximately sixty-six million years old.  At this time, there was a global extinction event.  This extinction was probably caused by the impact of an extra-terrestrial bolide.  This devastated life on Earth and led to a re-setting of ecosystems.  The composition of forests was altered as the extinction event affected both fauna and flora.

Fabiany Herrera in the field holding a grape fossil. Picture credit: Fabiany Herrera.

Picture credit: Fabiany Herrera

Dinosaur Extinction Helped Grape Growers

Herrera and his colleagues postulate that the extinction of the Dinosauria helped alter the flora within forests.

Co-author Mónica Carvalho explained:

“Large animals, such as dinosaurs, are known to alter their surrounding ecosystems. We think that if there were large dinosaurs roaming through the forest, they were likely knocking down trees, effectively maintaining forests more open than they are today.”

With the dinosaurs having died out and the absence of large mammals during the Palaeocene, forests became more crowded.  There were no large animals present to deplete the forest understorey and create a more open environment.  These new, dense forests provided an opportunity for plants like vines to become more widespread.  Ultimately, modern-day wine producers might have to thank dinosaurs for the evolution of the grape family of plants.

The diversification of mammals and birds may also have aided the spread of vines by helping to spread their seeds.

The Significance and Importance of Fossil Grapes

In 2013, Herrera’s PhD advisor and senior author of the new paper, Steven Manchester, published the paper describing the oldest known grape seed fossil from India.  Herrera suspected that ancient grape vines existed in South America too.

Herrera commented:

“Grapes have an extensive fossil record that starts about fifty million years ago.  I wanted to discover one in South America, but it was like looking for a needle in a haystack.  I’ve been looking for the oldest grape in the Western Hemisphere since I was an undergraduate student.”

Field work in the Colombian Andes with study co-author Mónica Carvalho provided the breakthrough.  Mónica discovered a fossilised grape seed.  The specimen was at least sixty million years old.  It was the first grape fossil to be found in South America.

Mónica Carvalho excitedly holding a grape fossil. Picture credit: Fabiany Herrera.

Picture credit: Fabiany Herrera

A Tiny Fossil Seed

The fossil seed is extremely small. However, Herrera and Carvalho were able to identify it based on its particular shape, size, and other morphological features. CT scans were undertaken to examine the fossil’s internal structure and confirm its affinity with the grape family.  This new taxon was named Lithouva susmanii.  The binomial name translates as “Susman’s stone grape”.  The name honours Arther T. Susman a supporter of South American palaeobotany at the Field Museum.

Co-author Gregory Stull of the National Museum of Natural History (Washington DC) explained the significance of these fossil grapes:

 “This new species is also important because it supports a South American origin of the group in which the common grape vine Vitis evolved.”

The field studies in Central and South America led to the scientific description of nine new species of fossil grapes.  These fossilised seeds not only tell the story of grapes’ spread across the Western Hemisphere, but also of the many extinctions and dispersals the grape family has undergone. The fossils are only distant relatives of the grapes native to the Western Hemisphere and a few, like the two species of Leea identified are only found in the Eastern Hemisphere today.

A Tumultuous Evolutionary Journey

These fossils suggest that the evolutionary journey of the grape family has been tumultuous.  Herrera commented that the fossil record of grapes demonstrates that these plants are extremely resilient.

Given the mass extinction our planet is currently facing, Herrera commented that studies like this one are valuable because they reveal patterns about how biodiversity crises play out.

Everything Dinosaur acknowledges the assistance of a media release from the Field Museum (Chicago) in the compilation of this article.

The scientific paper: “Cenozoic seeds of Vitaceae reveal a deep history of extinction and dispersal in the Neotropics” by Fabiany Herrera, Mónica R. Carvalho, Gregory W. Stull, Carlos Jaramillo and Steven R. Manchester published in Nature Plants.

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Ammonites were not in decline immediately before the End-Cretaceous extinction event that wiped out the dinosaurs.  Newly published research led by the University of Bristol has found that there is evidence to indicate that these cephalopods were still relatively successful at the end of the Age of Dinosaurs.  The study suggests the fate of ammonites was not set in stone.  Instead, the final few million years of their evolutionary history is more complex than previously thought.  Ammonite fossils might be very familiar, but we still have a lot to learn about the ammonoids.

Demonstrating a sequence of ammonite fossils identified from specific strata that helps to form a biostratigraphic column.  Ammonites provide an important resource to help with the relative dating of strata.  It was thought these marine molluscs were in decline in the Late Cretaceous, but new research challenges this theory.  Picture credit: Everything Dinosaur.

Picture credit: Everything Dinosaur

Ammonite Fossils

Ammonites were marine molluscs that flourished in the Earth’s seas and oceans for more than 350 million years before they became extinct.  They died out during the same chance event that wiped out the dinosaurs, pterosaurs and most of the marine reptiles sixty-six million years ago.

It had been suggested that the extinction of the ammonites was inevitable as changes in climate and marine biota took hold.  It had been thought that the number of species was in decline at the end of the Cretaceous.

Newly published research challenges this assertion.  Writing in the journal “Nature Communications”, the scientists demonstrate that a detailed study of the ammonite fossil record reveals a more nuanced and complex picture.

Lead author of the study Dr Joseph Flannery-Sutherland (University of Bristol), stated:

“The fossil record tells us some of the story, but it is often an unreliable narrator. Patterns of diversity can just reflect patterns of sampling, essentially where and when we have found new fossil species, rather than actual biological history.  Analysing the existing Late Cretaceous ammonite fossil record as though it were the complete, global story is probably why previous researchers have thought they were in long-term ecological decline.”

The colourful heteromorphic ammonoid model – CollectA Pravitoceras.  An ammonite of the Late Cretaceous.

The picture (above) shows a model of an ammonite with an irregularly coiled shell (heteromorphic ammonite).  This is the CollectA Pravitoceras ammonite figure from the “CollectA Prehistoric Life” range.

To view the range of CollectA prehistoric animal models and figures in stock at Everything Dinosaur: CollectA Prehistoric Life Models and Figures.

A Database of Late Cretaceous Ammonite Fossils

In a bid to better understand Late Cretaceous ammonite speciation the researchers constructed a new database of Late Cretaceous ammonite fossils to help fill in the sampling gaps in their record.

Co-author of the study, Cameron Crossan, a 2023 graduate of the University of Bristol’s Palaeobiology MSc programme, explained:

“We drew on museum collections to provide new sources of specimens rather than just relying on what had already been published.  This way we could be sure that we were getting a more accurate picture of their biodiversity prior to their total extinction.”

Using this database, the researchers then analysed how ammonite speciation and extinction rates varied in different parts of the world. If ammonites were in decline through the Late Cretaceous, then their extinction rates would have been generally higher than their speciation rates wherever the team looked.  However, the team found that the balance of speciation and extinction changed both through geological time and between different geographic regions.

Two different types of ammonite (a regularly coiled homomorphic ammonite and an irregularly coiled heteromorphic ammonite) in a Late Cretaceous marine environment. Picture credit: Callum Pursall.

The differences in ammonoid diversification in different parts of the world has not been fully explored.  However, it is crucial to understanding their state prior to the mass extinction event.

Co-author Dr James Witts (London Natural History Museum), explained:

“These differences in ammonoid diversification around the world is a crucial part of why their Late Cretaceous story has been misunderstood.  Their fossil record in parts of North America is very well sampled, but if you looked at this alone then you might think that they were struggling, while they were actually flourishing in other regions.  Their extinction really was a chance event and not an inevitable outcome.”

Why Did Ammonoids Continue to be Successful?

To discover more about the factors responsible for the continued success of ammonoids, the team looked for possible influencing criteria that might have caused their diversity to change.  There are two contrasting theories.  Were speciation and extinction rates driven mainly by environmental conditions like sea temperatures and sea levels (the Court Jester Hypothesis), or by biological processes like pressure from predators and intraspecific competition (the Red Queen Hypothesis).

Co- author Dr Corinne Myers (University of New Mexico) commented:

“What we found was that the causes of ammonite speciation and extinction were as geographically varied as the rates themselves.  You couldn’t just look at their total fossil record and say that their diversity was driven entirely by changing temperature, for example. It was more complex than that and depended on where in the world they were living.”

Dr Flannery-Sutherland added:

“Palaeontologists are frequently fans of silver bullet narratives for what drove changes in a group’s fossil diversity, but our work shows that things are not always so straightforward. We can’t necessarily trust global fossil datasets and need to analyse them at regional scales. This way we can capture a much more nuanced picture of how diversity changed across space and through time, which also shows how variation in the balance of Red Queen versus Court Jester effects shaped these changes.”

Everything Dinosaur acknowledges the assistance of a media release from the University of Bristol in the compilation of this article.

The scientific paper: “Late Cretaceous ammonoids show that drivers of diversification are regionally heterogeneous” by Joseph Flannery-Sutherland, Cameron Crossan, Corinne Myers, Austin Hendy, Neil Landman and James Witts published in Nature Communications.

The Everything Dinosaur website: Prehistoric Animal Models and Toys.