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Jon Tennant

Jon began university life as a geologist, followed by a treacherous leap into the life sciences. He spent several years at Imperial College London, investigating the extinction and biodiversity patterns of Mesozoic tetrapods – anything with four legs or flippers – to discover whether or not there is evidence for a ‘hidden’ mass extinction 145 million years ago. Alongside this, Jon researched the origins and evolution of ‘dwarf’ crocodiles called atoposaurids. Prior to this, there was a brief interlude were Jon was immersed in the world of science policy and communication, which greatly shaped his views on the broader role that science can play, and in particular, the current ‘open’ debate. Jon tragically passed away in 2020.

Getting into open science

October 21, 2015

This was originally posted at: https://thewinnower.com/papers/2301-my-open-science-story

It never really occurred to me not to be open. From the moment I started my PhD, I made a promise to myself that everything I did would be open and transparent. By this, I don’t just mean access to published papers – I wanted the data, and the information that I was generating to be freely available, and understandable to everyone. Apparently, this makes you a ‘radical’, but to me the alternatives just didn’t appeal. I didn’t see the sense in paywalls, in not sharing, in doing things for any reason but the benefit of the commons.

I remember during my Masters, back in 2011, vowing that my first paper would be published in PLOS ONE – I couldn’t fathom the idea that research I’d spent so long on wouldn’t be freely available. It took 3 years, but I eventually made it happen. My next paper was in PeerJ – I wanted to show that publishing open access early on in your career doesn’t cost anything, and is the easiest approach that benefits the most people. That’s when I really started to get into open science. Hitting paywalls when trying to do your research, or not knowing where the data was to support the conclusions of papers – these are huge impediments to researchers at all levels, and frankly I didn’t understand why it was the norm.

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Crocodiles feeling the heat of extinction

September 24, 2015

New research on crocodiles shows that a combination of changing sea levels and temperatures were responsible for driving their biodiversity over millions of years.

Living crocodiles are threatened by climate change, with 10 out of 23 species at a high risk of extinction. As ectotherms, animals which require external sources of heat to function, they are sensitive to changes in temperature. With 2-4 degrees of increasing global temperatures predicted over the next century, these ruling reptiles have never been more threatened.

The fossil record is our gateway into understanding the evolutionary history of crocodiles. They actually have a long and complex ancestry, going back around 250 million years. During this time, crocodiles and their ancestors, known collectively as crocodyliforms, diversified into an array of forms, including 12-15 foot giants, dwarfed species no bigger than a cat. Some groups even took to the seas, evolving sleek and ‘dolphin-like’ forms, including flippers! The origin of modern crocodiles, known as crocodylians, was around 80 million years ago, during the Cretaceous period. During this time, most of the Earth was experiencing high temperatures, and known as a ‘greenhouse world’.

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Nessie dwarfed by new Scottish crocodile

September 11, 2015

Yes, Nessie had to be in the title. Am I sorry? A little. But not enough to not use it.

Colleagues from the University of Edinburgh and myself have described the first Scottish crocodile fossil! It’s from the Isle of Skye, from a time known as the Middle Jurassic, and dates back around 160 million years ago. Based on a partial bit of a jawbone (the dentary), it’s hardly the most spectacular fossil we’ve ever found, but it tells quite a neat story.

Based on the features we could identify of the jawbone, we were able to identify the specimen as belonging to Theriosuchus. This genus has quite a complicated history, and currently 5 species are assigned to it that span some 100 million years! That’s pretty long lived for a single genus. Theriosuchus belongs to a group known as Atoposauridae, which based on our current understanding went extinct along with the non-avian dinosaurs at the end of the Cretaceous period.

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New species of ‘river dolphin’ reveals their ancient marine origins

September 7, 2015

A new species of extinct dolphin closely related to modern Amazonian ‘river dolphins’, but which dwelled in ancient oceans, is helping to solve the mystery of how and when dolphins adapted for life away from the sea.

Freshwater dolphins are endangered, largely due to human activity. In modern ecosystems, only five or six species remain, and among these, the Yangtze ‘river dolphin’ was declared ‘functionally extinct’ in 2006.

These animals are truly remarkable, and show what scientists have interpreted as adaptations for helping to navigate the murky waters of the winding rivers they inhabit: broad, paddle-shaped flippers, and long narrow snouts – much longer than their modern, sea-dwelling cousins – and flexible necks for catching rapidly darting prey.

An artist's recreation of Isthminia panamensis feeding on a flatfish. Many features of this new species appear similar to today’s ocean dolphins, yet the new fossil species is more closely related to the living Amazon River dolphin. Image: Julia Molnar / Smithsonian Institution

An artist’s recreation of Isthminia panamensis feeding on a flatfish. Many features of this new species appear similar to today’s ocean dolphins, yet the new fossil species is more closely related to the living Amazon River dolphin. Image: Julia Molnar / Smithsonian Institution

Scientists from the Smithsonian discovered a new genus and species of extinct ‘river dolphin’, hailing from the Caribbean Coast of Panama 6 million years ago during a time known as the Miocene. Based on a skull and parts of the right flipper, they estimate it could grow to more than 9 feet in length, just slightly larger than its modern relatives. The new animal is named Isthminia panamensis, as a dedication to the people of the Republic of Panama, and the many scientists who’ve studied the biology and geology of the region.

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