Extinct, Evolved, Enchanted

Iguanodon is one of the first three dinosaurs to ever be named and belongs to an important group of herbivorous dinosaurs that possessed large and conical thumb claws. This bizarre ‘thumb spike’ characterises many of these dinosaurs, yet exactly what function it evolved to perform remains a two-century-old mystery. Utilising contemporary digital techniques in palaeontology, we used four independent analyses to investigate whether the thumb spike might have evolved for stabbing, cracking open seeds, nuts or fruit, raking leaves from trees, or ornamental display. First, we compared spike shape to the claws of living animals and tracked the evolution of its shape and size throughout time. Following this, we measured the strength of the spike under different simulated functions, and constrained possible spike usage based on the mobility of the forelimb. Overall, our shape analysis and evolutionary reconstructions suggest against fruit-cracking and leaf-raking as functions to have driven the evolution of the thumb spike, and anti-predatory stabbing seems unlikely based on limited forelimb mobility. However, ornamental display and stabbing combat amongst iguanodontians remain as plausible functions that may have led to thumb-spike evolution. This potential use in signalling and stabbing between members of the same species suggests a possible level of social complexity that nicely fits with depictions of these dinosaurs being social, group living animals. We highlight how recent technological advancements in the discipline of palaeontology allow us to revisit old questions, in this case, shedding light onto a centuries-old mystery.

The Dodo is one of the most iconic animals in pop culture and has almost become the mascot for extinct species. Despite this, most people still believe the exaggerated caricature of the Dodo is representative of the animal's actual biology, physiology and extinction; namely that Dodo’s were fat, stupid animals who due to living on an island paradise lost their ability to respond to predators and were easily hunted to extinction by the first humans to arrive on Mauritius. However, over the past two decades, new research on the Dodo has challenged this pervasive and inaccurate caricature and revealed the Dodo for what it really was; a hardy, well-adapted bird and a lesson on the dangers of anthropogenic environmental change.

Ash is one of the most dominant species in UK broadleaved woodlands, contributing up to 10 million tonnes of national carbon stock. However, the species is currently threatened by ash dieback disease (Hymenoscyphus fraxineus), but what does this mean?

I present an analysis of 40 years of data on ash dynamics, assessing the impacts of ash dieback on the population mortality and carbon stocks of five natural ash populations in the UK. We further investigate potential environmental indicators for developing severe ash dieback symptoms or mortality from the disease. Together, our results highlight the importance of environmental and neighbourhood factors in the resilience of infected ash trees and long term stability of the carbon stocks they contain.