The discovery of Homo naledi, a new species of hominin (the group encompassing modern humans, extinct human species, and all close human ancestors) was announced in September 2015. Found in a deep, nearly inaccessible cave system, this was the largest concentration of hominin bones ever found in Africa. The unusual distribution of bones suggested symbolic behaviour (e.g., deliberate placement by other H. naledi). The find attracted global media attention, including a feature in National Geographic. This discovery had such an impact that it was easily identified as one of the top 10 science discoveries of 2015 by numerous news outlets. The deposits, however, remain undated, leaving their evolutionary significance uncertain – were they a direct human ancestor or another branch on the family tree?
In the last talk of the 2017 Speaker Series, Dr. Eric Roberts, Associate Professor and Head of Geosciences, James Cook University, Queensland, Australia, presents an overview of the discovery of the site and discusses the efforts that went into unravelling the complex geological context of the cave system. He finishes with an overview of his team’s efforts and progress over the last two years at dating the fossils and refining our understanding of this important new hominin locality.
Adaptive radiation is when a group of animals evolve into different forms to fill different roles in their environment. In his talk, Dr. Ben Evans, McMaster University, provides evidence for an example of an adaptive radiation; the fanged frogs of Southeast Asia. Different species of fanged frogs have unique characteristics, including body size and reproductive strategy that allow them to co-exist in the same habitat. Through comparison to frogs in the Philippines and other species of animals, Evans discusses how fanged frogs underwent rapid speciation on Sulawesi, and how this fast-paced evolution led to remarkable changes. He also explains the broader context of fanged frog evolution for conservation and evolutionary studies.
Alberta is home to six native species of snakes. They include the venomous prairie rattlesnake, the bull snake (that can grow up to two metres long), and the western hog-nosed snake that rolls over and plays dead when frightened. Snakes are feared and misunderstood by most of the human population and this can lead to their persecution and destruction. All of Alberta’s snakes are protected by provincial law, but this still does not stop some people from intentionally killing them, turning them into pets, or selling live ones.
Officer Zimmer spent several years working in snake country in the southeast corner of the province both protecting snakes and dealing with snake issues. In his presentation, he talks about identifying native snakes, how to prevent encounters, and protect native snake habitat. He also provides tips on what to do if you’re bitten by a snake.
The actinopterygians, or ray-finned fishes, are a substantial and significant component of modern vertebrate (animals with backbones) diversity. Ray-finned fishes are bony and have paired fins that are supported by rays (the actinosts) that insert directly in the body. Examples of modern ray-finned fishes include trout, eels, and bettas. Despite their prevalence today, the early evolution of this group is poorly understood compared to other major groups, driven by a lack of informative fossil data.
In his talk, Conrad Wilson explains how recent work on Early Carboniferous fossil sites from Nova Scotia and around the world provide new insight into the evolution of this group and how the development of the modern vertebrates may have been influenced by the mass extinction at the end of the Devonian Period (419 – 359 million years ago).
Mosasaurs were large, flipper-bearing swimming lizards from the age of the last dinosaurs, about 100–66 million years ago. Typically reaching the size of a pickup truck in length—and some nearly twice as long—over 70 mosasaur species are reported today based on the fossils collected from all over the world. Out of this highly diverse assemblage, halisaurine mosasaurs were small and seemed less well adapted to life in water since they lacked the well-developed flippers and tail fin of their larger contemporaries. Yet these small mosasaurs became increasingly more common in the fossil record towards the end of the Cretaceous, indicating their evolutionary success alongside their larger, fast-swimming cousins.
In his talk, Dr. Takuya Konishi, from the University of Cincinnati, explains why a recently discovered skull from Japan sheds new light on halisaurine mosasaurs’ potential survival strategy: that halisaurines evolved a pair of large, forward-facing eyes that would have increased their ability to see in the dark, allowing them to hunt at night.
Non-avian theropods are among the closest extinct relatives to birds, but our understanding of their diversity, evolution, and extinction are greatly hampered by their incomplete fossil record. Isolated teeth from the Western Interior Basin, though, provide a continuous sample of these taxa through the last 18 million years of the Cretaceous.
In his talk, Larson explains how the morphology of these teeth can be examined both within a single formation to recognize patterns of evolution and across formations to examine changes in morphology through time.
The extinction of mammoths is the most prominent of Late Pleistocene extinctions that wiped out nearly 70% of large mammals (megafauna) from western Europe through South America about 10,000 years ago. However, on small islands off the coast of Alaska and Siberia, populations of mammoths persisted for many thousands of years after mainland populations disappeared.
In his talk, Dr. Duane Froese from the University of Alberta presents new research on the extinction of mammoths and other megafauna from Arctic North America and the causes of the final extinction of a population on St. Paul Island, Alaska, about 6000 years ago.