Abstracts (first author)
Phylogeography and morphology of the South American Annual Killifish genus, Austrolebias
The genus Austrolebias consists of over 30 species of freshwater annual killifish. These fish reside in ephemeral pools across a wide region of South America including parts of Brazil, Uruguay, Paraguay, Argentina and Bolivia. Austrolebias possess a peculiar and interesting life-history. Males and females dive together into the muddy substrate of the pond and deposit their gametes. Later, these adults are often seen dying in shallow water as the ponds completely evaporate during the beginning of the dry season. The eggs then go through several stages of diapause until hatching is triggered by the earliest wet season rains, after which the fish grow rapidly and the process is repeated. The large geographic range of Austrolebias means that the genus is subject to considerable variation in climate. I reveal which climate variables are most important in determining the distribution of Austrolebias by using data collated from my own collection trips, primary literature, online biodiversity databases as well as the records of amateur collectors. Larger species of Austrolebias can be up to 13cm in length, the smallest only 4cm. Recent phylogenetic work has shown that large species have been derived from small species in at least 3 separate instances. I use phylogenetic independent contrasts to investigate whether any bioclimatic variables can explain this variation in size. In addition, species distribution models (SDMs) are built using Maxent and subsequently compared using ENMTools in order to identify whether those species that are morphologically similar possess a similar climatic niche. The nature of the Austrolebias life cycle suggests that it is sensitive to climate change. Current SDMs are compared to 2050 SDMs using the HadCM3 model with multiple emission scenarios to predict the future range shifts of Austrolebias in order to discern the effect climate change will have on this genus.