A 350-million-year-old marine 
ecosystem in Scotland 
(Painting by Robert Nicholls)

Oxypteriscus, an extinct ray-finned fish

The earliest shell-crushing ray-fin, Fouldenia, 348 million years ago 
(Painting by John Megahan)


Lauren Cole Sallan, PhD
Assistant Professor
Earth and Environmental Science

& Evolution Cluster
University of Pennsylvania
CV  Google Citations Impact Story

Research Interests
Macroevolution, Macroecology,
Early Vertebrates, Ichthyology 
Mass Extinction, Phylogenetics
Biomechanics, Evo-Devo

Listen to a Palaeocast interview about our research on early vertebrate macroevolution and paleobiology

Research Summary

      We are interested in long-term biodiversity trends, large-scale ecological dynamics, patterns of diversification, mass extinction, and other macroevolutionary processes. In order to answer major questions about these areas, we apply quantitative and descriptive approaches to the fossil records of Paleozoic vertebrates (half of their history) and ray-finned fishes (half of living diversity). 
        Modern vertebrate biodiversity began in the Paleozoic (541-251 million years ago), an interval containing both the origins of major living groups (e.g., ray-finned fishes, tetrapods) and major events in their evolutionary history (e.g., the end-Devonian mass extinction and the subsequent diversification of survivors, 359 million years ago). This period contains multiple "natural experiments" (e.g., environmental and ecological changes) revealing common patterns of diversification, extinction, and morphological evolution. 
        Ray-finned fishes (Actinopterygii; e.g. salmon, tuna and their relatives) have dominated aquatic ecosystems since the mid-Paleozoic, come in myriad functional forms, and are widely used in evolutionary and ecological research. They also have an excellent fossil record, containing thousands of complete specimens and preserving traits from which function and ecology can be inferred.
        Investigation of these two records has already revealed significant macro-evolutionary patterns and processes. These include the role of global events and mass extinction in structuring vertebrate ecosystems and the ecological, environ-mental and even developmental drivers of early and modern biodiversity (see Publications). 

A 310-million-year-old freshwater ecosystem in Illinois
(Painting by John Megahan)

A phylogeny of living ray-finned fishes

A later shell-crushing ray-fin, 
Styracopterus, 340 million years ago
(Painting by John Megahan)