Research projects

Prof. Dr. Christian Klug

The Devonian nekton radiation in a time of biodiversity crises

Leadership/contacts

Duration

July 2023 to June 2027

Funding sources

SNF, Personen- und Projektförderung

Collaborations

Regions

Summary

Although vertebrates originated already in the Cambrian, the major groups we know today evolved later. Remarkably, some important evolutionary novelties occurred in the Silurian and Devonian. For example, the oldest teeth are known from the early Silurian (439 million years old) and some analyses suggest that they originated already 450 million years ago, but jawed fishes became really abundant and diverse in the Devonian. Also, tetrapods, the four-legged vertebrates, evolved in the Devonian. The Devonian, however, also saw some of the most severe mass extinctions of the past half billion years. We address the question, how the diversification of swimming animals like fish and cephalopods could happen between these biodiversity crises.
Our research is based in field work in the Moroccan Anti-Atlas, at the northwestern margin of the great Sahara Desert. In that region, sediments from small marine basins are exposed, which are world-renowned for their abundant fossils. Remarkably, remains of the fierce-looking placoderm Dunkleosteus were already described 70 years ago. Isolated shark teeth are also quite common, but only recently, we started finding well-preserved skeletons of a series of various fish groups such as ancestors of sharks, chimaeras, ray-finned fish and lobe-finned fish. These new discoveries allow us to better understand their anatomy and mode of life. Additionally, they help us to reconstruct their evolution.
In this project, we will start by studying those fishes, which are not well unknown or even unknown. Then, we ill include the new knowledge into analyses to reconstruct their evolution through time. We will then compare their evolution with that of other swimming animals, the cephalopods, in order to see whether there are similarities in the timing of evolutionary events (such as originations or extinctions of groups).
Then, we will use the knowledge of jaws and teeth as well as geochemical analyses to find out what those fishes were eating. We expect that this information, when put into its time frame, will help us understand the interplay between mass extinctions, evolutionary changes and ecological changes in the Devonian. We also hope to find out, how fast those groups, which were severely affected by mass extinctions, diversified in the aftermath.