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Evolution of neurocranial anatomy in coelacanth fishes

Are there differences between species during the early Triassic and modern coelacanths?

Supervisors:

Dr. Martin Rücklin (main supervisor),

Benedict King (daily supervisor)

 

Background and context:

Coelacanths are one of only two surviving lineages of non-tetrapod sarcopterygians. Their brain and inner ear anatomy is unusual, the brain is particularly tiny and the inner ear provides unique features. Our knowledge of the evolution of coelacanth neurocranial anatomy is primarily based on Diplocercides, from the Devonian period (nearly 400 million years old). Almost nothing is known of what happened between Diplocercides and the living Latimeria. Well-preserved coelacanth specimens from the Triassic of Greenland offer a unique opportunity to fill this gap through the use of micro-CT scanning technology.

 

Objective and goals: 

Coelacanths are often considered “living fossils” due to their apparently low rates of changes of the gross morphology. This study offers the opportunity to test whether or not a similar pattern of low rates is seen in the evolution of the neurocranium. Are coelacanths from the Triassic essentially identical to the modern Latimeria? Study of several different genera may also show whether or not there are differences between species during the early Triassic, a time when coelacanths appear to have undergone a diversification event.

 

Methods, tasks and approach:

 Micro-CT scanning will be performed on the specimens and digital reconstructions performed in the software Mimics or Avizo. A possible extra part of the project will involve producing a phylogenetic tree of coelacanths using new information discovered during the project.

 

Requirements: 

Knowledge of comparative anatomy, background in Biology and Palaeobiology. Ability to learn digital methods (full training will be provided).