Evolution of Deep-Sea Fishes

All animals that have evolved in the deep sea are under similar selective pressures as a result of the environmental extremes (e.g., little to no penetrable sunlight, high atmospheric pressure). This extreme habitat has led to massive convergence in animal morphology and behavior across deep-sea organisms ranging from the production and emission of light (bioluminescence) to the evolution of enlarged fangs and gaping mouths. This multidisciplinary project investigates the processes that have impacted the evolution of deep-sea fishes and their success in this fascinating aquatic realm. This study integrates phylogenetic relationships based on genetic and morphological data, comparative morphology, ecology, and evolutionary biology in an effort to broaden our understanding of fishes that have evolved, thrived, and diversified in the deep sea.

An example of this work is our open-access publication, published in the journal Marine Biology, investigating the evolution of species-specific bioluminescent structures in the deep-sea lineages of lanternfishes (Myctophiformes) and dragonfishes (Stomiiformes). We show, for the first time, that deep-sea fishes that possess species-specific bioluminescent structures (e.g., lanternfishes, dragonfishes) that may be used for communication are diversifying into new species at a more rapid rate than deep-sea fishes that utilize bioluminescence in ways that would not promote isolation of populations (e.g., camouflage, predation). This work adds to our understanding of how life thrives and evolution shaped present-day biodiversity in the deep sea, the largest and arguably least explored habitat on earth.

Davis, M.P., Holcroft, N.I., Wiley, E.O., Sparks, J.S., and Smith, W.L. (2014). Species-Specific Bioluminescence Facilitates Speciation in the Deep Sea. Marine Biology. DOI: 10.1007/s00227-014-2406-x.

Funding for our work on the evolution of deep-sea fishes is provided by the National Science Foundation (NSF Award: DEB 1258141NSF Award: DEB 1257555


  • Matthew Davis