Phylogeography and Evolution of Mesophotic Coral Ecosystems
[Thesis]
Copus, Joshua M.
Bowen, Brian R.
University of Hawai'i at Manoa
2020
133
Ph.D.
University of Hawai'i at Manoa
2020
In this dissertation, I begin to address the phylogeography and evolution of the unique reef fish fauna of the mesophotic zone, generally regarded as beginning at 30 - 150 m depth. Chapter 1 is an introduction to the topic and background for subsequent chapters. As the field of mesophotic research matures, we can move beyond descriptive studies and begin to construct hypotheses for the origins and evolution of mesophotic reef fishes. Accordingly, Chapter 2 describes the habitat persistence hypothesis (HPH), which postulates that mesophotic reef fish communities are older and more stable than their shallow water counterparts. This hypothesis is based on two fundamental observations; 1) Mesophotic communities are extend below the surface waters that are subject to glacial sea level changes on a scale of 106 years, and 2) The shallow water biodiversity gradient, extending from the Coral Triangle (between Philippines, Indonesia, and New Guinea) to Rapa Nui in the eastern Pacific, may not apply to mesophotic communities. This chapter is a formal description of the HPH, and outlines a set of testable hypotheses to evaluate the validity of the HPH. Chapter 3 is a description of the mesophotic fish species Neoniphon pencei. Chapter 4 is a description of the mesophotic fish species Luzonichthys seaver, and Chapter 5 is a description of the mesophotic fish species Prognathodes geminus. These data will provide some of the first descriptions of MCE fishes, and provide a beginning point for testing phylogenetic hypotheses about the origins of mesophotic fishes. Chaper 6 provides a brief conclusion.