Macroevolution and spatial distributions

Survival of an organism is unquestionably linked to its interactions with other organisms. However, abiotic factors, such as habitat, may contribute to organismal success and be a signal of evolutionary history. While closely related species likely live in environments that are more similar compared to distant relatives, modern hypotheses of fish relationships show close allies living in dramatically different environments. Examples include some of the deepest living vertebrates on earth (cusk-eels; Ophidiidae) sister to a shallow-water clade (pearlfishes; Carapidae) and forthcoming research targets questions about transitions among environments of depth and salinity.