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Data from: Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin

Citation

Rosenthal, Eric I.; Holt, Amanda L.; Sweeney, Alison M. (2018), Data from: Three-dimensional midwater camouflage from a novel two-component photonic structure in hatchetfish skin, Dryad, Dataset, https://doi.org/10.5061/dryad.31v01

Abstract

The largest habitat by volume on Earth is the oceanic midwater, which is also one of the least understood in terms of animal ecology. The organisms here exhibit a spectacular array of optical adaptations for living in a visual void that have only barely begun to be described. We describe a complex pattern of broadband scattering from the skin of Argyropelecus sp., a hatchetfish found in the mesopelagic zone of the world's oceans. Hatchetfish skin superficially resembles the unpolished side of aluminum foil, but on closer inspection contains a complex composite array of sub-wavelength-scale dielectric structures. The superficial layer of this array contains dielectric stacks that are rectangular in cross-section, while the deeper layer contains dielectric bundles that are elliptical in cross-section; the cells in both layers have their longest dimension running parallel to the dorsal-ventral axis of the fish. Using the finite-difference time-domain approach and photographic radiometry, we explored the structural origins of this scattering behavior and its environmental consequences. When the fish’s flank is illuminated from an arbitrary incident angle, a portion of the scattered light exits in an arc parallel to the fish's anterior-posterior axis. Simultaneously, some incident light is also scattered downward through the complex birefringent skin structure and exits from the ventral photophores. We show that this complex scattering pattern will provide camouflage simultaneously against the horizontal radially symmetric environmental light in this habitat, the predatory bioluminescent searchlights that are ubiquitous here. The structure also directs light incident on the flank of the fish into the downwelling, silhouette-hiding counterillumination of the ventral photophores.

Usage Notes

Funding

National Science Foundation, Award: NSF-1351935, ACI-1053575

Location

Rhode Island
Eastern United States
Atlantic Ocean
Delaware