Meeting Abstract
The uncommonly complex eyes of stomatopod crustaceans, or mantis shrimp, feature unique anatomical and physiological features that are thought to illustrate visual adaptations. Gonodactyloid mantis shrimp eyes have six equatorial midband rows and four spectral types of filters to detect the variety of light stimuli in their shallow coral reef habitats. On the other hand, most squilloid mantis shrimp are associated with darker light environments, have only two midband rows, and lack filters altogether. In addition to their unique anatomical specializations, mantis shrimp eyes contain the largest diversity of light-sensitive visual pigments known for animals. We now describe a photosensitive ventral eye associated with the cerebral ganglion, or brain, in a gonodactyloid mantis shrimp (Neogonodactylus oerstedii), which is the first direct evidence of extraocular photoreception in mantis shrimp. In this gonodactyloid, transcripts that could encode middle- and long-wavelength-sensitive opsins (the protein component of visual pigments) are expressed in the ventral eye and in several additional neuropils, where they may be involved in circadian photoentrainment, shelter-seeking behaviors, multisensory integration, or other functions. In a squilloid mantis shrimp (Squilla empusa), we also observe a well-defined ventral eye and several extra-retinally expressed opsin transcripts, suggesting that mantis shrimps inhabiting different light environments and with differing eye complexities are similarly equipped with extraocular photoreceptors.
