As in other crustaceans (Cronin, 1986; Warrant and Nilsson, 2006), lobsters have a reflecting superposition eye that is highly sensitive to light (Barnes and Goldsmith.
The advantage of a superposition eye is its sensitivity at lower light intensities, albeit at the expense of speed of vision (Warrant et al, 1996; Warrant, 1999; Warrant and Nilsson, 2006).
However, even with light-induced damage to their superposition eyes (Chapman et al., 2000), adult Norway lobsters (Nephrops norvegicus) exhibit no change in survival and growth.
comm., and Juberthie-Jupeau, 1972; Alvinocaris markensis: Chamberlain, 2000); or in which juvenile individuals feature apposition eyes, but adults have superposition eyes (e.g., Panulirus longipes: Meyer-Rochow, 1975; mysids and euphausiids: Nilsson et al., 1986); or in which the dioptric elements are lost and the retina changes from the imaging type to a nonimaging one (bresiliid shrimps: Gaten et al., 1998).
The ontogenetic development of refracting superposition eyes in crustaceans: transformation of optical design.
Morphology of the reflecting superposition eyes
of larval oplophorid shrimps.
If reflecting superposition eyes
, with their characteristic square array of facets, represent the primitive condition in adult decapods (Gaten, 1998), then remnants of the square facets might be expected even though these optics are not used in vent shrimps.
(1982) suggested that anomuran half-crabs of the superfamily Galatheoidea possess reflecting superposition eyes. Research by Meyer-Rochow et al.
If the lack of a clear-zone is real and not artifactual (clear-zones in the superposition eyes of deep-sea decapods can easily collapse and, on account of their fragility and delicateness, may remain undetected as shown by Nilsson, 1990), the closer approximation of the massively developed rhabdom to the much wider dioptric elements, in combination with the backing of a tapetum from behind, could be interpreted as an adaptation to improve sensitivity, especially to point sources.