A novel eye in 'eyeless' shrimp from hydrothermal vents of the Mid-Atlantic Ridge.
Rimicaris exoculata is a shrimp that swarms over high-temperature (350 degrees C) sulphide chimneys at Mid-Atlantic Ridge hydrothermal fields (3,600 m). This shrimp lacks an externally differentiated eye, having instead a pair of large organs within the cephalothorax immediately beneath the dorsal surface of the transparent carapace, connected by large nerve tracts to the supraesophageal ganglion. These organs contain a visual pigment with an absorption spectrum characteristic of rhodopsin. Ultrastructural evidence for degraded rhabdomeral material suggests the presence of photoreceptors. No image-forming optics are associated with the organs. We interpret these organs as being eyes adapted for detection of low-level illumination and suggest that they evolved in response to a source of radiation associated with the environment of hydrothermal vents.
Van Dover
C L
CL
Woods Hole Oceanographic Institution, Massachusetts 02543.
Szuts
E Z
EZ
Chamberlain
S C
SC
Cann
J R
JR
D000818:Animals; D033364:Decapoda / Q000033:anatomy & histology*; D005123:Eye / Q000032:analysis / Q000033:anatomy & histology*; D006358:Hot Temperature; D010786:Photoreceptor Cells / Q000032:analysis / Q000033:anatomy & histology; D012168:Retinal Pigments / Q000032:analysis; D012243:Rhodopsin / Q000032:analysis; D013053:Spectrophotometry
D012168:Retinal Pigments; D012243:Rhodopsin