congresos y reuniones científicas
The genus Buccinanops (d’ Orbigny, 1841): No eyes or blind eyes?
Antwerp, Belgium
Congreso; World Congress of Malacology; 2007
Institución organizadora:
The genus Buccinanops groups seven species, all endemic to the South Western Atlantic. Buccinanops cochlidium ranges from Rio de Janeiro, Brazil (23º S) to Comodoro Rivadavia in Patagonia, Argentina (45º S). They occur constantly during the whole year and are easily collected by SCUBA diving around Península Valdés. In San José Gulf (42º25´ S; 64º31´ W) they commonly live in shallow waters between 4 y 15 meters depth, buried in sandy bottoms. Animals are medium in size reaching up to 120 mm length, and are typically blind. The genus name means no eyes, due to the lack of visible eyes.In this work we recognize for the first time the presence of eyes in this genus. Observations evidenced the presence of eye spots in the embryos of Buccinanops cochlidium, during intracapsular development as well as in the young hatchlings. The tentacles were histologicaly studied in late “veliger” stage embryos, juveniles and adults. Eyes were found only in embryonary tentacles which presented censory cells, corneal cells and a lens. No evidence of an eye was found in continuouse seried cuts of an adult tentacle. The possible location and functionality, if any, of the eyes in the adults remain unknown. Tentative hypothesis on embryonary eye evolution, at he beginning of this work, were: 1) The embryonic eye is reabsorbed and disappears. 2) The eye is conserved but is covered by the overgrowth of tentacle tissue (inner migration). 3) The eye is modified so that it is no longer functional and then migrates into the tentacle. Ontogenic development evolution of the eye’s ultrastructure, functionality and location is currently being studied.