About the Cover
Cover
Asperspina is a microscopic gastropod that lives within the interstitial spaces of benthic marine sediments. Species of Asperspina and other acochlidean molluscs represent a highly divergent group of opisthobranchs with a host of morphological adaptations to this space-restricted, sedimentary world, including a highly elongate body, a spicule-reinforced body wall, and simple internal anatomy. Despite these differences from their more familiar and much larger relatives, such as Aplysia californica and Tritonia diomedea, acochlideans possess a very similar neural architecture. The confocal photomicrograph on the cover reveals the musculature and serotonergic nervous system of the head-foot complex in a species of Asperspina collected from subtidal sediments in eastern Florida.
On pages 43-54 of this issue, Hochberg provides the first immunohistochemical insights into the structure of the acochlidean nervous system. Through the use of anti-serotonin antibodies and confocal laser scanning microscopy, he presents evidence that the distribution of serotonergic perikarya in the major ganglia of Asperspina closely resembles their distribution in much larger gastropods. Moreover, innervation of the head-foot complex, including the foot and chemosensitive rhinophores, also shows several striking similarities to model anaspids and nudibranchs. The results suggest that the evolution of the acochlidean bauplan (its fundamental body plan), which involved a major decrease in body size, was not accompanied by considerable structural changes in the architecture of the nervous system.
Credits: Photo, Rick Hochberg (University of Massachusetts Lowell); cover layout, Beth Liles (Marine Biological Laboratory).
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Copyright © 2007 by the Marine Biological Laboratory.
