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Regeneration of posterior segments and terminal structures in the bearded fireworm, Hermodice carunculata (Annelida: Amphinomidae)

Authors


  • Contributions: Ahrens, Marshall, and Schulze initiated, directed and completed the research for this publication at Texas A&M University at Galveston. Living specimens were collected by Ahrens. Tissue preparation, histological analysis, slide preparation, and staining were conducted by Ahrens and Marshall. Statistical analyses were carried out by Ahrens. Ahrens composed the manuscript, with additional contributions by Kudenov, Schulze, and Marshall.

ABSTRACT

Like many other annelids, bearded fireworms, Hermodice carunculata, are capable of regenerating posterior body segments and terminal structures lost to amputation. Although previous research has examined anterior regeneration in other fireworm species, posterior regenerative ability in fireworms remains poorly studied. As the morphology of the anal lobe (a small, fleshy terminal structure of unknown function) has been used to distinguish East and West Atlantic H. carunculata populations, there is a more imminent need to understand the morphology and organization of tissues in specimens undergoing posterior regeneration, and the timeframe in which significant developmental changes occur. To further investigate this phenomenon, we amputated the posterior segments of living H. carunculata specimens collected from the Gulf of Mexico and monitored posterior regeneration over a 6-month study period. Although many aspects of posterior regeneration in H. carunculata are consistent with the findings of other annelid regeneration studies, histological analysis revealed that once formed, anal lobe morphology remains relatively unchanged at all stages of posterior regeneration; East Atlantic morphotypes were not observed in the West Atlantic specimens studied here. Additionally, we found that the ventral nerve chord, which is partially responsible for the regeneration of lost body parts in polychaete annelids, terminates within the anal lobe, suggesting that this structure may play a role in the formation of new segments. J. Morphol. 275:1103–1112, 2014. © 2014 Wiley Periodicals, Inc.

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