Regeneration in the Brittle-Star Ophiocoma Pumila, with Reference to the Influence of the Nervous System

Effects of disc and arm loss on regeneration byMicrophiopholis gracillima (Echinodermata: Ophiuroidea) in nutrient-free seawater

“…In contrast, Morgulis (1909) showed that the rate of arm regeneration (ram/d) in Ophiocoma pumila with 1 to 3 arms removed was equivalent to those with 4 to 5 arms removed. However, the arm structure of these two species is dissimilar, and length is a poor measure of true regeneration because it does not necessarily reflect small changes in biomass or tissue content (Clements et al 1988).…”

“…Conflicting studies have suggested that the rate of arm regeneration is either positively correlated with (Zeleny 1903) or independent of (Morgulis 1909) the amount of arm loss. Salzwedel (1974) demonstrated that the total length and dry weight of regenerating arms increases with increasing arm loss, although the rate slows somewhat over time.…”

Regeneration neurohormones and growth factors in echinoderms

“…Despite this background, cellular aspects of the regeneration process in ophiuroids are little understood. Some very early studies suggested the involvement of the nerve (Zeleny 1903;Morgulis 1909), while most recent work has focused on the ecological benefits and impacts of the extensive regeneration seen in many species (Stancyk et al 1994). These animals are certainly excellent subjects for studying the energetic costs of regrowth versus other physiological processes.…”

“…The nervous system is well known for its central role as a promoter/inducer of regenerative processes in both vertebrates and invertebrates. Echinoderms are no exception to this; for example, a putative role for the nervous system during regeneration was proposed long ago (Goldfarb 1909;Morgulis 1909Morgulis , 1912, while more recently, it was clearly shown that in asteroids, regeneration of an amputated arm cannot occur in the absence of the RNC, and moreover, the presence of the nervous system is needed throughout the regeneration period (Huet 1975(Huet , 1980. In crinoids, armregeneration processes always involve the nervous system, which acts as an important source/vehicle for the different families of migratory cells, including stem elements (amoebocytes) and differentiated elements (phagocytes, granule cells), that are primarily responsible for both repair processes and growth of new tissues (Candia Carnevali et al 1989.…”

Wound healing and arm regeneration in Ophioderma longicaudum and Amphiura filiformis (Ophiuroidea, Echinodermata): comparative morphogenesis and histogenesis

“…In this group, arm regeneration is the most explored phenomenon. However, there are only few older morphological/histological studies describing arm regeneration in ophiuroid species (Morgulis 1909;Zeleny 1903;DawydoV 1901), whilst recent literature tends to focus speciWcally on physiological, ecological or molecular aspects of regeneration (Clark et al 2007;Thorndyke 2006, 2007;Bannister et al 2005; Thorndyke et al , 2003Makra and Keegan 1999;Sköld and Rosenberg 1996;Stancyk et al 1994;Aronson 1991;Walsh et al 1986;Salzwedel 1974), leaving unsolved many fundamental morphological and histological questions, vital so as to provide basic information needed to better understand the evolutionary and adaptive signiWcance of the regenerative phenomena throughout Echinodermata. Preliminary studies on arm regeneration in ophiuroid species suggested that the phenomenon can be comparable in its main aspects to arm regeneration in crinoid species ; Thorndyke and Candia Carnevali 2001).…”