Arm regeneration frequencies in Florometra serratissima (Crinoidea, Echinodermata): impact of depth of habitat on rates of arm loss

作者：Baumiller Tomasz K^*

来源：Cahiers de Biologie Marine, 2013, 54(4): 571-576.

• Predation
• Onshore-offshore trends
• Comatulids

Today stalked crinoids are restricted to depths greater than 100 m whereas the fossil record indicates that they were diverse and abundant in shallow water through most of their history. Their disappearance from shallow settings started sometime in the mid-Mesozoic, coincident with the Mesozoic Marine Revolution; not surprisingly, predation has been hypothesized as the cause of their displacement and their present-day bathymetric distribution. Implicit in this is that predation pressure on crinoids decreases with depth of habitat. To test this in modern oceans, patterns of arm regeneration in the comatulid crinoid Florometra serratissima A.H. Clark, 1907, collected at depths ranging 80 to over 1100 m were examined. The application of a newly developed method for reconstructing predation pressure, defined here as "the attack frequency experienced by the prey" (Aronson, 1987, p. 187), from patterns of regenerating arms indicates that arm loss rates decrease with depth: shallowest individuals of F. serratissima lose an arm once every two months, while those from the greatest depth lose an arm very infrequently, less than once every two years. Assuming that arm loss is a consequence of interactions with predators and not abiotic factors, rates of arm loss indicate that predation pressure is depth-dependent.

• 出版日期2013