Feeding behavior of Spurilla sp. (Mollusca: Opisthobranchia) with a description of the kleptocnidae sequestered from its sea anemone prey. Zoological Studies 51(7): 905-912. Cnidocysts are sequestered from cnidarian prey by aeolid nudibranchs and stored in the tips of their appendages (cerata). The kleptocnidae of 11 specimens of Spurilla sp. are described in detail. The types and relative abundances of prey cnidocysts in nudibranch cerata were highly variable, suggesting exclusive anemone consumption. Spirocysts and several types of microbasic p-mastigophores, microbasic b-mastigophores, and basitrichs were found in external and internal tissues of sea anemone prey. This is the 1st report of predation of aeolid Spurilla sp. on the sea anemones Antholoba achates, Metridium senile lobatum, and Parabunodactis imperfecta from the rocky intertidal of Patagonia (Chubut Province, Argentina) and on Anthothoe chilensis and Tricnidactis errans at Mar del Plata (Buenos Aires Province, Argentina). Photographs and digital videos of aeolidacean feeding behavior were recorded in situ and in aquaria. The purpose of this study was to provide valuable information on the diet of Spurilla sp. from Argentina using field observations and descriptions of the kleptocnidae.Fil: Garese, Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: García Matucheski, Stella. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; ArgentinaFil: Muniain, Claudia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Acuña, Fabian Horacio. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. San Martín; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
