Reproductive biology of the brooding feather star Phrixometra nutrix, from the southwestern Atlantic

Abstract

Reproduction of the brooding feather star Phrixometra nutrix was studied from the deep southwestern Atlantic Ocean. Samples were collected using dredge trawlers and fishing nets on board the B/O Puerto Deseado, between 91 and 512 m depth. Reproductive biology was studied using modern optical techniques including histology and scanning electron microscopy. Here we present the first record of genital papillae for class Crinoidea. Genital papillae have been reported in all extant echinoderm classes except for Crinoidea. In addition, a high proportion (16%) of hermaphroditic specimens was found in the analyzed samples. Finally, cystidean and pentacrinoid stages were found inside the marsupium of Phrixometra nutrix. It is expected that this work will enable further discoveries of crinoid reproductive biology considering the ecological and phylogenetic importance of brooding crinoids.