Jeanne Renaud-Mornant began her career in 1951 and quickly became interested in meiofauna, a fauna compartment defined by Mare in 1942[1] consisting of small benthic metazoans smaller than a millimetre in size.
[2] Soon after, she participated in the first international conference on meiofauna in Tunis[3] and became increasingly involved in the scientific community by contributing to the creation of the International Association of Meiobenthologists that she chaired in 1976-1977[4] and participating in the editorial board of the official newsletter of the IAM: Psamonalia.
[6] In 1967, her work caused her to be asked by the National Museum of Natural History in Paris to assume charge of the national collection of "Vers libres" ("Free worms")[3] in which Renaud-Mornant added in 1986, the meiofauna section[7] that is today a full collection consisting of specimens of free-living marine nematodes of Gastrotricha, Kinorhyncha, Tardigrades, Turbellaria, rotifers, annelids, and various minor groups such as Loricifera.
She also participated in the staging of the meiofauna space of the Gallery of Evolution.
[8] A recognised morphologist,[3] Jeanne Renaud-Mornant also participated in many activities in the areas of eco-physiology, and phylogeny of meiofauna.