From Google Art Project via Wikimedia; spots throughout image and cracked paint flaws on forehead, nose, neck, and bertha removed with Photoshop. I do not know what the white spot in her chignon is.
Maria Leonor's formal dress has a waist band and probable natural waistline. It also has a flared panel rising from the bow at her waist.
Keywords: 1866, de Ribera y Fieve, Maria Leonor Salm-Salm, duquesa de Osuna, Salm-Salm family, Osuna family, Spanish, straight coiffure, wavy coiffure, chignon, off shoulder vee neckline, modesty piece, bertha, lace, quarter length tight sleeves, bows, cuffs, waist band, floral bodice ornament, floral sleeve ornament, necklace, earrings