Obtención del Esqueleto de la Zarigüeya Andina de Orejas Blancas (Didelphis pernigra) Mediante la Utilización de un Protocolo Modificado de Osteotecnia del Laboratorio de Anatomía Animal de la Universidad Central del Ecuador

Osteotechnics methods allow for the preparation and preservation of bone specimens free of organic material residues. These methods consist of a combination of natural, chemical, and/or physical processes, enabling the creation of realistic skeletons for educational and exhibition purposes. The Animal Anatomy Laboratory at the Faculty of Veterinary Medicine of the Central University of Ecuador received a donated white-eared Andean opossum (Didelphis pernigra), an omnivorous marsupial widely distributed in the Andean region and often targeted due to a lack of understanding of its ecological role. This study presents modifications made to the standard osteotechnicsprotocol to preserve bone morphology as close as possible to its natural state. After dividing the specimen into four parts — skull, limbs, rib-sternum complex, and vertebral column — the first modification was implemented by cooking the parts in a 10 % sodium chloride solution for four hours instead of using calcium oxide. The bones were removed every 15 minutes to manually remove residual soft tissue. For whitening, hydrogen peroxide concentration was increased from 10 % to 30 %. The bones were then rinsed with water and sun-dried for four days. Since the connective tissue between the joints of the spine, hands, and feet was preserved, assembling the skeleton required only joining the four main sections using wire and silicone, avoiding the need for cyanoacrylate adhesive combined with sodium bicarbonate. These three modifications yielded a skeleton comprising 220 bones with a natural coloration and maintained connective tissue between small joints. The specimen was suspended from a wooden frame to facilitate mobility and display during veterinary and environmental educational activities.