Abstract
For cats (Felidae), the forelimb plays a crucial role in their lifestyle, both for locomotion and for hunting. While there are studies on the anatomy of large and medium-sized felids, there are few on small Neotropical felids such as Leopardus geoffroyi. The present work complements a previous study by describing in detail the muscles of the forearm and autopodium, comparing them in a functional and phylogenetic context with other Feliformia species, and providing the first muscle maps of these regions for L. geoffroyi. For this purpose, both forelimbs of three adult specimens of L. geoffroyi were examined. Detailed dissections were performed to document the shape, orientation, origin, and insertion of each muscle, as well as to create their respective muscle maps. Obtained myological descriptions were compared with previously published data from other species within the suborder Feliformia. Additionally, 21 characters were optimized in search of a phylogenetic pattern. Subsequently, the dry weight values of each muscle were recorded and the relative weights of functional muscle groups were calculated. This set of indices was included in a principal components analysis (PCA) to observe the distribution of the species within this myological morphospace. The myological configuration of the forearm and autopodium of L. geoffroyi presents similarities with other felids, although some variations were observed in some muscles, both at an intraspecific level and with other species of the order Carnivora. Muscle brachioradialis is more developed in climbing species or those capable of manipulating prey than in cursorial species where it is reduced or absent. In cursorial carnivorans, m. pronator quadratus is long and thin and acts as a forearm stabilizer, while in felids and other climbing or arboreal Feliformia species it is wider, favoring the rotation of the forearm for climbing or hunting. Muscle pronator teres is short and close to the elbow in cursorial carnivorans, offering stability, while in climbing species it has a distal insertion, allowing greater force in rotation. The PCA showed a segregation of terrestrial species from scansorial and arboreal species, related to some myological variations. Retractors of the forelimb are more developed in terrestrial species, which optimizes the movement of the body during the stride, as well as a greater development of the elbow extensors, allowing greater propulsion force for running. Adductor muscles of the forelimb show a greater development in scansorial and arboreal species, which provides them with the necessary strength for climbing and, in the case of felids, a greater capacity to catch and hold prey. This work provides the first detailed description of the forearm and autopodium musculature in L. geoffroyi, revealing a generalist myological configuration, that is, it shares morphological characteristics with both cursorial and climbing or arboreal species, but without reaching a degree of specialization. This work contributes to the understanding of the functions linked to different ways of life and provides an anatomical source for future comparative anatomy studies in evolutionary and functional frameworks for current or fossil species.