Anatomical and functional differences of the thoracic limb muscles and nerves of two procyonids (Procyon cancrivorus and Nasua nasua) and the domestic cat (Felis catus)

• Ano de defesa: 2025
• Autor(a) principal: García, Juan Fernando Vélez
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Carnivora; Evolução; Evolution; Inervação; Innervation; Membro torácico; Miologia; Myology; Thoracic limb
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/10/10132/tde-11022026-140857/

The crab-eating raccoon (Procyon cancrivorus), South American coati (Nasua nasua) and the domestic cat (Felis catus) are three mammal species that belong to the order Carnivora. Procyon cancrivorus and Nasua nasua belong to the family Procyonidae, and Felis catus to the family Felidae. These three species have scansorial locomotion, which means that they are mainly of terrestrial habits, but also can climb trees. The three species have different type of stance of the thoracic limb on the substrate. Thereby, the Procyon cancrivorus is semi-digitigrade, Nasua nasua is palmigrade, and Felis catus is digitigrade. Furthermore, they have other locomotor abilities that differ among them, as the digging abilities of Nasua nasua, the high hand skills of Procyon cancrivorus, and high abilities to capture prey of Felis catus. Thus, these adaptations should be reflected in the thoracic limb muscles and brachial plexus nerves since the muscular system evolve together the nervous system. Although there are previous studies in these species, several of them uses a former terminology, differ among them and there is no a comparative statistical analysis to establish functional differences among the proportional masses among the three species. Furthermore, most of these studies did not use the innervation to establish the homology and evolutionary derivation of the muscles. Therefore, the present thesis aimed to report the anatomical and functional differences of the thoracic limb muscles and nerves among P. cancrivorus, N. nasua and F. catus. Formaldehyde-fixed carcasses of the three species were used in this study with the permission of the Bioethics Committees of the involved institutions. The procyonids cadavers were collected with the Environmental license (SISBIO Nr. 37072-2). No specimens were sacrificed to this study. Gross dissections were made on the cervical, pectoral and thoracic limb regions to describe the origin and distribution of the brachial plexus and the characteristics of the muscles. Most homologies and evolutionary derivation inferences of the three species could be established within the order Carnivora based on the topology, origin, insertion, innervation, and anatomical variants. Among them, Felis catus had a pectoantebrachialis muscle, which is not present in both procyonids and could have derivate from the pectoralis descendens muscle. The tensor fasciae antebrachii muscle divided into two parts in Procyon cancrivorus. Several Felis catus specimens had atavistic muscles as the coracobrachialis longus muscle, articularis humeri and one had a caput breve of the biceps brachii muscle. The articularis humeri muscle was present in several cases of Nasua nasua. Differing from previous studies, all specimens of Nasua nasua presented an accessory belly derived from the flexor digitorum superficialis muscle. Most proportional masses of the intrinsic thoracic limb muscles were statistically similar between Felis catus and Procyon cancrivorus, and both species differed with Nasua nasua in most regional and functional groups. In conclusion, the muscle mass adaptations are more related to the type of stance of the thoracic limb, whereas the presence of accessory bellies is more related with the phylogeny.