Anatomy of facial nerve in maned wolf (Chrysocyon brachyurus - Illiger, 1815)

Abstract

Maned Wolf (Chrysocyon brachyurus) is considered one of the largest and most beautiful canids in South America, inhabits the Cerrado biome, and presents nocturnal habits, especially during the twilight period. It is in danger of extinction, mainly due to anthropic activity in its habitat. What certainly raises the importance of studying and better understanding its biology. The mammalian Facial Nerve is the seventh cranial pair and controls the functions of facial expression muscles and others. Once the anatomical descriptions of this canid are scarce, this paper aimed to describe the anatomy of Facial n. in Maned Wolf and correlate it with that of domestic canids, a phylogenetically close species whose anatomy is well known. For this research, four adult specimens were used, whose carcasses were collected along highways in southeastern Goiás State - Brazil (SISBIO 37072-2), or donated by the Wildlife Screening Center (CETAS) in Catalão - Goiás State. The specimens were fixed in a 10% aqueous formalin solution and stored in the same solution. Dissection was performed by macroscopic anatomical methods. The research was carried out with a favorable opinion of the Animal Use Ethics Committee (CEUA) of the Federal University of Uberlândia (UFU) (under n° 067/12). Anatomical preparations of post-mortem Maned Wolf did not reveal the presence of Caudal Auricular, Internal Auricular, nor Stylohyoid n.. Small ramifications of Facial n. can be considered as collateral branches. The Facial n. emerged as a single trunk, Facial n. Trunk, which branches into Auriculopalpebral, Dorsal Buccal, and Ventral Buccal n..