Variação morfológica do plexo braquial em quatro espécies de morcegos filostomídeos (Chiroptera, Phyllostomidae)

Abstract

Despite the remarkable morphological modifications that occurred in the thoracic limbs of bats, information about the brachial plexus in this group is still scarce. This study aimed to describe the origin, composition, and distribution of these peripherical nerves in four species of Phyllostomidae. Both antimers of six Artibeus lituratus, five Desmodus rotundus, seven Glossophaga soricina, and five Phyllostomus hastatus—all males, adults, and from the Adriano Lúcio Peracchi Collection (UFRRJ)—were dissected. After complete exposure of the structure, I found that the brachial plexus of D. rotundus and P. hastatus are formed by the same roots (C5 – T1), while the fourth cervical spinal nerve and the second thoracic spinal nerve are present in G. soricina (C4 – T1) and A. lituratus (C5 – T2), respectively. There was intraspecific variation e asymmetry both in the origin of the structure and in the combinations of the nerve segments for forming the terminal branches. Still, the distribution to the target muscles and patagium was more conserved. Data presented here support the presence of two distribution patterns of the nerves to the muscles in Chiroptera, and the innervation of the membranes seems to be explained by embryogenesis. Although the phyllostomid bats brachial plexus is similar to that of other terrestrial Laurasiatheria, aspects identified in these bats and apparently unique to Chiroptera, may be related to anatomical changes in the thoracic limbs functionally liked to flight.