O sistema reprodutor masculino em Xenarthra (Mammalia) e implicações evolutivas

Abstract

The magnaorder Xenarthra is one of the major groups of placental mammals and is largely restricted to South America. It composed of 31 living species, classified in 14 genera distributed in six families and two orders:. Cingulata, including a single family Dasypodidae and Chlamyphoridae (armadillos), and Pilosa, with families Cyclopedidae (silky/pygmy anteater) and Myrmecophagidae (anteaters), Bradypodidae and Megalonychidae (sloths). The phylogenetic relationship among the three groups of Eutheria mammals not yet well established, and there are three main topologies proposed: (a) Afrotheria as the basal most group (Exafroplacentalia hypothesis), (b) Xenarthra as the basal most group (Epitheria hypothesis), or (c) boreoeutheria as the basal most group (Atlantogenata hypothesis). The urogenital system has often been used as a tool in phylogenetic studies with several groups of metazoa. But in mammals, it is still little explored. The characteristics of Xenarthra reproductive system are still poorly described in the literature. The male genital systems are responsible for developing, mature, transport and store sperm. The structure of the reproductive tract of these animals have a mixture of characters supposedly ancestral and derived recently. Were have done deep descriptions of Myrmecophaga tridactyla (giant anteater) urogenital sistem with donated or loaned specimens. Subsequently, a survey was made from the literature of the reproductive systems of various kinds of magnaordem Xenarthra, which were compared with other Eutherians mammals and also a metateria mammal. Since then, the character of this complex were mapped, in order to verify that they supported any of the three cases of Eutheria rooting