Taxonomia, morfologia e filogenia molecular de protistas ciliados (Ciliophora, Litostomatea) encontrados em ruminantes domésticos

Abstract

The dissertation is divided into three sections. Section 1 provides a detailed taxonomic and morphological study, in which 36 species of rumen ciliates in cattle and sheep were inventoried, based on live observation, semipermanent preparations, pyridinated silver carbonate impregnation and scanning electron microscopy. This section provides new information on important morphometric characters for the taxonomy of this group, with the description of infraciliature and the importance of using techniques ciliatológicas underused in the characterization of rumen ciliates. In Section 2 aiming to reveal the somatic and oral infraciliature for wide spectrum of genera and species of rumen ciliates, were made modifications to existing protocols for the pyridinated silver carbonate impregnation and established a modified protocol that allowed allowed impregnation of infraciliatura oral and nuclear apparatus of all 36 species of rumen ciliates of cattle and sheep fed with cane sugar bagasse. The proposed protocol is simple, quick and easy to be reproduced, being advantageous for taxonomists interested in perform survey studies of ruminal biota and animal scientists and ecologists interested in understanding the taxocenose and structure of the rumen ciliates. Section 3 presents a phylogenetic study of the family Ophryoscolecidae based on 18S-rDNA gene information, including five new sequences. The main results were: ¹ confirmation of the monophyly of the Entodiniinae and Ophryoscolecinae subfamilies; 2 Diplodiniinae subfamily is considered paraphyletic; 3 oral infraciliature patterns reflect evolutionary divergence in the family Ophryscolecidae; 4 confirmation of monophyly of oral ciliature patterns Entodinium-type, Ostracodinium-type (Ostracodinium gracile and Ostracodinium mammosum), Epidinium-type and Ophryoscolex-type; 5 the ancestral condition of Entodinium-type suggested by some authors could not be verified using information from 18S-rDNA gene. The inconsistencies observed between the morphological and molecular data reflect the need to increase the number of 18S rDNA gene sequences to family Ophryoscolecidae representatives and investigate the evolution of this group using other molecular markers.