The phylogeny of the different groups of cnidarians remains elusive, since there is no consensus of what are the relationships between the different classes and orders that comprise the phylum. The spermiotaxonomy has been used as phylogenetic criteria in different groups of Metazoa. For Cnidaria there are few studies describing the morphology of the male reproductive system and sperm at the level of light microscopy and transmission electron microscopy. Specimens of the species Tamoya haplonema and Chiropsalmus quadrumanus (Cubozoa), Lychnorhiza lucerna and Chrysaora lactea (Scyphozoa), were collected near the Marine Biology Center of the University of São Paulo and near the bases of the Oceanographic Institute of USP (Cananéia and Ubatuba Bases) from August to October 2014 and from April to June 2015. Samples of the species Carukia barnesi, Chironex fleckeri and Chiropsella bronzie (Cubozoa) and Cassiopea sp. (Scyphozoa), were collected along the Australian east coast from March to May 2016. For histological and histochemistry description of the male gonads, samples were fixed in 4% paraformaldehyde prepared with water from the collection site and sodium phosphate buffer 0.2M for 24 hours. After that, the samples were processed following the protocol for historesin. Fragments of male gonads were fixed in modified Karnovsky solution (2.5% glutaraldehyde and 0.08% paraformaldehyde in 0.1 M sodium cacodylate buffer, pH 7.4) and glutaraldehyde (2.5% glutaraldehyde in cacodylate buffer 0.1M sodium in seawater vacuum Millipore filtered, pH 7.2-7.4). Then the samples were processed according to transmission electronic microscopy protocol. In this dissertation it is described the comparative spermatogenesis of the cubozoans T. haplonema and C. quadrumanus, under histology and histochemistry, showing the gonadal cycle (Chapter 1). We also describe the spermatogenesis and sperm morphology, under light microscopy and ultrastructure, for the Cubozoa species T. haplonema, C. quadrumanus, Carukia barnesi, Chironex fleckeri and Chiropsella bronzie (Chapter 2). For the Scyphozoa species, Lychnorhiza lucerna, Chrysaora lactea and Cassiopea sp., we describe the spermatogenesis process, under light transmission electronic microscopy, describing the macroscopic structure of the male gonad (Chapter 3). Additionally, in the final chapter, it is highlighted the comparative morphology of sperm of all species studied, evidencing possible unique features of each class, enumerating possible sperm characters (Chapter 4) (AU) |
