Filogenia de Mycalina Hajdu, van Soest & Hooper, 1994 (Poecilosclerida, Demospongiae): dados morfológicos e moleculares

Abstract

At Phylum Porifera the proposition of classificatory schemes is troublesome, especially by the morphological low level complexity of specialization, paucity of distinctive characters and high plasticity. More robust classifications emerged since the XIXth. century. Poecilosclerida Order only began to be outlined by the initiative of Zittel (1878) with the recognition of "Monaxonida", i.e., a recognition of symmetry pattern in spicules categories. Ridley and Dendy (1887) presented a new classification of the sponges of the group "Monaxonida." Topsent (1894) created the Poeciloscleridae Family, and latter (1928) erected to Order, by emphasizing the presence of chelae as microscleras. Posteriorly, van Soest (1984) and Bergquist and Fromont (1988) undertook a discussion of this classification based on a phylogenetic perspective. A robust classification and consensus was not achieved before from the works of Hajdu et al. (1994a, 1994b) and Hajdu (1994, 1995), with the establishment of the Suborders: Mycalina, Myxillina and Microcionina. Nevertheless, the internal relationship of Mycalina Suborder s families remained in doubt, especially regarding the inclusion of Podospongiidae, Isodictyidae, and the relationship between Poecilosclerida and Order Haplosclerida. In this study, we proposed the revision of the classification of Mycalina Suborder based on morphological and molecular data. Phylogenetic analysis was performed in three taxonomic levels, Species, Genus and Family, based on morphological data. The molecular phylogenetic analysis was made using partial sequences of Large Subunit ribosomal RNA (LSU rRNA). Samples of Mycalina were amplified by PCR and sequenced. Based of these, I concluded that: Families Cladorhizidae, Guitarridae, Mycalidae and Hamacanthidae are monophyletic. For this last, the transformation series, sigmancistra>cyrtancistra> diancistra>clavidisc, was confirmed. The position of Family Podospongiidae within Mycalina was well supported, but need to be studied with molecular data to determine monophyletic status. Family Esperiopsidae needs to be further studied based on morphological data; and Amphilectus Genus needs to be revised, probably it is splited and would be transfered to Order Haplosclerida together with Family Isodictyidae. Family Desmacellidae is not monophyletic, Biemna and Neofibularia are probably not Poecilosclerida and should be transferred to a position close to Tetractinellida. Desmacella is probably a true Mycalina with a basal position in the Suborder. The other genera need to be studied with molecular data. Order Haplosclerida is probably the sister group of Poecilosclerida; the series of transformation sigma>chela was established based on morphological and molecular data. Suborder Mycalina is not monophyletic as defined in Hajdu and van Soest (2002a).