Revisão da ordem Polypteriformes (Actinopterygii: Cladistia): morfologia e taxonomia

Abstract

The order Polypteriformes is known from the Triassic to the Recent and represents the sister group of all other extant actinopterygians. Extant polypteriforms are represented by the unique African family, Polypteridae. The polypterids form a monophyletic assemblage of two nominal genera: Polypterus, the bichirs, with 13 species, and the monospecific Erpetoichthys, the reedfish. Despite being studied for over 200 years, there is still no consensus on the valid species belonging to the group and the phylogenetic relationships within it. The present thesis seeks to help elucidate some of these questions and is divided into three drafts. The drafts aim to i) produce a detailed description of the osteology of Polypterus senegalus and compare it with the osteology of 9 other species of Polypteriformes to try to find new characters to more clearly separate species, and later help to elucidate the phylogenetic relationships within the group; ii) analyze the intraindividual and intraspecific morphology on the pinnules of Polypterus bichir, to understand the morphological variation on the pinnules in a single species, to determine their validity as taxonomic tools to later assess the validity of the fossil taxa erected on isolated material; and iii) analyze the ganoin ornamentation on the scales of different body regions of Polypterus bichir, to understand if the ganoin tubercle ornamentation in these scales remain constant, independently of its position on the body, and can be used to separate species or groups. For each draft, we found that i) the differences on the rostral, lacrimal, spiracular series, opercular region and caudal fin are some promising features to separate the extant polypteridae species; ii) there is a pattern on the morphology related to the anteroposterior axis on the dorsal fin. We also report morphological differences on the pinnules of the different specimens and inconsistencies between our findings and previous studies; and iii) that these parameters are considerably variable, no matter the body region, and overlapping with the data for other species in the literature, thus not possible to find any distinguished pattern on them