Revisão de espécies neotropicais relacionadas ao gênero Alona (Crustacea, Chydoridae), com ocorrência no Brasil

Abstract

Alona genus was, for a long time, considered the main group of species within the family Chydoridae, presenting high diversity when compared to other genera. The reason behind this statement emerges from the polyphyletic nature of Alona, which has been the subject of intensive taxonomic changes in order to establish natural groups. Thus, the aim of this thesis was to review Neotropical species related to the genus Alona, occurring in Brazil. Different populations of the two main lineages of Alona, the Hexalona-branch and Coronatella-branch were analyzed. Three species groups of Hexalona-branch were evaluated and the results pointed to the description of: Alona margipluma Sousa, Elmoor-Loureiro & Santos, 2015 representing the costata-group; Alona cf. intermedia and Alona sp. nov. 1 representing the intermedia-group; Alona cf. guttata representing the guttata-group. The gen. nov. 1 and sp. nov. 2 also belongs to Hexalona-branch, but could not be fitted in any group of known species due to the distinct set of morphological characteristics observed in the main head pores, postabodme, limbs I, III and IV. The results related to Coronatella-branch led to the description of three new species of the genus Coronatella: C. paulinae Sousa, Elmoor-Loureiro & Santos, 2015, C. serratalhadensis Sousa, Elmoor-Loureiro & Santos, 2015 and C. undata Sousa, Elmoor-Loureiro & Santos, 2015. At the same time, the morphology of C. poppei (Richard, 1897) has been fully reviewed and the absence of C. rectangula (Sars, 1861) in tropical regions was confirmed. Furthermore, the pulchella-group of Alona sensu lato has a new species with geographical distribution in the southern portion of South America: this species was named Alona kaingang Sousa, Elmoor-Loureiro & Santos, 2015 (now considered to belong to the genus Ovalona). In addition, this thesis proposes a new genus, which includes Alona dentifera and Alona siamensis.