New findings of Hexalona-branch representatives in Brazil, with a description of Prenda gen. nov. (Crustacea: Anomopoda: Aloninae)

ABSTRACT

Altogether, Coronatella and Hexalona-branches are considered the main lineages of Aloninae – a subfamily of common bottom-dwelling microcrustaceans in freshwater environments. Although the taxonomic features of Brazilian members of the Hexalona-branch have been summarised for species from the costata-group and affinis-group, a revision of other widely distributed species in the world is still lacking in this country. The aim of this paper was to study the morphology of Brazilian populations from the guttata-group and intermedia-group, and to describe a new genus from the Hexalona-branch. The parthenogenetic females of Alona cf. guttata from Brazil have similar morphology when compared to data from the literature, but the armature of the terminal claw of its males seems to be different from those of Alona guttata sensu stricto, Alona barbulata and Alona werestschagini. The intermedia-group is formed by Alona elisae sp. nov., which seems to be endemic to the Cerrado of Brazil Central, and Alona isabellae sp. nov., which is widely distributed in Brazil; this species has a labral keel armed with 2–4 setulae, and postabdomen with setulae of lateral fascicles longer than the level of marginal denticles, morphological traits that differentiate it from Alona elisae sp. nov. Another endemic species from the Hexalona-branch is Prenda arvensis gen. nov. and sp. nov., which has two main head pores, a reduced seta on endite 1 of the first limb, sixth limb is a wide lobe. The potential of biodiversity from the Hexalona-branch from Brazil is still underestimated, and a global revision of the guttata-group and intermedia-group is very important for the progress of Aloninae taxonomy and systematics.

http://zoobank.org/urn:lsid:zoobank.org:pub:0A2E4A30-0C9C-43E8-8E72-1DEDA6AFF3C3

KEYWORDS:

• Alona intermedia
• Alona guttata
• endemism
• head pores
• limbs
• morphology

Acknowledgements

We are deeply grateful to Dr. Cristina Stenert, MSc Raquel Freiry and Dr. Leonardo Maltchik for the donation of the material from Rio Grande do Sul state. We also thank members of GEEA for collecting samples used in this manuscript. We also thank Ms. Susan Casement and MSc Diego M. Magalhães for revising the English version of this manuscript. We are grateful to Dr. Eliana A. Panarelli, Dr. Gilmar Perbiche Neves and Dr. Ricardo Lourenço Pinto for their suggestions on the initial draft of this manuscript. We are deeply thankful to an anonymous reviewer and Dr. Anna Nerentina for valuble cricitism, comments and suggestions that have improved this manuscript. The first author received a scholarship from the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

Disclosure statement

No potential conflict of interest was reported by the authors.