Review of the family Rivulidae (Cyprinodontiformes, Aplocheiloidei) and a molecular and morphological phylogeny of the annual fish genus Austrolebias Costa 1998

Abstract

The family Rivulidae is the fourth most diverse clade of Neotropical fishes. Together with some genera of the related African family Nothobranchiidae, many rivulids exhibit a characteristic annual life cycle, with diapausing eggs and delayed embryonic development, which allows them to survive in the challenging seasonal ponds that they inhabit. Rivulidae also includes two species known as the only the self-fertilizing vertebrates and some species with internal fertilization. The first goal of this article is to review the systematics of the family considering phylogenetic relationships and synapomorphies of subfamilial clades, thus unifying information that is dispersed throughout the literature. From this revision, it is clear that phylogenetic relationships within Rivulidae are poorly resolved, especially in one of the large clades that compose it, the subfamily Rivulinae, where conflicting hypotheses of relationships of non-annual and annual genera are evident. The second goal of this work is to present an updated phylogenetic hypothesis (based on mitochondrial, nuclear, and morphological information) for one of the most speciose genus of Rivulidae, Austrolebias. Our results confirm the monophyly of the genus and of some subgeneric clades already diagnosed, but propose new relationships among them and their species composition, particularly in the subgenus Acrolebias.

Trait evolution and historical biogeography shape assemblages of annual killifish

“…Austrolebias bellottii and Austrolebias apaii were treated as the same species because A. apaii is a junior synonym of A. bellottii (García et al, 2012). We also decided to merge Austrolebias vazferreirai and Austrolebias cinereus for the comparative analyses in this paper, including the *BEAST analysis, in agreement with a recent proposal to consider A. vazferreirai a junior synonym of A. cinereus (Loureiro et al, 2018). Here, we refer to both as A. vazferreirai, as most individuals included were originally assigned to that species.…”

Austrolebias queguay (Cyprinodontiformes, Rivulidae), a new species of annual killifish endemic to the lower Uruguay river basin

“…According to a recent morphological and molecular phylogenetic analysis the new species (Austrolebias sp; figs 9-12, Loureiro et al 2018), is closely related to A. bellottii, and both represent the sister clade of A. melanoorus + A. univentripinnis. Interestingly, body shape of A. queguay is more similar to the phylogenetically and distributional distant species of the group, in the Negro and Yaguarón river basins (A. melanoorus and A. univentripinnis) than to A. bellottii, whose nearest localities are just 50 km away downstream and 25 five meters below the new species range.…”

“…In spite of the low statistical support of A5 and the unnamed clade in morphological analyses (Costa 2006(Costa , 2010, mitochondrial and total evidence phylogenetic reconstructions, support the monophyly of both clades , 2012, 2014, Loureiro and García 2008Loureiro et al 2018). However, these analyses differ in the relationships between and within them, and with other Austrolebias species groups.…”

“…Austrolebias sp. in Loureiro et al (2018) Holotype. ZVC-P 13576, male, 39.4 95°, 24.9-26.5 mm SL, CAP 1194, GP 3381-3383), same data of the holotype.…”

“…However, these analyses differ in the relationships between and within them, and with other Austrolebias species groups. According to Garcia et al (2014) and Loureiro et al (2018), A. patriciae is not closely related to the "A. bellottii" species group, and according to Garcia et al (2012), A. apaii should be considered a synonym of A. bellottii, a proposal that was followed by Calviño et al (2016).…”