Molecular phylogeny of Planaltina Böhlke (Characidae: Stevardiinae) and comments on the definition and geographic distribution of the genus, with description of a new species

Abstract

A molecular phylogeny of Planaltina, including the three previously described species and an undescribed species, is presented. The monophyly of the genus, included in Diapomini, is strongly supported. Its sister group, the remaining Diapomini, includes only species without modified caudal-fin squamation in the present analysis (species of Diapoma with caudal organs were not sampled). Creagrutus is sister to Planaltina plus remaining Diapomini instead of Planaltina being sister to Creagrutus plus Diapomini, as a previous analysis had suggested. Species of Planaltina form two clades: P. britskii plus the new species, with low support (< 50%); and P. myersi plus P. glandipedis, with higher support. Planaltina is rediagnosed from all Characidae based on the morphology of the caudal organ, the absence of a humeral spot and the presence of a complete lateral line. Comments on the caudal-fin squamation of Diapoma and Lepidocharax burnsi, on the type-series of L. burnsi and on the geographic distribution of Planaltina and Lepidocharax species are provided. Finally, a formal description of the aforementioned new species and a novel identification key to Planaltina are presented.

Spatial distribution patterns and predictors of fish beta‐diversity in a large dam‐free tributary from a Neotropical floodplain

“…Alonso, Corumbataí, Mourão and Keller Rivers) present comparatively lower water discharge (Leli et al, 2017), probably favouring species dispersal towards sites environmentally similar with the lower Ivaí River basin. Thus, we suspect that the middle Ivaí River basin acts as an ecological barrier (environmental filters and dispersal limitation) for a subset of fish species, corroborating the hypotheses made by Deprá et al (2018). Simultaneously, interchange of individuals between mainstem channel and sites close to the river mouth is expected (see López‐Delgado et al, 2019), as well as the presence of taxa typical from headwaters in specific habitat patches.…”

“…Thus, we suspect that the middle Ivaí River basin acts as an ecological barrier (environmental filters and dispersal limitation) for a subset of fish species, corroborating the hypotheses made by Deprá et al (2018). Simultaneously, interchange of individuals between mainstem channel and sites close to the river mouth is expected (see L opez-Delgado et al, 2019), as well as the presence of taxa typical from headwaters in specific habitat patches.…”

Length‐weight relationships for seven endemic fish species from streams of the last two large remaining dam‐free tributaries of the Upper Paraná River Floodplain in the Paraná State, Brazil

“…When collected, from November 1994 (older vouchers, NUP 1,387 and NUP 1,408) to July 2019 (latest voucher, NUP 16,016), those specimens were fixed with 10% formalin and are preserved in 70% alcohol. Most of the specimens measured and weighed are type material (paratypes) or non‐types designated used in the original descriptions of the species studied (Deprá et al., 2018; Graça & Pavanelli, 2008; Pavanelli, 2006; Reis et al., 2020b; Roxo et al., 2014; Tencatt et al., 2014; Zawadzki et al., 2016). The vouchers specimens used and their records are shown in Table 1 and Figure 1, respectively.…”

A new species of Diapoma (Characiformes, Characidae, Stevardiinae) from the Rio Paraná basin, with an identification key to the species of the genus

“…Species of Diapoma have two different patterns of caudal-fin squamation: a set of two to five unmodified and relatively large scales covering the anterior one-third of each lobe and a set of multiple modified scales forming a pouch-like structure on the lower lobe (see Menezes & Weitzman, 2011). Both types of terminal caudal-fin squamation differ from those present in related genera such as Planaltina or Lepidocharax, especially in adult males (see further comparisons on the squamation of these genera in Menezes et al, 2003;Ferreira et al, 2011;Menezes & Weitzman, 2011;Deprá et al, 2018) It seems that the phylogenetic placements of H. wajat and H. procerus need to be revised using morphological and molecular data before changing their generic position (under ongoing study by J.A.V.R. ).…”