A new species of Boehlkea (Characiformes: Characidae: Stevardiinae) from the rio Japurá, Amazon basin, Brazil

ABSTRACT A new species of Boehlkea is described from rio Japurá, Amazon basin. The new species differs from B. fredcochui by the presence of a vertically elongate humeral spot (vs. absence), complete lateral line (vs. incomplete), four rows of scales below lateral line (vs. three), and lower number of branched anal-fin rays (17-21 vs. 22-25), and from B. orcesi by the higher number of maxillary teeth (13-14 vs. 5-12), greater head length (27.9-29.9% vs. 24.3-27.5% of SL), and by the color pattern (basal half of dorsal-fin, distal portion of pelvic-fin, lower caudal-fin lobe and anal-fin with black chromatophores vs. absence of black chromatophores in the fins)

Sperm phylogeny of Characidae (Teleostei, Characiformes)

The phylogeny of the very diverse Neotropical fish family Characidae has been the subject of several recent contributions based on morphological characters, molecular data or both in combined analyses. In cases of conflict between these kinds of data, resolution by combined analyses most often tends to agree with the molecular evidence, given the disproportionate number of characters it contains in comparison with morphological datasets. This happens especially after the advent of massive DNA sequencing methods. In this contribution, we present the most comprehensive set of characters from sperm and spermiogenesis of the Characidae. Since these traits are not expected to be functionally correlated with the general morphology or molecular markers, we consider them a third source of data. We provide a phylogenetic analysis from a combined dataset of seven molecular markers (6444 characters), general morphology (520 characters) and reproductive features (94 characters) coded for 165 species of characiform fishes. Parsimony analyses were done under extended implied weighting under 30 different combinations of weighting schemes and strengths. Most parsimonious trees from two different weighting conditions were selected as representative samples of the obtained topologies, in order to evaluate the performance of the reproductive characters. One of these hypotheses is more conservative regarding the currently accepted phylogenies and the other is the most parsimonious tree that we found as the best correlated with the morphological data. Reproductive characters are shown to be more homoplastic than general morphology and DNA, but provided synapomorphies for 23–24 nodes that had no morphological synapomorphies, justifying their use in phylogenetic analyses. Also, in combination with data from general morphology and considering details of the phylogenetic analysis, they showed to have the potential to challenge well-established hypotheses based on molecular data.Fil: Mirande, Juan Marcos. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Baicere Silva, Clarianna M.. Universidade Do Estado de Mato Grosso (unemat);Fil: Santana, Júlio C. O.. Universidade do Brasília; BrasilFil: Quagio Grassiotto, Irani. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Spermatic characteristics and sperm evolution on the subfamily Stevardiinae (Ostariophysi: Characiformes: Characidae)

The monophyly and phylogenetic relationships among the members of Clade A characids (sensu Malabarba & Weitzman), later redefined and named as the Stevardiinae (sensu Mirande), have been primarily supported by traditional morphological and molecular data. Herein were examined, described and compared spermiogenesis and sperm ultrastructure of 12 species of the genera Boehlkea, Bryconacidnus, Bryconamericus, Creagrutus, Cyanocharax, Hemibrycon, Knodus, Odontostoechus, Piabina, and Rhinobrycon in order to evaluate possible phylogenetic signals and their potential use in recovering relationships of the Stevardiinae. All examined species demonstrated a nuclear rotation equal or less than 95º resulting in a lateral position of the double nuclear fossa and flagellum. In all species, sperm nuclei are slightly elongate toward the flagellum, the proximal centriole is partially inside the nuclear fossa and lies anterior and oblique to the distal centriole, and the midpiece is short and strongly asymmetric. All species analyzed herein and other species previously examined for these systems in the Stevardiinae share homologous sperm characteristics as evidenced by spermiogenesis, further supporting the monophyly of this clade. Spermatozoa of the Stevardiinae further show three morphotypes (M1, M2, M3) of arrangement of centrioles, flagellum, nucleus and midpiece, hypothesized as successively derived in a series of transformation from the most basal morphotype (M1)

An assessment approach for application of spermatic data in phylogenetic analyses: Within the genus Moenkhausia Eigenmann, 1903 (Characiformes: Characidae)

Spermiogenesis and sperm ultrastructure from 21 species of Moenkhausia and others related genera are described. To evaluate the phylogenetic signals, 18 unordered characters were utilized in implied weighting analysis through the program TNT 1.1. Four variations of spermiogenesis were found. In the earliest spermatids, the nucleus can be positioned lateral, eccentric, strongly eccentric or nearly medial in relation to the distal centriole. The nuclear rotation can be present or absent. These spermiogenesis processes are related or intermediate to Type I and Type III. Taking into account the degrees of nuclear rotation during the spermiogenesis and other characteristics, distinct forms of spermatozoa are observed among the species analyzed. The phylogenetic analysis yielded a single most parsimonious tree with fit value 2.70000 and the topology obtained founds Moenkhausia as non-monophyletic. However, some hypothesis of relationships previously proposed viz the clade 20, which contains the type species Moenkhausia xinguensis, is recovered herein. This clade is supported by five synapomorphies, and it allows the supposition that these species constitute a monophyletic group. The whole topology is presented and discussed. © 2012 The Authors. Acta Zoologica © 2012 The Royal Swedish Academy of Sciences

Testing the phylogenetic hypotheses of Stevardiinae Gill, 1858 in light of new phenotypic data (Teleostei: Characidae)

The Stevardiinae are a high diverse subfamily of Characidae, the richest family of Neotropical fishes. Many species are inseminating (internal fertilization) and consequently display diverse morphology of reproductive organs and sperm cells. We test the monophyly and internal relationships of the Stevardiinae through a phylogenetic analysis based on a new set of morphological characters, including reproductive traits, combined with publicly available molecular data. We defined 176 characters from general morphology and primary and secondary sexual characters, coded for 54 species. Analyses were made under parsimony using a broad range of extended implied weighting parameters. Given the different morphological characters we use, this analysis provides additional synapomorphies and an independent test for previous hypotheses based on morphological and combined morphological and molecular datasets. Our final hypothesis is a single most parsimonious tree of 6341 steps obtained under three different weighting schemes. This recovers the monophyly of the tribes Creagrutini, Diapomini, Glandulocaudini, Hemibryconini, Landonini (including Eretmobryconini), Stevardiini, and Xenurobryconini. It also supports the recognition of the monotypic tribe Phenacobryconini. Insemination is ambiguously optimized as present in the common ancestor of Stevardiinae and in the common ancestor of all members of the subfamily except for Landonini. That reconstruction constitutes a novel hypothesis about the evolution of insemination within Characidae.Fil: Ferreira, Katiane M.. Universidade Federal de Mato Grosso; BrasilFil: Mirande, Juan Marcos. Fundación Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Quagio Grassiotto, Irani. Universidade Estadual Paulista "júlio de Mesquita Filho"; BrasilFil: Santana, Júlio C. O.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Baicere Silva, Clarianna Martins. Universidade Federal de Mato Grosso; BrasilFil: Menezes, Naércio A.. Universidade de Sao Paulo; Brasi