New species of the Pseudancistrus barbatus group (Siluriformes, Loricariidae) with comments on its biogeography and dispersal routes

Phylogeny and biogeography of the Brazilian–Guiana Shield endemic Corymbophanes clade of armoured catfishes (Loricariidae)

Numerous rivers, interrupted by large waterfalls and extensive rapids, drain the geologically ancient Guiana Shield Highlands. We describe a new armoured catfish genus and two new species endemic to the upper Ireng and Kuribrong rivers, respective tributaries of the Amazon and Essequibo basins in western Guiana. Corymbophanes ameliae sp. nov. is distinguished by having vermiculations on the abdomen, bands on the caudal fin, the anal fin i,5 and narrow caudal peduncle. Yaluwak primus gen. & sp. nov. is distinguished by having evertible cheek odontodes, a plated snout, a tall caudal peduncle and absence of adipose fin and iris operculum. We present a new molecular phylogenetic analysis inclusive of these and several related genera that suggests that the Corymbophanes clade (Araichthys, Corymbophanes, Cryptancistrus, Guianancistrus, Hopliancistrus and Yaluwak) originated in the Guiana Shield with secondary dispersal to the Brazilian Shield. Within the Guiana Shield, relationships among Corymbophanes and Yaluwak are consistent with geodispersal between drainages via headwater capture, although an uplift-mediated relictual distribution cannot be ruled out. ND2 haplotype structure among C. ameliae populations suggests that ichthyofaunal diversity on the Guiana Shield escarpment is shaped not only by inter-, but also intrafluvial barriers to gene flow.

A history of the biogeography of Amazonian fishes

ABSTRACT The history of knowledge about Amazonian biogeography is as rich as its fish community, and a fascinating theme of study in itself. Several current paradigms and controversies about Amazonian fish biogeography are rooted in principles dating from the second half of the 18th to the first half of the 19th centuries. The present work establishes a relationship between current biogeographical ideas and their old predecessors, on the basis of a chronologically-oriented historical continuity analysis. The advent of evolutionary theory has not contributed significantly to a transformation of the knowledge on the biogeography of Amazonian fishes. On the other hand, the two main schools of biogeographical thought (dispersalist and vicariant) had major implications on how Amazonian fish distribution is interpreted. The process was gradual and many hypotheses have combined elements from each of the two schools. Chronologically, practically the entire tradition of Amazonian biogeography takes place within the evolutionary paradigm, although its founder Louis Agassiz was himself an anti-evolutionist. The birth of Amazonian biogeography is Agassiz´s travel in Amazon. That document makes it clear that the author did not consider dispersal as a valid explanation for the biogeographical patterns he found. Later, Carl Eigenmann helps to spread the dispersalist tradition as a model for biogeographical explanations in fish distributions, a phase which lasted until the late 20th century. A major shift occurs with the contributions of Marylin Weitzman, Stanley Weitzman and Richard Vari, who associated the temporal framework of phylogenetic hypotheses with distribution patterns, underscoring the predictive power of vicariant biogeography. The present-day paradigm begins with the work of John Lundberg and attempts to incorporate geomorphological and phylogenetic information into integrative biogeographical hypotheses. Some emblematic problems have delayed proposition of general hypotheses on the phylogenetic biogeography of South American fishes, such as the poor state of knowledge of their species-level systematics; an incomplete distributional record for most species and sparse or non-existent data on the phylogenetic history of most supraspecific taxa. Such drawbacks are now being corrected at a fast pace. Recent advances on geographical distribution and an increasing number of phylogenetic hypotheses will allow unprecedented large-scale biogeographic analyses, including those based on event models and Bayesian inference. Thus, the biogeography of South American fishes, especially Amazonian ones, should soon experiment a new age of progress. The success of that new phase will depend on its ability to recognize and segregate multiple overlapping temporal layers of hydrological changes, and to develop analytical tools that can deal with temporal mixing.

An integrative framework to reevaluate the Neotropical catfish genus Guyanancistrus (Siluriformes: Loricariidae) with particular emphasis on the Guyanancistrus brevispinis complex

Characterizing and naming species becomes more and more challenging due to the increasing difficulty of accurately delineating specific bounderies. In this context, integrative taxonomy aims to delimit taxonomic units by leveraging the complementarity of multiple data sources (geography, morphology, genetics, etc.). However, while the theoretical framework of integrative taxonomy has been explicitly stated, methods for the simultaneous analysis of multiple data sets are poorly developed and in many cases different information sources are still explored successively. Multi-table methods developed in the field of community ecology provide such an intregrative framework. In particular, multiple co-inertia analysis is flexible enough to allow the integration of morphological, distributional, and genetic data in the same analysis. We have applied this powerfull approach to delimit species boundaries in a group of poorly differentiated catfishes belonging to the genus Guyanancistrus from the Guianas region of northeastern South America. Because the species G. brevispinis has been claimed to be a species complex consisting of five species, particular attention was paid to taxon. Separate analyses indicated the presence of eight distinct species of Guyanancistrus, including five new species and one new genus. However, none of the preliminary analyses revealed different lineages within G. brevispinis, and the multi-table analysis revealed three intraspecific lineages. After taxonomic clarifications and description of the new genus, species and subspecies, a reappraisal of the biogeography of Guyanancistrus members was performed. This analysis revealed three distinct dispersals from the Upper reaches of Amazonian tributaries toward coastal rivers of the Eastern Guianas Ecoregion. The central role played by the Maroni River, as gateway from the Amazon basin, was confirmed. The Maroni River was also found to be a center of speciation for Guyanancistrus (with three species and two subspecies), as well as a source of dispersal of G. brevispinis toward the other main basins of the Eastern Guianas.

Ichthyofauna of the upper Juruena river on Chapada dos Parecis, Mato Grosso, Brazil

Abstract The fishes herein included were collected in four small streams of the upper rio Tapajós basin. Through fieldwork carried out in 2011, 2013 and 2014 during the low water season 1.728 specimens belonging to 22 species distributed in 11 families, and five orders were captured. Characidae was the most representative family both in number of species and specimens captured. The most abundant species were Hyphessobrycon melanostichos, H. hexastichos, and H. notidanos. Five species are recognized as new, and four as endemic to the upper rio Tapajós basin. This study represents the first fish inventory for the region and will provide valuable information for the conservation of the poorly known diversity of fishes of the Chapada dos Parecis, in the headwaters of the upper rio Tapajós basin.

Phylogenetic and morphological characterization of trypanosomes from Brazilian armoured catfishes and leeches reveal high species diversity, mixed infections and a new fish trypanosome species

Background

Several Trypanosoma species transmitted by leeches infect marine and freshwater fish worldwide. To date, all South American fish trypanosome species identified have been based on unreliable morphological parameters. We recently isolated and cultured trypanosomes from the Brazilian armoured catfishes Hypostomus luetkeni and H. affinis. Here, we report the first phylogenetic analyses of South American (Brazilian) trypanosomes isolated from fish, and from leeches removed from these fish. We also analysed morphologically and morphometrically the different forms of fish, leech and cultured trypanosomes.

Methods

V7V8 SSU rRNA and gGAPDH sequences were used for phylogenetic analysis of Brazilian fish and leech trypanosomes. Trypanosomes from cultures, fish blood and leech samples were also characterized morphologically and morphometrically by light and electron microscopy.

Results

In blood smears from fish high trypanosome prevalence (90–100 %) and parasitemia (0.9-1.0x10²) were observed. Phylogenetic relationships using SSU rRNA and gGAPDH showed that, despite relevant sequence divergence, all Brazilian fish (and derived cultures) and leech trypanosomes clustered together into a single clade. The Brazilian clade clustered with European, North American and African fish trypanosomes. Based on sequence analysis, we uncovered a new species of Brazilian fish trypanosome, Trypanosoma abeli n. sp. Trypanosoma abeli cultures contained pleomorphic epimastigotes, small trypomastigotes and rare sphaeromastigotes. Ultrastructural features of T. abeli included a cytostome-cytopharynx complex in epi- and trypomastigotes, a compact rod-like kinetoplast, lysosome-related organelles (LROs) and multivesicular bodies. Trypanosomes found in fish blood smears and leech samples were highly pleomorphic, in agreement with sequence data suggesting that catfishes and leeches often have mixed trypanosome infections.

Conclusions

Trypanosoma abeli n. sp. is the first trypanosome from South American fishes isolated in culture, positioned in phylogenetic trees and characterized at the ultrastructural level. Trypanosoma abeli n. sp. is highly prevalent in H. luetkeni and H. affinis armoured catfish from the Atlantic Forest biome, and in other catfish species from the Amazon and the Pantanal. Sequencing data suggested that Brazilian catfish often have mixed trypanosome infections, highlighting the importance of molecular characterization to identify trypanosome species in fishes and leeches.

Electronic supplementary material

The online version of this article (doi:10.1186/s13071-015-1193-7) contains supplementary material, which is available to authorized users.

Two new species of Pseudancistrus (Siluriformes, Loricariidae) from the Amazon basin, northern Brazil

Two new species of Pseudancistrus, a genus diagnosed by non-evertible cheek plates and hypertrophied odontodes along the snout margin, are described from two drainages of the Brazilian Shield: Pseudancistruskayabi from the rio Teles Pires (rio Tapajós basin) and Pseudancistrusasurini from the rio Xingu. The new species are distinguished from congeners (Pseudancistrusbarbatus, Pseudancistruscorantijniensis, Pseudancistrusdepressus, Pseudancistrusnigrescens, Pseudancistrusreus, and Pseudancistruszawadzkii) by the coloration pattern. Pseudancistruskayabi has dark bars on the dorsal and caudal fins which are similar to that of Pseudancistrusreus from the Caroní River, Venezuela. Pseudancistrusasurini is unique among Pseudancistrus in having whitish tips of the dorsal and caudal fins in juveniles to medium-sized adults.

Multilocus molecular phylogeny of the suckermouth armored catfishes (Siluriformes: Loricariidae) with a focus on subfamily Hypostominae

The Neotropical catfish family Loricariidae is the fifth most species-rich vertebrate family on Earth, with over 800 valid species. The Hypostominae is its most species-rich, geographically widespread, and ecomorphologically diverse subfamily. Here, we provide a comprehensive molecular phylogenetic reappraisal of genus-level relationships in the Hypostominae based on our sequencing and analysis of two mitochondrial and three nuclear loci (4293bp total). Our most striking large-scale systematic discovery was that the tribe Hypostomini, which has traditionally been recognized as sister to tribe Ancistrini based on morphological data, was nested within Ancistrini. This required recognition of seven additional tribe-level clades: the Chaetostoma Clade, the Pseudancistrus Clade, the Lithoxus Clade, the 'Pseudancistrus' Clade, the Acanthicus Clade, the Hemiancistrus Clade, and the Peckoltia Clade. Results of our analysis, which included type- and non-type species for every valid genus in Hypostominae, support the reevaluation and restriction of several historically problematic genera, including Baryancistrus, Cordylancistrus, Hemiancistrus, and Peckoltia. Much of the deep lineage diversity in Hypostominae is restricted to Guiana Shield and northern Andean drainages, with three tribe-level clades still largely restricted to the Guiana Shield. Of the six geographically widespread clades, a paraphyletic assemblage of three contain lineages restricted to drainages west of the Andes Mountains, suggesting that early diversification of the Hypostominae predated the late Miocene surge in Andean uplift. Our results also highlight examples of trophic ecological diversification and convergence in the Loricariidae, including support for three independent origins of highly similar and globally unique morphological specializations for eating wood.