STATUS DE CONHECIMENTO DO ACARI-ZEBRA Hypancistrus zebra Isbrücker & Nijssen, 1991 (SILURIFORMES, LORICARIIDAE)

The present work aimed to review the literature on studies carried out on the “acari-zebra” (Hypancistrus zebra Isbrücker & Nijssen, 1991). The data search was performed in four scientific databases (Capes journals, Google Scholar, Scielo, ScienceDirect and Web of Science Core Collection), using the scientific and common name of the species as keywords. Articles were selected when they had any of the keywords used in the title or abstract, excluding works from gray literature. After selecting the articles in the scientific databases, a careful reading was carried out in order to characterize the taxonomy, biology, ecology, fisheries and conservation status of H. zebra. The “acari-zebra” is an ornamental species endemic to the Xingu River basin, which has a high economic value internationally. It was recently added to the endangered species list due to overfishing of the species. Literature on H. zebra proved to be very scarce, with only basic information on taxonomy, fisheries, reproductive aspects and studies aimed at cultivation. Among the studies to be carried out, we highlight the characterization of growth and reproductive dynamics. These studies will enable a better understanding of the biology of the species and will contribute to a definition of the technological package of reproduction in captivity.

Theatre and Indigenous Peoples: Learning to Imagine New Worlds in End Times

This article examines the relationship between the performing arts and Amerindian peoples, specifically the Araweté, Juruna/Yudjá and Kamayurá peoples, which belong to the Tupi branch, whom I met as part of postdoctoral research carried out from February 2018 to January 2019, at the University of São Paulo (USP). It analyses the conjuncture of the fight of Amerindian and riparian peoples before the destruction of the forest and rivers of the Amazon, based on case studies of two theatre performances: Altamira 2042, a scenic ritual instauration triggered by listening to the testimony of the Xingu river about the Belo Monte dam, and Os Um e Os Outros (The One and the Others), loosely based on The Horatians and the Curiatians by Bertolt Brecht.

Phylogeography of Baryancistrus xanthellus (Siluriformes: Loricariidae), a rheophilic catfish endemic to the Xingu River basin in eastern Amazonia

Baryancistrus xanthellus (Loricariidae) is an endemic fish species from the Xingu River basin with its life history in the shallow rapid waters flowing over bedrock substrates. In order to investigate the genetic diversity and demographic history of B. xanthellus we analyzed sequence data for one mitochondrial gene (Cyt b) and introns 1 and 5 of nuclear genes Prolactin (Prl) and Ribosomal Protein L3 (RPL3). The analyses contain 358 specimens of B. xanthellus from 39 localities distributed throughout its range. The number of genetically diverged groups was estimated using Bayesian inference on Cyt b haplotypes. Haplotype networks, AMOVA and pairwise fixation index was used to evaluate population structure and gene flow. Historical demography was inferred through neutrality tests and the Extended Bayesian Skyline Plot (EBSP) method. Five longitudinally distributed Cyt b haplogroups for B. xanthellus were identified in the Xingu River and its major tributaries, the Bacajá and Iriri. The demographic analysis suggests that rapids habitats have expanded in the Iriri and Lower Xingu rivers since 200 ka (thousand years) ago. This expansion is possibly related to an increase in water discharge as a consequence of higher rainfall across eastern Amazonia. Conversely, this climate shift also would have promoted zones of sediment trapping and reduction of rocky habitats in the Xingu River channel upstream of the Iriri River mouth. Populations of B. xanthellus showed strong genetic structure along the free-flowing river channels of the Xingu and its major tributaries, the Bacajá and Iriri. The recent impoundment of the Middle Xingu channel for the Belo Monte hydroelectric dam may isolate populations at the downstream limit of the species distribution. Therefore, future conservation plans must consider the genetic diversity of B. xanthellus throughout its range.

Effects of the Belo Monte hydro-electric-dam complex on crocodilians in the Xingu River, Brazilian Amazonia

The Belo Monte hydroelectric dam on the Xingu River has the third largest generating capacity of any hydroelectric dam in the world. We conducted surveys of crocodilians (Caiman crocodilus, Paleosuchus trigonatus) by boat in the Xingu River at the site of the dam prior to (2013-2015), and after filling (2016-2017). While the number of C. crocodilus sighted decreased with increasing water level, there was no difference in numbers prior to, and after reservoir filling. The number of P. trigonatus was unaffected by both water level prior to and after reservoir filling. Reservoir filling had little effect on the number of crocodilians using the forest around the Xingu River reservoir. Most crocodilians seen in forest surveys were P. trigonatus, both before and after reservoir filling, but C. crocodilus was recorded occasionally in the forest. It seems that most Amazonian crocodilians are sufficiently generalist to adapt to the new conditions created by the construction of dams, at least in the short-term. However, there may be long-term collateral effects on crocodilian populations from dams, due to as deforestation and improved access for hunters.

Two new species of monogenoidean parasites (Platyhelminthes: Neodermata) of ornamental fish of Loricariidae (Siluriformes) from the Xingu River, Brazilian Amazon

Two new monogenoidean species of Unilatus Mizelle & Kritsky, 1967 found in the gills of loricariids in the Lower Xingu-Iriri rivers are described: Unilatus humboldtii sp. nov. from Baryancistrus niveatus (Castelnau, 1855), Panaque armbrusteri Lujan, Hidalgo & Stewart, 2010, Pseudacanthicus sp. (type-host), and Scobinancistrus aureatus Burgess, 1994; and Unilatus luciarappae sp. nov. from P. armbrusteri. Unilatus humboldtii sp. nov. is distinguished from other congeneric species due to its anterior anchor with well-developed superficial root with depressed or truncated distal portion, and inconspicuous or reduced deep root; anterior bar with posteromedial projection; hooks of pair 1 with dilated shaft comprising 2/3 of the hook length; spiraled male copulatory organ with approximately 16–18 counterclockwise loops. Unilatus luciarappae sp. nov. is characterized by having anterior anchor with well-developed superficial root and reduced deep root, slightly curved shaft, elongated, slightly curved, and tapered point; spiraled MCO with approximately 18–19 counterclockwise loops, with median distal bulbous portion and remaining portion tapered and elongated, comprising 1/4 of the body length; and accessory piece comprising approximately 2/3 of the MCO length. More than fifty years after the description of the type species of Unilatus from an artificial environment (U.S. aquaria), this study represents the first formal record and description of Unilatus species from hosts collected in natural habitats in the Xingu River. Considering the impact of the Belo Monte dam on the formerly pristine conditions of the study region and the importance of loricariids for the ornamental fish trade, we recommend monitoring monogenoidean diversity, parasite-host interaction, as well as the dispersion patterns and pathogenicity of these parasites.