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.

A Review on Fish Sensory Systems and Amazon Water Types With Implications to Biodiversity

“…Most Neotropical freshwater fish diversity occurs in the Amazon basin, where circa 3,000 valid species occur (Dagosta and de Pinna, 2019). Many hypotheses considering different factors as evolutionary drivers of the Amazon fish biodiversity have been developed (Dagosta and de Pinna, 2018). Alfred Russell Wallace (1853) was the first to hint possible ecological reasons for Amazonian fish diversity (Pires et al, 2018).…”

Existing protected areas provide a poor safety‐net for threatened Amazonian fish species

“…The Amazon superbasin contains by far the most species‐rich freshwater fish fauna on Earth, with more than 2,700 known species (Dagosta & de Pinna, 2019). Little is known about the patterns of geographical distribution, species richness and endemicity of Amazonian fishes (Dagosta & de Pinna, 2018), which partly explains why this fish fauna continues to be largely ignored by regional‐scale conservation plans.…”

Two new catfish species of typically Amazonian lineages in the Upper Rio Paraguay (Aspredinidae: Hoplomyzontinae and Trichomycteridae: Vandelliinae), with a biogeographic discussion

“…It is intuitively obvious that headwater stream capture resulted in the presence of Amazonian elements in the upper rio Taquari. Such events are often associated with the upper reaches of adjacent basins and is largely responsible for the historically reticulate nature of river drainages (Lima & Ribeiro, 2011;Dagosta & de Pinna, 2017) (Fig. 8).…”

“…Of course, its predictions apply to not-yet-known results of past events. With progress in knowledge about phylogenetic relationships and distribution of Neotropical fishes, it becomes increasingly clear how geomorphological past events shaped ichthyological diversity (Albert & Reis, 2011;Dagosta & de Pinna, 2018;Albert et al, 2020). Because fishes have extremely limited dispersal abilities across land, the ichthyofaunal composition of a basin is an imprint of its history with other basins.…”

“…Temporal mixing results from overlapping geomorphological processes that cause hydrological mixing between neighboring basins (i.e., connection, diversion, sector capture, etc.). Consequently, basins present a mosaic of fish assemblages composed of elements from different geographic origins recruited across dif-ISSN On-Line: 1807-0205 ISSN Printed: 0031-1049 ISNI: 0000-0004-0384-1825 ferent times and events (Lima & Ribeiro, 2011;Dagosta et al, 2014;Dagosta & de Pinna, 2017).…”