Phylogenetic Systematics of Neotropical Catfishes

Neotropical catfishes (Siluriformes) encompass an extraordinary radiation of suckermouth and armoured taxa that dominate freshwater ecosystems across Central and South America. Phylogenetic systematics has advanced through the integration of molecular sequence data, morphological character matrices and time‐calibrated trees to resolve relationships among diverse lineages such as Loricariidae, Trichomycteridae and Callichthyidae. These studies reveal repeated episodes of cladogenesis triggered by Miocene tectonic uplift, marine incursions and riverine capture events. Key groups, including Hypostomus, Loricariinae tribes and Guyanancistrus, exhibit cryptic diversity masked by convergent morphologies adapted to benthic feeding and rheophilic habitats. Modern approaches combine mitochondrial and nuclear markers with geometric morphometrics, underpinned by Bayesian and coalescent frameworks, to delimit species and infer ancestral area distributions. This robust phylogenetic scaffolding informs taxonomic revisions, clarifies biogeographic corridors such as the Upper Paraná–Amazon connections, and underlies conservation prioritisation in the face of habitat fragmentation and hydroelectric developments.

Research from Nature Portfolio

Recent studies have harnessed multilocus phylogenies to trace the diversification of a widespread genus within the La Plata Basin. Time‐calibrated analyses demonstrate that multiple colonisation events from Amazonian lineages occurred during the Middle Miocene, facilitated by palaeodrainage connections and intermittent marine barriers. These reconstructions show that Miocene marine transgressions acted both as dispersal corridors at low sea levels and as vicariant barriers at high stands, synchronising speciation pulses with hydrogeological shifts. Ancestral‐habitat reconstructions indicate several independent transitions from upland streams to lowland floodplain systems, accompanied by accelerated rates of cladogenesis and morphological innovation in oral and pectoral elements for substratum adhesion.

Phylogenetic Systematics of Neotropical Catfishes publication trend

The graph below shows the total number of articles in phylogenetic systematics of neotropical catfishes across all publications each year (not limited to Nature Index journals).

Technical terms

Cladogenesis: The branching process by which a lineage splits into two distinct lineages, resulting in increased biodiversity.

Monophyletic: A group of organisms that consists of a common ancestor and all its descendants, forming a single “clade.”

Time‐calibrated phylogeny: A phylogenetic tree in which branch lengths are scaled to represent absolute time, often using fossil or geological calibration points.

Synapomorphy: A shared derived character state that is present in an ancestral species and its descendants, used to diagnose clades.

Bayesian inference: A statistical method for estimating phylogenetic trees that uses probabilities to evaluate the likelihood of alternative evolutionary scenarios.

References

1. Multilocus phylogeny and historical biogeography of Hypostomus shed light on the processes of fish diversification in La Plata Basin. Scientific Reports (2021).
2. A combined molecular and morphological phylogeny of the Loricariinae (Siluriformes: Loricariidae), with emphasis on the Harttiini and Farlowellini. PLOS ONE (2021).
3. An integrated approach clarifies the cryptic diversity in Hypostomus Lacépède 1803 from the Lower La Plata Basin. Anais da Academia Brasileira de Ciências (2019).
4. An integrative framework to reevaluate the Neotropical catfish genus Guyanancistrus (Siluriformes: Loricariidae) with particular emphasis on the Guyanancistrus brevispinis complex. PLOS ONE (2018).