28/07/2026
The Gymnotiformes are an abundant, diverse, and ecologically significant component of the nocturnal ichthyofauna of most major Neotropical freshwater habitats. The authors in this study present a taxonomically inclusive molecular phylogeny of Gymnotiformes, with analyses that provide strong support for a concordant species-level phylogenetic arrangement and propose a revised classification of Gymnotiformes, including new suprageneric names and reassignments of some taxa and species.
"We found support for six monophyletic families, including Electrophoridae (electric eels). We propose two new suborders corresponding to electric signal type: Pulseoidei (pulse-type) and Sinusoidei (wave-type), an arrangement that does not allow determination of whether a pulse or wave-type signal was ancestral."
"Our study provides a robust phylogenetic framework for Gymnotiformes and establishes a foundation for future work on systematics, biogeography, trait evolution, and comparative neurobiology."
𝗥𝗲𝘀𝗲𝗮𝗿𝗰𝗵 𝗧𝗶𝘁𝗹𝗲
Molecular phylogenetics and a new taxonomy of the neotropical electric fishes (Actinopterygii: Otophysi: Gymnotiformes)
Open-access - https://www.sciencedirect.com/science/article/pii/S105579032600148X
𝗖𝗶𝘁𝗮𝘁𝗶𝗼𝗻
Francesco H. Janzen, Mark H. Sabaj, William G.R. Crampton, Nathan R. Lovejoy, Molecular phylogenetics and a new taxonomy of the neotropical electric fishes (Actinopterygii: Otophysi: Gymnotiformes), Molecular Phylogenetics and Evolution, 2026, 108678, ISSN 1055-7903, https://doi.org/10.1016/j.ympev.2026.108678
𝗔𝗯𝘀𝘁𝗿𝗮𝗰𝘁
The order Gymnotiformes—Neotropical electric eels and knifefishes—comprise a distinctive lineage of freshwater fishes characterized by electrogenesis and electroreception. Despite their ecological, evolutionary, and neurobiological significance, phylogenetic relationships within the order remain incompletely resolved.
We present the most taxonomically inclusive molecular phylogeny of Gymnotiformes to date, based on two mitochondrial and seven nuclear genes from 202 species representing 31 of 36 extant genera. Maximum likelihood and Bayesian inference analyses provide strong support for a concordant species-level phylogenetic arrangement that we use to propose a revised classification of Gymnotiformes, including new suprageneric names and reassignments of some taxa and species.
We found support for six monophyletic families, including Electrophoridae (electric eels). We propose two new suborders corresponding to electric signal type: Pulseoidei (pulse-type) and Sinusoidei (wave-type), an arrangement that does not allow determination of whether a pulse or wave-type signal was ancestral. In Apteronotidae, the subfamilies Sternarchorhamphinae and Apteronotinae are supported; within Apteronotinae, we establish the tribe Steatogenini to include 𝑃𝑜𝑟𝑜𝑡𝑒𝑟𝑔𝑢𝑠, 𝑆𝑡𝑒𝑟𝑛𝑎𝑟𝑐ℎ𝑒𝑙𝑙𝑎, and close relatives.
We resolve the non-monophyly of 𝐴𝑝𝑡𝑒𝑟𝑜𝑛𝑜𝑡𝑢𝑠 with generic reassignments. For Sternopygidae, we support the monophyletic subfamilies Sternopyginae and Eigenmanniinae and resolve polyphyly in 𝑅ℎ𝑎𝑏𝑑𝑜𝑙𝑖𝑐ℎ𝑜𝑝𝑠 and 𝐸𝑖𝑔𝑒𝑛𝑚𝑎𝑛𝑛𝑖𝑎 via generic reassignments. Within 𝐺𝑦𝑚𝑛𝑜𝑡𝑢𝑠, we support six species groups.
We confirm the sister-group relationship between Hypopomidae and Rhamphichthyidae and clarify their internal structure, including support for six species groups within the diverse genus 𝐵𝑟𝑎𝑐ℎ𝑦ℎ𝑦𝑝𝑜𝑝𝑜𝑚𝑢𝑠.
Our study provides a robust phylogenetic framework for Gymnotiformes and establishes a foundation for future work on systematics, biogeography, trait evolution, and comparative neurobiology.
𝗣𝗵𝗼𝘁𝗼 𝗖𝗿𝗲𝗱𝗶𝘁
Representatives of the six gymnotiform families Apteronotidae (A), Sternopygidae (S), Gymnotidae (G), Electrophoridae (E), Hypopomidae (H), and Rhamphichthyidae (R). Top to bottom, and left to right, are: 𝑅ℎ𝑎𝑚𝑝ℎ𝑖𝑐ℎ𝑡ℎ𝑦𝑠 𝑟𝑜𝑠𝑡𝑟𝑎𝑡𝑢𝑠 (R), 𝐴𝑟𝑐ℎ𝑜𝑙𝑎𝑒𝑚𝑢𝑠 𝑗𝑎𝑛𝑒𝑎𝑒 (S), 𝑆𝑡𝑒𝑟𝑛𝑎𝑟𝑐ℎ𝑜𝑟ℎ𝑎𝑚𝑝ℎ𝑢𝑠 𝑚𝑢𝑒𝑙𝑙𝑒𝑟𝑖 (A), 𝐸𝑖𝑔𝑒𝑛𝑚𝑎𝑛𝑛𝑖𝑎 𝑚𝑎𝑔𝑜𝑖 (S), 𝐺𝑦𝑚𝑛𝑜𝑡𝑢𝑠 𝑐𝑎𝑟𝑎𝑝𝑜 (G), 𝑆𝑡𝑒𝑟𝑛𝑎𝑟𝑐ℎ𝑜𝑟ℎ𝑦𝑛𝑐ℎ𝑢𝑠 𝑠𝑝. (A), 𝐴𝑝𝑡𝑒𝑟𝑜𝑛𝑜𝑡𝑢𝑠 𝑔𝑎𝑙𝑣𝑖𝑠𝑖 (A), 𝑂𝑟𝑡ℎ𝑜𝑠𝑡𝑒𝑟𝑛𝑎𝑟𝑐ℎ𝑢𝑠 𝑡𝑎𝑚𝑎𝑛𝑑𝑢𝑎 (A), “𝐴𝑝𝑡𝑒𝑟𝑜𝑛𝑜𝑡𝑢𝑠” (Genus B) 𝑐𝑢𝑐ℎ𝑖𝑙𝑙𝑒𝑗𝑜 (A), 𝐴𝑝𝑡𝑒𝑟𝑜𝑛𝑜𝑡𝑢𝑠 𝑒𝑠𝑐ℎ𝑚𝑒𝑦𝑒𝑟𝑖 (A), 𝐴𝑝𝑡𝑒𝑟𝑜𝑛𝑜𝑡𝑢𝑠 𝑐𝑓. 𝑎𝑙𝑏𝑖𝑓𝑟𝑜𝑛𝑠 (A), 𝐺𝑦𝑚𝑛𝑜𝑟ℎ𝑎𝑚𝑝ℎ𝑖𝑐ℎ𝑡ℎ𝑦𝑠 𝑠𝑝. (R), 𝑆𝑡𝑒𝑟𝑛𝑎𝑟𝑐ℎ𝑜𝑟ℎ𝑦𝑛𝑐ℎ𝑢𝑠 𝑚𝑎𝑟𝑟𝑒𝑟𝑜𝑖 (A), 𝑆𝑡𝑒𝑟𝑛𝑜𝑝𝑦𝑔𝑢𝑠 𝑎𝑒𝑞𝑢𝑖𝑙𝑎𝑏𝑖𝑎𝑡𝑢𝑠 (S), 𝐴𝑑𝑜𝑛𝑡𝑜𝑠𝑡𝑒𝑟𝑛𝑎𝑟𝑐ℎ𝑢𝑠 𝑑𝑒𝑣𝑒𝑛𝑎𝑛𝑧𝑖𝑖 (A), 𝑆𝑡𝑒𝑎𝑡𝑜𝑔𝑒𝑛𝑦𝑠 𝑑𝑢𝑖𝑑𝑎𝑒 (R), 𝐵𝑟𝑎𝑐ℎ𝑦ℎ𝑦𝑝𝑜𝑝𝑜𝑚𝑢𝑠 𝑜𝑐𝑐𝑖𝑑𝑒𝑛𝑡𝑎𝑙𝑖𝑠 (H), 𝐻𝑦𝑝𝑜𝑝𝑜𝑚𝑢𝑠 𝑎𝑟𝑡𝑒𝑑𝑖 (H), and 𝐸𝑙𝑒𝑐𝑡𝑟𝑜𝑝ℎ𝑜𝑟𝑢𝑠 𝑚𝑢𝑙𝑡𝑖𝑣𝑎𝑙𝑣𝑢𝑙𝑢𝑠 (E). Photos by M. Sabaj.
© 2026 the Author(s). Published in the journal Molecular Phylogenetics and Evolution. An open-access article, distributed under the terms of the Creative Commons Attribution 4.0 International (CC-BY-4.0) deed. https://creativecommons.org/licenses/by/4.0/
