06/06/2025
Researchers look into a potential hybrid zone in the endemic species of 𝐻𝑦𝑝𝑎𝑛𝑐𝑖𝑠𝑡𝑟𝑢𝑠 from the lower and middle rio Xingu, Brazil. Hybridization poses a threat to the genetic integrity of the parent species and may accelerate the decline of these already endangered species in this rapidly degrading environment. The author's findings are crucial for guiding conservation strategies and understanding the complex diversification processes in the rio Xingu.
Open-access - https://www.scielo.br/j/ni/a/ZRNq9v4jM5jH8GqZHRBbkLH/
"The Volta Grande do Xingu, one of the most important refuges of freshwater fish diversity in the Amazon, hosts a complex ecosystem where endemic species of 𝐻𝑦𝑝𝑎𝑛𝑐𝑖𝑠𝑡𝑟𝑢𝑠, such as 𝐻. 𝑧𝑒𝑏𝑟𝑎, 𝐻.𝑠𝑒𝑖𝑑𝑒𝑙𝑖, and 𝐻.𝑦𝑢𝑑𝑗𝑎, coexist sharing the same habitat. The drastic environmental changes caused by the construction of the Belo Monte Hydroelectric Plant and the severe droughts experienced in recent years, exacerbated by climate change, have fragmented their habitats and might be increasing contact between these three species."
𝗥𝗲𝘀𝗲𝗮𝗿𝗰𝗵 𝗧𝗶𝘁𝗹𝗲
Geometric morphometrics reveal a potential hybridization zone in endemic species of 𝐻𝑦𝑝𝑎𝑛𝑐𝑖𝑠𝑡𝑟𝑢𝑠 (Siluriformes: Loricariidae) from the lower and middle rio Xingu
𝗖𝗶𝘁𝗮𝘁𝗶𝗼𝗻
Kerniske, F. F., Dalcin, R. H., Sousa, L. M., & Artoni, R. F.. (2025). Geometric morphometrics reveal a potential hybridization zone in endemic species of 𝐻𝑦𝑝𝑎𝑛𝑐𝑖𝑠𝑡𝑟𝑢𝑠 (Siluriformes: Loricariidae) from the lower and middle rio Xingu. Neotropical Ichthyology, 23(2), e240107. https://doi.org/10.1590/1982-0224-2024-0107
𝗔𝗯𝘀𝘁𝗿𝗮𝗰𝘁
The Volta Grande do Xingu, one of the most important refuges of freshwater fish diversity in the Amazon, hosts a complex ecosystem where endemic species of 𝐻𝑦𝑝𝑎𝑛𝑐𝑖𝑠𝑡𝑟𝑢𝑠, such as 𝐻. 𝑧𝑒𝑏𝑟𝑎, 𝐻.𝑠𝑒𝑖𝑑𝑒𝑙𝑖, and 𝐻.𝑦𝑢𝑑𝑗𝑎, coexist sharing the same habitat. The drastic environmental changes caused by the construction of the Belo Monte Hydroelectric Plant and the severe droughts experienced in recent years, exacerbated by climate change, have fragmented their habitats and might be increasing contact between these three species.
Using geometric morphometrics, this study reveals a concerning morphological overlap between 𝐻.𝑠𝑒𝑖𝑑𝑒𝑙𝑖 and 𝐻.𝑦𝑢𝑑𝑗𝑎 which indicates hybridization in impacted areas and threatens to dilute the unique genetic characteristics of these parental species. In contrast, 𝐻. 𝑧𝑒𝑏𝑟𝑎 remained morphologically distinct, reinforcing its status as a highly vulnerable species. Hybridization poses a threat to the genetic integrity of the parent species and may accelerate the decline of already endangered species in this rapidly degrading environment.
These findings are crucial for guiding conservation strategies and understanding the complex diversification processes in the rio Xingu.
𝗣𝗵𝗼𝘁𝗼 𝗖𝗿𝗲𝗱𝗶𝘁
Lateral, dorsal, and ventral views of 𝐻𝑦𝑝𝑎𝑛𝑐𝑖𝑠𝑡𝑟𝑢𝑠 individuals, showing the anatomical landmarks used in the geometric morphometric analysis. A. Lateral view: 1) Anterior limit of the orbital bone; 2) Posterior limit of the orbital bone; 3) Inferior limit of the orbital bone; 4) Superior limit of the orbital bone; 5) Anterodorsal edge of the operculum bone; 6) Tip of the snout; 7) Base of the supraoccipital process; 8 ) Origin of the dorsal-fin spine; 9) Posterior limit of the dorsal-fin base; 10) Anterior limit of the adipose-fin base; 11) Posterior limit of the adipose-fin base; 12) Medial point of the vertical line through the distal margin of the hypurals; 13) Center of the nostril opening; 14) Insertion of the pectoral-fin spine; 15) Insertion of the pelvic-fin spine; 16) Anal-fin insertion; 17) Base of the first procurrent ray of the caudal fin (upper lobe); 18 ) Base of the first procurrent ray of the caudal fin (lower lobe). B. Dorsal view: 1) Left eye; 2) Right eye; 3) Center of the left nostril opening; 4) Center of the right nostril opening; 5) Tip of the snout; 6) Anterodorsal edge of the left operculum bone; 7) Anterodorsal edge of the right operculum bone; 8 ) Leftmost point of the body; 9) Rightmost point of the body; 10) Origin of the dorsal-fin spine; 11) Anterior limit of the adipose-fin base; 12) Caudal-fin insertion. C. Ventral view: 1) Anterior margin of the oral disc; 2) Left margin of the oral disc; 3) Right margin of the oral disc; 4) Posterior margin of the oral disc; 5) Anterodorsal edge of the left operculum bone; 6) Anterodorsal edge of the right operculum bone; 7) Insertion of the left pectoral-fin spine; 8 ) Insertion of the right pectoral-fin spine; 9) Tip of the left pectoral-fin spine; 10) Tip of the right pectoral-fin spine; 11) Leftmost point of the body; 12) Rightmost point of the body; 13) Origin of the left pelvic-fin spine; 14) Origin of the right pelvic-fin spine; 15) Tip of the left pelvic-fin spine; 16) Tip of the right pelvic-fin spine; 17) Anterior limit of the anal-fin base; 18 ) Center of the a**s; 19) Posterior limit of the adipose-fin base; 20) Caudal-fin insertion. Scale bars = 1 cm.
Copyright © 2025 the Author(s). Published in Neotropical Ichthyology journal. This paper is released under a Creative Commons Attribution 4.0 International (CC BY 4.0) licence. https://creativecommons.org/licenses/by/4.0/
