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| Urkumayu micracanthus (Regan 1912) Urkumayu gladysae (Calviño & Alonso 2010) Urkumayu, new genus Alonso, Terán, Aguilera, Montes, Serra Alanís, Calviño, Vera-Alcaraz, Cardoso, Koerber & Mirande, 2024 |
Highlights
• New phylogenetic hypothesis for diverse Neotropical fish genus Corydoras
• Integration of molecular and morphological data from 153 species
• Discovery of a new clade, including Andean and upper Paraná basin species
• Identification of emerging endemicity hotspots in NW La Plata basin
• Description of a new species and assessment of conservation status
Abstract
The knowledge about the diversity and phylogeny of South American callichthyid armored catfishes of the subfamily Corydoradinae is still growing, after important recent contributions, and many species have uncertain relationships. In this study, we present the first combined phylogenetic hypothesis for the genus based on five genes, 83 morphological characters, and 153 species, providing synapomorphies for some of the main genera of Corydoradinae, as recently defined. The inclusion of species not previously analyzed in a phylogenetic context challenged the monophyly of Hoplisoma and required the definition of a new genus for endemic species from the Andean portion of the northwestern La Plata basin (ANWLP): Hoplisoma gladysae, H. micracanthum, and H. petracinii. We found Hoplisoma non monophyletic with Hoplisoma sensu stricto not sister to a clade of species herein named the ‘Hoplisoma’ paleatum clade. In this clade we recovered a new species of Hoplisoma, which is endemic to the upper Bermejo basin, as sister to ‘Hoplisoma’ paleatum from the lower La Plata basin. The new species is distinguished from all congeners by a unique coloration similar to that of the syntopic H. micracanthum, suggesting a putative case of Müllerian co-mimicry.
Key words: Müllerian co-mimicry, coloration, endemic species, Upper Bermejo, threatened species
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| Live individuals. (A) Urkumayu micracanthus (CI-FML 7014, 30.3 mm SL). (B) Urkumayu gladysae (CI-FML 8109, 30.1 mm SL). (C) Urkumayu petracinii (CI-FML 8110, 26.9 mm SL). |
Urkumayu, new genus Alonso, Terán, Aguilera, Montes, Serra Alanís, Calviño, Vera-Alcaraz, Cardoso, Koerber, Mirande
Type species: Corydoras gladysae Calviño & Alonso 2010
Diagnosis: Urkumayu is distinguished from the remaining genera of Corydoradinae by the following unique combination of characters: supraoccipital and nuchal plate not in contact, posterior expansion of pharyngobranchial triangular, and ossified portion of pectoral spine strongly reduced.
Included species: Urkumayu gladysae (Calviño & Alonso 2010) n. comb., Urkumayu micracanthus (Regan 1912) n. comb., Urkumayu petracinii (Calviño & Alonso 2010) n. comb.
Etymology: Urkumayu, masculine gender, from the Quechua language, compound of urku meaning mountain and mayu for river, referring to the habitat where most species of this genus are found.
Distribution: It has a disjunct distribution in northwestern Andean La Plata Basin in Argentina.
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| ‘Hoplisoma’ osvaldoi n. sp. alive individual immediately after capture (CI-FML 5360, 41.6 mm SL). ‘Hoplisoma’ osvaldoi n. sp. (left) (CI-FML 5360, 41.6 mm SL) and Urkumayu micracanthus (right) (CI-FML 7011, 28.8 mm SL) immediately after capture. Anta Muerta creek (-23.117134 S, -64.497133 W). |
Hoplisoma osvaldoi, new species Alonso, Terán, Aguilera, Montes, Serra Alanís, Calviño, Vera-Alcaraz, Cardoso, Koerber, Mirande
Etymology: The specific epithet honors Jorge Osvaldo Fernández Santos, an esteemed aquarist and fish collector who made significant contributions to the knowledge of Argentinean fish by collecting and generously donating numerous specimens to scientific collections and collaborating with ichthyologists. He had been an avid promoter of the fish keeping hobby, particularly with respect to native species. As a result, this species is named in recognition of Osvaldo’s contributions to the study and knowledge of Argentina’s fishes.
Felipe Alonso, Guillermo Enrique Terán, Gastón Aguilera, Martin Miguel Montes, Wilson Sebastián Serra Alanís, Pablo Calviño, Héctor Samuel Vera-Alcaraz, Yamila Cardoso, Stefan Koerber and Juan Marcos Mirande. 2024. Integrative Phylogeny of Corydoradinae (Siluriformes: Callichthyidae) with an emphasis on Northwestern La Plata Species, including Descriptions of A New Genus and Species. Zoologischer Anzeiger. In Press. DOI: doi.org/10.1016/j.jcz.2024.11.006
