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| Titanolebias calvinoi Alonso, Terán, Alanís, Waldbillig, Montes, Bugeau, Barneche, Shimabukuro, Táboas, Maroli & Almeida, 2025 |
ABSTRACT
The genus Titanolebias comprises the largest-bodied seasonal killifishes, inhabiting temporary wetlands of the La Plata Basin and adjacent areas in South America. Here, we describe a new species from the Eastern Chacoan region, representing the first record of the genus in this area, providing important biogeographic and evolutionary insights. Phylogenetic analyses confirm the monophyly of Titanolebias, placing T. monstrosus as the sister species to the remaining species of the genus and recovering the new species as sister to a clade composed of T. prognathus, T. elongatus, and T. cheradophilus. Titanolebias species, exhibits reduced sexual dimorphism, potentially associated with a trophic shift toward larger prey in the origin of this genus and presents several potential cases of aggressive mimicry. Megalebias genus represents a case of convergent evolution towards ichthyophagy with Titanolebias. Morphological analyses reveal that the new species present the diagnostic characters of the genus Titanolebias and can be distinguished by its unique coloration and other morphological traits. Behavioral and ecological data are also provided. Despite its restricted distribution and the vulnerability of ephemeral wetlands to habitat loss, the species is found within a National Park. This discovery provides valuable insights into convergent evolution linked to trophic shifts and contributes to the understanding of the evolution, phylogeny, ecology, and biogeography of Neotropical fishes, offering new avenues for future research and conservation policies for this threatened group of fishes.
Key words: sexual dimorphism, aggressive mimicry, biogeography, endemisms, temporary wetlands, annual fishes, conservation, Aplocheiloidei
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| Live color pattern variability and ontogenetic changes in Titanolebias calvinoi n. sp. males. |
Titanolebias calvinoi, new species
Etymology: The specific epithet is dedicated to Pablo Andrés Calviño, in recognition of his notable contributions to Neotropical ichthyology and his pioneering efforts in the study and promotion of knowledge about killifish. Calviño has not only actively participated in scientific research on this group of fish but has also distinguished himself as one of the most notable aquarists and breeders in the region. Additionally, he has significantly contributed to the training of human resources in this field, enhancing public awareness and understanding through the organization of activities, creation of dissemination materials, and his dedicated teaching efforts, being one of the founders of the Killi Club Argentino (KCA). The term calvinoi is a patronymic in the genitive case.
Felipe Alonso, Guillermo Enrique Terán, Wilson Sebastián Serra Alanís, Marcos Martin Waldbillig, Martin Miguel Montes, Baltazar Bugeau, Jorge Adrian Barneche, Marina Ibañez Shimabukuro, Francisco González Táboas, Malena Maroli and Matías Jesús Almeida. 2025. The Rise of a Titan: A New Species of the giant Titanolebias Killifishes, and its phylogeny (Cyprinodontiformes: Rivulidae). Zoologischer Anzeiger. In Press DOI: doi.org/10.1016/j.jcz.2025.04.009 [3 May 2025]
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