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| Pseudocorynopoma stanleyi Malabarba, Chuctaya, Hirschmann, Oliveira & Thomaz, 2020 DOI: 10.1111/jfb.14572 |
Abstract
Species delimitation is a permanent issue in systematics. The increasing recognition of geographically isolated populations as independent lineages allowed by new methods of analysis has inflated the species‐populations dilemma, which involves deciding whether to consider separate lineages as different species or structured genetic populations. This is commonly observed between fishes of adjacent river basins, with some lineages being considered allopatric sister species and others considered isolated populations or variants of the same species. Pseudocorynopoma doriae is a characid diagnosed from its single congener by the number of anal‐fin rays and sexually dimorphic characters of males, including distinct fin colouration. The authors found variation in the colour pattern between isolated populations previously identified as P. doriae but no variation in scale or fin‐ray counts. They analysed molecular evidence at the population level and morphological differences related to life history (e.g., colour dimorphism related to inseminating behaviour). The results provide compelling evidence for the recognition of a new species of Pseudocorynopoma despite the lack of discrete differences in meristic data. The recognition of the new species is consistent with biogeographical evidence for the long‐term isolation of the respective river drainages and with differences between the ichthyofaunal communities of these rivers.
Keywords: cryptic species, molecular phylogeny, phylogeography, population genetics, species concept, Stevardiinae
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| Live specimens of Pseudocorynopoma stanleyi, showing the colour pattern and shape of fins; (D) mature male (UFRGS 22112, 52.5 mm SL) and (E) immature male (UFRGS 22112, 48.0 mm SL) from the laguna dos Patos drainage. All specimens represented in scale |
Pseudocorynopoma stanleyi new species
Habitat and ecological notes: Pseudocorynopoma stanleyi is a typical surface feeder. This species feeds mainly on allochthonous arthropods, especially insects, even in fall and winter months (May, June, July and August) when they are less abundant in subtropical areas (Graciolli et al., 2003). This fish is especially abundant under trees found along stream shores and usually disappears in stretches that have the gallery forest removed.
Etymology: The specific epithet stanleyi is in honour of Stanley H. Weitzman in recognition of his great contribution to the knowledge on the stevardiine characids and other Neotropical freshwater fishes. A genitive noun.
Luiz R. Malabarba, Junior Chuctaya, Alice Hirschmann, Eduardo Bitencourt de Oliveira and Andréa T. Thomaz. 2020. Hidden or unnoticed? Multiple Lines of Evidence Support the Recognition of A New Species of Pseudocorynopoma (Characidae: Corynopomini). Journal of Fish Biology.
DOI: 10.1111/jfb.14572
