Parodon nasus - taken under water in the Rio Claro at Cuiaba, Mato Grosso, Brazi
photo by Ivan Sazima
Parodon tortuosus Eigenmann and Norris, 1900
is a junior synonym of
Parodon nasus Kner, 1859
remarks:
The first record of a Parodon species from Argentina was that of Perugia (1891) sub Parodon nasus. López et al. (2003) considered Perugia’s record as a misidentification of P. suborbitalis and mentioned P. tortuosus as a separate species for Argentina.
Menni et al. (2005) mention "Parodon tortuosus (= P. nasus)" without giving reasons or references.
Pavanelli, author of the chapter about Parodontidae in CLOFFSCA (2003), considered P. tortuosus a synonym of P. nasus without providing a diagnosis. This step was probably based on the results of her PhD thesis (Revisao taxonômica da Familia Parodontidae), which does not count as published in the sense of the ICZN, and thus systematical changes included therein are not available. The recent work of Bellafronte et al. support Pavanelli’s opinion.
published in:
Bellafronte, E., V.P. Margarido & O. Moreira-Filho (2005):
Cytotaxonomy of Parodon nasus and Parodon tortuosus (Pisces, Characiformes). A case of synonymy confirmed by cytogenetic analyses.
Genetics and Molecular Biology 28 (4): 710-716
abstract (from publication):
Morphological and cytogenetical studies were carried out on the freshwater fish Parodon nasus and Parodon tortuosus in order to evaluate a putative synonymy. The diploid chromosome number observed in both species was 2n = 54 (48M/SM and 6ST) with no differences between the sexes. Despite slight differences in the pattern of heterochromatin distribution and the number of cusps in symphysean teeth, the location of nucleolar organizer regions (NORs) and 5S rRNA genes (both species-specific features) were similar in both species. The remarkable similarity observed between these allopatric species supports recent taxonomical reviews indicating that P. tortuosus is a synonym for P. nasus.
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