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Uzeda, P. L. C. et al. 2026 (3)

Description: A new species of the small-sized armoured catfish genus Neoplecostomus is described from Neotropical Atlantic coastal drainages, in southeast Brazil. The new species can be readily diagnosed from all congeners by having the first plates of the ventral series reduced in size, rounded and ventrally displaced, resulting in a naked band between the mid-ventral and ventral series of plates. Additionally, the species exhibits marked sexual dimorphism in dentition: Females possess numerous slender teeth, while males have fewer, more robust teeth. We report the second known case of sympatry between congeneric species of Neoplecostomus, a rare condition for the genus, and provide insights into its biogeographic and ecological patterns, (Uzeda, P.L.C. et al. 2026). Habitat: Neoplecostomus azevedosantosi is currently known from the Itaba poana and Benevente River basins, two Atlantic coastal drainages insoutheastern Brazil. Within the Itabapoana River basin, specimens are known from the São Domingos stream and Preto River, both of which originate on the southern slopes of the Caparaó National Park. The species is also known from the main channel of the Benevente River, downstream of the São Joaquim reservoir. Sexual Dimorphism. Females and males of Neoplecostomus azevedosantosi can be distinguished by typical hypoptopomatine features for sexual dimorphism, such as the presence of a papilla just posterior to the urogenital opening in males (vs. papilla absent in females), and the presence of an enlarged skinfold along the dorsal surface of the unbranched pelvic fin ray in males (vs. skinfold absent in females). Additionally, N. azevedosantosi exhibits sexual dimorphism in dentition, in which females present 30–47 slender premaxillary teeth (vs. 18–29 robust premaxil-lary teeth in males), and 28–42 slender dentary teeth (vs. 14–28 robust dentary teeth in males), (Uzeda, P.L.C. et al. 2026). Etymology: The specific epithet 'azevedosantosi' is in honour of Valter M. Azevedo-Santos, Brazilian ichthyologist and dear friend, for his outstanding contributions to freshwater ecology and conservation biology. A noun in the genitive case.

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Loricariidae

South America: Taba-poana and Benevente River basins, two Atlantic coastal drainages in southeastern Brazil.

11.5cm. (4½ins)

20-25°c (67-77°f.)

6.0-7.2.

Fish in the News 2026.
Uzeda, P. L. C., Pessali, T. C., Katz, A. M., Ottoni, F. P., Langeani, F., & Silva, P. C. (2026). A new sexually dimorphic species of the armoured catfish genus Neoplecostomus (Siluriformes: Loricariidae) from Neotropical Atlantic coastal drainages. Journal of Fish Biology, 1–10.