Integrative taxonomy of Imparfinis (Siluriformes, Heptapteridae) from the Upper Paraná River basin, Brazil, with description of a new species.

The Neotropical family Heptapteridae comprises 228 valid species widely distributed in South America. Imparfinis is one of the most diverse genera of this family, with 25 valid species widely distributed, inhabiting streams from Costa Rica to Argentina. Old descriptions coupled with lack of recent systematic studies of the species of Imparfinis from the Upper Paraná river basin have led to a taxonomic impediment and hindered the advancement of studies in other areas, such as ecology, cytogenetic, phylogenetic, and evolution. We conducted the first integrative study analyzing both molecular and morphological data of Imparfinis from the Upper Paraná River basin. Our analyses strongly support the existence of four independent evolutionary lineages in this river system, three of them are the nominal species I. mirini, I. schubarti, and I. piperatus, and a new species from Goiás state described herein.

Moenkhausia andrica (Characiformes: Characidae): a new species from the rio Tapajós basin, Brazil, with minute fin hooklets in females.

In this study, a new species of Moenkhausia is described from the upper rio Juruena, rio Tapajós basin, Brazil. It is distinguished from all congeners by the presence of minute bony hooks in all fins of both mature females and males and combination of a prepelvic region flattened, dorsal portion of the humeral blotch extending two scales horizontally and vertically, lateral line with 28-32 scales, five scale series above and below lateral line; circumpeduncular scales 13-14, anal-fin rays 16-19 and dorsal portion of eyes blue in live specimens. The new species is also supported by high divergence in the mitochondrial gene cytochrome c oxidase subunit I (COI). The presence of minute fin bony hooks in both females and males, population variations and late development of the lateral line in Moenkhausia andrica are discussed.

Taxonomy of Moenkhausia australis Eigenmann, 1908 (Characiformes, Characidae) with a discussion on its phylogenetic relationships.

The species Moenkhausia australis was described based on two specimens from arroyos Trementina and Chagalalina, Rio Paraguai basin, Paraguay. Its taxonomic history is complex and for many years the species was considered a synonym of Moenkhausia sanctaefilomenae. Moenkhausia australis shares a reticulated color pattern with the Moenkhausia oligolepis/M. sanctaefilomenae complex, being more similar within the species included in the complex to M. oligolepis, M. sanctaefilomenae, and M. forestii, with which it shares a prepelvic region laterally compressed, a feature also observed in Bario steindachneri. The laterally compressed prepelvic region is inferred to be putatively synapomorphic for the subgroup herein denominated as Moenkhausia oligolepis group. Our results, based on both molecular and morphological data, support the validity of Moenkhausia australis, which can be readily distinguished from the other members of the group by possessing the following combination of characters: complete lateral line, 23-27 scales in the lateral line, and five scales series above and below the lateral line. Our analysis also indicates three genetic structured populations of M. australis, from Rio Paraguai, upper Rio Paraná, and Rio Madeira basins. Since they are not diagnosable by morphological characters, we conservatively maintain these three genetic lineages as a single species.

A new species of Hemigrammus Gill 1858 (Characiformes: Characidae) from the upper Rio Negro, Amazon basin, Brazil.

A new species of Hemigrammus is described from the upper Rio Negro, Amazon basin, Brazil. The new species is distinguished from all congeners by its unique color pattern consisting of a single humeral blotch clearly spaced from a conspicuous midlateral dark stripe, which extends from fifth or sixth anteriormost vertical scale row to the basis of the middle caudal-fin rays. Comments on its putative relationships are provided.

New species of Neoplecostomus (Neoplecostomini: Loricariidae) lacking adipose fin from upper Rio Paraná basin, central Brazil.

In the present study, we describe a new species of Neoplecostomus from central Brazil. The new species is known from Córrego Cachoeira a right tributary of the upper Rio Paraná basin. It can be distinguished from all congeners by absence of adipose fin or azygous plates on the dorsum surface of the caudal peduncle. Additionally, the new species differs from N. botucatu and N. paranensis by having a dark caudal fin with a unique v-shaped hyaline vertical area and a larger lower lip. A discussion on the morphological variation of adipose fin among species of Neoplecostomus is also provided.