Who is Andesiops peruvianus (Ulmer, 1920) (Ephemeroptera: Baetidae)? New insight from the type basin using morphological and molecular analyses.

Andesiops peruvianus (Ulmer, 1920) is a small minnow mayfly with a distribution throughout the Andes Mountains, mainly in lotic environments. In recent years, the taxonomic status of the species has been shifting, even finding out molecular and morphological evidence to consider it as a cryptic species. In this work, we collected seven specimens of A. peruvianus from the Lake Titicaca in Peru, the type locality and perform molecular and morphological analyses to test their relationship with specimens from other regions. The species delimitation analysis revealed the existence of five MOTUs for specimens identified as A. peruvianus along the Andes Mountains, while the Lake Titicaca specimens formed a single MOTU with high interspecific distance. In this MOTU were found specimens with different types of abdominal gills, from translucent to markedly tracheated supporting the hypothesis of phenotypic plasticity at the abdominal gill level. Also, an extension in the range of tarsal claw denticles, from 10-12 to 10-14, were observed, higher than what were found in other regions. Our results support A. peruvianus as a species complex and reveal A. peruvianus from Titicaca as a single MOTU. Future morphological revisions of topotype specimens as well as from other Andean regions are required to strengthen the diagnosis of informative characteristics at both the larval and adult stage to elucidate the real status of the species.

Fishes from Yarinacocha lake: an emblematic Amazonian ecosystem in the lower Ucayali River basin, Pucallpa, Peru / Peixes do lago Yarinacocha: um ecossistema amazônico emblemático na bacia do baixo rio Ucayali, Pucallpa, Peru

The Yarinacocha lake is an emblematic ecosystem of the Peruvian Amazon, representing the main point of fish landing and a tourist attraction in the city of Pucallpa. The wide fauna diversity in this area has made it the target of various studies, although for fish species most of them were focused on commercial species. In this work, we carried out the first ichthyofauna species inventory of the Yarinacocha lake, sampling throughout the entire lake during the rainy and dry seasons and considering also all previously recorded species deposited in the Ichthyological Collection of the MUSM with the same locality. A total of 164 fish species were recorded, representing 10 orders (plus Eupercaria), 34 families and 116 genera. Characiformes was the order with more species (68 spp., 41.5%) followed by Siluriformes (59 spp., 36%), Cichliformes (17 spp., 10.5%), and Gymnotiformes (8 spp., 4.9%). The most highly represented families, including almost 55.5% of the total diversity obtained, were Characidae (23 spp., 14%), followed by Cichlidae (17 spp., 10.4%), Loricariidae (14 spp., 8.5%), Pimelodidae (13 spp., 7.9%), Doradidae (13 spp., 7.4%) and Anostomidae (12 spp., 7.3%). From the total fish species recorded in this study, only 22 are considered protected species following the IUCN criteria and 109 species have commercial importance, including 90 ornamental species (54.8%). Our results contribute to the knowledge of the ichthyofauna of the Yarinacocha lake and can be used as a starting point for its conservation and sustainable management over time.

O lago Yarinacocha é um ecossistema emblemático da Amazônia peruana, representando o principal ponto de desembarque de peixes e também uma atração turística da cidade de Pucallpa. A grande diversidade faunística nesta área a tornou alvo de vários estudos, embora para as espécies de peixes a maioria deles tenha sido focada em espécies comerciais. Neste trabalho, realizamos o primeiro inventário da ictiofauna do lago Yarinacocha, amostrando todo o lago durante as estações chuvosa e seca, e também considerando todas as espécies depositadas na Coleção Ictiológica do MUSM dessa localidade. Um total de 164 espécies de peixes foram registradas, representando 10 ordens (mais Eupercaria), 34 famílias e 116 gêneros. Characiformes foi a ordem com mais espécies (68 espécies, 41,5%), seguida por Siluriformes (59 espécies, 36%), Cichliformes (17 espécies, 10,5%) e Gymnotiformes (8 espécies, 4,9%). As famílias mais representadas, incluindo quase 55,5% da diversidade total obtida, foram Characidae (23 spp., 14%), seguido por Cichlidae (17 spp., 10,4%), Loricariidae (14 spp., 8,5%), Pimelodidae (13 spp., 7,9%), Doradidae (13 spp., 7,4%) e Anostomidae (12 spp., 7,3%). Do total de espécies de peixes registradas neste estudo, apenas 22 são consideradas espécies protegidas seguindo os critérios da IUCN e 109 espécies têm importância comercial, incluindo 90 espécies ornamentais (54,8%). Nossos resultados contribuem para o conhecimento da ictiofauna do lago Yarinacocha e podem ser utilizados como ponto de partida para sua conservação e manejo sustentável ao longo do tempo.

Use of complete mitochondrial genome sequences to identify barcoding markers for groups with low genetic distance.

Complete mitochondrial sequences can be rapidly obtained and are widely available, providing a great source of species information and allowing for the discovery of new specific molecular markers. However, for some taxonomic groups, traditional approaches for species delimitation are impaired by the low genetic distance values. In these cases, other species-level markers are used. For Prochilodus, which includes important neotropical fish species, species-level delimitation usually results in poor phylogenetic resolution when using mitochondrial COI/cytB genes as barcoding markers because of low genetic variability and low species-level resolution. Thus, in this study, we developed an approach to design and validate new barcoding markers with high species-level resolution obtained from the D-loop region, using Prochilodus spp. as a model. For the new barcoding marker validation, the amplicon region was used to infer the phylogenetic relationships of Prochilodus spp. through three distinct methods: Bayesian inference (BI), Neighbor-Joining method (NJ), and Maximum Likelihood method (ML). The phylogenetic relationships of Prochilodus spp. revealed high resolution at species-level, nonoverlapping clades, and high branch support. The genetic distance results allied to two different clustering methods (Bayesian Poisson tree processes and automatic barcode gap discovery) revealed the existence of a barcoding gap, thus, validating the use of the barcoding markers designed in this study. The approach proposed here may, therefore, be expanded to other taxa to access and validate new barcoding markers with higher resolution at the species level.

Leporinus elongatus (Characiformes, Anostomidae): complete mtDNA sequence of an economically important fish from the Paraná and La Plata river basins.

Leporinus elongatus is an important commercial fish found in the La Plata and Paraná River basins. Next-generation sequencing was used to sequence the mitochondrial DNA (mtDNA) of L. elongatus. The mtDNA was assembled using the CLC Workbench software v. 9.0 and subsequently aligned to other 10 complete fish mitochondrial sequences to enable phylogenetic analysis using MEGA 7.0. The complete mtDNA molecule had 16,784 bp and its GC content was 43%. The mtDNA structure was similar to that of other vertebrates: two ribosomal RNA, 22 transfer RNA, 13 protein-coding genes, and a D-loop region containing 1115 bp. Phylogenetic analysis yielded a tree with high bootstrap value that was coherent with the current phylogeny proposed for Characiformes.

Complete mitochondrial DNA of Hoplias intermedius (Günther, 1864) (Ostariophysi: Characiformes: Erythrinidae).

Mitochondrial complete genome (mtDNA) of Hoplias intermedius, commonly known as "traírão" is presented. DNA from a muscle tissue sample was sequenced by next-generation sequencing. To corroborate the results, phylogenetic analysis was performed with MEGA6 to compare the complete mitogenome of H. intermedius with genomes of other Characiformes species. The mtDNA molecule was circular and 16,629 bp in length. Gene content included 22 tRNA genes, 2 rRNA genes, 13 protein-coding genes and a D-loop noncoding region. All genes had ATG as the start codon. Six genes carried complete stop codons of AGG (COI), TGA (ND6) and TAA (ND1, ATPase 8, ND4L and ND5), while seven genes had incomplete stop codons. Phylogenetic relationships with other Ostariophysi species placed H. intermedius together with H. malabaricus as a monophyletic group belonging to the order Characiformes.

Pimelodus maculatus (Siluriformes, Pimelodidae): complete mtDNA sequence of an economically important fish from the São Francisco river basin.

Pimelodus maculatus is an important commercial fish found in the São Francisco and Paraná river basins. NGS was used to sequence the mtDNA of P. maculatus. The mtDNA was annotated and aligned with that of 25 other fish species to enable phylogenetic analysis. The complete mtDNA molecule had 16,561 bp and its GC content was 43.7%; the structure was similar to that of other vertebrates: 2 rRNA, 22 tRNA, 13 protein-coding genes, and a D-loop region containing 914 bp. Phylogenetic analysis yielded a tree with a high bootstrap coefficient that was coherent with the actual phylogeny of the species.