Phylogenetic relationships of the species of Acestridium Haseman, 1911 (Siluriformes: Loricariidae)

A combined molecular and morphological phylogeny of the Loricariinae (Siluriformes: Loricariidae), with emphasis on the Harttiini and Farlowellini

We present a combined molecular and morphological phylogenetic analysis of the Loricariinae, with emphasis on the Harttiini (Cteniloricaria, Harttia, and Harttiella) and Farlowellini (Aposturisoma, Farlowella, Lamontichthys, Pterosturisoma, Sturisoma, and Sturisomatichthys). Character sampling comprised seven molecular markers (the mitochondrial Cytb, nd2, 12S and 16S, and the nuclear MyH6, RAG1 and RAG2) and 196 morphological characters. A total of 1,059 specimens, and 159 tissue samples were analized, representing 100 species. A Bayesian Inference analysis was performed using the concatenated data matrix, which is comprised of 6,819 characters. The Loricariinae were found to comprise the tribes (Hartiini (Loricariini, Farlowellini)), the latter two elevated from subtribes. A Maximum Parsimony analysis was also performed using the same data matrix in order to reveal phenotypical synapomorphies to diagnose each clade. Two MP trees were found with a length of 14,704 steps, consistency index of 0.29 and retention index of 0.61, which were summarized in a strict consensus tree. Harttiini includes (Harttiella (Cteniloricaria, Harttia), and Farlowellini includes (Lamontichthys (Pterosturisoma (Sturisoma (Sturisomatichthys, Farlowella)))). Aposturisoma was recovered nested within Farlowella and is synonymyzed to the latter. Sturisoma was corroborated as strictly cis-Andean, while Sturisomatichthys encompasses, besides the valid species already included in the genus, the trans-Andean species once belonging to Sturisoma sensu lato. Identification keys and phylogenetic diagnoses of family-group taxa and genera of both the Harttiini and the Farlowellini are provided.

Species delimitation in a range-restricted group of cascudinhos (Loricariidae: Epactionotus) supports morphological and genetic differentiation across coastal rivers of southern Brazil

Epactionotus species are known for inhabiting the rocky-bottom stretches of fast-flowing rivers in a limited geographic area along the Atlantic coast of southern Brazil. These species are endemic to single coastal river drainages (two neighbouring drainages for Epactionotus bilineatus) isolated from each other by the coastal lacustrine environments or the Atlantic Ocean. E. bilineatus is from the Maquiné and Três Forquilhas River basins, both tributaries of the Tramandaí River system, whereas E. itaimbezinho is endemic to the Mampituba River drainage and Epactionotus gracilis to the Araranguá River drainage. Recent fieldwork in the Atlantic coastal drainages of southern Brazil revealed new populations in the Urussanga, Tubarão, d'Una and Biguaçu River drainages. Iterative species delimitation using molecular data (cytochrome c oxidase subunit I) and morphology (morphometrics and meristics) was applied to evaluate species recognition of isolated populations. With regard to new data, the genus was re-diagnosed, the status of Epactionotus species/populations was re-evaluated, formerly described species were supported and population structure was recognized. As for the newly discovered populations, both morphological and molecular data strongly support the population from the Biguaçu River drainage, in Santa Catarina State, as a new species. Molecular data revealed strong per-basin population structure, which may be related to species habitat specificity and low or no dispersal among drainages.

An appraisal of the phylogenetic relationships of Hypoptopomatini cascudinhos with description of two new genera and three new species (Siluriformes: Loricariidae)

ABSTRACT The discovery of three new taxa of Hypoptotopomatini with ambiguous generic assignment prompted a reanalysis of the phylogenetic relationships of the tribe. The analysis focused on a data matrix of 56 terminals and 107 morphological characters comprising the three new taxa, most species of Hypoptopoma and Otocinclus, and all other species of the tribe. The 162 maximally parsimonious trees of 382 steps, consistency index of 0.41, and retention index of 0.83 were then summarized in a strict consensus tree. The results confirm the monophyly of the Hypoptopomatini, recover four genera as monophyletic (Acestridium, Hypoptopoma, Niobichthys, and Otocinclus), revealed Hypoptopoma and Oxyropsis to be non-monophyletic; and revealed two new genera within Hypoptopomatini. Additionally, Otocinclus was found to be sister to a group with all remaining genera of the tribe; Acestridium and Niobichthys were found to be sister to each other and that clade sister to a group formed by ((Leptotocinclus + Hypoptopoma [part]) + (Nannoxyropsis (Oxyropsis + Hypoptopoma [part]))). Based on this framework, changes to the classification and the taxonomy of the Hypoptopomatini are suggested and the new taxa are described.