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

Abstract

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.

Chromosomal Rearrangements and Origin of the Multiple XX/XY1Y2 Sex Chromosome System in Harttia Species (Siluriformes: Loricariidae)

“… Schematic representation of the phylogenetic relationships among Harttia species adapted from the Londoño-Burbano and Reis (2021) . Harttia sp.1 and H. intermontana are not being represented since they were not included in such previous analysis.…”

“…The chromosomal number ranges from 2n = 52 to 62, including B chromosomes and different SCSs ( Blanco et al, 2012 , 2017 ; Deon et al, 2020 ; Sassi et al, 2020 ; Sassi et al, 2021 ). In phylogenetic reconstructions, three distinct clades were proposed for the genus, thus reinforcing the extensive diversification experienced by the lineage; also, it is grouping the species according to their South American distribution: (I) from the Guyana shield rivers; (II) from the northern Brazilian rivers; and (III) from the Brazilian south/southeast rivers ( Londoño-Burbano and Reis, 2021 ). Three SCSs were detected so far: (1) the X 1 X 1 X 2 X 2 /X 1 X 2 Y system, present in H. punctata , H. duriventris, and H. villasboas , and (2) a proto/neo-XX/XY system in H. rondoni , both belonging to clade II, and (3) the XX/XY 1 Y 2 system in H. carvalhoi, H. intermontana, and Harttia sp.1, species which belong to clade III ( Centofante et al, 2006 ; Blanco et al, 2017 ; Sassi et al, 2020 ; Sassi et al, 2021 ; Deon et al, submitted ).…”

Adding New Pieces to the Puzzle of Karyotype Evolution in Harttia (Siluriformes, Loricariidae): Investigation of Amazonian Species

“…In the most recent phylogenetic analysis of the subfamily Loricariinae [ 51 ], the existence of three clades within the Harttia genus was proposed. The earliest-diverging clade is composed of H. guianensis , H. tuna , H. fluminensis , and H. surinamensis which inhabit waters from the Guiana shield.…”

“…The description of the H. guianensis karyotype in the present study reinforces the proposal of 2n = 58 as the ancestral 2n for the genus [ 34 ]. If we keep in mind that this species is basalmost in the clade, as pointed by phylogenetic reconstructions [ 51 , 52 ], and that it shares the same 2n with other Harttia species from other clades, such as H. gracilis , H. longipinna , and H. punctata , such hypothesis is still valid but lacks profound reconstruction analysis. Furthermore, although not a common occurrence, the syntenic organization of at least some sites of both rDNA classes is also considered as a basal karyotype feature for Loricariidae fishes [ 53 ]; this is a pattern that we also found in the karyotype of H. guianensis , in which 5S and 18S rDNA site share the location on the chromosome pair 25.…”

“…1 [ 35 ]. Given the position of H. guianensis at the base of Harttia phylogeny [ 51 ], it seems probable that this second 5S rDNA site has been eliminated during evolution in many Harttia species while it was retained in a subset of them.…”