Morphological, molecular, and life cycle study of a new species of Oligogonotylus Watson, 1976 (Digenea, Cryptogonimidae) from Colombia

Abstract

The present study describes Oligogonotylusandinus sp. nov. and its life cycle from a rural fish farm in Sopetrán, Antioquia, Colombia. The endemic species of snail Aroapyrguscolombiensis and the fishes Poeciliacaucana and Andinoacaralatifrons are identified as the first intermediate host, the second intermediate host and the definitive host, respectively. The new species was defined through an integrative approach, combining the traditional morphology of its developmental stages with molecular analyses of the markers ITS2 from ribosomal DNA and COI from mitochondrial DNA. This new species can be distinguished from its congeners by genetic divergence, the position of the vitelline fields, and the number of gonotyls. This work represents the first report of a species of this genus in South America.

Keywords: Blue mojarra; Cauca molly; Oligogonotylus; South America; Trematoda; taxonomy.

Figure 1.

Type locality of the new species of Oligogonotylus from La Miranda village, Sopetrán, Antioquia, Colombia. Map made in ArcGIS 18.1.

Figure 2.

Micrographs of different stages of Oligogonotylusandinus sp. nov. A, B cercariae emerged from Aroapyrguscolombiensis, as temporary mounts C encysted metacercaria from Poeciliacaucana, as a temporary mount D unencysted metacercaria isolated from P.caucana, as a permanent slide E, F paratype specimens, as temporary mounts G holotype adult specimen, isolated from A.latifrons, as a permanent slide. Scale bars: 20 μm (A, B); 20 μm (C, D); 100 µm (E–G).

Figure 3.

Developmental stages of Oligogonotylusandinus sp. nov. A pleurolophocercous cercaria emerged from AroapyrguscolombiensisB encysted metacercaria isolated from the muscle of PoeciliacaucanaC unencysted metacercaria isolated from P.caucanaD holotype, adult isolated from the large intestine of the trans-Andean cichlid Andinoacaralatifrons. Scale bars: 20 μm (A); 20 μm (B, C); 100 µm (D).

Figure 4.

Paratypes of Oligogonotylusandinus sp. nov.; adults at different degrees of maturity A specimen in partly lateral orientation with the first eggs in utero; gonotyls were not observed B, D–F specimens with the seminal receptacle visible (left on B and F, right on E and D) and four gonotyls A, C, D, F specimens with the vitelline duct visible A, D, E specimens with the seminal vesicle dorsal to the ventral sucker. Scale bars: 100 μm (A–F).

Figure 5.

Phylogenetic relationships of ITS2 sequences of Oligogonotylusandinus sp. nov., Oligogonotylusmanteri, and Oligogonotylusmayae. Phylogenetic tree reconstructed using the maximum-likelihood method based on the symmetrical model with gamma distribution (SYM+G). Numbers on the branches correspond to the ultrafast bootstrap approximation support values. Each terminal is identified by the alphanumeric accession number of GenBank. Terminals in orange correspond to the sequences obtained in this report. Diagram made with IQ-TREE 2.1.3.

Figure 6.

Phylogenetic relationships of COI sequences of Oligogonotylusandinus sp. nov., Oligogonotylusmanteri, and Oligogonotylusmayae. Phylogenetic tree reconstructed using the maximum-likelihood method based on the general time reversible with gamma distribution model (GTR+G). Numbers on the branches correspond to the ultrafast bootstrap approximation support values. Each terminal is identified by the alphanumeric accession number of GenBank. Terminals in blue correspond to the sequences obtained in this report. Diagram made with IQ-TREE 2.1.3.

Figure 7.

Phylogenetic relationships of COI and ITS2 concatenated sequences of Oligogonotylusandinus sp. nov., Oligogonotylusmanteri, and Oligogonotylusmayae. Phylogenetic tree reconstructed using the maximum-likelihood method based on the general time reversible with proportion of invariable sites and gamma distribution model (GTR+I+G) model. Numbers on the branches correspond to the ultrafast bootstrap approximation support values. Terminals in red correspond to the sequences obtained in this report. Diagram made with Garli IQ-TREE 2.1.3.