Lack of mtDNA genetic diversity despite phenotypic variation and environmental heterogeneity in the exotic suckermouth armored catfish (Pterygoplichthys pardalis)

• Published in: Biological invasions 2023-04, Vol.25 (4), p.1035-1056
• Main Authors: Vargas-Rivas, Alan G., Barba-Macias, Everardo, Sánchez, Alberto J., Castellanos-Morales, Gabriela
• Format: Article
• Language: English
• Subjects: Amplification; Biomedical and Life Sciences; Catfish; Chemical properties; Deoxyribonucleic acid; Developmental Biology; DNA; Ecology; Freshwater & Marine Ecology; Genetic diversity; Haplotypes; Heterogeneity; Homogeneity; Hybrids; Introduced species; Invasive species; Life Sciences; Mitochondrial DNA; Morphology; Nonnative species; Original Paper; Phenotypic variations; Physicochemical properties; Plant Sciences; Population growth; Pterygoplichthys; Pterygoplichthys disjunctivus; Pterygoplichthys pardalis; River basins; Taxonomy
• ISSN: 1387-3547; 1573-1464
• DOI: 10.1007/s10530-022-02961-w

Molecular data is useful to determine the taxonomic identity and origin of invasive species. A reliable identification and a complete reference database are key for the adequate management of invasive species. South American suckermouth armored catfish ( Pterygoplichthys spp.) are invasive species that cause severe environmental and socioeconomic impacts. Although different species ( Pterygoplichthys pardalis and Pterygoplichthys disjunctivus ), and possibly hybrids, have been identified based on ventral spots’ patterns, there remains taxonomic uncertainty regarding the Pterygoplichthys spp. individuals that are becoming invasive. We used genetic data to make inferences about the number of invasion events and found that there were one or few introduction events, followed by rapid spread and population growth. When we analyzed environmental variation of the sampling sites (based on physico-chemical properties), we observed both environmental differentiation between basins and environmental homogeneity within one of the studied river basins. We then analyzed the morphological variation between morphotypes and found that in addition to the variation in the ventral patterns, we observed size differences between individuals from different basins. We amplified the CYTB and COI mitochondrial DNA regions and found a unique haplotype which is shared across the sampled basins. Finally, we found that all the suckermouth armored catfish in the different basins were P. pardalis or of hybrid origin, and the lack of diversity in the mitochondrial DNA suggested a common origin. Our study highlights that combining genetic, morphological and ecological data provides complementary evidence to understand the introduction and invasion process.