Phylogeny, genetics, and the partial life cycle of Oncomegas wageneri in the Gulf of Mexico

Abstract

Despite the diversity and ecological importance of cestodes, there is a paucity of studies on their life stages (i.e., complete lists of intermediate, paratenic, and definitive hosts) and genetic variation. For example, in the Gulf of Mexico (GoM) 98 species of cestodes have been reported to date; however, data on their intraspecific genetic variation and population genetic studies are lacking. The trypanorhynch cestode, Oncomegas wageneri, is found (among other places) off the American Western Atlantic Coast, including the GoM, and has been reported as an adult from stingrays and from several teleost species in its larval form (as plerocerci). This study represents the first report of 2 previously unregistered definitive hosts for O. wageneri, namely the Atlantic sharpnose shark Rhizoprionodon terraenovae and the southern stingray Hypanus americanus. In this work, partial sequences of the 28S (region D1–D2) ribosomal DNA were analyzed to include O. wageneri within an eutetrarhynchoid phylogenetic framework. All O. wageneri individuals (which included plerocerci and adults) were recovered as monophyletic and Oncomegas celatus was identified as the sister species of O. wageneri. Furthermore, population genetic analyses of O. wageneri from the southern GoM were carried out using DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (COI) gene, which reflected high genetic variation and a lack of genetic structure among the 9 oceanographic sampling sites. Based on these results, O. wageneri is panmictic in the southern GoM. More extensive sampling along the species entire distribution is necessary to make more accurate inferences of population genetics of O. wageneri.

Integrative taxonomy of Serrasentis gibsoni n. sp. (Acanthocephala: Isthmosacanthidae) from flatfishes in the Gulf of Mexico

“…The barcoding sequence data generated for Serrasentis gibsoni n. sp. individuals from eight different oceanic sites in the GoM revealed extremely high intraspecific genetic variation (0.0057 nucleotide diversity) Martínez-Aquino et al (2020). recently detected high intraspecific genetic variation with similar values (0.0086 nucleotide diversity), using the same molecular marker for the trypanorhynch cestode, Oncomegas wageneri (Linton, 1890) Dollfus, 1929, from C. chittendeni from the GoM.…”

“…takes place in demersal and/or reef-associated habitats. Future studies of acanthocephalans from the GoM following a study program as suggested by Blasco-Costa & Poulin (2017) to elucidate parasite life cycles (i.e., approaches based on morphological matching and/or genetic matching [e.g., Martínez-Aquino et al 2017, 2020]), can provide a foundation to develop a taxonomical diagnosis of each specific phase of the species of acanthocephalans.…”

“…individuals from eight different oceanic sites in the GoM revealed extremely high intraspecific genetic variation (0.0057 nucleotide diversity). Martínez-Aquino et al (2020) recently detected high intraspecific genetic variation with similar values (0.0086 nucleotide diversity), using the same molecular marker for the trypanorhynch cestode, Oncomegas wageneri (Linton, 1890) Dollfus, 1929, from C. chittendeni from the GoM. However, it is necessary to include more parasites from many more oceanic sites and a wider range of molecular markers to describe how evolutionary forces act within the parasite populations of the GoM (e.g., population genetic structure).…”

HELMINTOS PARÁSITOS INTESTINALES DE LA RAYA HYPANUS AMERICANUS (HILDEBRAND & SCHROEDER, 1928) EN CHACHALACAS, VERACRUZ, MÉXICO

“…El cestodo O. wageneri ya ha sido registrado en otros elasmobranquios para la misma zona de estudio (Méndez & Dorantes-González, 2017;Méndez et al, 2018;Martínez-Aquino et al, 2019). Vidal-Martínez et al (2014) (Fusco & Overstreet, 1978) Cárdenas & Lanfredi, 2005 es conocido por infectar peces de la familia Scaridae, la cual está incluida en la dieta de la raya látigo.…”

Polycyclic aromatic hydrocarbons in the cestode Oncomegas wageneri parasite of Mexican flounder Cyclopsetta chittendeni

“…Oncomegas wageneri is a larval cestode infecting flatfishes collected from oil extraction zones of the Mexican Gulf of Mexico (Vidal-Martínez et al 2014;Centeno-Chalé et al 2015;Vidal-Martínez et al 2015;Martínez-Aquino et al 2019). This parasite is a good candidate for the detection of PAH metabolites because it has a wide geographical distribution in the Gulf of Mexico, has a high prevalence and mean abundance in its host, and inhabits the intestine of the flatfishes where it can be exposed to whatever the host is ingesting (including food contaminated with PAH) (Vidal-Martínez et al 2014).…”