Using DNA barcoding to relate cystacanths and adults of Corynosoma australe (Acanthocephala: Polymorphidae) of the Southeastern Pacific Ocean (Off Peru Coast)

Abstract The objective of this study is to use DNA barcoding to relate cystacanths and adults belonging to the acanthocephalans genus Corynosoma found in the southeastern Pacific Ocean off the coast of Peru. For this, we sampled three species of commercial fish ( Paralichthys adspersus , Paralabrax humeralis and Cheilodactylus variegatus ) and two South American sea lions Otaria byronia stranded on the beaches of the city of Huacho and Barranca, department of Lima. A total of 509 larvae were found in the body cavity of 95 fish (total prevalence 54.28%, total mean intensity 8.64), moreover, a total of 127 adults were found in the large intestine of two South American sea lion (P = 100%, MI = 63.5). We isolated 203 larvae of P. humeralis (P = 65.71%; MI = 8.83; MA = 5.8), 235 (P = 54.29%; MI = 12.37; MA = 6.71) of C. variegatus and 71 (P = 42.86%; MI = 4.73; MA = 2.03) of P. adspersus . All adult and larval specimens were morphologically identified as Corynosoma sp. We performed phylogenetic analysis and generated cytochrome c oxidase subunit 1 (cox1) gene sequences that were compared with sequences available from GenBank. Likewise, using maximum likelihood (ML) and Bayesian inference (BI) revealed that the 16 new sequences (four adults and twelve larvae) were grouped into a clade formed by Corynosoma australe . Therefore, our results contribute to broaden the range of paratenic hosts as well as to record the presence of C. australe in the definitive host. In addition, it is the first analysis that confirms the presence of C. australe using DNA barcoding, allowing its geographical distribution to be extended to the Southeast Pacific Ocean off the coast of Peru.