Diphyllobothrium sprakeri n. sp. (Cestoda: Diphyllobothriidae): a hidden broad tapeworm from sea lions off North and South America

Abstract

Background The systematic of several marine diphyllobothriid tapeworms of pinnipeds has been revised in recent years. However, 20 species of Diphyllobothrium from phocids and otariids are still recognized as incertae sedis. We describe a new species of Diphyllobothrium from the intestine of California sea lions Zalophus californianus (Lesson) (type-host) and South American sea lions Otaria flavescens (Shaw). Methods Zalophus californianus from the Pacific coast of the USA and O. flavescens from Peru and Argentina were screened for parasites. Partial fragments of the large ribosomal subunit gene (lsrDNA) and the cytochrome c oxidase subunit 1 (cox1) mitochondrial gene were amplified for 22 isolates. Properly fixed material from California sea lions was examined using light and scanning electron microscopy. Results A total of four lsrDNA and 21 cox1 sequences were generated and aligned with published sequences of other diphyllobothriid taxa. Based on cox1 sequences, four diphyllobothriid tapeworms from O. flavescens in Peru were found to be conspecific with Adenocephalus pacificus Nybelin, 1931. The other newly generated sequences fall into a well-supported clade with sequences of a putative new species previously identified as Diphyllobothrium sp. 1. from Z. californianus and O. flavescens. A new species, Diphyllobothrium sprakeri n. sp., is proposed for tapeworms of this clade. Conclusions Diphyllobothrium sprakeri n. sp. is the first diphyllobothriid species described from Z. californianus from the Pacific coast of North America, but O. flavescens from Argentina, Chile and Peru was confirmed as an additional host. The present study molecularly confirmed the first coinfection of two diphyllobothriid species in sea lions from the Southern Hemisphere.

A case report of live-stranded rough-toothed dolphin (<i>Steno bredanensis</i>) with plastic debris ingestion on the Pacific coast of Japan

“…2a ). Molecular identification using two of these strobilae, following methods described in previous studies [ 8 , 16 ], showed 100% and 99.78% identities with the sequences of Diphyllobothrium sp. During the autopsy, four larvae of a cestode ( Clisthobothrium delphini ) were obtained from the blubber tissue.…”

Parasites of invasive pink salmon, Oncorhynchus gorbuscha (Walbaum, 1792) (Actinopterygii: Salmonidae), in the Kandalaksha Bay of the White Sea

“…PCR were performed as described by . Sequences of the cox2 and cox1 genes have a high resolving power to identify species in anisakids and metacestodes, respectively, while the 28S rRNA gene sequences can be used as a marker for analysis of evolutionary events at the genus level and above (e.g., Mattiucci and Nascetti 2008;Hernández-Orts et al 2021).…”