Morphological and molecular characterization of two new species of Andracantha (Acanthocephala: Polymorphidae) from New Zealand shags (Phalacrocoracidae) and penguins (Spheniscidae) with a key to the species.

Two new species of Andracantha (Polymorphidae) are described from the intestine of the shags Leucocarbo chalconotus (Gray) and Phalacrocorax punctatus (Sparrman), and the penguin Eudyptula minor (Forster) from southern South Island, New Zealand. Andracantha leucocarboi n. sp. is distinguished from its congeners by having no genital or ventral trunk spines, but possessing a scattering of small spines between the anterior fields of spines. This is the first record of a species of Andracantha from a penguin. Circumbursal papillae are illustrated in a scanning electron micrograph for the first time in the polymorphids. Andracantha sigma n. sp. is distinguished by the sigmoid shape of its largest proboscis hook, hook VIII, and having the ventral field separated from the posterior disc field by an aspinous gap. A Maximum Likelihood tree from cox1 and large ribosomal subunit (LSU) data shows A. leucocarboi n. sp. to be more closely related to A. gravida than A. sigma n. sp. and the genus Andracantha as sister to Corynosoma spp. Genetic distances between species of Andracantha are comparatively large. A key to the species of Andracantha is provided.