Broadening diversity in the Arostrilepis horrida complex: Arostrilepis kontrimavichusi n. sp. (Cyclophyllidea: Hymenolepididae) in the western red-backed vole Myodes californicus (Merriam) (Cricetidae: Arvicolinae) from temperate latitudes of the Pacific Northwest, North America

Hymenolepidid cestodes: Diversity, morphological and molecular characterization of a new species, and phylogeny of parasitic species of rodents from North and South America

Rodents are hosts of a wide diversity of cestodes. Fifteen genera included in the family Hymenolepididae parasitize rodents, and only four of these genera have been recorded from the Neotropical region. The purpose of this paper is to update species of Hymenolepididae from rodents, describe a new species of Hymenolepis based on morphological and molecular characterization (ITS1 rDNA and cox1 mtDNA), comparing the features among the species from North and South American rodents, and provide phylogenetic inferences of Hymenolepididae from rodents based on sequences available in the GenBank. Rodents were collected in the Parque Provincial Ernesto Tornquist, Buenos Aires, Argentina. Hymenolepis ivanovae n. sp. differs from other Hymenolepis species registered from North and South American rodents by body size, scolex, suckers, cirrus sac, cirrus, testes, and eggs, among others. Comparative morphometric data for Hymenolepis species from North and South American rodents is provided. Molecular analyses place H. ivanovae n. sp. within the genus Hymenolepis with strong support, and show it close to species of zoonotic importance. The new species is the first species of Hymenolepis described from Sigmodontinae rodents.

Discovery of Arostrilepis tapeworms (Cyclophyllidea: Hymenolepididae) and new insights for parasite species diversity from Eastern North America

Species of the genus Arostrilepis were discovered and definitively identified for the first time in rodents from geographically disparate localities along the Appalachian Mountain range of eastern North America (West Virginia, Virginia, and Maine). These are the first confirmed records for species of Arostrilepis occurring east of the Rocky Mountains and the Mississippi River in North America. Arostrilepis gardneri n. sp. is described on the basis of specimens obtained from two phylogenetically divergent rodent hosts: Southern Red-Backed Vole Myodes gapperi (Cricetidae: Arvicolinae) (from West Virginia) and the Woodland Jumping Mouse Napaeozapus insignis (Dipodidae: Zapodinae) (West Virginia, Virginia, and Maine). Additionally, in a mixed infection, specimens of Arostrilepis insperata n. sp. were also found in a Southern Red-Backed Vole from West Virginia. These previously unknown species are primarily distinguished from congeners based on shape, dimensions, and spination (pattern, shape, and size of spines) of the cirrus. Specimens of A. gardneri n. sp. are further characterized by the relative position and length of the cirrus-sac, arrangement of the testes, and relative size of the external seminal vesicle and seminal receptacle. Specimens of A. insperata n. sp. are structurally most similar to A. macrocirrosa from the western Nearctic and Palearctic but with consistently greater dimensions for the cirrus-sac, testes, and seminal receptacle. Phylogenetic analysis of Arostrilepis spp. using partial sequences of the mitochondrial cytochrome b gene and the nuclear second ribosomal internal transcribed spacer strongly supported the status of A. gardneri n. sp. and A. insperata n. sp. within an unresolved clade of congeners in Red-Backed Voles (Myodini and species of Myodes). Our observations extend the known geographic distribution for species of Arostrilepis to the Appalachian Mountains in either a disjunct or possibly continuous but patchy range across North America. Prior observations, summarizing field and museum collections, had suggested that geographic ranges for a diverse assemblage of Arostrilepis in North America were largely restricted to the north-western region of the continent, with historical connections to Beringia and Eurasia. Recognition of a more extensive distribution is consistent with a history of episodic biotic expansion and isolation under a dynamic of taxon pulses for arvicoline rodents and an associated parasite fauna in the Nearctic during the Quaternary. Occurrence in a dipodid rodent represents an event of host colonization from an arvicoline source.

Postembryonic development of Arostrilepis microtis Gulyaev et Chechulin, 1997 (Eucestoda: Hymenolepididae) in springtails (Collembola: Entomobryidae)

The development of the metacestode stages of Arostrilepis microtis (Eucestoda: Hymenolepididae) studied on the basis of an experimental infection of springtails (Collembola: Entomobryidae) is described for the first time. A complete description of the ontogeny from oncosphere to fully a developed metacestode is given. The postembryonic development within the intermediate host includes one invagination. Cysts are without an anterior invagination pore, and the cercomer does not separate after the full maturation of larva. The comparison of morphology and maturation rate of larval cestodes of A. microtis with A. beringiensis and A. tenuicirrosa is presented. Cysticercoids of A. microtis are significantly larger and require a longer period of development than those of A. beringiensis and A. tenuicirrosa.