Rodentocestus

Haukisalmi, Voitto, Hardman, Lotta M., Hoberg, Eric P. & Henttonen, Heikki, 2014, Phylogenetic relationships and taxonomic revision of Paranoplocephala Lühe, 1910 sensu lato (Cestoda, Cyclophyllidea, Anoplocephalidae), Zootaxa 3873 (4), pp. 371-415 : 398-399

Rodentocestus n. g.

( Fig. 20 )

Etymology. The name of the new genus refers to the wide host distribution of its representative species in myomorph and sciuromorph rodents. “ Rodentocestus ” is masculine.

Diagnosis. Strobila long and usually wide. Scolex relatively large, rather well demarcated from or gradually merging with neck. Suckers slightly protruding or embedded within scolex, directed antero-laterally. Proglottids transversely elongated, length/width ratio in mature proglottids 14–27%. Genital pores infrequently or frequently (and irregularly) alternating. Genital ducts pass dorsal to longitudinal osmoregulatory canals. Testes antiporal, anterior and antero-poral to ovary, extending beyond ventral longitudinal canals bilaterally. Testes mostly not overlapping ovary. Cirrus sac relatively short, not usually extending to ventral longitudinal canal. Vagina relatively short, usually not overlapping ventral longitudinal canal; tubiform or slightly widened distally. Seminal receptacle long, elongated, usually with narrow distal “neck”. Ovary median or slightly poral, usually narrow relative to proglottid width; does not extend to longitudinal canals. Vitellarium median or slightly poral with respect to ovary. Early uterus extensive, densely reticulated, overlapping ovary. In cricetid ( Arvicolinae , Neotominae ) and sciurid rodents in North America and Europe.

Type-species: R. freemani ( Haukisalmi, Henttonen & Hardman, 2006) n. comb.

Paranoplocephala freemani Haukisalmi, Henttonen & Hardman, 2006

Other species:

R. aquaticus ( Genov, Vasileva & Georgiev, 1996) n. comb. Paranoplocephala aquatica Genov, Vasileva & Georgiev, 1996 Paranoplocephala genovi Gubányi, Tenora & Murai, 1998 n . syn.

R. sciuri ( Rausch, 1947) n. comb.

Andrya sciuri Rausch, 1947

Paranoplocephala sciuri ( Rausch, 1947) Tenora, Murai & Vaucher, 1985

Holotype of R. freemani : USNPC 95643.

Remarks. Rodentocestus is morphologically a rather uniform assemblage, particularly with respect to the distribution of testes (extending beyond the ventral canals bilaterally) and the shape of the seminal receptacle (elongate with a distinct distal “neck”). The type species R. freemani differs from other congeneric species in its peculiarly wide longitudinal ventral canals, but the taxonomic significance of this feature remains unknown. Rodentocestus differs from Cookiella particularly in the lateral distribution of testes (extending beyond the ventral longitudinal canals bilaterally in the former, but not in the latter). For morphological differences between Rodentocestus and Tenoraia , see the Remarks section for the latter genus.

So far, R. freemani is known only from Microtus xanthognathus (type host) and Ondatra zibethicus from Alaska ( Haukisalmi et al. 2006). The present phylogenetic analyses show, however, that a congeneric, possibly conspecific cestode occurs in Microtus oeconomus in North-East Siberia (Omolon River). Rodentocestus freemani appeared as a basal, unresolved lineage in all sequence data sets. No molecular data exist for R. aquaticus and R. sciuri .

Figures

FIGURE 20. Rodentocestus freemani from Microtus xanthognathus from Alaska (USA). A. Scolex and neck. B. Mature proglottid. Redrawn from Haukisalmi et al. (2006).