Chionocestus

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 : 383-384

Chionocestus n. g.

( Fig. 9 )

Etymology. The name of the new genus refers to the Greek “chioni” (χιόνι, snow) and Chionomys ( nivalis ), the only known host of C. yoccozi . “ Chionocestus ” is masculine

Diagnosis. Strobila of intermediate length, relatively wide. Scolex wide, but relatively short, apically flattened, with irregular protuberances formed by large intensely staining cells. Suckers large, directed laterally or anterolaterally. Neck short and wide, minimum width ca. 75% of scolex width. Length/width ratio of mature proglottids ca. 30%. Proglottids craspedote with well-developed velum. Genital pores unilateral. Genital ducts pass dorsal to longitudinal osmoregulatory canals. Testes distributed antiporally and anteriorly to ovary, few testes usually extending beyond antiporal ventral canal; testes not reaching corresponding poral canal. Testes overlap slightly margins of ovary. Distal end of cirrus sac blunt, formed by few large vesicles; cirrus sac extending across poral ventral canal. Vagina and vaginal tube widening distally, positioned postero-ventral or posteriorly to cirrus sac, slightly shorter than cirrus sac. Seminal receptacle pyriform or slightly asymmetrically elongated. Ovary poral. Vitellarium usually bipartite, parts connected by narrow isthmus. Early uterus densely reticulated, anterior, ventral to other organs, extending across longitudinal canals bilaterally, with lateral parts widening posteriorly. In the snow vole Chionomys nivalis ( Cricetidae : Arvicolinae ) in southern Europe.

Type species: C. yoccozi (Haukisalmi & Henttonen, 2005) n. comb.

Paranoplocephala yoccozi Haukisalmi & Henttonen, 2005

Holotype of C. yoccozi : USNPC 95380 (included in the present phylogenetic analysis).

Remarks. Chionocestus resembles Parandrya , Microticola and Beringitaenia in having a wide (>65% of scolex width) and usually short neck, transversely elongated mature proglottids (length/width ratio 10–29%), primarily antiporally positioned testes that do not reach the poral ventral canal and porally positioned ovary. Chionocestus differs from all the latter genera by its distinctive scolex, cirrus sac and vitellarium. In addition, it can be distinguished by the distribution of testes from Parandrya and Beringitaenia (testes extending less porally in the latter), by the shape of the seminal receptacle from Parandrya (distinctly elongated) and Beringitaenia (ovoid) and by the body length from Beringitaenia (distinctly shorter in the latter).

Chionocestus yoccozi formed an unresolved clade with Parandrya spp., Gallegoides ( arfaai ) and Microcephaloides spp. in all sequence data sets.

Figures

FIGURE 9. Chionocestus yoccozi from Chionomys nivalis from France. A. Scolex and neck (redrawn from Haukisalmi et al. 2002). B. Mature proglottid.