Rauschoides

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 : 390-392

Rauschoides n. g.

( Fig. 14 )

Etymology. The name of the new genus refers to the late Robert L. Rausch, a pioneer and eminent figure in the taxonomy and zoogeography of anoplocephalids and other cestodes of Arctic mammals. “ Rauschoides ” is feminine.

Diagnosis. Strobila of moderate length and width; very flat, transparent. Scolex small, merging gradually with neck. Suckers slightly protruding, directed antero-laterally. Neck narrow and usually long. In well-relaxed specimens anterior strobila and neck prominently elongated, thread-like. Proglottids craspedote, but velum short. Length/width ratio of mature proglottids usually high (37–63%). Genital pores either unilateral 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 usually prominent, extending across antiporal longitudinal canals. Vagina tubiform, long, but shorter than cirrus sac. Seminal receptacle large, of variable shape (pyriform, elongate, irregularly ovoid). Ovary median, large, may fill whole space between ventral longitudinal canals. Vitellarium median with respect to ovary. Early uterus extensive, densely reticulated, ventrally overlapping ovary and other organs. In collared lemmings, Dicrostonyx spp. ( Cricetidae : Arvicolinae ) in Arctic Eurasia and North America.

Type species: R. arctica (Rausch, 1952) n. comb.

Andrya arctica Rausch, 1952

Paranoplocephala arctica (Rausch, 1952) Tenora, Murai & Vaucher, 1985 Other species: R. alternata (Haukisalmi, Wickström, Hantula & Henttonen, 2001) n. comb.

Paranoplocephala alternata Haukisalmi, Wickström, Hantula & Henttonen, 2001

Holotype of R. arctica : USNPC 37356.

Remarks. The comparison of Rauschoides with morphologically related genera is complicated by the fact that the former occurs as two distinct morphotypes corresponding to R. arctica and R. alternata . These morphotypes are genetically rather similar, one of the molecular markers suggesting that they might actually be conspecific (Wickström et al. 2001, Wickström et al. 2003). Rauschoides arctica (type species) has unilateral genital pores and testes that do not extend beyond the poral ventral canal, whereas R. alternata has frequently (and irregularly) alternating genital pores and testes that regularly extend beyond the poral ventral canal.

Among the five genera characterized by a narrow neck and long vagina (group 3.1.), Rauschoides is most similar to Douthittia and Eurotaenia ( Arctocestus and Lemminia have a less extensive transverse distribution of testes in the poral part of the proglottid). Compared with Douthittia and Eurotaenia , Rauschoides has more numerous testes in the antiporal lateral field and a larger and less symmetrical seminal receptacle. In addition, Rauschoides spp. have, on average, the smallest scoleces among Paranoplocephala s. l., and their strobilae are very flat, often transparent, which also seems to differentiate it from other Paranoplocephala -like species.

Although Rauschoides shows a strong phylogenetic association with Arctocestus serratus in nad1 data and a moderately supported (94%) association in cox1 data, the high genetic divergence and morphological differences support the independent status of Rauschoides and Arctocestus . The phylogenetic position of Rauschoides + Arctocestus clade (nad1 data) remains undetermined.

Figures

FIGURE 14. Rauschoides arctica (A, B) and R. alternata (C) from Dicrostonyx groenlandicus. A. Mature proglottid from Wrangel Island (Russia). B. Scolex and neck from Wrangel Island (Russia). C. Mature proglottid from Byron Bay (Canada). Redrawn from Haukisalmi et al. (2001).