Microticola

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 : 384-386

Microticola n. g.

( Fig. 10 )

Etymology. The name of the new genus refers to Microtus (representing the tribe Microtini), the hosts of all known species of Microticola . “ Microticola ” is masculine.

Diagnosis. Strobila of intermediate length; wide. Scolex relatively wide. Suckers directed laterally or anterolaterally. Neck short, wide relative to scolex width (minimum width 68–85%), usually expanded; expanded region attaining or slightly exceeding scolex width. Proglottids transversely elongated; length/width ratio of mature proglottids 16–20%. Proglottids distinctly craspedote. Genital pores unilateral or frequently (and irregularly) alternating. Genital ducts pass dorsal to longitudinal osmoregulatory canals. Testes mainly antiporal, maximally reaching poral margin of vitellarium; position of testes with respect to antiporal ventral longitudinal canal variable (non-overlapping, overlapping, beyond). Testes usually slightly overlapping margins of ovary. Cirrus sac usually overlapping or extending across ventral longitudinal canal. Vagina short (usually less than half of cirrus sac length), with thick external cell layer slightly widening distally. Seminal receptacle long, elongate. Ovary poral. Vitellarium median with respect to ovary. Early uterus densely reticulated, anterior, ventral to other organs, partly overlapping ovary, extending across longitudinal canals bilaterally, with lateral parts slightly widened posteriorly. In voles of the genus Microtus ( Cricetidae : Arvicolinae ) in North America and Eurasia.

Type species: M. etholeni ( Haukisalmi, Henttonen, Niemimaa & Rausch, 2002) n. comb.

Paranoplocephala etholeni Haukisalmi, Henttonen, Niemimaa & Rausch, 2002

Other species: M. blanchardi ( Moniez, 1891) sensu Tenora et al. 1985b n. comb.

Anoplocephala blanchardi Moniez, 1891

Taenia blanchardi ( Moniez, 1891) Braun, 1894

Anoplocephaloides blanchardi ( Moniez, 1891) Baer, 1923

Paranoplocephala blanchardi ( Moniez, 1891) Baer, 1927

Holotype of M. etholeni : USNPC 91874.

Remarks. Microticola resembles Chionocestus , Parandrya and Beringitaenia in having a wide (>65% of the 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. Microticola distinctly differs from the related genera by its short vagina (relative to the cirrus sac length). In addition, Microticola differs from Parandrya in the length of the neck, cirrus sac (all shorter in Microticola ) and seminal receptacle (longer in Microticola ). Microticola also has a characteristic “neck swelling”, which is missing in Parandrya and other related genera. The latter feature also serves to distinguish Microticola from Beringitaenia . Other differences concern the length of the body and neck (both shorter in Beringitaenia ), shape and length of the seminal receptacle (ovoid/pyriform and short in Beringitaenia ) and poral position of the vitellarium in Beringitaenia . Microticola has been compared with Chionocestus in the Remarks section for the latter species.

The three Microticola species formed an exclusive, strongly supported (99%) monophyletic group in the nad1 data and moderately supported (90%) group in the concatenated data, but did not show a supported association in the cox1 data. Therefore, an alternative solution would be to treat the basal P. blanchardi separate from the other two species, and propose two new genera instead of one. However, there seems to be no taxonomically important morphological differences among the three species, which favours the idea that they should represent the same genus. Microticola does not show phylogenetic affinity with the morphologically most similar genera ( Chionocestus , Parandrya and Beringitaenia ). The sister group of Microticola remains undefined.

All sequence data sets showed that Microticola sp. from Microtus sp. from China (Fenglin) is genetically divergent from the other Microticola species and therefore probably represents an independent species. However, the only available specimen in Microtus sp. could not be unambiguously separated from the other congeneric species (especially P. blanchardi ) and was therefore not described as new. The sister species of Microticola sp. from China is M. etholeni from North America.

Figures

FIGURE 10. Microticola etholeni from Microtus pennsylvanicus from Alaska (USA). A. Scolex and neck. B. Mature proglottid. Redrawn from Haukisalmi et al. (2002).