Lemminia

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 : 394-396

Lemminia n. g.

( Fig. 17 )

Etymology. The name of the new genus refers to the tribe Lemmini , to which all known hosts of Lemminia spp. belong. “ Lemminia ” is feminine.

Diagnosis. Strobila short or of moderate length, usually narrow. Scolex globular, merging rather abruptly with neck. Suckers slightly protruding, directed laterally or antero-laterally. Minimum neck width on average 42–56% of scolex width. Proglottids slightly craspedote (velum short), long relative to their width (length/width ratio ca. 50% in mature proglottids). Genital pores unilateral or infrequently (and irregularly) alternating. Genital ducts pass dorsal to longitudinal osmoregulatory canals. Testes forming compact, often oblique group antiporal and anterior to ovary; individual, scattered testes reaching poral side of proglottid, but not being in contact with poral longitudinal osmoregulatory canal. From few to several antiporal testes extending across antiporal ventral longitudinal canal.

Testes mostly not overlapping ovary. Cirrus-sac long and relatively thin, usually slightly curved anteriad, extending across poral longitudinal canals. Vagina tubiform, of uniform width, covered by thin cell layer; overlapping or extending across poral ventral longitudinal canal, slightly shorter than cirrus-sac. Seminal receptacle relatively small, spherical or subspherical. Ovary median or slightly poral. Vitellarium poral with respect to ovary. Early uterus anterior, sparsely reticulated, ventral to other organs, extending laterally beyond longitudinal canals. In lemmings of the genera Lemmus , Myopus and Synaptomys (tribe Lemmini ) in northern Eurasia and North America.

Type species: L. fellmani (Haukisalmi & Henttonen, 2001) n. comb.

Paranoplocephala fellmani Haukisalmi & Henttonen, 2001

Other species: L. gubanovi ( Gulyaev & Krivopalov, 2003) n. comb.

Paranoplocephala gubanovi Gulyaev & Krivopalov, 2003

Holotype of L. fellmani : MZH 20507.

Remarks. Among genera in the group 3.1. (cestodes with a narrow neck and long vagina relative to the cirrussac), Lemminia most closely resembles Douthittia . Lemminia and Douthittia differ from each other primarily in the distribution, number and size of testes. In Lemminia testes are rather numerous, small (relative to the proglottid size) and positioned primarily antero-antiporal to ovary, not overlapping the latter. In Lemminia , individual testes may occur on the poral side, but they do not reach the poral ventral longitudinal canal. The larger, fewer testes of Douthittia are primarily anterior to ovary, usually reaching the poral ventral longitudinal canal and significantly overlapping the ovary (being usually in contact with the vitellarium). Also, the testes of Lemminia extend across the antiporal ventral longitudinal canal more markedly than those of Douthittia . Other differences between Lemminia and Douthittia include the size of the seminal receptacle (smaller in Lemminia ), the shape of the cirrus sac (slender and anteriorly curved in Lemminia , wide and straight in Douthittia ), and, on average, more elongated proglottids in Lemminia .

Lemminia differs from Eurotaenia and Rauschoides by its less extensive distribution of testes in the poral part of the proglottid, and from Rauschoides and Arctocestus by its smaller number of testes lateral to the antiporal ventral canal. More specifically, most of the testes in Eurotaenia lie anterior to the ovary, usually overlapping the poral ventral longitudinal canal, whereas in Lemminia they are primarily antiporal and antero-poral to ovary, not reaching the poral canal. Also, the vagina of Eurotaenia is very thickly beset with intensely-stained cells (the corresponding layer in Lemminia is inconspicuous) and the seminal receptacle of Lemminia is significantly smaller than that of Eurotaenia and their cirrus sacs are of different shapes (more elongated and curved anteriad in Lemminia ). In addition, the sparsely reticulated (anterior) early uterus in Lemminia distinguishes it from all of the other Paranoplocephala -like cestodes, including Eurotaenia and Rauschoides (densely reticulated in the latter).

In all sequence data sets, L. fellmani from Lemmus lemmus from Finland formed a strongly supported clade with Lemminia sp. from Lemmus trimucronatus from Alaska. In addition, an unidentified species of Lemminia from Synaptomys borealis from Alaska was strongly associated with Lemminia spp. from Lemmus spp. in cox1 data (the specimen from Synaptomys could not be amplified for nad1). It is assumed that the two unidentified Lemminia spp. represent undescribed species; the available material, however, is not suitable for complete description and characterization. The cox1 data (but neither nad1 nor concatenated data) showed a slightly supported association (93%) with high genetic divergence between Lemminia and Rauschoides .

Figures

FIGURE 17. Lemminia fellmani from Lemmus lemmus. A. Scolex and neck from Finland. B. Mature proglottid from Norway. Redrawn from Haukisalmi & Henttonen (2001).