Two new cestode species of Neoskrjabinolepis Spasskii, 1947 (Cyclophyllidea: Hymenolepididae) from the tundra shrew Sorex tundrensis Merriam (Mammalia: Soricidae) in Alaska and Chukotka

Abstract

Descriptions, illustrations and differential diagnoses for two new species of Neoskrjabinolepis Spassky, 1947, i.e. N. (Neoskrjabinolepis) fertilis n. sp. and N. (Neoskrjabinolepidoides) hobergi n. sp., are given. Neoskrjabinolepis (Neoskrjabinolepis) fertilis was found in the shrew Sorex tundrensis Merriam on the Seward Peninsula (Alaska, USA) and from the mouth of the Anadyr River (Chukotka, Russia), and N. (Neoskrjabinolepidoides) hobergi was found in Sorex tundrensis on the Seward Peninsula (Alaska, USA). Neoskrjabinolepis fertilis n. sp. is characterised by having: rostellar hooks 38-42 μm long and provided with a small epiphyseal thickening of the handle; a long cirrus (85-100 μm), consisting of a basal region with claw-shaped spines and a parabasal region with small, thin needle-shaped spines; a cirrus-sac extending well into the median field; and 55-70 eggs per gravid uterus. Neoskrjabinolepis (Neoskrjabinolepidoides) hobergi n. sp. is characterised by having: rostellar hooks 63-65 μm long and provided with a large epiphyseal thickening of the handle; a short cirrus (45-50 μm), consisting of a basal region with small claw-shaped spines and a parabasal region with thin, needle-shaped spines; cirrus-sac reaching slightly into the median field; and 36-45 eggs per gravid uterus.

Neoskrjabinolepis paradoxa n. sp. from shrews on Sakhalin Island, Russia, with an amended diagnosis of Neoskrjabinolepis Spassky, 1947 (Cestoda: Cyclophyllidea: Hymenolepididae), a key, and a review on geographical distribution of the species

“…Sixteen species parasitize Palearctic shrews (Kornienko et al 2007, 2008, 2010, 2022b; Kornienko & Binkienė 2008; Kornienko & Gulyaev 2011). Two species from Nearctic shrews of Alaska ( N. hobergi and N. fertilis ) have been described (Kornienko & Dokuchaev 2012).…”

“…N. paradoxa n. sp. is characterized by a serial strobilar development and therefore belongs to the subgenus Neoskrjabinolepis ( Neoskrjabinolepidoides ) Kornienko, Gulyaev & Melnikova, 2006, which currently includes 10 species: N. singularis (Cholodkowsky, 1912); N. nadtochijae Kornienko, Gulyaev & Melnikova, 2006; N. corticirrosa Kornienko, Gulyaev & Melnikova, 2007; N. kedrovensis Kornienko, Gulyaev & Melnikova, 2007; N. nuda Kornienko, Gulyaev, Melnikova & Georgiev, 2008; N. merkushevae Kornienko & Binkiene, 2008; N. gvosdevi Kornienko, Erzhanov & Gulyaev, 2010; N. kunashiriensis Kornienko & Gulyaev, 2011; N. nana Kornienko & Gulyaev, 2011; and N. hobergi Kornienko & Dokuchaev, 2012.…”

“…Two species, N. singularis and N. merkushevae , from the European part of the Palearctic Region and from the south of West Siberian, have been recorded (Kornienko et al 2006; Kornienko & Binkiene 2008). The remaining eight species from the shrews of the Asiatic part of the Palearctic (mainly in the Far East) have been described (Kornienko et al 2006, 2007; Kornienko & Gulyaev 2011; Kornienko & Dokuchaev 2012), with the exception of N. gvosdevi. This species has not been recorded outside the Kazakh Uplands and is considered endemic to Kazakhstan.…”

“…The main differential criteria of the genus Neoskrjabinolepis included in the modified genus diagnosis (Kornienko et al 2008) are the type of strobilation, the shape and size of rostellar hooks, the size of the cirrus sac and its position relative to poral osmoregulatory canals, the size and armament of the cirrus, the number of eggs in uterine proglottid, and positioning of the uterus located in the median field of a proglottid, not beyond osmoregulatory canals. Later, in the American species N. hobergi found in Sorex tundrensis Merriam from the Seward Peninsula (Alaska, USA), a different positioning of the uterus in the proglottid was discovered: having different degrees of maturity (postmature and gravid proglottids), with the uterus crossing osmoregulatory canals and reaching lateral areas of the proglottid (Kornienko & Dokuchaev 2012).…”

“…Cestodes of the genus Neoskrjabinolepis Spassky, 1947 are characterized by high species richness and widespread occurrence in the Holarctic, as evidenced by their finds in various species of shrews Sorex (Mammalia: Soricidae) during faunal studies in various regions of Eurasia (from the Pyrenees to Chukotka and the Japanese islands) and North America (Alaska) (Zarnowski 1955; Prokopič 1958; Schaldybin 1964; Arzamasov et al 1969; Jourdane 1971; Vaucher 1971; Prokopič & Matsaberidze 1972; Prokopič et al . 1974; Eltyshev 1975; Genov 1984; Roots 1992; Novikov 1995; Hanzelová & Ryšavý 1996; Tkach & Zhumabekova 1996; Sawada 1999; Anikanova et al 2001, 2002; Irzhavsky & Gulyaev 2002; Binkiene 2006; Binkiene et al 2011; Kornienko 2012; Kornienko & Dokuchaev 2012, 2023; Haukisalmi 2015; Kirillov et al 2018; Kornienko et al 2022c).…”