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

Abstract

A taxonomic review was performed on cestodes of the genus Neoskrjabinolepis Spassky, 1947 that parasitize different species of Sorex shrews in different regions of the northern Palearctic and in the Nearctic (Alaska, USA). Information on Palearctic Neoskrjabinolepis cestodes published in various articles is summarized. An overview of the geographical distribution of the Neoskrjabinolepis species is also presented. Currently, the genus includes 17 species. In the European part of the Palearctic, four species of the genus are registered; in the Asian part, 13 species; and on the American continent (Seward Peninsula, Alaska, USA), two species. Descriptions, illustrations, and differential diagnoses are given for a new species of Neoskrjabinolepis, i.e. N. paradoxa n. sp., which was found in shrews Sorex unguiculatus Dobson and S. caecutiens Laxmann on Sakhalin Island. A unique feature of the new species is irregularly alternating genital pores in the uterus series in the strobila. Amended new differential features (positioning of the uterus relative to osmoregulatory canals and alternation of genital pores) of genus diagnosis and an identification key for Neoskrjabinolepis spp. are presented.

Cestode diversity in shrews from islands in the Sea of Japan and the Sea of Okhotsk

“…Later, we proved the validity of both species, and a further 15 species have been described within the genus (Kornienko et al, 2006, 2023). Additionally, it has been reported that N. singularis does not occur east of Transbaikalia (Kornienko et al, 2023). Photos of rostellar hooks of N. singularis and their size reported by Sawada and Kobayashi (1993) correspond to N. kedrovensis.…”

“…At the time of publication by Sawada and Kobayashi (1993), there was a longstanding discussion about the existence within the genus Neoskrjabinolepis of one or two species having a trans-Palearctic range (i.e., N. singularis and N. schaldybini Spassky, 1947 [Kornienko et al, 2023]). Later, we proved the validity of both species, and a further 15 species have been described within the genus (Kornienko et al, 2006, 2023). Additionally, it has been reported that N. singularis does not occur east of Transbaikalia (Kornienko et al, 2023).…”

“…Therefore, Sawada and Kobayashi (1993) recorded four species of cestodes on Sakhalin: E. longibursata , M. skrjabini , N. kedrovensis , and N. morosovi. Later, several new cestode species have been described from Sakhalin shrews belonging to genera Soricinia , Spasskylepis , and Neoskrjabinolepis : S. sawadai , S. tiunovi , N. nana , and N. paradoxa (Lykova et al, 2005; Zubova et al, 2010; Kornienko & Gulyaev, 2011; Kornienko et al, 2023).…”

“…Data about shrew cestodes from Sakhalin, Kunashir and Hokkaido were sampled at the end of the last century and at the beginning of the current century. These were either faunal summaries of cestodes (Sato et al , 1988; Sawada & Koyasu, 1991, 1995; Sawada & Asakawa, 1992; Sawada & Kaneno, 1992; Sawada & Kobayashi, 1993; Karpenko, 1997; Sawada, 1999) or descriptions of new species (Sawada & Harada, 1990; Sawada & Koyasu, 1991; Karpenko, 1999; Lykova et al , 2005, 2006; Zubova et al , 2008a, b; Kornienko et al , 2008a, 2023). This resulted in the assumption of high species diversity of shrew cestodes on these islands.…”