Morphology, genetic characterization and molecular phylogeny of pinworm Skrjabinema longicaudatum sp. n. (Oxyurida: Oxyuridae) from the endangered Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae)

Abstract

Background The Tibetan antelope Pantholops hodgsonii (Abel) (Artiodactyla: Bovidae) is an endangered and endemic species of mammal to the Qinghai-Tibetan Plateau. Parasites and their caused parasitic diseases are considered to be important threats in the conservation of the Tibetan antelope. However, our present knowledge of the composition of the parasites from the Tibetan antelope remains limited. Methods Large numbers of nematode parasites were collected from a dead Tibetan antelope. The morphology of these nematode specimens were observed using light and scanning electron microscopy. The nuclear and mitochondrial DNA sequences [i.e. small ribosomal DNA (18S), large ribosomal DNA (28S), internal transcribed spacer (ITS) and cytochrome c oxidase subunit 1 ( cox 1)] were amplified and sequenced for molecular identification. Moreover, phylogenetic analyses were performed using maximum likelihood (ML) inference based on 28S and 18S + 28S + cox 1 sequence data, respectively, in order to clarify the systematic status of these nematodes. Results Integrated morphological and genetic evidence reveals these nematode specimens to be a new species of pinworm Skrjabinema longicaudatum sp. n. (Oxyurida: Oxyuridae). There is no intraspecific nucleotide variation found between different individuals of S. longicaudatum sp. n. in the partial 18S, 28S, ITS and cox 1 sequences. However, the high level of nucleotide divergence was revealed between the new species and its congeners in 28S (8.36%) and ITS (20.3–23.7%) regions, respectively. Molecular phylogenetic results supported that the genus Skrjabinema should belong to the subfamily Oxyurinae (Oxyuroidea: Oxyuridae), instead of the subfamily Syphaciidae or Skrjabinemiinae in the traditional classification, which formed a sister relationship to the genus Oxyuris . Conclusions A new species of pinworm Skrjabinema longicaudatum sp. n. (Oxyurida: Oxyuridae) was described. Skrjabinema longicaudatum sp. n. represents the first species of Oxyurida (pinworm) and the fourth nematode species reported from the Tibetan antelope. Our results contribute to our knowledge on the species diversity of parasites from the Tibetan antelope, and also clarified the systematic position of the genus Skrjabinema .

Morphological and molecular studies on a nematode parasite, Syphacia obvelata, infecting laboratory mice (Mus musculus) in Saudi Arabia

“…The primary discriminating tool among these nematodes was based on morphological examination of male worms which include the presence/absence of gubernaculum, shape and size of spicules, number and form of mamelons and cloacal papillae (Landaeta-Aqueveque et al, 2007;Dewi et al, 2014;Khalil et al, 2014;Abdel-Gaber, 2016;Behnke et al, 2022). Regarding the insufficient criteria to differentiate between pinworms, molecular advanced tools have been recently used to discriminate closely related oxyurid species (Cao et al, 2020;Omer et al, 2020). The nuclear small subunit ribosomal DNA (18S) (Abdel-Gaber, 2016;Stewart et al, 2018) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) (Okamoto et al, 2007;Stewart et al, 2018) were used for molecular identification of Syphacia species.…”