Rhigonema naylae n. sp. (Rhigonematomorpha: Rhigonematidae) a new parasitic nematode from a Japanese polydesmid millipede (Polydesmida: Xystodesmidae)

Abstract

Rhigonema naylae n. sp. (Rhigonematomorpha: Rhigonematidae) is described from the hindgut of the polydesmid millipede Parafontaria laminata (Attems, 1909) (Polydesmida: Xystodesmidae), from Aichi prefecture, Japan. The new species is characterized by having a medium sized body in both sexes, the cephalic collar partially fused to the body cuticle, but not overhanging the body contour; cervical region densely covered in short, fine microtrichs that extend from the posterior margin of the cephalic collar to ca. 1.5 oesophagus lengths posterior to the basal bulb; tail short and conoid, subulate in females and with a short mucron in males; female genital tract of Type 2 according to Adamson (1987); males with a complement of 23 copulatory papillae, one post-cloacal pair lateral and two sub-dorsal. This arrangement of copulatory papillae is typical from the African/Asian species and contributes to the segregation of R. naylae n. sp. from the American/Australasian taxa. Description is supplemented by SEM images. Partial sequences of the D2-D3 LSU rDNA and 18S SSU rDNA were obtained. This constitutes the second species of the genus Rhigonema Cobb, 1898 described from the Japanese archipelago.

Symbiosis of the millipede parasitic nematodes Rhigonematoidea and Thelastomatoidea with evolutionary different origins

“…The body size of T. claudiae is smaller than that of R. naylae ; the females have a typical umbrella-like head and long tail, and the males have a tiny body with a spicule (Fig. 2 ) [ 45 , 46 ]. No clear sexual dimorphism was detected in either nematode species during the juvenile stage; however, it was possible to distinguish the two species at any developmental stage.…”

“…420 mya) [ 23 , 41 ], it is a good model for understanding the evolutionary and ecological relationships between these parasitic nematodes and between hosts and parasites. We previously described the two nematode species, Rhigonema naylae (Rhigonematoidea) and Travassosinema claudiae (Thelastomatoidea), which are parasites of the xystodesmid millipede species Parafontaria laminata (Polydesmida: Xystodesmidae) in Aichi Prefecture, Japan [ 45 , 46 ]. Both nematode species are in the suborder Spirurina, but in different infraorders.…”

“…Both nematode species are in the suborder Spirurina, but in different infraorders. Rhigonema naylae belongs to the infraorder Rhigonematomorpha, which includes the millipede parasites Ransomnematoidea [ 40 , 42 ] and Rhigonematidae [ 32 , 45 , 46 ], and the amphibian and reptile parasite Cosmocercoidea [ 8 , 9 ]. Travassosinema claudiae is a member of the Oxyuridomorpha, which includes a wide variety of parasites, such as vertebrate-parasitic Oxyuroidea [ 49 ], invertebrate-parasite Coronostomatoidea [ 55 ], and Thelastomatoidea [ 53 , 47 , 48 ].…”

Molecular identification of a new species of Rhigonema (Nematoda: Rhigonematidae) and phylogenetic relationships within the infraorder Rhigonematomorpha

“…However, the current genetic database for these nematodes remains very limited. In Rhigonematomorpha, only 21 nominal species have been genetically characterized [ 14 – 17 , 19 , 20 ], and most of the data available are represented by the 18S and 28S sequences, which are commonly used for molecular phylogeny of higher taxa within Nematoda [ 21 – 26 ]. Although the nuclear internal transcribed spacer (ITS) region and the mitochondrial cox 1 and cox 2 genes are widely used as powerful and practical genetic markers for revealing sibling or cryptic species, delimiting phenotypic variation and identifying species in the infraorders Ascaridomorpha, Spiruromorpha and Oxyuridomorpha [ 27 – 44 ], they have been scarcely employed in studies pertaining to Rhigonematomorpha species.…”

Influence of anthropogenic factors on the fauna of diplopods in the steppe zone of Ukraine

“…Дослідженнями Malysheva et al (2020), проведеними в Республіці Адигея (Російська Федерація), виявлено, що в задній кишці Pachyiulus krivolutsky Golovatch, 1977 (Julida, Julidae) паразитує Severianoia pachyiuli Malysheva et al, 2020 (Oxyuridomorpha). Morffe & Hasegawa (2017) Janardanan, 1987 (Eugregarinida, Stenophoridae), споронти яких досягають 2361 на 432 мкм (Janardanan, 1987). Організм диплоподи Carlogonus palmatus Demange, 1977 (Spirostreptida, Harpagophoridae) населяють грегарини Stenoductus carlogoni Janardanan, Ramachandran, 1987 (Eugregarinorida, Stenophoridae) (Janardanan, Ramachandran, 1987).…”