New species Semitobrilus filipjevi sp. n. from Laos and taxonomic structure of the genus Semitobrilus Tsalolikhin, 1981 (Nematoda: Tobrilida, Tobrilidae, Neotobrilinae)

S.Ya. Tsalolikhin

Proceedings of the Zoological Institute RAS, 2020, 324(4): 525–534 · https://doi.org/10.31610/trudyzin/2020.324.4.525

Full text

Abstract

A description of the new species Semitobrilus filipjevi sp. n. from Laos is given. The new species differs from the other species of the genus by its long head setae. The new species differs from S. pellucidus in the length of the head setae (more than 50% of the head width) and the presence of crystalloids in the body cavity. The new species was discovered in the silty-sandy soil from a forest pond in southern Laos. An identification key of the species and a refined diagnosis of the genus Semitobrilus is provided. The species characters and species composition of the genus Semitobrilus are discussed. It is proposed to synonymize the species S. closlongicaudatus (Gagarin, 1971) with the species S. longicaudatus (Hofmaenner, 1913). The species S. gagarini (Ebsary, 1982) is transferred to the category sp. inq. The length of the head setae is the main character of the species. The presence of crystalloids in the body cavity is an unreliable character. Errors in the descriptions of S. ebsaryi, S. gagarini, and S. pellucidus are discussed. The work used the materials from the collection of the Zoological Institute of the Russian Academy of Sciences, including the original slides by I. N. Filipjev.

Key words

Laos, free-living nematodes, taxonomy, Semitobrilus

Submitted July 2, 2020 · Accepted October 17, 2020 · Published December 25, 2020

References

Bastian H.C. 1865. Monograph on the Anguillulidae, or free Nematoids, marine, land and freshwater with descriptions of 100 new species. Transactions of the Linnean Society of London, 25: 73–184. https://doi.org/10.5962/bhl.title.14153

Brakenhoff H. 1913. Beitrag zur Kenntnis der Nematodenfauna des nordwestdeutschen Flachlandes. Abchandlungen Naturwissenschaftlicher Verein zu Bremen, 22: 267–311.

Bütschli O. 1873. Beiträge zur Kenntnis der freilebenden Nematoden. Nova Acta der Deutschen Academie der Naturforschung, 36: 3–144.

Bütschli O. 1876. Untersuchungen über freilebende Nematoden und die Gattung Chetonotus. Zeitschrift für Wissenschaftliche Zoologie, 26: 363–413.

De Man J.G. 1881. Die einheimischen, frei in der reinen Erde und im süssen Wasser lebenden Nematoden monographisch bearbeitet. Tijdschrift der Nederlandsche Dierkundige, 5: 1–104. . https://doi.org/10.5962/bhl.title.46884

De Man J.G. 1884. Die frei in der reinen Erde und im süssen Wasser lebenden Nematoden der niderländischen Fauna. E.J. Brill, Leiden, 206 p. https://doi.org/10.5962/bhl.title.46884

Ebsary B.A. 1982. Canadian species of Tobrilus (Nematoda: Tobrilidae) with description of three new species. Canadian Journal of Zoology, 60: 3048‒3062. https://doi.org/10.1139/z82-387

Filipjev I.N. 1928. Free-living nematodes from Oka river. Arbeiten der Biologischen Wolga-Station, 5 (2–3): 81–112. [In Russian].

Gagarin V.G. 1971. New and rare species of nematodes from the Uchinsky, Dubossarsky and Mingechaursky water reservoirs. Zoologicheskiy Zhurnal, 50: 981–989. [In Russian].

Gagarin V.G. 1993. Free-living nematodes in freshwaters of Russia and adjacent lands. Gidrometeoizdat, St. Petersburg, 352 p. [In Russian].

Gagarin V.G. and Gusakov V.A. 2013. Neotripyla vulgaris gen. n., sp. n. and Semitobrilus andrassyi sp. n. (Nematoda, Triplonchida) from freshwater bodies of Vietnam. Zootaxa, 3716(4): 565–576. http://doi.org/10.11646/zootaxa.3716.4.4

Hofmänner B. 1913. Contribution à l'étude des nematodes libres du Lac Léman. Revue Suisse zoologique, 21: 589–658. https://doi.org/10.5962/bhl.part.82534

Juget J. 1969. Description de quelques formes rares ou nouvelles de Nématodes libres du basin du Léman. Bulletin de la Société Vaudoise des Sciences Naturelles, 70: 141–173.

Loof P.A.A. and Riemann F. 1976. Taxonomy of the Tobrilus-longus group. Nematologica, 22: 15–48. https://doi.org/10.1163/187529276X00030

Meyl A.H. 1961. Freilebende Nematoden. In: P. Brohmer, P. Ehrmann and G. Ulmer (Eds). Die Tierwelt Mitteleuropas, vol. 1 (5a). Verlag Quelle & Meyer, Leipzig, 164 p.

Schneider W. 1923. Niederrheinische freilebende Nematoden. Zoologischer Anzeiger, 56: 264‒281.

Schneider W. 1925. Freilebende Süsswassernematodenaus ostholsteinischen Seen nebst Bemerkungen über die Nematodenfauna des Madü- und Schaalsees II. Archiv für Hydrobiologie, 15: 536–584.

Tsalolikhin S.Ya. 1981. A revision of the genus Tobrilus (Nematoda, Tobrilidae). Zoologicheskiy Zhurnal, 60: 1302–1313. [In Russian].

Tsalolikhin S.Ya. 1983. Nematodes of families Tobrilidae and Tripylidae of world fauna. Nauka, Leningrad, 232 p. [In Russian].

Tsalolikhin S. Ya. 2000. Review of the genus Semitobrilus (Nematoda, Enoplida, Tobrilidae). Zoologicheskiy Zhurnal, 79: 267–271. [In Russian].

Tsalolikhin S.Ya. 2019. New species Monhystera tibetica sp. n. (Nematoda, Monhysterida) from West Tibet. Proceedings of the Zoological Institute RAS, 323(4): 568–574. [In Russian]. https://doi.org/10.31610/trudyzin/2019.323.4.568

Yanliang P. and Coomans A. 2000. Tree species of Tobrilidae (Nematoda: Enoplida) from Li River at Guiling, China. Hydrobiologia, 421:77–90. https://doi.org/10.1023/A:1003981807711

Zullini A. 2006. Order Triplonchida. In: A. Eyualem-Abebe, I. Andrássy and W. Traunspurger (Eds). Freshwater Nematodes: Ecology and Taxonomy. CABI Publisheng, Wallingford: 293–325. https://doi.org/10.1079/9780851990095.0293