ZOOSYSTEMATICA ROSSICA, 26(2): 205–208 25 DECEMBER 2017 Monhystrella andreana sp. nov. (Nematoda: Monhysterida) from Chile Monhystrella andreana sp. nov. (Nematoda: Monhysterida) из Чили S.YA. TSALOLIKHIN С.Я. ЦАЛОЛИХИН S.Ya. Tsalolikhin, Zoological Institute, Russian Academy of Sciences, 1 Universitetskaya Emb., St Petersburg, 199134, Russia. E-mail: [email protected] A description of Monhystrella andreana sp. nov. from brackish water lake in Tierra del Fuego, Chile, is given. The new species differs from the most morphologically close M. macrura (de Man, 1880) mainly in shorter tail and pharynx (esophagus), and in longer spicules. Дано описание нового вида Monhystrella andreana sp. nov. из солоноватоводного озера Огненной Земли (Чили). Новый вид отличается от наиболее морфологически близкого M. macrura (de Man, 1880) более короткими хвостом и глоткой (пищеводом) и более длинными спикулами. Key words: South America, free-living nematodes, Monhystrella, new species Ключевые слова: Южная Америка, свободноживущие нематоды, Monhystrella, новый вид INTRODUCTION The genus Monhystrella Cobb, 1918 in- cludes about 30 species (Andrassy, 2005); Nematodes were collected from the san- most of them were found in inland brackish dy littoral zone of brackish water lake Lago and fresh waters, as well as in hot springs de los Cisnes (Tierra del Fuego, Chile), on all continents. A large number of species eastern shore 5 km N of Porvenir, 53. described from Africa (Abebe & Coomans, 25020°S, 70. 34614° W, height about 0 m, by 1996; Filipjev, 1931) and South America Dr Andrey Przhiboro in March 2017. Lago (Abebe & Coomans, 1995; Andrássy, 1963, de los Cisnes is a shallow hypersaline lake 1968; Loof, 1964). The taxonomy of the surrounded by grassy landscape. The lake is genus is thoroughly reviewed by Andrássy located at a distance of 3 km from the west- (1981) and Jacobs (1987). ern coast of Terra del Fuego. Water salin- ity is 50 g/l; water pH is around 9.4. The DESCRIPTION OF THE SPECIES sampling locality is a flat lake shore with Order MONHYSTERIDA numerous limestone macrostromalites up to 1 m high. The samples were collected from Family MONHYSTERIDAE the water margin zone between the foots of Genus Monhystrella Cobb, 1918 stromatolites. The collected substrate is wet limestone sand and gravel mixed with fine Monhystrella andreana sp. nov. detritus and various organic remains (bird (Figs 1–4; Table) feathers, parts of vegetation etc.), mostly Holotype. Female; Chile, lake Lago de los with high contents of hydrogen sulfide; the Cisnes, 10 March 2017, Coll. A. Przhiboro. Mi- substrate formed an irregular 0.5–2 cm lay- croscope slide No. A-8706, Zoological Institute, er on the solid limestone plate in 0.3–1.5 m St Petersburg. above the water line. Nematodes were fixed Paratypes. Four females and three males, the in 4% formalin. same data as for holotype. © 2017 Zoological Institute, Russian Academy of Scienсes 206 S.YA. TSALOLIKHIN. MONHYSTRELLA ANDREANA SP. NOV. FROM CHILE Table. Morphometrics of Monhystrella andreana sp. nov. All measurements are in μm and in the form: range (mean ± s.d.). Character Holotype (femail) Females (n=8) Males (n=3) L 689 676–780 (724±18) 592–728 (651) a 29.9 27.7–33.9 (30.1±1) 32.9–38.3 (34.8) b 6.7 6.1–8.2 (6.7±0.3) 6.2–7 (6.5) c 4.8 4.8–5.9 (5.2±0.2) 6.2–7.9 (7.1) c´ 8.5 8–11 (9±1) 4–6 (5) Body width 23 23–27 (24±1) 19 Pharyngeal length (esophagus) 103 95–115 (108±3) 95–104 (99) Tail length 145 102–162 (142±9) 80–101 (92) Spinneret 6 4–5 (4.5) 4–6 (5) Anal body width 17 15–19 (17±1) 15–18 (17) V% 57 53–58 (57±1)% – V – anus 148 148–205 (174±9) – V – anus / tail 1.1 1.1–1.4 (1.3±0.1) – Gonad 230 220–230 (227±10) 350–480 (400) NR% ~60% ~60% ~60% Cephalic seta ~1 ~1 ~1 Amphid diameter 3.5 3–3.5 3–3.5 Distance from center of amphid 12 10–12 (11) 11 to head edge Body wide at amphid 16 14–16 (15±1) 10–11 Spicule length (along chord) – – 28–29 Gubernaculum – – 3–4 Description. Cuticle thin, about 0.5 μm. dium small. Anterior part of mid-intestine Somatic setae few, distribution variable. La- forming well demarcated progaster. Renet- bial papillae undetectable. Four shorter ce- te gland posterior to progaster; excretory phalic setae on lip region. Lip region offset. pore anterior to level of nerve ring. Rectum Stoma with one denticle. Amphidial fovea shorter than anal body width. Reproductive circular, center of amphid at 10–12 μm from system of females monodelphic prodelphic. anterior body end. Esophagus (pharynx) Mature eggs in uterus absent. Postvulval muscular, more or less cylindrical anteri- uterine sac absent. Vagina short, not mus- orly, without developed terminal bulb. Car- cular. Tail elongate-conoid anteriorly and © 2017 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 26(2): 205–208 S.YA. TSALOLIKHIN. MONHYSTRELLA ANDREANA SP. NOV. FROM CHILE 207 Figs 1–4. Monhystrella andreana sp. nov. 1, head; 2, pharynx (esophagus); 3, mail tail; 4, entire body of female. Scale bars: 5 μm for fig. 1; 10 μm for figs 2, 3; 50 μm for fig. 4. slender posteriorly. Spinneret not very long. REFERENCES Reproductive system of males monorhic, Abebe E. & Coomans A. 1995. Freshwater nem- proorhic. Spicules comparatively long and atodes of the Galápagos. Hydrobiologia, 299: slender. Tail conoid anteriorly and slender 1–51. posteriorly, similar to female. Abebe E. & Coomans A. 1996. Aquatic nema- Comparision. Monhystrella andreana sp. todes from Ethiopia. Hydrobiologia, 324: nov. is most close to the widespread M. ma- 53 –77. crura (de Man, 1880) from which it differs Andrássy I. 1963. The zoological results of Gy. in shorter tail and esophagus at greater Topál᾿s collectings in South Argentina. An- body length, shorter head setae, structure nales Historico-Naturalles Masei Nationalis Hungarici, 55: 243–273. of stoma and relatively longer spicules. Andrássy I. 1968. Nematoden aus den Galerie- Etymology. This species is named in hon- wäldern des Acaray-Flusses. Opuscula or of my colleague Dr Andrey A. Przhiboro, Zoologica, Budapest, 8(2): 167–315. who collected the material in the lakes of Andrássy I. 1981. Revision of the order Mon- Tierra del Fuego. hysterida (inhabiting soil and inland wa- ters). Opuscula Zoologica Budapest, 17– ACKNOWLEDGEMENTS 18(1): 13–47. Andrássy I. 2005. Free-living nematodes of Hun- I am very grateful to Dr Andrey A. Przhiboro gary, 1. Budapest: Hungarian Natural His- for collecting material in South America. tory Museum. 518 p. © 2017 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 26(2): 205–208 208 S.YA. TSALOLIKHIN. MONHYSTRELLA ANDREANA SP. NOV. FROM CHILE Filipjev I.N. 1931. Report on freshwater Nema- trridae) with keys to the species. Zoologica toda. Proceedings of the Zoological Society of scripta, 16(3): 191–197. London, 2: 443–429. Loof P.A.A. 1964. Free-living and plant-parasit- Jacobs L.J. 1987. A redefinition of the genus ic nematodes from Venezuela. Nematologica, Monhystrella Cobb (Nematoda, Monhys- 10(2): 201–300. Received 17 Oct. 2017 / Accepted 14 Nov. 2017 Editorial responsibility: A.Yu. Ryss © 2017 Zoological Institute, Russian Academy of Scienсes, Zoosystematica Rossica 26(2): 205–208