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52 • PROCEEDINGS OF THE HELMINTHOLOG1CAL SOCIETY

The Synonymy of the Parasites Nematodirus oiratianus Raevskaia, 1929 and Nematodirus lanceolatus Ault, 19441

KAY S. SAMSON USDA, Agricultural Research Service, Disease and Parasite Research Division, Las Cruces, New Mexico

Nematodirus oiratianus Raevskaia, 1929 (see closer to the edge of the bursa than in N. Raevskaia, 1931) was first described from oiratianus and that a retrograde prong between Altai wapiti ( canadensis asiaticus) and the spicules was lacking. Also, he was unable domestic ( aries) in Asiatic . to find eggs as large as those described for It has since been recovered from other rumi- N. oiratianus. nant hosts in several localities in the USSR. The first report of N. lanceolatus from North The Index Catalog of Medical and Veterinary America was that of Gilmore and Allen (1960) Zoology lists the following host records: water who found it in in New buffalo ( bubalis), bezoar ( Mexico. They identified their specimens tenta- aegagrus), domestic goat (C. hircus), Siberian tively as N. lanceolatus because the measure- (C. sibirica), roe (Capreo- ments of the spicules more nearly corresponded lus capreolns) and (C. pygargus bedfordi), to those described for that species than to European (Cervus elaphus xanthop- N. oiratianus. This same tentative identifica- ygus), sika (C. nippon), Dzeren antelope tion was given to specimens from domestic (Gazella siibgutturosa), Siberian (Ovis sheep and in New Mexico ammon), Armenian (O. ophion arme- (Allen, 1959 and unpublished data) and to niana), ( rupicapra cau- specimens from Colorado (Pill- casica), and (Saiga tatarica). more, 1961). Becklund and Senger (1967) The males of N. oiratianus can be distin- recorded N. lanceolatus from Montana big- guished by the characteristic shape of the . Apparently there is no published record terminal ends of their spicules. Each spicule of this species from . divides and the resulting rod-shaped parts To clarify the apparent taxonomic confusion fuse distally to form a lancet-shaped structure, concerning N. oiratianus and N. lanceolatus, the point of which extends completely to the the author undertook the studies on morphol- posterior border of a surrounding membranous ogy described in this report. Since females expansion. The spicules illustrated by Raev- in the Nematodirus have few characters skaia (1931) had a retrograde prong at the of taxonomic value, this study involved males site of their junction. The females contained principally. Detailed comparisons were made unusually large eggs (0.255-0.272 mm long of 77 males from domestic sheep in New and 0.119-0.153 mm wide). Mexico, four from the same host in Argentina, Ault (1944) discovered nematodes similar that were supplied by Dr. C. N. Ault, and a to N. oiratianus in domestic sheep in Argen- total of 51 from Siberian mountain , tina, but because of differences he considered Siberian argali, domestic sheep, and domestic significant, Ault named his species N. lanceo- cattle in the USSR. The Russian specimens latus. Type specimens of N. oiratianus were were kindly supplied by Dr. S. N. Boev, Insti- not available to him for comparison, so his tute of Zoology, Academy of Sciences of the conclusions were based on the description Kazakh, Alma-Ata, USSR. given iii Travassos (1937). Ault observed in The structure of the distal ends of the spic- his specimens that the externo-dorsal rays were ules was carefully noted, as was the location of the externo-dorsal rays of the bursa. Other 1 A portion of a thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, New characters examined were length of body, Mexico State University, Las Cruces. This work was carried out in cooperation with the New width of anterior end, length of , Mexico Agricultural Experiment Station and is a contri- width in front of bursa, length of spicules in- bution to the Western Regional Project W-35—Nematocle Parasites of . cluding terminal ends, size of lateral lobes of

Copyright © 2011, The Helminthological Society of Washington OF WASHINGTON, VOLUME 35, NUMBER 1, JANUARY 1968 53 bursa, and length of dorsal rays. Comparisons mens examined in this study are considered were first made of all specimens from domestic minor and within the bounds of intraspecific sheep. Next, measurements of specimens from variation. Therefore, it is the opinion of the domestic sheep were compared with measure- author that N. lanceolatus Ault, 1944, should ments obtained from specimens from cattle and be placed in synonymy with N. oiratianiis wild ruminants in . The measurements Raevskaia, 1929. This opinion is supported by of all specimens obtained for this study were recent observations by Samson (1966) that then compared with the original measurements large eggs comparable in size with those in the given for N. oiratianiis by Raevskaia and those original description of N. oiratianiis are occa- given for N. lanceolatus by Ault. Some of the sionally associated with both natural and ex- data were treated by analysis of variance. perimental infections in domestic sheep in New A comparison of the spicules of the various Mexico. specimens revealed no important differences. Literature Cited The retrograde prong which Ault mentioned as being present in the illustration of IV. oira- Allen, R. W. 1959. The occurrence of Nema- tianiis was not discerned in any of the spicules. todirus lanceolatus in domestic sheep in the The externo-dorsal rays of the four speci- United States. J. Colo.-Wyo. Aeacl. Sci. 4 mens from domestic sheep in Argentina were (11): 53. situated somewhat closer to the edge of the Ault, C. N. 1944. Nematodes parasitos de los bursa than the rays in specimens from both bovinos y ovinos en la Argentina (Segunda nota). Rev. Med. Vet., Buenos Aires, 26: domestic and wild ruminants in Siberia and 497-509. domestic sheep in New Mexico, but this dif- Becklund, W. W., and C. M. Senger. 1967. ference alone is not considered sufficient to Parasites of Ovis canadensis canadensis in warrant placing the Argentina forms in a Montana, with a checklist of the internal and separate species. Total lengths of specimens external parasites of the Rocky Mountain big- varied considerably as might be expected, and horn sheep in . J. Parasit. 53: in some cases these differences were statis- 157-165. tically significant. There is, however, some Gilmore, R. E., and R. W. Allen. 1960. Hel- difficulty in measuring total lengths of males minth parasites of pronghorn antelope (Antilo- because they are invariably coiled. The great- capra americana) in New Mexico with new est difference in average total lengths was host records. Proc. Helm. Soc. Wash. 27: 69-73. between Siberian cattle (8.77 mm) and Si- Pillmore, R. E. 1961. General investigations of berian mountain goats (12.51 mm), with the diseases and parasites. Quar. Rept. Colo. Dept. specimens from other sources ranging between and Fish, Oct., p. 101-102. these two. It is of interest, though, that Raevskaia, Z. A. 1931. Zur Charakteristik der Raevskaia (1931) gives a maximum total Nematoden der Gattung Nematodinis, Ran- length of 16.5 mm and that a specimen from som 1907. (Versuch einer monographischen New Mexico domestic sheep measured only Bearbeitung). Ztschr. Infektionskr. Haustiere. 7.38 mm. In our collection of males from 40: 112-136. pronghorn antelope in New Mexico, there are Samson, K. S. 1966. Preliminary studies on the some specimens as short as 7.20 mm. Despite life history of Nematodirus oiratianiis, an in- testinal parasite of ruminants. Program 42. this wide variation in total lengths of the Ann. Meet. Southwest, and Rocky Mountain worms, differences in lengths of spicules were Div. Am. As. Adv. Sci. p. 35-36. small and in no case significant, regardless of Travassos, L. P. 1937. Revisao da Familia host and geographical source. Trichostrongylidae Leiper, 1912. Monogr. The differences observed between the speci- Inst. Oswalclo Cruz. No. 1, 512 p.

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