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Schizorchis yamashitai sp. n. (Cestoda: Anoplocephalidae) from the Northern Ochotona hyperborea Pallas in Hokkaido

Robert L. Rausch University of Washington, [email protected]

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Rausch, Robert L., "Schizorchis yamashitai sp. n. (Cestoda: Anoplocephalidae) from the Northern Pika Ochotona hyperborea Pallas in Hokkaido" (1963). Faculty Publications from the Harold W. Manter Laboratory of Parasitology. 347. https://digitalcommons.unl.edu/parasitologyfacpubs/347

This Article is brought to you for free and open access by the Parasitology, Harold W. Manter Laboratory of at DigitalCommons@University of Nebraska - Lincoln. It has been accepted for inclusion in Faculty Publications from the Harold W. Manter Laboratory of Parasitology by an authorized administrator of DigitalCommons@University of Nebraska - Lincoln. THEJOURNAL OF PARASITOLOGY Vol. 49, No. 3, June 1963, p. 479-482

Schizorchis yamashitai sp. n. (Cestoda :Anoplocephalidae) from the Northern Pika Ochotona hyperborea Pallas in Hokkaido

ROBERT L. RAUSCH Arctic Health Research Center, Public Health Service, U. S. Department of Health, Education, and Welfare, Anchorage, Alaska

ABSTRACT Schizorchis yamashitai sp. n., from the northern pika in Hokkaido, is described and its morphological characteristicscompared with those of the three previously known species of Schizorchis Hansen, 1948. The zoogeography of Schizorchisspp. in is briefly discussed.

Three species of cestodes, all from pikas, Schizorchis yamashitai sp. n. Ochotona spp. (:Ochotonidae) are (Figs. 1 to 3) recognized in the genus Schizorchis Hansen, (All measurements in millimeters.) 1948. S. ochotonae Hansen, 1948, and S. Diagnosis: Strobila 100 to 185 long, with as caballeroi Rausch, 1960 are known from North many as 338 segments; maximum width, 3.5 to America; while S. altaica Gvozdev, 1951, oc- 3.75, attained in gravid segments. Strobila widens curs in eastern Eurasia. Since the cestodes of abruptly just posterior to scolex, gradually increas- ing in width through about one-fifth of its length; this genus are highly host specific, additional thereafter, strobilar width essentially uniform. All species might be expected in other Palearctic segments wider than long; mature segments with regions where the helminth fauna of pikas has length/width ratio of about 1:6; gravid segments, about 1:3. Gravid somewhat arched in not been investigated. The geographically iso- segments dorsoventral view. Margins of strobila slightly lated populations of the northern pika Ocho- serrate, with serrations more strongly defined to- tona hyperborea Pallas on the islands of Hok- ward posterior end of strobila. Scolex small and kaido and are especially interesting weakly developed, from 0.236 to 0.250 in width; from this standpoint. suckers about 0.085 in diameter. Unsegmented neck short or While in northern very lacking. Accessory longitudinal collecting Japan excretory canals numerous. Genital pores irregu- during July to August 1962, I secured five larly alternate, situated in posterior half of seg- specimens of O. hyperborea yesoensis Kishida mental margin. Genital primordia appear very in central Hokkaido. This paper describes a early; that of ovary visible within 1 mm of scolex, of within 10 mm. new species of Schizorchis found in three of and those male genital organs Genital ducts dorsal to ca- these . The cestode is named in honor longitudinal excretory nals. Cirrus sac elongate, 0.286 to 0.428 long by of Professor Jiro Yamashita, Head of the De- 0.042 to 0.064 in maximum width (average 0.344 partment of Parasitology, Faculty of Veterinary by 0.052) in mature segments; diameter greatest Medicine, Hokkaido University, who provided near distal end. Cirrus sac infrequently extending anteromediad as far as lateral margin of poral laboratory space and invaluable assistance in ventral excretory canal. Everted cirrus protruding connection with the field work in Japan. about 0.130, with diameter of about 0.025; spines The material consisted of eight cestodes, of present. Internal seminal vesicle ovoid and small, which six possessed gravid segments. One situated in proximal portion of cirrus sac; external specimen, stained with 2% methyl-green- seminal vesicle much coiled, extending mediad from cirrus sac to level of ovary. Testes was the others subspher- pyronin, partially dissected; ical, averaging 0.050 in diameter in mature seg- were stained with Semichon's acetic carmine ments, and numbering 34 to 53 per segment (aver- or Ehrlich's acid hematoxylin and mounted age 44). Testes distributed across segment near in toto. posterior margin and not separated into two dis- crete lateral groups; usually confluent posterior and dorsal to vitelline gland as best seen in post- Received for publication 1 October 1962. mature segments. Testes never extending laterally 479 480 THE JOURNAL OF PARASITOLOGY Vol. 49, No. 3

particularly in the details of the genital organs. (1 The strobila of S. ochotonae does not exceed 50 mm in length and, with a width of as much //1 as 5 mm in gravid segments, appears more or \\ less wedge-shaped. It has a larger number of testes (50 to 65), and these form two dis- I I~t/ i crete groups separated by the ovary and vitel- -- line gland. Hansen (1948) noted that the -~`- J- - two groups of testes in S. ochotonae are rarely connected, and then only by two or three testes; in his figure of the mature segment (p. 755, Fig. 2), the two fields are shown to 200~ be essentially discrete, and this was confirmed FIGURE 1. Scolex Schizorchis yamashitai sp. n. in four specimens of S. ochotonae which I col- lected from O. princeps (Richardson) in the as far as longitudinal excretorycanals; greater num- Teton Mountains, Wyoming. The cirrus sac ber of testes into aporal. Vagina, opening genital of S. ochotonae is both and rela- atrium posterior and somewhat ventral to cirrus absolutely sac, extending mediad from genital pore, parallel- tively larger than that of S. yamashitai, and it ing cirrus sac and external seminal vesicle, and extends farther mediad in the former. enlarging to form small seminal receptacle on ven- The strobila of S. caballeroi is longer (up tral surface of ovary. Multilobed ovary on poral to 64 mm) and proportionally narrower than side of midline, occupying most of length of seg- that of S. but it is more attenuated ment. Subspherical vitelline gland coarsely lobed, ochotonae, situated posterior and ventral to ovary near pos- and much less robust than that of S. yamashitai. terior margin of segment; vitelline gland persist- In S. caballeroi, the more numerous testes (50 ing in gravid segments. Uterus appearing as simple to 60) are disposed in two discrete, lateral transversetube in mature segments, slightly arched groups which extend on both sides from the and situated posterior to male genital duct, paral- leling latter on poral side, and largely ventral to ovary and vitelline gland to the proximal ovary. Uterus in mature segments extending lat- margin of the adiacent ventral longitudinal erad as far as proximal margin of ventral longi- excretory canal. The somewhat larger cirrus tudinal excretorycanal on both sides; in postmature sac of S. caballeroi extends mediad across and latter ca- gravid segments extending beyond about one-fourth of the width of the mature nals, or displacing them toward segmental margin. Distal ends of uterus enlarging first in postmature segment, whereas in S. yamashitai, the cirrus segments, posterior and anterior sacculations ap- sac extends only as far mediad as the poral pearing later; latter retaining identity in terminal ventral excretory canal. gravid segments. Eggs approximately spherical, S. yamashitai resembles S. altaica Gvozdev, 0.036 to 0.062 in diameter (average 0.049); pyri- form apparatus well developed. Embryo 0.013 to 1951, in the size and form of the strobila. The 0.019 in diameter (average 0.015). former appears to be significantly longer, ex- Host: Ochotona hyperborea yesoensis Kishida, the maximum recorded of S. 1930. ceeding length Habitat: Duodenum of host. altaica by as much as 25%. According to the Type locality: Mountains surrounding Lake published description and figures (Gvozdev, Shikaribetsu, Daisetsuzan National Park, central 1951), the female genital organs are situated Hokkaido. more anteriorly in S. altaica, and the ovary is Type: A slide containing an entire cestode has been deposited in the Helminthological Collection centrally located rather than nearer the poral of the U. S. National Museum, No. 59876. margin of the segment as in S. yamashitai. The Comparisons: The size and form of the testes are more numerous in S. altaica (50 to strobila serve readily to distinguish S. yama- 60), are disposed in two entirely separate shitai from the two Nearctic species, S. ocho- fields, and are situated more anteriorly in the tonae Hansen, 1948, and S. caballeroi Rausch, segment, extending on the poral side as far as 1960.1 Other morphological differences exist, the margin of the ventral excretory canal. The cirrus sac of S. altaica is longer than that of 1The number (USNM Helm. Coll. 39024) of the slide containing the type specimen of S. S. yamashitai and extends farther mediad. The caballeroi was omitted in the description. gravid uterus of S. altaica does not extend RAUSCH-NEW CESTODE FROM THE PIKA 481

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Schizorchis yamashitai sp. n.

FIGURE 2. Mature segment. Diagonal hatching denotes testes. Uterus is the narrow transverse tubular organ at midlevel of proglottid. FIGURE3. Gravid segment. beyond the ventral excretory canals, according silla Pallas, O. roylei Ogilby, O. rufescens Gray, to the original description. and O. thibetana Milne-Edwards; and Pika Cestodes collected from pikas O. alpina Lac6pbde (having separate foramina), with Pallas near Peschan Bay, Lake Baikal, were O. alpina Pallas, O. hyperborea Pallas, O. identified as S. altaica by Spasskii and Ryzhi- ladacensis Giinther, O. rutila Severtzov, and kov (1951). According to the information O. pallasi Gray. The two North American spe- provided by the latter and by Spasskii (1951), cies, O. princeps (Richardson) and O. collaris this was a smaller cestode (length 60 to 70 (Nelson), are also members of the latter mm), possibly even another species of Schiz- subgenus. orchis. Since gravid segments were present, The recent review of the helminths in pikas this appears to be a much smaller form which by Gvozdev (1962) indicates that S. altaica can be distinguished from S. yamashitai by the has been reported from three species of the size of the strobila. subgenus Ochotona (0. pusilla, O. daurica, and macrotis), and from three of the subgenus DISCUSSION O. Pika (0. alpina, 0. rutila, and O. pallasi). The Twelve Eurasian species of Ochotona were geographic region from which this cestode has recognized by Ellerman and Morrison-Scott been recorded encompasses the Kazakh Up- (1951). These comprise two subgenera: Ocho- land, the Altai, Pribaikal', Buriat-, and tona s. str. (having palatal and incisive foram- Tian-Shan' (Gvozdev, 1962). Various Eura- ina confluent), with O. daurica Pallas, O. sian species of Ochotona are sympatric (see koslowi Biichner, O. macrotis Giinther, O. pu- Bobrinskii et al., 1944, map 38), although they 482 THE JOURNAL OF PARASITOLOGY Vol. 49, No. 3 are more or less segregated ecologically. Ces- ACKNOWLEDGMENTS todes of the genus Schizorchis can hardly be The collection of mammals in Daisetsuzan expected to exhibit host specificity below the National Park was undertaken with Professor generic level in pikas, but in view of the eco- Masashi Ohbayashi, Department of Parasitol- logical diversity of the habitats of the various ogy, Faculty of Veterinary Medicine, Hokkaido species of Ochotona and the vast geographic University; Dr. Hisashi Abe, Zoological Mu- area involved, the existence of more than one seum, Faculty of Agriculture, Hokkaido Univer- species in Eurasian pikas might be expected. sity, whose exceptional efforts were responsible There is some indication of this in the report for capture of the pikas; Regional Forester of the cestode from Lake Baikal by Spasskii Haruo Kusama, Shikaoi, Hokkaido; and Mrs. and Ryzhikov (1951). I have not obtained R. V. Rausch, who also prepared the figures. the literature in which some of the records To these colleagues I express my thanks. have been published (cited by Gvozdev, LITERATURE CITED 1962), so it is uncertain whether the deter- BOBRINSKII,N. A., B. A. KUZNETZOV,AND A. P. minations can be considered reliable. KUZIAKIN.1944. Opredelitel' mlekopitaiush- The mammalian fauna of Hokkaido has a chikh SSSR. Sovetskaia Nauka, Moscow. large boreal component derived from , 440 p. ELLERMAN, J. R., AND T. C. S. MORRISON-SCOTT. evidently by way of Sakhalin. Since these 1951. Checklist of Palaearctic and Indian northern species must have invaded Hokkaido mammals 1758 to 1946. British Mus. (Nat. rather recently (i.e., during Pleistocene time), Hist.), London. 810 p. E. V. 1951. vid tsestod sem. Schizorchis yamashitai sp. n. may occur both GVOZDEV, Novyi Anoplocephalidaeot pishchukhi. Trudy Gel'- in Hokkaido (and Sakhalin) and eastern mint. Lab., Akad. Nauk SSSR 5: 143-145. Siberia. O. hyperborea is widely distributed - -. 1962. Analiz gel'mintofauny pishchukh in eastern Eurasia, but its helminths evidently (Ochotonidae) v sviazi s geograficheskim In have been thus far rasprostraneniemkhoziaev. Parazity dikikh investigated only by Kapi- zhivotnykh Kazakhstana. Trudy Inst. Zool., tonov (1961), who found no cestodes in a Akad. Nauk Kazakh. SSR 16: 63-80. small series examined in the lower Lena River HANSEN, M. F. 1948. Schizorchis ochotonae n. region, in the northwest part of the Verkhoiansk gen., n. sp. of anoplocephalid cestode. Am. Midl. Nat. 39: 754-757. Range. HOLLAND,G. P. 1958. Distribution patterns of The possibility cannot be excluded that S. northern fleas (Siphonaptera). Proc. 10th yamashitai is limited in distribution to Hok- Internatl. Cong. Ent. (1956) 1: 645-658. KAPITONOV,V. I. Ekologicheskie nabliu- kaido Sakhalin. The collared 1961. and, perhaps, deniia nad pishchukhoi (Ochotona hyperborea pika, O. collaris, occurring in Alaska and north- Pall.) v nizov'iakh Leny. Zool. Zhur. 40: western Canada, harbors a species of Schizor- 922-933. R. L. 1960. Studies on the chis unknown in Eurasian pikas, although it RAUSCH, helminth fauna of Alaska. XXXVII. Description of appears to be a comparatively recent (late Schizorchis caballeroi n. sp. (Cestoda : Anop- Pleistocene) migrant into North America locephalidae), with notes on other parasites (Rausch, 1962). Judging from both its hel- of Ochotona. Libro Homenaje al Dr. Eduardo Caballero y C. Mexico, D. F., p. 399-405. minths and its fleas, O. collaris has a closer 1963. A review of the distribution relationship to the Eurasian O. hyperborea than of holarctic Recent mammals. Proc. 10th to the Rocky Mountain O. princeps (Holland, Pacific Sci. Cong. In press. A. 1951. Osnovy tsestodologii. I. 1958; Rausch, 1960). Results of zoogeograph- SPASSKII, A.a Anoplotsefaliaty--lentochnye gel'minty dom- ical interest should be produced from further ashnikh i dikikh zhivotnykh. Akad. Nauk studies in northeastern Siberia and from the SSSR, Moscow. 735 p. ANDK. M. RYZHIKOV.1951. investigation of the helminths of pikas in Tibet, , Gel'minty pishchukh Pribaikal'ia. Trudy Gel'mint. Lab., China, and India. Akad. Nauk SSSR 5: 34-41.