Comparative Parasitology 68(2) 2001 - Peru State College

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224 COMPARATIVE PARASITOLOGY, 68(2), JULY 2001 Remarks Fischthal and Kuntz (1975) described Mesostephanoid.es taiwanensis from the small intestine of E. chinensis from Taipei Prefecture in Taiwan on the basis of a single specimen. We examined that specimen, USNPC No. 73148, and, even though it was not from the gallbladder, we considered our specimens from Vietnam conspecific with it. Data for the holotype fit those for our specimens. We, however, interpret differently the terminal genitalia described and illustrated by Fischthal and Kuntz (1975) in their Figure 15. Perhaps they misinterpreted the nonillustrated muscular looping of the metraterm as spines. In any event, the cirrus sac of the holotype contained a club-shaped seminal vesicle measuring about 260 u,m long, a straight pars prostatica 113 u,m long, and a short ejaculatory duct 45 fjim long. The metraterm coiled once prior to descending to the genital atrium. We observed spines in none of these features. Because of the lack of a spined cirrus and lack of anterior confluence of the bands of vitelline follicles, we consider that the species belongs to Szidatia Dubois, 1938, as Szidatia taiwanensis (Fischthal and Kuntz, 1975) comb. n. Dubois (1951) differentiated the monotypic genus Mesostephanoides Dubois, 1951, from other cyathocotylid genera on the basis of Mesostephanoides burmanicus (Chatterji, 1940), having a forebody to total body length ratio that we estimate as 1:1.14-1.18, a spined cirrus 300 (Jim long, and vitelline follicles confluent anteriorly. We consider the first 2 features of questionable generic significance, and an examination of M. burmanicus and related species may show that Mesostephanoides is a synonym of Gogatea Lutz, 1935, a genus with species having anteriorly confluent vitelline follicles. Szidatia taiwanensis resembles its 2 congeners in that the vitelline follicles are in separate lateral fields, as opposed to being in a single confluent field underlying the tribocytic organ as reported for species of Gogatea, the only other genus in Szidatiinae. Szidatia taiwanensis most closely resembles Szidatia nemethi Dollfus, 1953, from the water snake TV. maura (as N. viperina) from Charrat, Morocco, but differs from this species by having a much smaller tribocytic organ (283—447 jjim long by 246-423 |xm wide vs. 885 (Jim long by 765 u,m wide), larger eggs (140-169 jxm long by 80-99 (Jim wide vs. 105 Copyright © 2011, The Helminthological Society of Washington (xm long by 55 (Jim wide), and a club-shaped rather than a coiled seminal vesicle. Szidatia taiwanensis differs from S. joyeuxi, the type and remaining species in the genus, by having a longer esophagus (67-149 |JLm compared with 40 |xm), ceca that reach only to the level of the anterior testis rather than beyond the posterior testis, an acetabulum that lies between the middle and anterior % of the forebody rather than exactly in the middle, and oblique rather than tandem testes; the anterior testis is almost entirely within the forebody rather than in the hindbody, the seminal vesicle is club-shaped rather than coiled, and the eggs are larger (140- 169 (xm long by 80-99 (Jim wide vs. 100 (Jim long by 70 (xm wide). The minute papillae on the tegument at the posterior end, too small to illustrate to scale, probably serve a sensory function during mating or egg deposition. The intestine, the infection site of the specimen reported by Fischthal and Kuntz (1975), may have resulted from postmortem migration from the gallbladder. A few specimens of other species normally found in the gallbladder occasionally occur in the intestine normally. We do not think the difference in sites based on 1 specimen is significant. As with the echinostomate specimens of S. vietnamensis, the initial specimens of S. taiwanensis had been placed in fresh water prior to fixation in unheated formalin (see Fig. 6). Unlike those of S. vietnamensis, these specimens were not fixed under any pressure; nevertheless, their measurements and features varied dramatically from those obtained from specimens fixed with heat and used for the above description. Hindbody length was generally shorter (146- 506 (Jim vs. 326—762 (Jim), and both the anterior and posterior testes occurred entirely in the forebody of specimens exposed to water, whereas the posterior testis was always in the hindbody of heat-killed specimens. The cirrus sac was generally straighter in osmotically stressed specimens and more bent or curled in the region of the pars prostatica in heat-killed specimens. In addition, the tribocytic organ was greatly enlarged (492-650 (Jim long by 520-685 |xm wide vs. 283-447 fxm long by 245-423 ujn wide) in the stressed specimens. The most important difference due to fixation techniques pertained to the configuration of the vitellarium. In the stressed specimens, vitelline follicles appeared confluent anteriorly (horseshoe-shaped distribu-
tion) but were in independent lateral bands in heat-killed specimens. Because the presence or absence of an anterior vitelline confluence differentiates Gotatea from Szidatia, and the appearance of confluence can be influenced in cold-killed or freshwater-soaked specimens, the methods of fixation clearly have a bearing on taxonomic interpretations. Discussion Classification of Singhiatrema The position of Singhiatrema within Echinostomatiformes La Rue, 1957, continues to be debated by taxonomists. Ommatobrephinae Poche, 1926, was created for Ommatobrephus and Singhiatrema, and Parorchiinae Lai, 1936, was included in Ommatobrephidae on the basis of the generic level character of the collar spines (see Simha and Chattopadhyaya, 1967). Singhiatrematinae Simha, 1962, was later created to house Singhiatrema, presumably because the author considered the presence of collar spines to be of taxonomic importance at the subfamiliar rather than generic level. These changes resulted in Ommatobrephidae containing Ommatobrephinae, Parorchiinae, and Singhiatrematinae, each containing a single genus. Members of Ommatobrephinae and Singhiatrematinae differ only in the presence or absence of a single row of collar spines. We consider the presence or absence of collar spines to represent a generic feature only and, therefore, consider Singhiatrematinae a junior subjective synonym of Ommatobrephinae. Yamaguti (1971) considered Parorchiinae a subfamily in Philophthalmidae Travassos, 1918. We agree with Yamaguti in returning Parorchiinae to Philophthalmidae because members of that subfamily do not possess characters consistent with Ommatobrephidae. Most notably, parorchiines have tegumental spines, a conspicuous prepharynx, an external seminal vesicle, a spined cirrus, opposite testes that do not diverge anteriorly, and life cycles that involve birds and estuarine molluscs. Although no knowledge of the larval stages of species in Singhiatrema or Ommatobrephus is available, all known adults of species in these genera infect freshwater or terrestrial reptilian hosts, indicating a freshwater rather than an estuarine life cycle. Classification of Szidatia Contrary opinions regarding the status of key generic features of Gogatea and Szidatia have CURRAN ET AL.—TWO VIETNAMESE SNAKE DIGENEANS 225 formed the basis for debates over whether the 2 cyathocotylid subfamilies Szidatiinae and Gogatinae Mehra, 1947, should be synonymized (see Dubois, 1938, 1951, 1953; Mehra, 1947; Sudarikov, 1962; Yamaguti, 1971). Both subfamilies contain only a single genus, but the above discussion of Mesostephanoides should be noted. Lutz (1935) erected Gogatea and created the combination Gogatea serpentum (Gogate, 1932) for Prohemistomum serpentum Gogate, 1932, a parasite in the intestine of the colubrid snake X. piscator (as Natrix piscator) from the Union of Myanmar (as Burma). Lutz (1935) included Gogatea in his new subfamily Prohemistominae Lutz, 1935. Szidat (1936) added the new combination Gogatea joyeuxi (Hughes, 1929) for the cyathocotylid previously considered Prohemistomum joyeuxi (Hughes, 1929) from the colubrid water snake Natrix natrix scutata Pallas, 1771 (as Tropidontus natrix persa), by Joyeux and Baer (1934). That species developed in the snake when fed diplostomula consistent with diplostomula described by Hughes (1929) from Tunis, Morocco (Joyeux and Baer, 1934). Gogatea indicum Mehra, 1947, was subsequently described from X. piscator in India. Dubois (1938) observed that the vitellarium of G. joyeuxi consisted of 2 distinct rows of vitelline follicles, 1 on either side of the tribocytic organ. The vitellarium of other species in Gogatea consists of a confluent arch of follicles, lying dorsal to the tribocytic organ. Dubois (1938) erected Szidatia Dubois, 1938, on the basis of the differing configuration of the vitellaria and created the new combination S. joyeuxi for G. joyeuxi. Dubois (1938) also created the subfamily Szidatinae, emended as Szidatiinae by Yamaguti (1958), to house both Szidatia and Gogatea. Mehra (1947) did not consider that the difference in vitelline configuration warranted generic distinction and rejected Szidatia and therefore Szidatiinae. Instead, he created Gogatinae to contain all species of Gogatea, with G. serpentum as the type species. Dollfus (1953), Sudarikov (1962), and Yamaguti (1971) all accepted the generic distinctions established by Dubois (1938) and considered Gogatinae a junior synonym for Szidatiinae, retaining G. serpentum and S. joyeuxi as the type species for their respective genera. We concur with these authors and think that the different configuration of the Copyright © 2011, The Helminthological Society of Washington
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Volume 68 July 2001 Number 2 Former
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Comp. Parasitol. 68(2), 2001, pp. 1
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CRISCIONE AND FONT—DEVELOPMENT OF
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length did not exceed 1.2 mm. By da
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Agamidae) from Australia. Journal o
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infection with O. javaensis (C. D.
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CRISCIONE AND FONT—VARIATION OF O
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CRISCIONE AND FONT—VARIATION OF O
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and Font, 2001), the indication of
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U.S.A. (42°59'N; 88°21'W). Ten to
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Table 2. Prevalence (Pr) and Rana c
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transmission dynamics of these 3 tr
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196 in G. W. Esch, A. O. Bush, and
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Page 29 and 30: filariae of S. fallisensis was simi
Page 33 and 34: CARRENO ET AL.—DEER PARASITES IN
Page 35 and 36: ange of host species, but most coll
Page 37 and 38: Oestridae). Canadian Journal of Zoo
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Page 43 and 44: south-central New York salamanders.
Page 45 and 46: AGUIRRE-MACEDO ET AL.—ENDOHELMINT
Page 51 and 52: Table 1. Helminths found in freshwa
Page 53 and 54: •o d c o U rH CB 3 C8 H °Q 0 W T
Page 55 and 56: da-Lopez et al., 1985; Leon, 1992;
Page 57 and 58: especie del genero Goezici Zeder, 1
Page 59 and 60: JALISCO SALGADO-MALDONADO ET AL.—
Page 61 and 62: SALGADO-MALDONADO ET AL.—HELMINTH
Page 63 and 64: Table 3. Continued. Number of hosts
Page 71 and 72: tudio helmintologico de Chirostoma
Page 75 and 76: CURRAN ET AL.—TWO VIETNAMESE SNAK
Page 77: methods of fixation had not been kn
Page 81 and 82: tylidae Poche: Part 2. A contributi
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Page 89 and 90: Literature Cited Baker, M. R. 1978.
Page 91 and 92: Figure 1. Spores of Myxobolus gibbo
Page 93 and 94: CONE—DIAGNOSIS OF MYXOBOLUS 239 F
Page 95 and 96: Literature Cited Cone, D. K., and R
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Page 113 and 114: , D. Iglesias, and B. Fried. 1986.
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Page 117 and 118: RESEARCH NOTES 263 Table 1. Helmint
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Page 123 and 124: Kharchenko, V. A., G. M. Dvojnos, a
Page 125 and 126: id s „ ~ 55 **5 | «§ u ' *^ U
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RESEARCH NOTES 275 Figure 1. Cephal
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c Tj ;^ fn in ON o m ON "3 s ON gcd
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ticeps (Rudolphi, 1819), which also
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Nieto reviewed recent advances in t
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Adenomera hylaedactyla, 21 Algansea
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Honorary Membership, 282 Life Membe
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Schrankiana larvata, 21 Schrankiana
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*Edna M. Buhrer "Mildred A. Doss *
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