Tellervotrema beringi Mamaev 1965

Autor:	Blend, Charles K., Dronen, Norman O., Gardner, Scott L., Racz, Gabor R., Armstrong, Howard W.
Rok vydání:	2012
Předmět:	Opecoelidae Tellervotrema beringi Animalia Plagiorchiida Biodiversity Platyhelminthes Trematoda Tellervotrema Taxonomy
DOI:	10.5281/zenodo.6168241
Popis:	Tellervotrema beringi (Mamaev, 1965) (Figs. 4��7) Synonyms: Plagioporus beringi Mamaev, 1965. Hosts: Albatrossia pectoralis (Gilbert); Gadiformes: Macrouridae: Macrourinae; giant grenadier. Coryphaenoides sp.; Gadiformes: Macrouridae: Macrourinae. Localities: A. pectoralis: Northeastern Pacific Ocean, 44 �� 25 'N, 125 ��07'W, depth = 1,530 m, 14 /August/ 1964. Coryphaenoides sp.: Northeastern Pacific Ocean, 44 �� 38 'N, 125 �� 25 'W, depth = 2,800 m, 20 /February/ 1964; 44 �� 38 'N, 125 �� 50 'W, depth = 2,800 m, 30 /December/ 1963. Site: Intestine. Deposited Specimens: Collector JEM, HWML neotype 49709 (1 adult [McCauley ID # OTB- 42 -F- 1-11]), HWML paraneotypes 42665 (19 adult), HWML vouchers 42665 (2 adult & 6 immature); Collector JEM, HWML paraneotypes 42743, 42855 (2 adult). Prevalence: Coryphaenoides sp.: 2 of 2 host specimens (100 % infected). Intensity: Coryphaenoides sp.: only 1 specimen found in each fish. Mean intensity: Coryphaenoides sp.: 2 worms in 2 specimens or 1 worm/infected fish. Relative density/abundance: Coryphaenoides sp.: 2 worms in 2 specimens or 1.0 worm/total fish examined. Records: 1. Mamaev (1965); 2. Yamaguti (1971); 3. Gibson & Bray (1982); 4. Bray (1995); 5. Blend (1996); 6. Present study. Descriptions: 1, 6. Redescription. [Based on 22 specimens. Measurements and proportions are given in Table 3.] Body elongateoval, clavate or lanceolate, widest postequatorially; some individuals slightly hour-glass-shaped with narrowing of body around equatorial level. Forebody attenuated anteriorly, narrowing at bifurcal level. Hindbody rounded posteriorly and wider than forebody. Tegument smooth. Pre-oral lobe absent. Oral sucker subspherical, subterminal (terminal in a few specimens). Ventral sucker sessile, spherical to subspherical, wider than long in most specimens, larger than oral sucker, postbifurcal, preequatorial and located near junction of anterior and middle thirds of body. Prepharynx quite short. Pharynx muscular, elongate oval, majority wider than long. Oesophagus with tegumental lining, straight in most specimens (67 %) while sinuous in others (33 %). Intestinal bifurcation short distance anterior to ventral sucker. Caeca narrow yet distal ends can be inflated, unbranched, with thickened walls, running posteriorly along lateral sides of worm to end blindly near posterior extremity; ends of caeca arcuate in some individuals. Testes 2, tandem, irregularly indented to deeply lobed, transversely elongate, median, intercaecal, postequatorial, contiguous (91 %), rarely separated (9 %). Post-testicular region fairly sizeable, occupying posterior third of body. Cirrus-sac thin-walled, distinctly elongate in anterior portion, clavate to pyriform in shape, extending from point midway between left lateral body edge and midline in a long and either nearly straight or markedly curved posterodextral line beyond anterior margin of ventral sucker to overlap 1 / 5 to 3 / 4 length of ventral sucker, terminating well posterior to level of intestinal bifurcation near midline. Seminal vesicle bipartite; posterior portion saccular; anterior portion tubular, narrow, looping back and ventrally overlapping posterior portion before passing anterosinistrally in long straight line from near midline of worm to enter distal portion of cirrus-sac, which itself either continues anterosinistrally or turns sharply anteriorly over left cecum at level of intestinal bifurcation to proceed anteriorly to terminate in small, subcircular genital atrium. Prostate gland-cells well developed, numerous in cirrus-sac. Pars prostatica conspicuous and just anterior to or dorsally overlapping anterior margin of ventral sucker; narrow ejaculatory duct and cirrus present. Genital pore submedian, sinistral, midway between body margin and midline but can be either nearer to lateral margin or nearer to midline in some individuals, at level of intestinal bifurcation but can reach level of posterior oesophagus, preacetabular and closer to ventral sucker than oral sucker. collected off the coast of Oregon. Parasite T. beringi T. beringi n 2 20 Host Coryphaenoides sp. Albatrossia pectoralis Source of data HWML 42743 & 42855 1 HWML 49709 & 42665 1 Collector & fixation McCauley, host AFA injection McCauley, host AFA injection Length 2,540��2,960 (2,750) 1,680��3,440 (2,524) [n = 18] 2 Width at pharynx 356��405 (381) 316��599 (476) [n = 19] at VS 567��802 (685) 591��1,004 (751) at PT 543��786 (665) 664��1,269 (931) [n = 19] Forebody l 2 851��891 (871) 608��1,288 (862) [n = 19] Hindbody l 1,689��2,069 (1,879) 1,072��2,369 (1,637) [n = 19] Oral sucker (OS) l 216��272 (244) 148��308 (246) [n = 19] w 2 244��260 (252) 164��332 (247) [n = 19] Prepharynx l 16��36 (26) 0��80 (27) [n = 19] Pharynx l 124��148 (136) 76��168 (117) [n = 19] w 96��108 (102) 124��192 (153) [n = 19] Oesophagus l 220��316 (268) 162��592 (328) [n = 17] Ventral Sucker (VS) l 276��332 (304) 260��462 (350) [n = 19] w 276��389 (333) 284��567 (375) [n = 19] Cirrus-sac (CS) l 336��412 (374) 264��632 (443) [n = 19] w 136 (136) 100��256 (161) [n = 19] CS overlap VS 52��122 (87) 112��360 (211) [n = 17] Ejaculatory ductw 26 [n = 1] 6��24 (14) [n = 17] in distal CS Genital pore to lateral margin 124��184 (154) 68��288 (175) [n = 17] Pre-ovarian region l 1,360��1,460 (1,410) 1,045��2,000 (1,478) [n = 19] Ovary (OV) l 180��192 (186) 60��204 (124) w 232��332 (282) 164��344 (256) continued next page Parasite T. beringi T. beringi VS to OV 236��243 (240) 128��559 (297) [n = 19] Vitelline follicles l 56��100 (70) [n = 10] 42��98 (66) [n = 92] w 28��50 (39) [n = 10] 16��56 (31) [n = 97] Vitelline reservoir l 94��128 (111) 60��136 (86) [n = 18] w 58��100 (79) 80��180 (119) [n = 18] Uterus l 745��778 (762) 575��1,134 (853) w 180��332 (256) 296��548 (420) 1 These specimens were collected by Dr. James M. McCauley (deceased), Oregon State University, and housed at the Harold W. Manter Laboratory (HWML) under these accession numbers. 2 l, length; w, width; mean (parentheses); number [n] of measurements indicated where different from [n] in column heading. 3 Proportion of body length. Ovary deeply 3 - to 4 -lobed and clover-leaf-shaped, flattened longitudinally in several individuals, median to submedian, intercaecal, immediately pretesticular, contiguous with anterior testis, postequatorial in posterior portion of middle third of body. O��type located anterodorsal to ovary. Seminal receptacle canalicular, anterosinistral and dorsal to ovary. Laurer's canal opening proximate to left cecum. Vitellaria follicular, circumcaecal, circular or elongate oval or globular in shape, extending posterolaterally from level anterior to intestinal bifurcation to posterior extremity; interruption in vitelline field approximate to ventral sucker variable in number (0, 1 or 2 gaps), symmetry (gaps directly opposite ventral sucker, oblique to ventral sucker, or displaced longitudinally to near level of gonads) and location (near body margin or displaced medially to near midline of worm), producing two paired, non-confluent, isolated patches of vitelline follicles extending from prebifurcal level to region spanning distance between ovary and posterior margin of ventral sucker; remainder of vitelline follicles running posterolateral to ovary and testes, not confluent but encroaching somewhat in to immediate preovarian region, space between ovary and anterior testis and in to intertesticular area, completely confluent in posttesticular region. Vitelline reservoir elongate oval to subtriangular, median to submedian, dorsally overlapping anterior margin of ovary or immediately anterosinistral to it. Vitelline ducts overlap lateral margins of uterus, ovary and anterior testis. Uterus winding, intercaecal and filling up almost entire space between ovary and ventral sucker, proximal loops running anteriorly from ovary and narrowing over ventral sucker, distal loop turning anterosinistrally to terminate at genital pore. Metraterm straight, distal end noticeably curved toward genital pore in a few individuals, thin-walled, weakly developed, longitudinal fibers evident along wall. Eggs smooth, oval, slightly collapsed or crenulated in some specimens, yellow, non-filamented, operculate, with conspicuous knob or boss on one pole. Excretory vesicle tubular, I-shaped, thin in width, reaching to ovary along midline of worm. Excretory pore dorsal, subterminal, opening via a small sphincter; dark-stained cells surrounding pore. Remarks: Based on the same combination of diagnostic characteristics given above, these specimens key out to the genus Tellervotrema within Plagioporinae (Gibson & Bray 1982; Cribb 2005). We also have identified those individuals of Tellervotrema collected from A. pectoralis and Coryphaenoides sp. as T. beringi. As far as we are aware, there exists only one published description of T. beringi - the brief type description, given in Russian and originally named Plagioporus beringi by Mamaev (1965), who found intensities of 2��34 of these worms parasitizing seven individuals of Coryphaenoides sp. from the Bering Sea. Gibson & Bray (1982, p. 550��551) gave a brief list and table of features used to distinguish T. armstrongi from T. beringi, including in the latter species a larger egg size (100��110 �� 50��60 ��m vs 50.6��64 �� 24��35 ��m), a smaller sucker width ratio (1: 1.4 vs 1: 1.6��2.1), a more posteriorly situated genital pore (opening at the level of intestinal bifurcation vs opening at the level of about 30 % of the distance between the intestinal bifurcation and the pharynx), a more posteriorly-extended cirrus-sac and lateral gaps in the vitelline fields (cirrus sac reaches the rear edge of the ventral sucker and the vitelline gap is near this same level vs a cirrus-sac that is entirely anterior to or only reaches to the middle of the ventral sucker and the vitelline gap is at midacetabular level) and T. beringi possesses entire (smooth) rather than irregularly lobed testes. In almost all of these features as well as in overall appearance, our specimens described herein more closely match T. beringi than T. armstrongi. Also, the type host (Coryphaenoides sp.) and locality (Bering Sea) for T. beringi is more similar to the hosts (Coryphaenoides sp. and A. pectoralis) and locality (Pacific Ocean off Oregon) of our specimens; T. armstrongi is known primarily from macrourids of the genus Nezumia from the North Atlantic Ocean. Finally, these particular specimens possess a conspicuous knob or boss on one pole of the egg (Fig. 17), described by Mamaev (1965) as a ��носик�� or ��little nose, spout or bill�� (Shporkin pers. comm.). This feature is also apparent on the eggs of our specimens of T. armstrongi and was noted by Armstrong (1974) on the egg of �� Plagioporus sp. n. # 1 ��; however, this knob or boss was not mentioned in Gibson & Bray (1982), probably because their material contained collapsed or severely distorted eggs. There are a few minor differences between the type description of T. beringi and our specimens (see Table 3). Tellervotrema beringi was described and illustrated by Mamaev (1965, Fig. 1) as possessing in-part the following characteristics: a short prepharynx; large and smooth testes; a vitelline gap at the level of the posterior margin of the ventral sucker; and a large egg (100��110 �� 50��60 ��m). Observations of our specimens of T. beringi revealed more variability in these features. Some individuals possessed a distinct, short prepharynx (Fig. 4), yet we were not able to observe this feature in others (0��80 ��m long). While the absence of a prepharynx may be the result of contraction, we were unable to locate this feature in several specimens of T. beringi that showed no sign of contraction and the apparent lack of a prepharynx was noticeable in 1 / 3 of the measured specimens parasitising A. pectoralis. The testes in our specimens were somewhat smaller (120��340 �� 180��548 ��m vs 360��380 �� 750��780 ��m) and irregularly indented to deeply lobed; we did not observe any that were smooth. This might reflect the plasticity of this character in this genus as testes texture varied in T. armstrongi from smooth to irregularly indented to lobed. Combining our observations with Mamaev (1965), the testes texture of T. beringi varied from smooth to irregularly indented to deeply lobed (see Figs. 22��23). A third difference was the highly variable location of the vitelline gap which produced contrasting appearances in the Tellervotrema -like, paired, isolated, anterior vitelline groups. While we observed the presence of a vitelline gap at about the level of the posterior margin of the ventral sucker, the gap itself was quite variable in number (0, 1 or 2 gaps), symmetry (gaps directly opposite ventral sucker, oblique to ventral sucker, or displaced longitudinally to near level of gonads) and location (near body margin or displaced medially to near midline of worm) (see Figs. 11��16). Mamaev (1965) noted that almost all the trematodes of T. beringi that he found had the same gap within the vitelline field at the level of the ventral sucker, as seen in the �� type form�� (holotype), yet in several ��copies�� (paratypes or other specimens), he also noted that [they] did not have [this same pattern of vitelline follicles], indicative of the variability in the position of the vitelline gap. Finally, while the egg size of our specimens was smaller in length and barely overlapped that of the type measurement (80��102 ��m vs 100��110 ��m), the width of the egg was the same as in T. beringi (40��60 ��m vs 50��60 ��m) and the egg of our specimens of T. beringi was larger than that of T. armstrongi (50.6��64 �� 24��35 ��m [Gibson & Bray 1982 �� Table 1] and 47.5��66 �� 25��42 ��m in specimens described herein). We noted some variability between our specimens of T. beringi from A. pectoralis and from Coryphaenoides sp. Most conspicuous are those characteristics in which there is little or no overlap in measurements or proportions between both sets of T. beringi specimens (see Table 3); however, we believe these differences to be attributable to intraspecific variability and minimized in importance when compared to the inherent intraspecific variability already noted by previous authors for T. armstrongi (Gibson & Bray 1982). For example, there was an apparent difference in inter-testicular distance (AT to PT) between those specimens of T. beringi from Coryphaenoides sp. (44�� 92 ��m) and from A. pectoralis (testes are contiguous). However, this species and T. armstrongi are known to have testes that can be either contiguous or that can be separated by a short distance. The distance that the cirrus-sac extended beyond the anterior margin of the ventral sucker in T. beringi also varied: 52��122 ��m (1 / 5 to 1 / 3 ventral sucker length) in worms from Coryphaenoides sp. vs 112��360 ��m (1 / 3 to 3 / 4 ventral sucker length) in worms from A. pectoralis. While variable (�� = 55 % of ventral sucker length), both sets of specimens are comparable to the variability in this same feature described by Gibson & Bray (1982) for T. armstrongi (cirrus-sac entirely anterior to (0%) or extending to 50 % of ventral sucker length beyond anterior margin of ventral sucker). We discerned a difference in the length of the excretory vesicle between both sets of specimens of T. beringi (1,458 ��m vs 851��1,240 ��m). This can be attributed in-part to a very low number of observed measurements for this feature (n = 1 & n = 3, respectively) due to the gonads and, at times, the uterus occluding the view of the anterior extent of the excretory vesicle. Had more measurements been able to be obtained, this difference might have been nullified. The critical taxonomic importance of this feature in distinguishing Tellervotrema from other genera, the excretory vesicle extends to the level of the ovary (Gibson & Bray 1982; Cribb 2005), was confirmed for both sets of specimens of T. beringi. Perhaps the least explainable difference in Table 3 was the oral sucker (OS) to pharynx width ratio (2.4�� 2.5 vs 1.2 ��2.0). While there is overlap in the width of the oral sucker (244��260 vs 164��332), there is a difference in the width of the pharynx (96��108 ��m vs 124��192 ��m) between both sets of specimens. There is also a dissimilarity in the relationship of pharynx length to width between T. beringi from each host: 124��148 �� 96��108 ��m (length> width) vs 76��168 �� 124��192 ��m (width> length). The variability in these measurements may in-part explain the difference in OS:pharynx width ratio, but we remain uncertain as to the cause of this difference. We stress that the majority of all other dimensions measured, including egg size (see Table 3), between both sets of specimens of T. beringi overlapped in size and / or were practically identical to each other. Lastly, while one set of T. beringi had a low number of specimens (n = 2), these same specimens were collected from the type host genus (Coryphaenoides) and locality (North Pacific Ocean) as originally reported by Mamaev (1965). To further support our analysis, more congeneric parasite material is needed from species of Coryphaenoides inhabiting the deep waters off Oregon and elsewhere in the North Pacific Ocean (i.e. Kuramochi 2001, 2009, 2011). We were unable to provide ecological data (prevalence, intensity, mean intensity and relative density/abundance) for T. beringi in A. pectoralis. After investigating records at the HWML for Collection # 42665, we were unable to obtain data on the total number of specimens of A. pectoralis collected by JEM, the number of A. pectoralis infected with T. beringi, or the intensity of infection. As a result, we were unable to calculate mean intensity and relative density/abundance for this host species. We were unable to find in Mamaev (1965) any indication of what type specimens were deposited for T. beringi (as Plagioporus beringi). Two of us (CKB & NOD) obtained a published list (Mamaev 1975) of specimens housed at the Laboratory Published as part of Blend, Charles K., Dronen, Norman O., Gardner, Scott L., Racz, Gabor R. & Armstrong, Howard W., 2012, The deep-sea fish digenean genus Tellervotrema Gibson & Bray, 1982 (Opecoelidae: Plagioporinae): Re-evaluation of the type species, T. armstrongi Gibson & Bray, 1982 and T. beringi (Mamaev, 1965), pp. 1-29 in Zootaxa 3295 on pages 15-23, DOI: 10.5281/zenodo.208704 {"references":["Mamaev, Yu. L. (1965) Helminths of fish from the Bering Sea. In: Leonov, V. A., Mamaev, Yu. L. & Oshmarin, P. G. (Eds.), [Papers presented to Professorsko A. A. Sobolev on the 40 th anniversary of his scientific and teaching ability]. Akademiya Nauk, SSSR, Vladivostok, pp. 168 - 188. (In Russian)","Yamaguti, S. (1971) Synopsis of digenetic trematodes of vertebrates. Vol. 1, Keigaku Publishing Company, Tokyo, 1,074 pp.","Gibson, D. I. & Bray, R. A. (1982) A study and reorganization of Plagioporus Stafford, 1904 (Digenea: Opecoelidae) and related genera, with special reference to forms from European Atlantic waters. Journal of Natural History, 16, 529 - 559.","Blend, C. K. (1996) The digenetic trematodes parasitizing macrourid fishes from the Gulf of Mexico and Caribbean Sea: an examination of their systematics, zoogeography and host-parasite ecology, Texas A & M University, College Station, Texas, M. S. thesis, 305 pp.","Cribb, T. H. (2005) Family Opecoelidae Ozaki, 1925. In: Jones, A., Bray, R. A. & Gibson, D. I. (Eds.), Keys to the Trematoda. Volume 2. CABI Publishing and the Natural History Museum, Wallingford, pp. 443 - 531.","Armstrong, H. W. (1974) A study of the helminth parasites of the family Macrouridae from the Gulf of Mexico and Caribbean Sea: their systematics, ecology and zoogeographical implications, Texas A & M University, College Station, Texas, PhD dissertation, 329 pp.","Kuramochi, T. (2001) Digenean trematodes of anguilliform and gadiform fishes from deep-sea areas of Tosa Bay, Japan. In: Fujita, T., Saito, H. & Takeda, M. (Eds.), Deep-sea fauna and pollutants in Tosa Bay. National Science Museum Monographs, No. 20, Tokyo, pp. 19 - 30.","Kuramochi, T. (2009) Digenean trematodes of fishes from deep-sea areas off the Pacific coast of northern Honshu, Japan. In: Fujita, T. (Ed.), Deep-sea fauna and pollutants off Pacific coast of northern Japan. National Museum of Nature and Science Monographs, No. 39, Tokyo, pp. 25 - 37.","Kuramochi, T. (2011) Digenean trematodes of fishes caught in Sagami Bay, off Izu Islands and off Ogasawara Islands. Memoirs of the National Science Museum, Tokyo, 47, 51 - 63.","Mamaev, Yu. L. (1975) New taxa of helminths described and substantiated by researchers of the Laboratory of General Helminthology, Vladivostok. Trudy Biologo Pochvennogo Instituta, 26, 217 - 238."]}
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