(Eucestoda: Tetraphyllidea: Triloculariidae) in Urotrygon Chilensis (Chondrichthyes: Myliobatiformes: Urolophidae) from the Gulf of Nicoya, Costa Rica

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Faculty Publications from the Harold W. Manter Laboratory of Parasitology Parasitology, Harold W. Manter Laboratory of

10-1994

Escherbothrium molinae n. gen. et n. sp. (Eucestoda: Tetraphyllidea: Triloculariidae) in Urotrygon chilensis (Chondrichthyes: Myliobatiformes: Urolophidae) from the Gulf of Nicoya, Costa Rica

Reva Berman University of Toronto

Daniel R. Brooks University of Toronto, [email protected]

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Berman, Reva and Brooks, Daniel R., "Escherbothrium molinae n. gen. et n. sp. (Eucestoda: Tetraphyllidea: Triloculariidae) in Urotrygon chilensis (Chondrichthyes: Myliobatiformes: Urolophidae) from the Gulf of Nicoya, Costa Rica" (1994). Faculty Publications from the Harold W. Manter Laboratory of Parasitology. 219. https://digitalcommons.unl.edu/parasitologyfacpubs/219

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. J. Parasitol., 80(5), 1994, p. 775-780 ? American Society of Parasitologists 1994 ESCHERBOTHRIUMMOLINAE N. GEN. ET N. SP. (EUCESTODA:TETRAPHYLLIDEA: TRILOCULARIIDAE) IN UROTRYGONCHILENSIS (CHONDRICHTHYES: MYLIOBATIFORMES: UROLOPHIDAE)FROM THE GULFOF NICOYA,COSTA RICA

Reva Berman and Daniel R. Brooks Department of Zoology, Universityof Toronto, Toronto, Ontario, Canada M5S 1A1

ABSTRACTr:Cestodes collected in spiralvalves of the stingrayUrotrygon chilensis from the Pacificcoast of Costa Rica representan undescribedspecies of Tetraphyllidea.By possessing more than 2 loculi as well as an apical suckeron eachbothridium, the new speciesis diagnosablydistinct from all othertetraphyllidean genera; therefore, a new genus is proposed for it. The new species also possesses globularstructures irregularly arranged on the surfaceof the bothridia. We found similar structureson the bothridialfaces of Triloculariaacanthiaevulgaris, possibly indicatingphylogenetic relationships with the new species. This possibility is enhanced by the obser- vation that the bothridiaof T. acanthiaevulgariscomprise 2 loculi and an apical sucker,rather than 3 loculi.

Little is known about the parasite fauna of Escherbothrium molinae n. sp. elasmobranchs inhabiting the Pacific Ocean coast (Figs. 1-6, 8) of Central America. During the initial stages of Description(based on 35 specimens): Strobilacras- = = an inventory of the parasite biodiversity of Costa pedote, apolytic, up to 8.2 mm long (n 3 i1,x 5.2, SD = 1.3), composed of 19-39 (n = 28, x Rican elasmobranchs, stingrays were collected proglottides = 28, SD = 5.2). Scolex bilaterallysymmetrical, with from several locations in the Gulf of Nicoya and 4 pedicelated, cup-shapedbothridia. Scolex 493-1,019 the Guanacaste coast. Among the parasites col- wide (n = 31, c = 748, SD = 112). Pedicels contractile, lected were specimens of an undescribed and un- 34-159 long (n = 103, x = 83, SD = 24.2). Bothridia = = = usual tetraphyllidean eucestode, which we de- 306-600 long (n 120, x 463, SD 52.1) by 144- 344 wide (n = 119, X = 238, SD = 34.8), subdivided scribe and for which we propose a new genus. by muscularsepta into 4 largeand 2 small, somewhat triangular,loculi. Longitudinaledges of bothridiawith MATERIALSAND METHODS thin, contractile, velum-like membrane veiling bo- thridialface when relaxed.Bothridial apical suckeron Stingrayswere collectedat night using a beach seine. center of anterioredge of velum, 34-103 in diameter Cestodeswere relaxedin sea water,killed in a relaxed (n = 114, x = 66, SD = 10.9). Adherent surface of conditionwith hot water,fixed immediately with AFA, bothridiawith irregularnumber of irregularlyspaced and storedin 70%ethanol. Whole mountswere stained sphericalprotrusions. Caudal peduncle 141-506 long with Mayer'shematoxylin. Serial cross sectionsof pro- (n = 30, XJ= 313, SD = 76.5). Immature proglottides glottidsand scolices were cut 7j,m thick, stained with squareto longerthan wide. Matureproglottides longer Mayer'shematoxylin, and counterstainedwith eosin. than wide. Terminalattached proglottides tapered pos- Whole mounts and cross sections were mounted in teriorly, 375-1,469 long (n = 33, c = 881, SD = 19.5) CanadaBalsam. All measurementsare in micrometers = = = = by 109-244 wide (n 33, c 172, SD 34.6). Internal unless otherwise noted (n = sample size; x mean; in bundles = longitudinalmuscles relativelydiscrete lying SD standarddeviation). USNM Helm. Coll. refers near interior surface of tegument. Testes in 2 longi- to U.S. National Museum Collec- Helminthological tudinal preporalfields in anterior2/3 of proglottis, 19- tion, Beltsville, Maryland. 30 in total (n = 24, x = 23, SD = 2.8); 9-15 aporal (n = 24, c = 11.4, SD = 1.5), 9-15 poral (n = 24, x = Escherbothriumn. gen. 11.5, SD = 1.6); 29-73 in diameter (n = 120, x = 46, Diagnosis: Eucestoda:Tetraphyllidea: Triloculari- SD = 10.2). Cirrussac in posterior1/3 of proglottis, 38- idae. Scolex with 4 pedicellated bothridia. Each bo- 106 long (n = 29, xc = 70, SD = 12.4) by 23-62 wide thridiumwith apical suckerand muscularsepta divid- (n = 24, xc= 46, SD = 9.2), containing spined, eversible ing adherentsurface of bothridiainto loculi. Adherent cirrus.Vas deferens extensively coiled on aporal side surfaceof bothridia with irregularnumber of irregu- of cirrus sac posterior to testes. Genital pores alter- larly spacedspherical protrusions. Ovary X-shaped in nating irregularly,57-75% of total proglottis length cross section. from anterior end of terminal proglottid (n = 25, x = Typeand only species: Escherbothriummolinae. 62%, SD = 4.2). Genital atrium shallow. Vagina an- teriorto cirrussac and posttesticular,passing medially, curvingposteriorly around aporal side of cirrussac and around dorsal side of vas deferens.Vaginal sphincter Received 16 February1994; revised 25 April 1994; present. Ovary bilobed, V-shaped in frontal view, accepted25 April 1994. X-shaped in cross section, 178-438 long (n = 25, x = 775 776 THEJOURNAL OF PARASITOLOGY,VOL. 80, NO. 5, OCTOBER1994

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FIGURES1-4. Escherbothrium molinae n. gen. et n. sp. 1. Scolex. 2. Mature attached proglottis. 3. Terminal genitalia. 4. Cross section of mature proglottis at ovarian isthmus, showing X-shaped ovary (OV), oocapt (OC), osmoregulatory ducts (OD), longitudinal muscle (LM), and uterus (UT). BERMANAND BROOKS-NEW CESTODEFROM COSTA RICANSTINGRAY 777

-. m...,. _ - FIGURES 5-8. Photomicrographs of E. molinae n. gen. et n. sp. and Trilocularia sp. 5-6. Scanning electron photomicrographs of E. molinae n. gen. et n. sp. 5. En face view of scolex. Scale bar =125 gm. 6. En face close- up of bothridium showing 6 loculi and numerous rounded protrusions on bothridial surface. Scale bar =75 ,m. 7. Light photomicrograph of bothridium of Trilocularia sp. (USNM Helm. Coll. no. 7678), showing single anterior apical sucker (A) and two loculi (L). Scale bar = 100 Aum.8. Scanning electron micrograph of bothridial surface of E. molinae, showing apical sucker (A) and rounded protrusions (P). Similar structures appear on the bothridial surface of Trilocularia sp. Scale bar = 25 ,um.

291, SD = 58.9) by 64-130 wide (n = 25, x = 92, SD Taxonomic summary = 17.9), extending anteriorly to level of posterior extent Type host: Urotrygon chilensis (Gunther, 1871) of cirrus sac. Vitelline follicles medullary, lateral, with (Chondrichthyes: Myliobatiformes: Urolophidae). follicles dorsal and ventral to osmoregulatory ducts, Type locality: Costa de Pajaros, Gulf of Nicoya, extending from anterior extent of testicular fields to Costa Rica. Other locality: Punta Morales, Gulf of Ni- near posterior end of ovary, interrupted near level of coya, Costa Rica. ovarian isthmus; follicles not interrupted near genital Site of infection: Middle 1/3 of spiral valve. = pore. Vitelline follicles 6-50 in diameter (n 150, x Specimens deposited: Holotype: USNM Helm. Coll. = 24, SD = 6.9). Gravid detached proglottides not 84064. Paratype: USNM Helm. Coll. no. 84065. collected. Etymology: The species is named for Helena Mo- 778 THEJOURNAL OF PARASITOLOGY,VOL. 80, NO. 5, OCTOBER1994 lina-Urefia,Centro de InvestigacionesMarinas y Lim- suckers (listed above), is a monophyletic group nologicos (CIMAR)and Escuelade Biologia, Univer- only if the bothridial loculi exhibited by all its sidad de Costa Rica. The genus is named for M. C. taxa areevolutionarily homologous. Some mem- Escher,in light of the unusualarrangement of bothridial loculi, which remindedus of some of Escher'ssur- bers of the Onchobothriidae,e.g., Acanthoboth- realist drawings. rium van Beneden 1949, Acanthobothroides Brooks 1977, Calliobothriumvan Beneden 1850, and OnchobothriumBlainville 1828, also have DISCUSSION bothridialloculi. The assumptionthat the group The Tetraphyllidea,like most eucestodegroups, exhibitingbothridial loculi is monophyleticmust has a long history of classification but suffers thereforebe consideredtentative as well, pending from little rigorous phylogenetic examination, the documentation of additional charactersin- especially at levels of higher taxa. Traditional dicating phylogenetic relatedness among taxa classifications,e.g., Wardleand MacLeod(1952), within this group.To complicatematters further, Euzet (1959), and Yamaguti(1959), recognize2 the paraphyleticnature of the Phyllobothriidae majorfamilies, the Phyllobothriidaeand the On- makes the use of members of the Onchobothri- chobothriidae.These families are diagnosed on idae as outgroupsin any phylogeneticanalysis of the basis of the presence (Onchobothriidae)or phyllobothriidtaxa inappropriate(see Brooksand absence (Phyllobothriidae)of hooks associated McLennan, 1991; Wiley et al., 1991). The in- with the bothridia. This scheme has been con- herent weaknessin the 2-family classificationof venient from a nomenclaturalstandpoint but is the Tetraphyllideamay have led Schmidt(1986) weak phylogeneticallybecause absence of hooks to recognize 2 smaller families of phylloboth- is a pleisomorphictrait (Brookset al., 1991) and riids, the Dioecotaeniidae Schmidt, 1969, com- is thus not a robustcharacter upon which to base prising 1 genus with 2 species which Schmidt a grouping(Wiley et al., 1991). By lacking a di- removed to its own order, and the Triloculari- agnosing synapomorphy, the Phyllobothriidae idae, comprising3 genera with 4 species. (and associated smaller families) as a whole is a Escherbothrium molinae, because it lacks paraphyleticcollection of taxa of undetermined bothridialhooks and has bothridialloculi, might phylogenetic relationships. Phyllobothriidscan appear to be a member of the second group of be divided into animals that have apical suckers phyllobothriidsdiscussed above. The presence but lack bothridial loculi, e.g., Anthobothrium of both bothridialloculi and apicalsuckers, how- van Beneden 1850, CalyptrobothriumMonticelli ever, makes Escherbothriumdiagnosably dis- 1893, Clistobothrium Dailey and Vogelbein, tinct from all other tetraphyllideangenera and 1990, ClydonobothriumEuzet 1956, Crossoboth- suggests that it might represent a phylogeneti- rium Linton 1889, Monorygma Diesing 1863, cally transitionalform between some members OrygmatobothriumDiesing 1863, Rhodoboth- of the nonseptate phyllobothriids (which have rium Linton 1889, and the Phyllobothriumlac- apical suckers)and the septate phyllobothriids tuca species group (see Brooks and McLennan, (whichlack apical suckers). We thereforepropose 1993; Ruhnke, 1993) and species that have bo- a new genus to accommodateE. molinae. thridial loculi but lack apical suckers,e.g., Cau- No other tetraphyllideansare currently de- lobothrium Baer, 1948, Dioecotaenia Schmidt scribedas having both apical suckersand septate 1969, PentaloculumAlexander 1953, Rhabdo- bothridia. Members of the genus Trilocularia tobothriumEuzet, 1953, RhinebothriumLinton, Olsson 1867 have been diagnosed as having 1889, RhinebothroidesMayes, Brooksand Thor- bothridialfaces divided into 3 loculi,e.g., Schmidt son 1981, TriloculariaOlsson 1867, Tritaphros (1986). Published line drawingsof Trilocularia Lonnberg 1889, Zyxibothrium Hayden and specimens,e.g., Hyman (1951), Euzet(1959), and Campbell 1981, and the Phyllobothriumcentru- a scanningelectron microscopic (SEM)study by rum species group (see Brooks and McLennan, McCulloughand Fairweather(1983), show bo- 1993). The absence of bothridialloculi is a ple- thridia with 2 large posterior loculi and an an- siomorphictrait used to diagnosethe first group terior smaller structurewhich McCulloughand of phyllobothriidswhich, like the Phyllobothri- Fairweather(1983) termeda loculus.Rees (1953) idae as a whole, is a paraphyleticcollection of describedthe scolex morphologyof Trilocularia taxa of undeterminedphylogenetic relationships. as including a bothridium divided into 2 loculi The second group, comprised of those taxa that with an apicalsucker "lying immediately in front have bothridialloculi but lack bothridial apical of the bothridium,"concurring with earlier ob- BERMANAND BROOKS-NEW CESTODEFROM COSTA RICANSTINGRAY 779 servations (Southwell, 1925). We examined Escherbothrium, Trilocularia, Zyxibothrium, and specimens of Trilocularia sp. (USNM Helm. Coll. Pentaloculum appear closely related to each oth- nos. 7678 and 7679) and concur with Rees (1953) er only relative to tetraphyllidean species known that the bothridia comprise 2 loculi and an apical at this time. sucker (Fig. 7). Therefore, we believe that E. mol- ACKNOWLEDGMENTS inae actually represents the second known tetraphyllidean group possessing apical suckers and We gratefully acknowledge Helena Molina loculi associated with the bothridia. The shared Ureiia, Escuela de Biologia, Universidad de Cos- retention of a plesiomorphic trait, the apical ta Rica, for her generous logistical help, assis- sucker, is not sufficient to suggest any particular tance in the field, and friendship. We thank Na- hypothesis of phylogenetic relationships between than Lovejoy and Effie Gournis for their help in Escherbothrium and Trilocularia. The specimens collecting hosts and parasites, Dr. Jose Vargas, of Trilocularia and E. molinae that we examined, vice-director of the Centro de Investigaciones del however, possess rounded protrusions on the in- Mar y Limnologicos (CIMAR), and the staff of ner bothridial surface (see Fig. 8 for E. molinae). the CIMAR laboratory at Punta Morales for the This is a feature that we have not observed or kind use of their facilities, and for technical sup- found reported for other tetraphyllideans and port in collecting hosts, and the members of the which might, therefore, be synapomorphic for faculty of the Escuela de Biologia and Escuela de Trilocularia and Escherbothrium. If so, the trait Microbiologia, Universidad de Costa Rica. We might constitute robust grounds for recognizing thank Henry Hong of the Zoology Department, the Triloculariidae as a group distinct from other University of Toronto for his help with the SEM phyllobothriids. In addition, 1 of the electron portions of this study. This study was funded by photomicrographs of McCullough and Fair- operating grant A7696 from the Natural Sciences weather (1983) depicts a relaxed bothridium of and Engineering Council (NSERC) of Canada to Trilocularia acanthiaevulgaris, which is highly D.R.B. reminiscent of those of Escherbothrium. Trilo- LITERATURECITED cularia species, however, differ from E. molinae in a number of characteristics, including having BROOKS,D. R., E. P. HOBERG, ANDP. J. WEEKES. 1991. of the posteriorly positioned genitalia and genital pores Preliminaryphylogenetic systematic analysis majorlineages of the Eucestoda(Platyhelminthes: and dense spines covering the anterior surface of Cercomeria).Proceedings of the BiologicalSociety proglottides (Euzet, 1959). of Washington104: 651-668. Schmidt (1986) placed Zyxibothrium Hayden , AND D. A. McLENNAN. 1991. Phylogeny, and Campbell, 1981 and Pentaloculum Alex- ecologyand behavior:A researchprogram in com- of Press, in We parative biology. University Chicago ander, 1963 the Triloculariidae. examined Chicago,Illinois, 434 p. the holotype and paratypes of Zyxibothrium , AND . 1993. Parascript: Parasites and (USNM Helm. Coll. nos. 75906,75907-8). There the languageof evolution. SmithsonianInstitution is a marked similarity in the bifurcating structure Press, Washington,D.C., 429 p. L. 1959. Recherches sur les cestodes tetra- of the medial bothridial septa of Escherbothrium EUZET, phyllidesdes selaciensdes c6tes de France.Theses and Zyxibothrium, although Zyxibothrium lacks de Ph.D. Facult6 des Sciences, Universite de apical suckers or rounded protrusions on the in- Montpellier,Montpellier, France, 263 p. ner bothridial surface. We have not been able to HYMAN,L. H. 1951. The invertebrates,Vol. II. Platy- obtain any specimens of Pentaloculum for ex- helminthesand rhynchocoela.The acoelomateBi- lateria. McGraw-HillBook Inc., New but illustrations of the sco- Company amination, published York, New York, 550 p. lex depict bifurcating bothridial septa similar to MCCULLOUGH,J. S., ANDI. FAIRWEATHER.1983. An those of Zyxibothrium and Escherbothrium. We SEMstudy of the cestodes Triloculariaacanthiae- thus place Escherbothrium in the Triloculariidae, vulgaris,Phyllobothrium squali and Gilquiniasquali of the from the spiny dogfish. Zeitschriftfur Parasiten- pending phylogenetic analysis group. kunde 69: 655-665. Finally, E. molinae is a parasite of eastern Pa- REES,G. 1953. Some parasiticworms from fishes off cific Ocean tropical stingrays, whereas Trilocu- the coast of Iceland. Parasitology43: 4-14. laria inhabits sharks and Zyxibothrium skates RUHNKE,T. 1993. A new species of Clistobothrium from the northeastern Atlantic Ocean and Pen- (Cestoda:Tetraphyllidea), with an evaluation of the status of the Journalof Par- from western Pa- systematic genus. taloculum inhabits sharks the asitology79: 37-43. cific Ocean (New Zealand). Such a wide geo- SCHMIDT,G. D. 1986. Handbookof tapewormiden- graphic and host range may indicate that tification.CRC Press, Boca Raton, Florida,675 p. 780 THE JOURNALOF PARASITOLOGY,VOL. 80, NO. 5, OCTOBER1994

SOUTHWELL,T. 1925. A monograph on the Tetra- V. A. FUNK. 1991. The compleat cladist: A prim- phyllidea with notes on related cestodes. Univer- er of phylogenetic procedures. University of Kan- sity Press of Liverpool (Limited), London, U.K., sas Museum of Natural History Press, Lawrence, 368 p. Kansas, 158 p. WARDLE, R. A., ANDJ. A. MACLEOD. 1952. The zo- YAMAGUTI,S. 1959. Systema helminthum, Vol. II. ology oftapeworms. University of Minnesota Press, The cestodes of vertebrates. Interscience Publ., New Minneapolis, Minnesota, 780 p. York, New York, 860 p. WILEY,E. O., D. SIEGEL-CAUSEY,D. R. BROOKS,AND