Zygobothrium Diesing, 1850

Alves, Philippe V., Chambrier, Alain De, Luque, José L. & Scholz, Tomáš, 2018, Towards a robust systematic baseline of Neotropical fish tapeworms (Cestoda: Proteocephalidae): amended diagnoses of two genera from the redtail catfish, Phractocephalus hemioliopterus, Zootaxa 4370 (4), pp. 363-380 : 370

Genus Zygobothrium Diesing, 1850 —amended diagnosis

Diagnosis. PROTEOcEPhalIdaE , fORmER SUbfamIlY ZYgObOThRIINaE . TESTES, OVaRY aNd UTERUS mEdUllaRY; VITEllINE fOllIclES cORTIcal. MEdIUm-SIZEd, RObUST WORmS, STRObIla cRaSPEdOTE WITh fOUR VElUm-lIKE lacINIaTIONS ON Each PROglOTTId (TWO dORSal aNd TWO VENTRal); PROglOTTIdS WIdER ThaN lONg, VaRIablE IN ShaPE aNd SIZE. ScOlEX maSSIVE, WITh qUadRaNgUlaR aPIcal PaRT, WIThOUT aPIcal ORgaN, mUch WIdER ThaN STRObIla; PROlIfERaTIVE ZONE (NEcK) abSENT. SUcKERS ElONgaTE, dEEP, WITh bRIdgE-lIKE SEPTUm SEPaRaTINg TWO OPENINgS Of SINglE lOcUlUS. INTERNal lONgITUdINal mUScUlaTURE WEll-dEVElOPEd, WITh NUmEROUS bUNdlES Of mUSclE fIbERS. TESTES mEdUllaRY, IN ONE fIEld aNd 1–3 IRREgUlaR laYERS. CIRRUS-Sac ElONgaTE TO SlIghTlY SIgmOId, TWISTEd/cONSTRIcTEd IN ITS dISTal PaRT; cIRRUS aRmEd, WITh SPINITRIchES. GENITal PORES PRE-EqUaTORIal, IRREgUlaRlY alTERNaTINg. GENITal aTRIUm dEEP. OVaRY mEdUllaRY, WITh 2 fOllIcUlaR (gRaPE-lIKE) lObES, SOmETImES PENETRaTINg INNER lONgITUdINal mUScUlaTURE TO dORSal cORTEX; lObES WITh dORSal OUTgROWThS. VagINa aNTERIOR OR POSTERIOR TO cIRRUS-Sac, SURROUNdEd bY NUmEROUS chROmOPhIlIc cEllS IN dISTal (TERmINal) PaRT (pars copulatrix vaginae); VagINal SPhINcTER PRESENT. VITEllINE fOllIclES fORm TWO laTERal baNdS, REachINg TO aNTERIOR maRgIN Of PROglOTTIdS, ScaRcElY PRESENT ON PORal SIdE, I.E., PREPORallY. UTERINE dEVElOPmENT TYPE 2 accORdINg TO dE ChambRIER et al. (2004a, 2015a). PaRaSITES Of PImElOdId caTfIShES ( SIlURIfORmES : PImElOdIdaE ) IN NEOTROPIcal REgION.

Type and only known species. Zygobothrium megacephalum DIESINg, 1850 .

Differential diagnosis. ThE fORmER SUbfamIlY ZYgObOThRIINaE WOOdlaNd, 1933 cOmPRISES 8 gENERa: Amphoteromorphus DIESINg, 1850; Brooksiella REgO, ChUbb & PaVaNEllI, 1999; Gibsoniela REgO, 1984; Harriscolex REgO, 1987; Houssayela REgO, 1987; Nomimoscolex WOOdlaNd, 1933; Travassiella REgO, 1987; aNd Zygobothrium DIESINg, 1950 (SEE dE ChambRIER et al. 2017). Zygobothrium dIffERS fROm all Of ThESE gENERa aS WEll aS all REmaININg PROTEOcEPhalIdS bY ThE cOmbINaTION Of ThE fOllOWINg chaRacTERS: ThE PRESENcE Of UNIlOcUlaTE SUcKERS WITh TWO OPENINgS Each, SEPaRaTEd WITh a bRIdgE-lIKE SEPTUm, a cRaSPEdOTE STRObIla WITh fOUR VElUm-lIKE lacINIaTIONS ON EVERY PROglOTTId, cIRRUS-Sac TWISTEd IN ITS dISTal PaRT WITh aN aRmEd cIRRUS aNd ShORT dIgITaTE PROjEcTIONS ON ThE SURfacE Of ThE EmbRYOPhORE.