02210nas a2200229 4500008004100000245013500041210006900176300001200245490000700257520151400264653002501778653001401803653001501817653001201832653001101844653001301855653001701868100001901885700001701904700001901921856004001940 2005 eng d00aOphryoglena hemophaga n. sp. (Ciliophora: Ophryoglenidae): A Parasite of the Digestive Gland of Zebra Mussels Dreissena polymorpha0 aOphryoglena hemophaga n sp Ciliophora Ophryoglenidae A Parasite  a237-2430 v653 a

Ophryoglena hemophaga n. sp. is described from a freshwater Dreissena polymorpha population in the Rhine delta of the Netherlands. This is the first ophryoglenine species (order Hymenostomatida, suborder Ophryoglenina) recorded as a molluscan parasite. As is typical of ciliates in the suborder Ophryoglenina, O. hemophaga exhibits a polymorphic life history with cystment and reproduction by palintomy. Trophonts were observed within digestive gland lumina, and zebra mussel hemocytes were present in some of their digestive vacuoles. The presence of a single, longitudinal tract of multiple contractile vacuoles represents its most unique feature and distinguishes it from all other described Ophryoglena spp. The number of somatic kineties of O. hemophaga (range 50 to 62) is also a distinguishing feature, since it is the lowest described from any Ophryoglena sp. Other characteristics of this species include: ovoid to elongate trophonts 96 to 288 µm in length, with an elongate macronucleus 41 to 65 µm in length; tomonts 50 to 150 µm in diameter producing a clear mucous cyst envelope, whose thickness is approximately half of the tomont diameter; elongated theronts 96 to 131 µm in length which emerge after 1 to 3 cell divisions taking 36 to 48 h at 20 ± 3°C. Protomonts and theronts are, respectively, negatively and positively phototactic—characteristics that likely aid in maintenance of infection in zebra mussel populations.

10aContractile vacuoles10aPalintomy10aPhototaxis10aTheront10aTomont10aTrophont10aZebra mussel1 aMolloy, D., P.1 aLynn, D., H.1 aGiamberini, L. uhttp://dx.doi.org/10.3354/dao065237