Parvicapsula spinachiae n.sp. (Myxozoa, Parvicapsulidae) in Spinachia spinachia (L.) (Teleostei, Gasterosteidae) from Denmark.

Parvicapsula spinachiae sp. nov. is described from Spinachia spinachia (L.) (Teleostei, Gasterosteidae) from the northern Øresund, Denmark. The subspherical disporous plasmodia occur in the renal tubules and urinary bladder; the myxospores were found only in the urinary bladder. The myxospores are ovoid when viewed frontally and curved when viewed laterally. Mean maximum length is 10 microm and mean maximum width 5 microm. They have two spherical polar capsules in the apex and irregular thickenings at the posterior end. The newly described species is compared with the ten known species of Parvicapsula. It is most similar to Parvicapsula unicornis Kabata, 1962 but differs from this species by lacking the prominent suture and the posterior horn-like projection.