Morphological description and molecular identification ofMyxobolus dajiangensisn. sp. (Myxozoa: Myxobolidae) from the gill ofCyprinus carpioin southwest China

Plasmodia of interlamellar-vascular type were found in the vascular network of gill lamellae. Mature myxospores of M. dajiangensis n. sp. were elongated and pyriform from the frontal view. The myxospores were 14.8 ± 0.4 (13.9-15.6) µm in length, 8.0 ± 0.5 (7.2-9.1) µm in width, and 5.5 µm in thickness. The two polar capsules were pyriform and slightly different in length. The length of the larger polar capsules was 8.0 ± 0.4 (7.1-8.8) µm, and it was 7.4 ± 0.4 (6.1-8.0) µm for the smaller ones. The width of both polar capsules was 2.5 ± 0.2 (2.0-3.2) µm. The polar filaments within the polar capsules were each coiled nine to 11 turns. Comparative analysis of both the morphological and molecular data between the present speices and other similar species revealed that the present species is a novel species, Myxobolus dajiangensis n. sp. Also, M. koi (FJ710800) was misidentified and the congener with M. dajiangensis n. sp., depending on the secondary structures of SSU rRNA and phylogenetic analysis. Moreover, the cryptic species existed in the M. koi parasites.