Three actinosporean types (Myxozoa) from the oligochaete Branchiura sowerbyi in China.

Three actinosporean types--raabeia, aurantiactinomyxon, and guyenotia--from the oligochaete Branchiura sowerbyi Beddard collected from a crucian carp (Carassius auratus gibelio) pond are described in this report. Compared with the actinospores described previously, the raabeia type presents similar spore shape with the actinospore of Myxobolus cultus, except a much longer caudal process, 250.8 μm (217.5-276.3). The aurantiactinomyxon and guyenotia type significantly differ from other actinospores in its same collective group with different caudal process shape (taper and leaf-like) and dimension, 170.8 μm (167.5-176.3) and 18.5 μm (16.5-20.6), respectively. The partial 18S rDNA sequences of raabeia and aurantiactinomyxon types, and myxospores M. cultus, Myxobolus wulii, Myxobolus pyramidis, and Thelohanellus wuhanensis detected from pond-reared crucian carp were determined. Based on DNA sequences analysis, the raabeia type showed high genetic similarity (99.5-100%) with myxospore M. cultus Yokoyama, Ogawa & Wakabayashi, 1995 on the gills of crucian carp sampled from the same pond. The aurantiactinomyxon showed no more than 85.2% sequence similarity with myxospores determined in this report and other myxozoans available from GenBank.