Acanthocephala from amphibians in China with the description of a new species of Pseudoacanthocephalus (Echinorhynchida).

Amphibians of 24 species were surveyed for acanthocephalans in 4 nature reserves in 2 Chinese provinces during 2004–2006. Pseudoacanthocephalus bufonis (Echinorhynchida) occurred in both nature reserves in Guangxi Province. In the Jing Xi County Provincial Nature Reserve, P. bufonis infected 36 of 62 amphibians at a mean intensity of 9.9. Less than 250 km away, at Shiwandashan National Nature Reserve, 5 of 20 amphibians were infected at a mean intensity of 6.2. Pseudoacanthocephalus bufonis was not found in either of the reserves in Guizhou Province. In the Kuan Kuoshui Nature Reserve, 9 of 28 amphibians were parasitized at a mean intensity of 2.0 by a previously undescribed species of Pseudoacanthocephalus , and no acanthocephalan occurred in a small sample of 2 toads at Dashahe Nature Reserve. The new species, Pseudoacanthocephalus reesei n. sp., differs from all others in the genus by typically having 14 longitudinal rows of 4 hooks, each of which is much longer than corresponding hooks of any other species of the genus. The length of proboscis hooks increases from the apex to the base of the proboscis, further distinguishing the new species from all but Pseudoacanthocephalus nguyenthileae .