Caenonychus, a senior synonym of Speleorchestes (Acariformes: Nanorchestidae)

Supplementary images of the holotype and single known specimen of Caenonychus fallax Oudemans. 

Abstract of associated paper: The single known specimen of the monotypic genus Caenonychus Oudemans, 1902 was examined. No distinguishing characters could be found to justify the retention of Speleorchestes Trägårdh, 1909 as a separate genus from Caenonychus. Grandjean (1939) suspected these genera were synonymous but retained Speleorchestes as valid because of a difference between the two genera in opisthosomal shape. An artifactual explanation for the difference in opisthosomal shape is herein accepted based on the effects of applying different pressures to the coverslip over the same specimen. Therefore, Speleorchestes is treated as a junior synonym of Caenonychus.