Morphology of Bertiella studeri (Blanchard, 1891) sensu Stunkard (1940) (Cestoda: Anoplocephalidae) of human origin and a proposal of criteria for the specific diagnosis of bertiellosis.

Human material of an African specimen of Bertiella studeri (Blanchard, 1891), a typical intestinal cestode of monkeys, is described. Mature, postmature and gravid proglottides, and eggs, previously inadequately figured, are illustrated and photographed. The description of the species agrees with that provided by Stunkard (1940). A comparative study with other descriptions of the species is made in an attempt to clarify previous findings. The morphological differences reported in various earlier descriptions of the species suggest that B. studeri should be regarded as a "B. studeri species complex" Improvements are required in the descriptions of new future findings in order to clarify the specific diagnosis of human bertiellosis. Evidence suggests that a generalised diagnosis exclusively based on egg size and geographical distribution is insufficient to differentiate B. studeiri and Bertiella mucronata (Meyner, 1895), or additional species may be affecting humans.