Two new species of the genus Cheleocloeon Wuillot & Gillies 1993 (Ephemeroptera: Baetidae) from Tanzania and corrections to the generic diagnosis

Cheleocloeon clavifolium Kluge 2016, originally described from Zambia, is reported from Tanzania. A new species, Cheleocloeon acutipalpum sp. nov. is described from Usambara, Uluguru and Livingstone Mountains in Tanzania as larvae, imagines and subimagines of both sexes and eggs associated by rearing. Another new species, Cheleocloeon psammonella sp. nov. is described from Tanzania based on a single male subimago with associated larval exuviae and imaginal gonovectes already developed under subimaginal cuticle.

This unusual species has convergent similarity with those sand-inhabiting representatives of Procloeon Bengtsson 1915 that constitute the subgenera Pseudocentroptiloides Jacob (in Jacob & Glazaczow) 1987 and Psammonella Glazaczow (in Jacob & Glazaczow) 1987: all of them have a concave distal margin of the labrum, modified maxillae, blunt glossae and paraglossae, and long and slender claws lacking denticles. In connection with this, general characteristics of the genus Cheleocloeon Wuillot & Gillies 1993 are modified.