New Lower Maastrichtian megathyridid Brachiopods from the Phosphatic Chalk of Ciply (Mons, Belgium)

The Phosphatic Chalk of Ciply (upper part of the lower Lower Maastrichtian) was investigated for microbrachiopods in the Van Damme quarry at Ciply. Samples of this chalk were treated with a super saturated Glauber salt solution (method of SURLYK, 1972). Among the microbrachiopods collected, two new Megathyrididae were recognized: Megalhiris bidiscoidea n. sp. and Argyrotheca popielae n. sp. The presence of a new Megathiris species in this deposit is interesting because this genus is uncommon in Upper Cretaceous chalks.