First report of the Middle Devonian stringocephalid genus Paracrothyris (Brachiopoda) from North Africa

The stringocephalid genus Paracrothyris Wu in Wang et al., 1974 is reported for the first time from Givetian beds of the Western Sahara (Northwest Africa). Although only dorsal shell fragments have been found, the specimens can be assigned to this genus with certainty due to a combination of preserved characters: lack of a median septum, and the presence of crural plates in combination with a typical stringocephaloid morphology. The genus Paracrothyris (type species P. distorta Wu in Wang et al., 1974) was originally described from South China and later from Nevada, U. S. A., and has only been reported from beds of Givetian age (late Middle Devonian). From the palaeogeographical distribution, it is concluded that the larvae migrated throughout the Palaeotethys along the shelf of Northern Gondwana between Nevada and South China, supporting the hypothesis of decreasing provincialism in late Middle Devonian time.