Revision of the taxonomic status of Rhodanthidium sticticum ordonezi (Dusmet, 1915), an anthidiine bee endemic to Morocco (Apoidea: Anthidiini)

Rhodanthidium ordonezi (Dusmet, 1815) is recognized here as a valid species endemic to central and southern Morocco. It has previously been regarded as a subspecies of R. sticticum (Fabricius). The two taxa are in allopatry throughout most of their respective ranges, but probably cooccur in the Middle Atlas Mountains. They are clearly distinguished by their coloration and some aspects of their color patterns. Structural differences are minor, but a multivariate discriminant function analysis of 11 morphometric traits has showed that these are sufficient to assign 82.7% of all specimens correctly. While R. ordonezi has a restricted range in central and southern Morocco (extending over approximately 500 km), R. sticticum is widely distributed in the Mediterranean basin with a range extending over approximately 2500 km from east to west. The distribution areas of these two species are contiguous in the same ecozone of the Middle Atlas mountain range, but sympatric occurrence or a transition zone where intermediate specimens occur is not known.