Taxonomy and distribution of the Uvigerina peregrina plexus in the tropical to northeastern Atlantic.
Uvigerina peregrina Cushman 1923 and related taxa are extensively used for paleoceanographical studies. A high degree of inter- or intra-specific variability leaves the status of these species unclear and has hampered sound paleoenvironmental interpretations to date. The species concept and diagnostic features of Uvigerina peregrina and the closely related Uvigerina pigmea d’Orbigny 1826, Uvigerina peregrina parva Lutze 1986 are re-assessed in this paper. Uvigerina sp. 221 Lutze 1986 is formally described and named Uvigerina celtica n. sp. The overall size of the tests, the length/width ratio, and the morphology of costae are considered key diagnostic features while the presence or absence of spines is of minor importance for species characterization. Geographic and depth distributions of living Uvigerina taxa are described using faunal census data from the northwest African and western European continental shelf and slope from the 2 ° S to 70 ° N, and from the Caribbean. The regional distribution and inferred population dynamics reveal that Uvigerina peregrina, Uvigerina celtica n. sp. and Uvigerina pigmea are indeed different species. Uvigerina peregrina parva is most likely a subspecies of Uvigerina peregrina and not an ecophenotype.