Checklist, diversity and biogeography of ciliates (Ciliophora) from Chile

Abstract

There is a significant gap in research and knowledge on the diversity and distribution of Chilean ciliates. To tackle these issues, we used cultures and protargol preparations to describe the ciliates present in poorly explored areas. At these sites, we identified 45 ciliate morphospecies, 35 of which represent unprecedent records to Chile. Then, we brought together our records with literature data to construct a species checklist. This checklist summarises 132 years of data and describes the identity, habitat and distribution of 207 species, including 15 species potentially endemic to Chile. This checklist is far from complete: a diversity estimate suggests that at least two-thirds of the ciliate species occurring in Chile have yet to be described. The checklist is dominated by freshwater taxa because ciliates from marine, brackish and terrestrial environments have rarely been investigated in Chile. Finally, after controlling for sampling artefacts, we found that ciliates exhibit a bell-shaped latitudinal diversity gradient in Chile. This peculiar biogeographical pattern is common in Chile. Plants, animals and testate amoebae also exhibit a bell-shaped latitudinal diversity gradient in Chile. This finding suggests that the historical contingencies that drove the biogeography of the Chilean biota also shaped ciliate biogeography.

Keywords: Checklist of Chilean ciliates; Ciliate biogeography; Endemic protists; Latitudinal diversity gradient; Protists; South America.