Latitudinal distribution and genetic divergence between shallow and mesophotic cold-water gorgonians in Chile

Abstract

Abstract Most biodiversity studies of octocorals have focused on tropical shallow waters, particularly from Mexico to Peru, and more recently in Chile. The first description of a Chilean octocorals dates back to the H.M.S Challenger expedition in 1873–1876. Since then, only few descriptions of new soft coral species from this region have been published. In addition, the taxonomic status of most gorgonians reported from the temperate Pacific coast of South America is dubious due to the loss of the original type material for most taxa. Here, we use morphological characters and nuclear and mitochondrial markers to reevaluate the taxonomy of the Chilean gorgonians Phycogorgia fucata and Leptogorgia chilensis, and describe a new species named Leptogorgia pichicuyensis sp.n. We present the first description of their latitudinal distribution patterns. Our results support the monophyly of the Chilean gorgoniids investigated, and the provisional placement of P. fucata with other species of the genus Leptogorgia in the absence of further specimens of Phycogorgia in GenBank. Our distribution analyses reveal a clear biogeographic break congruent with the Central Chile and Araucanian marine ecoregions. Overall, our study provides the first integrative taxonomic study of Southern Eastern Pacific cold-water gorgonians suggesting a higher number of species than expected for this underexplored region.