Data from: Niche divergence by deep-sea octocorals in the genus Callogorgia across the continental slope of the Gulf of Mexico

Environmental variables that are correlated with depth have been suggested
to be among the major forces underlying speciation in the deep sea. This
study incorporated phylogenetics and ecological niche models (ENM) to
examine whether congeneric species of Callogorgia (Octocorallia:
Primnoidae) occupy different ecological niches across the continental
slope of the Gulf of Mexico (GoM), and whether this niche divergence could
be important in the evolution of these closely related species.
Callogorgia americana americana, C. americana delta, and C. gracilis were
documented at 13 sites in the GoM (250-1000 m) from specimen collections
and extensive video observations. On a first order, these species were
separated by depth, with C. gracilis occurring at the shallowest sites, C.
a. americana at mid-depths, and C. a. delta at the deepest sites.
Callogorgia a. delta was associated with areas of increased seep activity
whereas C. gracilis and C. a. americana were associated with narrow, yet
warmer, temperature ranges and did not occur near cold seeps. ENM
background and identity tests revealed little to no overlap in ecological
niches between species. Temporal calibration of the phylogeny revealed the
formation of the Isthmus of Panama was a vicariance event that may explain
some of the patterns of speciation within this genus. These results
elucidate the potential mechanisms for speciation in the deep sea,
emphasizing both bathymetric speciation and vicariance events in the
evolution of a genus across multiple regions.