Colonisation and speciation on seamounts, evidence from Draconematidae (Nematoda) of the Great Meteor Seamount

Abstract

The coarse calcareous sediments covering the plateau of the Great Meteor Seamount harbour 15 species of Draconematidae. Representatives of three genera are reported for the first time from the Atlantic region. The majority of Draconematidae from the plateau belong to four interstitial Dracograllus species. Three new species of the genus Prochaetosoma seem to form an endemic group on the plateau. Together with different morphotypes of a Dracograllus species, these species indicate an isolation of the Great Meteor Seamount. Possible areas are identified from which Draconematidae may have colonised the Great Meteor Seamount, among others shallow water habitats of the North Atlantic and Mediterranean Sea, or surrounding deep—sea habitats, especially reefs of cold—water corals of the North Atlantic. This study shows that Draconematidae have a much wider distribution than assumed before occurring also in many oceanic habitats, inclusively seamounts, than in subtidal or sublittoral ones where they have mainly been collected so far.