On the origin of misophrioid copepods from anchialine caves

Phylogenetic relationships between the known genera of the order Misophrioi da permit the identification of two lineages: one consisting of the family Misophriidae Brady; 1878 which comprises seven genera, and a new, monotypic family, the Palpophriidae Boxshall & Jaume, 1999; the other consisting of another new family, the Speleophriidae Boxshall & Jaume, 1999, comprising e ight genera. Habitat exploitation by these families is discussed: members o f the Misophriidae are primarily hyperbenthic, those of the Palpophriidae a nd Speleophriidae are primarily cavernicolous in anchialine habitats. The o ccurrence of misophriids in littoral and submarine caves is interpreted as evidence of a relatively recent landward extension of the habitat range in this family, from a shallow-water hyperbenthic ancestor. The distribution o f speleophriids in anchialine caves is interpreted as resulting from a colo nization episode prior to the closure of the Tethys Sea. The analysis also indicates that deep-water forms may represent a secondary colonization rath er than an indication of deep-water ancestry for the entire order.