On the origin of misophrioid copepods from anchialine caves

Phylogenetic relationships between the known genera of the order Misophrioida 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 eight genera. Habitat exploitation by these families is discussed: members of the Misophriidae are primarily hyperbenthic, those of the Palpophriidae and Speleophriidae are primarily cavernicolous in anchialine habitats. The occurrence 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 of speleophriids in anchialine caves is interpreted as resulting from a colonization episode prior to the closure of the Tethys Sea. The analysis also indicates that deep-water forms may represent a secondary colonization rather than an indication of deep-water ancestry for the entire order.