A review of the Xarifiidae (Copepoda, Poecilostomatoida), parasites of scleractinian corals in the Indo-Pacific

The family Xarifiidae, copepod parasites of corals, now contains four genera, Xarifia (with 75 species, including 27 new species described in this review), Orstomella (2 species), Lipochrus (1 species), and Zazaranus (1 species). For all previously known species, the host corals, the general locality, and features for recognition are given. Keys are provided for the four genera and for the species of Xarifia.

Xarifiids are known in the tropical Indo-Pacific extending from the Red Sea and Madagascar eastward to southern Japan, Enewetak Atoll, and New Caledonia, but have not been found farther eastward in Moorea, Hawaii, or Panama. In tabular form the host corals and the geographical distribution for each species of Xarifia are given.

Identification of species of Xarifia is easier when based on females rather than on males, since females often have diagnostic processes or knobs above the fifth legs. The armature of the rami of legs 1–4 provides important criteria for the determination of species. Six useful diagnostic features are given in tabular form for all species of Xarifia.

Nearly half of the species of Xarifia are known from a single species of coral. Host preference is suggested on the generic level, with 16 species occurring only in Acropora. Several species of Xarifia (as many as seven) may occur in a single coral colony. Acropora and Pocillopora are most often parasitized.

Since species such as Xarifia sabiuraensis and Xarifia obesa may show considerable variation in certain features, for example, the processes or knobs above the fifth legs in the female, the study of a large number of specimens from all hosts and a variety of localities is advisable.

Although evolutionary lines within the Xarifiidae are obscure, certain species may be assumed to be related on the basis of external morphological features and host preferences. In Xarifia, four groups, each with three or more species, and 10 pairs of species are distinguished.