Virginia Institute of Marine Science
Bulletin of Marine Science
A review of taxonomy, anatomy, ontogeny, ecology, and phylogeny of the ophidiiform family Carapidae was conducted using over 2,300 larval, juvenile and adult specimens. A cladistic classification based on swimbladder morphology, developmental and osteological characters of the vertebral column, fins, pectoral and pelvic girdles, gill arches, ethmoid, jaws, and habitat is presented. A total of 31 species (6 new names and one unnamed larval form) in seven genera are recognized in two subfamilies. A species previously assigned to Echiodon is made the type of a new monotypic genus. Species of the tribe Carapini are rearranged in the genera Carapus and Encheliophis largely on the basis of swimbladder morphology. Larvae are described for all genera except Encheliophis whose larvae are predicted to resemble those of Carapus. The vexillifer larva is unique to carapids. The tenuis juvenile stage, however, may be restricted to the ecologically specialized genera, especially Carapus and Encheliophis. The family is distributed over broad depth (0-2,000 m) and latitudinal (ca. 65-degrees-N to 60-degrees-S) ranges. In general taxa with more plesiomorphic characters are found in deeper water and higher latitudes while taxa with more apomorphic characters are found in tropical, shallow water. Highly specialized inquiline behavior is found in both tribes of the Carapinae and our phylogenetic hypothesis specifies independent acquisition of molluscan inquilinism, at least. Within the Carapini the genus with the most apomorphic characters, Encheliophis, is the most successful holothurian inquiline and the only holothurian inquiline in the Indo-Pacific. Species in its sister genus, Carapus, "switch" to non-holothurian primary hosts (asteroids or ascidians) when sympatric with Encheliophis in the Indo-Pacific. Atlantic species of Carapus retain holothurians as primary hosts. The distribution of sister species is usually allopatric and suggests that the presence or absence of inquiline behavior has no bearing on mode of speciation. Vicariance of sister species is frequently along depth or latitudinal gradients. There are no amphi-American sister species; the sister group of all eastern Pacific species or populations of carapids is either another Pacific form or an Atlantic-Pacific clade.
Markle, DF and Olney, JE, Systematics Of The Pearlfishes (Pisces, Carapidae) (1990). Bulletin of Marine Science, 47(2), 269-410.