ИСТИНА

Copepods are common and abundant symbionts of marine invertebrates, including echinoderms, which contains sea stars, sea urchins, brittle stars, sea cucumbers and crinoids. Despite their small size, copepods can have a significant impact on their hosts. A large amount of data on interactions of copepods with echinoderms has been accumulated in the literature. However, due to the scattered nature of this information, it can be difficult to assess the diversity and level of knowledge of copepods associated with a particular taxonomic group. In this study, data on copepods associated with echinoderms from the World Ocean were collected and analyzed for the first time. The study identified 232 literature sources published from 1851 to 2018, which recorded 2080 findings of three orders, 35 families, 96 genera, and 290 species of copepods in symbiosis with five classes, 23 orders, 66 families, 134 genera, and 240 species of Echinodermata. Remarkably, copepods and their hosts were identified to species level in almost all findings, with only 31 instances where either the copepod or the host species could not be identified. Approximately half of the symbiotic pairs (245 out of 515) were recorded from a single finding. Symbiotic copepods were found in 11 of the 12 regions of the World Ocean, with the highest diversity found in the Central (111 species) and Western (80 species) Indo-Pacific regions. Most of the findings (480 out of 574) were made at depths up to 25 meters. While 45 findings were made at depths over 100 meters, including thirteen at depths greater than 1000 meters. The deepest finding was the cyclopoid Brychiopontius falcatus Humes, 1974, found on a holothurian collected from a depth of 4426-4435 meters. The most frequently encountered copepod families were the cyclopoids Lichomolgidae (623 findings, 49 species) and Synapticolidae (375 findings, 46 species), as well as the siphonostomatoids Asterocheridae (260 findings, 43 species). In each class of echinoderms, there was an order that was the leader in the number of findings and species of copepod symbionts: for sea stars, the order Valvatida (609, 34); for sea cucumbers, the order Holothuriida (346, 37); for feather stars, the order Comatulida (170, 31); for sea urchins, the order Camarodonta (169, 17); and for brittle stars, the order Amphilepidida (166, 17). This study was supported by the Russian Science Foundation within the framework of scientific project 22-24-00365.