Abstract:

Aims: Oncaeidae are small copepods that serve an important role in marine ecosystems, with high abundance and rich diversity. Studies on the taxonomic diversity of these species still have great deficiencies, and its ecological function status may be underestimated. To improve the understanding of Oncaeidae, this paper reviews the research progress of taxonomy, species diversity, distribution and ecology of Oncaeidae, and also discusses the difficulties and technological trends in research of global Oncaeidae diversity.

Progresses: Since Giesbrecht's description of this taxon at the end of the 19th century, new species of Oncaeidae have been discovered and described. They are widely recorded in the Atlantic, Indian, Pacific, Mediterranean, and polar oceans, and occur in the upper, middle, and deep layers of the ocean. To date, 115 species have been described. Descriptions of species diversity of Oncaeidae in China started late, with only 11 species of Oncaeidae were recorded in the China Sea, and related ecological studies are relatively weak. Oncaeidae species are small in size with many morphological similarities, making it difficult to distinguish the many sister species and intrapesional types. Therefore, many studies complement traditional taxonomic identification methods with molecular biology techniques. These molecular techniques allow for the exploration of cryptic species, so as to improve the efficiency of species discovery and description. With recent deepening of the research, the distribution, feeding habits, population characteristics and behavior characteristics of Oncaeidae have received greater attention, resulting in an increasingly diverse body of taxonomic research for this group.

Prospects: With the rapid development of marine science technology, as well as many advanced scientific research

vessels and manned submersibles now being used for oceanographic studies, biological sampling of the ocean is constantly being enriched. This will promote the rapid development of taxonomic and biodiversity research in the waters around China, and further the taxonomic research of Oncaeidae, leading to new insights about the distribution and diversity of taxa in this group.

Key words: Oncaeidae, taxonomy, species diversity, distribution