Abstract | Introduction | Presentation | Diversity | Main marine currents | The different oceanic zones : Summary of the species - Marine currents and other maps | Cosmopolitanism and endemism | Species indicative of continental drift | Species whose localization is difficult to explain | Anthropic mechanisms | Conclusion

Introduction :

An inventory of 2693 marine species and brackish-water species of planktonic copepods (named and 132 spp.) and their respective locations, has been established from the work of Giesbrecht (1892) up to 2019. 9901 publications were analyzed (cf.  List of the studied authors ), taking into account all the synonymies recognized as such by the various authors from the end of the nineteenth century to the present day. Zoogeography of the species is based on the number N of citations in the examined publications for each species. The entire work is based on a sum of N which is equal to 65822.

The species belong to eight of the nine orders in the Copepoda class. Of this total, one hundred and fifteen forms belong to strictly brackish- or fresh-water families (Pseudodiaptomidae, Sulcanidae) or genera (Eurytemora, Senecella, Limnoithona), or, as in the case of "Saphirella" (Clausidiidae), are juveniles of a hyperbenthic genus (Hemicyclops) from the coastal zone. A benthic genus, Tisbe (Harpacticoïde), was incidentally found in some planktonic samples, but it was not included in the inventory.

Most of the species and forms recorded are marine and planktonic. Some, however, are from brackish waters, but they belong to marine genera such as Acartia, or to a family such as Pontellidae, or live near the bottom (hyperbenthic forms: Parkiidae, Pseudocyclopidae, Pseudocyclopiidae, Ridgewayidae, Stephidae), or in submarine excavations (Epacteriscidae, Fosshageniidae, Speleoithonidae). Exceptionally, some are meiobenthic (Sarsicopia polaris) or live in the cavity of a holothurian (Rhapidophorus wilsoni).

The validity of some species cited is debatable, as the descriptions and illustrations of many forms are insufficiently detailed. The synonymies reflect this lack of precision in a certain number of forms. Certain species are still subject to controversy, which explains why their geographical distribution is not very reliable, and it is clear that for some of them the geographical locations must be verified.

In some cases a species is known from only one sex, so it is probable that for certain genera the number of species is over-estimated.

We have excluded from the numbering system, hence from the recorded forms all those species that may be considered uncertain or indeterminable, despite the fact that they are cited in the list of species in families. Forms cited as sp. in faunal lists without any illustrations or other data have not been included; only, for which minimal data is given, are listed.

The list of forms in the text defines and rectifies the earlier texts. A more precise estimate of the number of species and of the mechanisms responsible for their distribution can only be obtained by a thorough revision of each genus, combined with the geographical distribution of their forms. There are about one hundred uncertain forms and sixty one have not been reported since 1911.