For the kingdom Animalia, 1,552,319 species have been described in 40 phyla in a new evolutionary classification. Among these, the phylum Arthropoda alone represents 1,242,040 species, or about 80% of the total. The most successful group, the Insecta (1,020,007 species), accounts for about 66% of all animals. The most successful insect order, Coleoptera (387,100 species), represents about 38% of all species in 39 insect orders. Another major group in Arthropoda is the class Arachnida (112,201 species), which is dominated by the mites and ticks (Acari 54,617 species) and spiders (43,579 species). Other highly diverse arthropod groups include Crustacea (66,914 species), Trilobitomorpha (19,606 species) and Myriapoda (11,885 species). The phylum Mollusca (117,358 species) is more diverse than other successful invertebrate phyla Platyhelminthes (29,285 species), Nematoda (24,783 species), Echinodermata (20,509 species), Annelida (17,210 species) and Bryozoa (10,941 species). The phylum Craniata, including the vertebrates, represents 64,832 species (for Recent taxa, except for amphibians): among these 7,694 described species of amphibians, 31,958 species of “fish” and 5,750 species of mammals.

/pdf/an-outline-of-higher-level-classification-and-survey-of-3gsfus3b30.pdf

An outline of higher-level classification and survey of taxonomic richness

The zoogeographic distributions of the 2,814 species of copepods reported from freshwater are analysed. Faunal diversity is compared between zoogeographic regions: the Palaearctic region has more than double the species richness of the next most diverse region, the Neotropical. Historical factors affecting levels of diversity are identified. More than 90% of all freshwater copepods are endemic to a single-zoogeographic region and endemic genera occur in all regions except Antarctica. Species that are not endemic to a single region include the highly vagile and cosmopolitan species occurring in four or more regions. The greatest faunal connectivity, as identified by Sorensen’s Index, is between Palaearctic and Nearctic regions, and identifies the Holarctic taxa. Key human-related issues, such as the role of copepods as vectors for human parasites and the losses caused by parasitic copepods in commercial aquaculture, are mentioned.

/pdf/global-diversity-of-copepods-crustacea-copepoda-in-j9brp3fjr8.pdf

Global diversity of copepods (Crustacea: Copepoda) in freshwater

Knowledge of the diets of tropical fish larvae is limited to only a few taxa. Here, we describe the diets of 591 individuals from 50 families of tropical larval shorefishes collected off the Northwest Shelf of Australia (21° 49' S, 114° 14' E), effectively doubling the number of families for which there is dietary data available. The diversity of prey items eaten differed significantly among families. The majority of fish larvae ate copepods but there were some interesting exceptions. Chaetodontids ate only chaetognaths, acanthurids and nemipterids ate appendicularians, and tetra- odontids ate predominately non-copepod prey (44% decapod larvae, 20% bivalves and 15% pro- tists). Within the fish families that specialised on copepod prey there were marked differences in the types of copepod prey, with a clear preference shown for calanoid copepods, particularly small calanoids such as Bestiolina similis and Temora spp. Copepod communities in the area are food- limited and we suggest that the ability of some larval fishes to feed on components of the microbial food web may be an important determinant of their success.

/pdf/glimpse-into-guts-overview-of-the-feeding-of-larvae-of-2niheihj7u.pdf

Glimpse into guts: overview of the feeding of larvae of tropical shorefishes

Summary

1. With few exceptions, copepods dominate over other crustacean and non-crustacean invertebrate groups in ground water. They have colonised a vast array of habitats in continental ground waters, where they are represented by over 1000 species in six orders: Platycopioida, Misophrioida, Calanoida, Cyclopoida, Harpacticoida, Gelyelloida. However, members of only the last four orders entered genuine fresh ground water.



2. Stygobiotic copepods show a wide range of morphological and physiological adaptations to different groundwater habitats. They frequently exhibit simplifications in body plans, including reductions in appendage morphology, which is regarded as a result of paedomorphic heterochronic events.



3. Copepod distributions at small spatial scales are most strongly affected by habitat type and heterogeneity, with sediment grain size and availability of organic matter being important habitat characteristics. Large-scale spatial distributions (biogeographical) are mainly related to past geological, climatic and geographical processes which occurred over medium to long time scales.



4. Such processes have affected colonisation patterns and diversification of copepods in ground water, leading to a number of phylogenetic and distributional relicts and a high degree of endemism at different taxonomic levels. This is reflected in the composition of groundwater copepod communities characterised by distantly related species in the phylogenetic tree.



5. Copepods dominate the species richness of groundwater fauna in all regions and on all continents where more than cursory surveys have been carried out, i.e. in Europe, North and Latin America as well as in Australia.



6. Species-specific microhabitat preferences, high proportions of local endemics, high proportions of phylogenetic and distributional relicts, and higher-level taxonomic diversity are all factors suggesting that copepods are a useful indicator group of overall species richness for defining conservation priorities in ground water.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2427.2009.02185.x

Diversity, ecology and evolution of groundwater copepods

http://olsonlab.com/resources/Publications/Huys.2007.Monstrilloida.pdf

Extraordinary host switching in siphonostomatoid copepods and the demise of the Monstrilloida: integrating molecular data, ontogeny and antennulary morphology.

Sheila H. Halsey

Papers

An introduction to copepod diversity.