How to use Advanced Search

The Advanced Search page allows searching by taxonomic group, geological age and citation details and can return lists of species with or without images and citations.

Screenshot of the advanced search page and notes on its main components

Search scope & output

There are three dropdown menus here

Taxonomic criteria

Age Window

Use the sliders to select an interval of geological time and the search results will only include taxa which occur within that interval. This is very useful in combination with the Tags to check for possible identifications of an unknown nannofossil.


The sliders here allow searching by coccolith size, number of segments (only for nannoliths), coccosphere size or number of coccoliths on a coccosphere. In each case the database holds a range of possible values for the taxon so you only need to enter one size to see if it fits inside that range. In some cases these come from published compilations, but more often they were compiled using information in the original description combined with the range of sizes in images compiled on the the database, plus a bit of expert knowledge. They are certainly not definitive, but should capture the typical size range, probably with a bias toward larger specimens. This data is also given on the species pages, together with a note on the source of the data.


This part should be self-explanatory. The buttons allow you to select morphological criteria to search for. There are tooltip notes to explain the terms, and you can also explore them by doing searches. For more details the INA Terminology guide (Links Menu - Terminology) provides longer explanation of terms, and illustrations. Usually the tags will not uniquely identify a species, but they should allow a user to identify a limited set of possibilities. This works especially well if it is combined with a geological age constraint. The search uses logical AND, so if you search for a number of criteria then only taxa meeting all those criteria will be returned. NB This system was comprehensively revised in late 2019/early 2020 and extended to cover the Mesozoic. All species in the Mesozoic and Cenozoic modules are now covered.
Tags for a species (Futyania petalosa) as displayed on a species page.

Search summary

The search summary is a text description of the search which has been run. Use this to help understand what is happening, so you can adjust the search if you get unexpected results.

Identifying an unknown species

Try setting the age of the sample, as far as you know it using the time-scale selector then select one or two unambiguous features of the specimen, e.g elliptical with central cross. You can then review the possibilities and possibly add more terms to refine the search.

Note for nerds the search system uses logical AND so if multiple criteria are selected it is easy to construct a search which will not return any results. For example a search for holococcolith AND placolith. On the other hand the tags have been added liberally - e.g. if a central area structure might be interpreted as either a grill or a cross then both tags are added.