Tags, Metrics and 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.

To allow searching by morphological criteria we have now added a large database of morphometric data and morphological tags. The coverage for this is nearly complete for the Extant and Cenozoic, but the Mesozoic has not yet been done - and the whole system is still under development (Sept 2017). Feedback is very welcome (you can use the forum page).

Tags for a species (Futyania petalosa) on a species page.

Using advanced search - some advice

Tag and metrics options as they appear on the advanced search page, along with the search summary

Taxonomic criteria

Within the database the full hierarchy of parent taxa is stored for each taxon - e.g. "Syracosphaerales/Rhabdosphaeraceae/Cyrtosphaera/Cyrtosphaera aculeata". The Within taxa search option allows you to search this and so find e.g all taxa belonging to the Rhabdosphaeraceae.

Likewise the full formal taxonomic citation [e.g. Cyrtosphaera aculeata (Kamptner 1941) Kleijne, 1992] is stored in one database field and can be searched using the Citation includes option. You can use this to e.g. find taxa described by a particular author.


The primary data here are

It should be noted that the metrics are at this stage a rather rapidly produced compilation and need review and update. The objective would be for the range estimates to encompass the vast majority of species but exclude rare exceptionally small or large specimens (top/bottom 5%). In practice the estimates are probably skewed toward larger specimeens as these are most often illustrated, especially in LM. In some case range-estimates have been extended to give likely range without any direct evidence (e.g if an original author quoted a size range of 9-10µm this may have been extended to 8-11µm, this is noted in the source notes as "range extended").

On the Advanced Search page sliders are used to constrain the search to taxa of particular size ranges.


Tags are descriptive terms for an aspect of the morphology. They are designed to allow searches such as for "elliptical coccoliths with a cross in the central-area ". To build up the tags and to help users find them they are classified into tagsets covering different aspects of coccolith morphology. Each taxon may have several tags in a tagset, or indeed none. So this is not a classic character matrix, but there is so much variation been taxa that it was not possible to produce a single simple matrix and this scheme was the simplest one we could devise.

On the Advanced Search page dropdown menus are used to constrain the search to taxa which have been tagged with particular tags.

Tags for the main part of the lith Tags for the central-area and process Tags for the coccosphere Tags for crystallography/appearance in cross-polarised light

Further explanation. Notes have been given described explaining each tag and tagsets. These are included on the Advanced Search page as tooltips - i.e. if you hover over the text then after a slight delay a little box will appear explaining the term - like this. For more explanation of the terms see the Young et al. 2003 Terminology Guide, on the INA website and via the Links Menu. In principle a tag should be present for all species it could apply to and if not this is indicated (E.g. "disk-like" is applied only to holococcoliths).

example of a tooltip - short explanations like this are available for every term.

Tags as a summary of morphology

Taken together the tags provide a sort of summary of the morphology. However, this is essentially accidental and does not always work, for various reasons. First, morphological characters only shown by one or two species are generally excluded, even though they may be important and distinctive. This proved necessary in order to keep the total number of tags reasonable. Second, qualitative characters based on e.g. the relative size of structures have mostly been avoided since they are ambiguous, even though they are often important parts of species definitions. Third, the tags often overlap, e.g. a taxon may have tags for both cross and axial-cross, because either term might be searched for. Or it may have plan_view_tags such both elliptical and circular outline (since specimens may show both). Indeed tags can even seem contradictory - for instance many taxa are tagged as have the central-area both vacant and with a grill - this is because they have delicate grills which are are often missing so a user might reasonably search either for grill or vacant depending on the preservation and means of observation. So, remember tags are designed primarily for searching and the tagset may seem like an odd description of the taxon.

Likewise the tags are not designed as an identification key. In some cases it is possible to identify a species purely from its tags but more often a search will recover a range of possibilities and tags are meant to include all species which might fit. For example all Lophodolithus species have almost the same tags

Development and feedback

The tags, and metrics, have been compiled for this website and are not well-tested. This has been a major effort; there are 15,000 tags in the database and 4160 metrics and here are almost certainly numerous mistakes, omissions and imperfections in the data. If you find it useful please do review the data on taxa you know and send us suggestions for corrections. Any feedback on use of the system would also be appreciated. This can be done as comments on individual taxon pages, as comments on the forum page or by email to jeremy.young@ucl.ac.uk. Likewise the next project needs to be to develop tags and metrics for the Mesozoic taxa and assistance in doing this would be useful.