My second question in relation to GBIF web services is whether it is possible to request a list of GBIF IDs (keys) for those species (subspecies/variants/cultivars etc) that have occurence data with coordinates within a geographic region specified as part of the web service query.  Specifically, I am hoping to use a WKT polygon and the geometry query parameter as described on the occurrences web services page to define the region.  

I am also hoping to constrain results using a request parameter that indicates a taxonomic rank that all matching species IDs have (e.g. return the IDs of all species that are in the Lepidoptera order. 

It would also be great if results could be constrained to require that the occurrences driving the results were between a specified start and end date. 

Note that for performance reasons on both sides it would be great to retrieve the relatively small number of GBIF IDs rather than the potentially huge numbers of occurrence records for each species.

Again, many thanks for any assistance that can be provided.

Regards