We have recently added a new table at the top of the Orthologues view. This table shows the number of species that have a 1:1, 1:many or many:many orthology relationship with the current gene. This table shows that information for the human BRCA2 gene:
The table also contains a ‘Show details’ column. This can be used to restrict the list of orthologues shown on the page to this or these species clades.
Please, refer to the Ensembl documentation at http://www.ensembl.org if you want to know more about how we infer orthologues.