Table 1. Results of the BaTS tests for association of virus phylogeny with host species taxonomy.

Host species grouping (no. of categories)	Mean association index	Mean parsimony score	P
Mammalian Order (8)	0.47	13.79	<0.01
Mammalian Family (19)	1.69	26.00	<0.01
Modified Order grouping* (10)	1.44	26.74	<0.01

^*Host species are grouped according to mammalian order, except bats (split into Old/New World bats), primates (split into Old/New World monkeys and apes) and ungulates (grouped into a single category). See Table S3 for further details.