1	Pedipalp four-segmented, anterior tips of coxae-I with projections	Debsacarus oribatoides
–	Pedipalp five-segmented, anterior tips of coxae-I without projections	2
2	Body elongate to rectangular	Testudacarus elongatus complex
–	Body oval	3
3	Body large (>700 µm female and >650 male dorsal length), dull coloration common; within and west of the Rocky Mountains	Testudacarus americanus complex (except Testudacarus rollerae)
–	Body small (<700 µm female and <650 male dorsal length), bright coloration (orange, red, violet, blue) common; present throughout North America	(Testudacarus minimus complex, Testudacarus hitchensi complex, Testudacarus rollerae)...4
4	Anterio-medial platelet wide (>140 µm) and more than or nearly twice as wide as long	Testudacarus rollerae
–	Anterio-medial platelet unmodified (<140 µm) and far less than twice as wide as long	5
5	Anterio-medial and anterio-lateral platelets with consistent coloration (either colored or colorless across)	Testudacarus minimus complex
–	Anterio-lateral platelets with coloration and anterio-medial platelet colorless	Testudacarus hitchensi complex