Cryptosporidium tyzzeri n. sp. (Apicomplexa: Cryptosporidiidae) in domestic mice (Mus musculus)

► Cryptosporidium tyzzeri n. sp. is described based on molecular and biologic evidence. ► It has smaller oocysts than Cryptosporidium parvum and does not infect calves and lambs. ► Unlike C. parvum in mice, it does not appear to infect the colon. ► It is genetically distinct from C. parvum and other Cryptosporidium spp. ► Life cycle stages are described by light and electron microscopy.