Phylogeny of stenophorid gregarines from millipedes (Diplopoda)

: The gregarines from millipedes are diverse and understudied parasites. They are distributed across five families of eugregarines, but the majority of their species belong to family Stenophoridae, where their phylogenetic relationships are not well understood. Here we obtain 20 new gregarine sequences from millipede hosts and employ environmental sequence data to examine the phylogeny within the family. Phylogenetic analyses with SSU rDNA and combined SSU, 5.8S and LSU rDNA datasets recover all novel sequences as a monophyletic group consisting of six clades, five of which have not been recognized before. The stenophorids are sister to Gregarinoidea in the phylogenies, hence we redefine the group as Stenophoroidea Clopton, 2009. We describe four new species of Stenophora and show that the phylogeny of these gregarines does not follow the phylogeny of their millipede hosts.