The phylogenetic position of eriophyoid mites (superfamily Eriophyoidea) in Acariformes inferred from the sequences of mitochondrial genomes and nuclear small subunit (18S) rRNA gene

- Two new mitochondrial gene rearrangement patterns were found in eriophyoid mites.
- Monophyly of Eriophyoidea was consistently recovered.
- Eriophyoidea is outside Trombidiformes but within Acariformes.
- Eriophyoid mites diverged from other mites in the Devonian (384 Mya).

Eriophyoid mites (superfamily Eriophyoidea) comprise >4400 species worldwide. Despite over a century of study, the phylogenetic position of these mites within Acariformes is still poorly resolved. Currently, Eriophyoidea is placed in the order Trombidiformes. We inferred the high-level phylogeny of Acari with the mitochondrial (mt) genome sequences of 110 species including four eriophyoid species, and the nuclear small subunit (18S) rRNA gene sequences of 226 species including 25 eriophyoid species. Maximum likelihood (ML), Bayesian inference (BI) and Maximum parsimony (MP) methods were used to analyze the sequence data. Divergence times were estimated for major lineages of Acari using Bayesian approaches. Our analyses consistently recovered the monophyly of Eriophyoidea but rejected the monophyly of Trombidiformes. The eriophyoid mites were grouped with the sarcoptiform mites, or were the sister group of sarcoptiform mites + non-eriophyoid trombidiform mites, depending on data partition strategies. Eriophyoid mites diverged from other mites in the Devonian (384 Mya, 95% HPD, 352-410 Mya). The origin of eriophyoid mites was dated to the Permian (262 Mya, 95% HPD 230-307 Mya), mostly prior to the radiation of gymnosperms (Triassic-Jurassic) and angiosperms (early Cretaceous). We propose that the placement of Eriophyoidea in the order Trombidiformes under the current classification system should be reviewed.

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