Rhynchohydracarus armiger, de Castro & Proctor & Lofego, 2022

de Castro, Luiz A. S., Proctor, Heather C. & Lofego, Antonio C., 2022, A new species of Rhynchohydracarus Lundblad 1936 (Acariformes: Hydrachnidiae: Hydryphantoidea: Rhynchohydracaridae) from central Brazil, with DNA barcodes, a key for known species and a proposal for the homologies of dorsalia, ventralia,, Acarologia 1936 (1), pp. 161-173 : 168

Rhynchohydracarus armiger n. sp. differs from the three already described species in the following three diagnostic characters: 1) anterior margin of the prodorsum (i.e., roof of camerostome) wrinkled, medially separated, and bearing protuberances on the tips; 2) excretory plate hexagonal, accompanied by a similar and smaller post-excretory platelet; 3) in males, the plates that bear cxgl -2 are fused with pregen, almost surrounding the genital field. In other named species of Rhynchohydracarus , prodorsum is smooth, having a median split in R. dividuus shorter than that of R. armiger . Excretory plate is pentagonal in R. testudo and oval in both R. dividuus and R. carmenae . Pregen and postgen fused in males of R. dividuus and R. testudo , forming a unique plate surrounding genital flaps as well as cxgl-2. In R. carmenae these structures are separated, both in male and female.

DNA Barcoding

DNA was successfully amplified and mitochondrial cytochrome C oxidase subunit I gene (COI) sequenced from two of the four R. armiger specimens; sequence data have been deposited in BOLD Systems https (://www.boldsystems.org/) and GenBank (https://www. ncbi.nlm.nih.gov/), with the following accession codes: holotype female, 679 base pairs (BOLD: ENBRA012-21, GenBank: MZ444663 ) and paratype male, 679 base pairs (BOLD: ENBRA011-21, GenBank: MZ444679 ).