Belongs within: Erythracarinae.
Erythracarus is a cosmopolitan genus of predatory mites distinguished from closely related genera by having widely spaced setae ve on the prodorsum, and having an elongated finger-like projection on the palptibia. In members of the E. pyrrholeucus group (E. festinus to E. katherinae in the tree below), tarsi I and II are pseudosegmented and twisted with phylliform setae (Otto 1999).
Characters of adult (from Otto 1999): Prodorsum with an area of more finely striated cuticle; setae ve further apart than setae sce; naso conspicuous; c series with two setae, series d, e, f with one seta, all setae inserted in striated cuticle; one pair of distinct corneas; pair of swellings present posterior to pair of corneas ; more than ten setae on each genital valve; group of 16–54 setae either side anterolateral to genital valves; row of four to seven setae posterolateral to genital valves. Palp femur and genu fused, segment with two dorsal setae; palp tibia with setae o1 and o2 on conspicuously elongated finger-like projection and four to five setae on remainder of segment; seta o1 distinctly spiniform, with coarse teeth dorsally, two rows of minute teeth ventrally; seta o2 feather-like; palp tarsus with minute solenidion ω in proximal half, internal ducts absent. Length of legs increasing from I–IV; tarsi longer than tibiae, with two lateral claws and shorter empodial claw; basi- and telofemora ventrally fused, dorsally separated; tarsi I and II with two solenidia ω and one eupathidium ε; lateral tarsal claws with transverse ventral ridges; tibia IV with more than 25 setae.
Erythracarus Berlese 1903O99 (see below for synonymy)
| i. s.: E. epigeus (Koch 1837) [=Erythraeus epigeus]O99
| E. hirsutus (Menge 1854) [=Erythraeus hirsutus]O99
| E. lagopus (Menge 1854) [=Erythraeus lagopus]O99
| E. proavus (Menge 1854) [=Erythraeus proavus]O99
| E. raripilus (Menge 1854) [=Erythraeus raripilus]O99
| E. sabulosus (Berlese 1885) [=Erythraeus sabulosus]O99
| E. sachalinensis (Zacharda 1985) [=*Palaeoerythracarus sachalinensis]O00
| E. tricolor (Lucas 1847)O99, E12 [=Erythraeus tricolorO99]
|--+--E. barbarus Otto 1999O99
| `--E. ciliatus Otto 1999O99
`--+--E. avius Otto 1999O99
|--E. grahami (Meyer & Ryke 1960) [=Bechsteinia grahami]O99
`--+--E. amnicolus Otto 1999O99
|--E. flavipes Otto 1999O99
`--+--E. parietinus (Hermann 1804)O99 (see below for synonymy)
`--+--E. festinus (Meyer & Ueckermann 1987) [=Bechsteinia festina]O99
`--+--E. pyrrholeucus (Hermann 1804)O99 (see below for synonymy)
`--+--E. nasutus Otto 1999O99
`--+--E. decoris Otto 1999O99
`--+--E. elegans Otto 1999O99
`--E. katherinae Otto 1999O99
Nomen nudum: Erythracarus simku Kishida 1959O99
Erythracarus Berlese 1903O99 [incl. Bechsteinia Oudemans 1936O99, Chabrieria Oudemans 1936O99, Palaeoerythracarus Zacharda 1985O00]
Erythracarus parietinus (Hermann 1804)O99 [=Trombidium parietinumO99, Anystis parietinumH98, Erythraeus parietinusB82, Tarsotomus parietinusO99; incl. Erythraeus comes Berlese 1886O99, Erythracarus comesO99, Bechsteinia solarii Ueckermann 1987O99, Erythraeus spinatus Banks 1894O99, Erythracarus spinatusO99]
Erythracarus pyrrholeucus (Hermann 1804)O99 [=Trombidium pyrrholeucumO99; incl. Bechsteinia californica McGregor 1956O99, Erythraeus ruricola Dugès 1834O99, *Erythracarus ruricolaO99, Trombidium ruricolumCF77, *Bechsteinia schneideri Oudemans 1936O99, Tarsotomus terminalis Banks 1916O99, *Chabrieria terminalisO99]
*Type species of generic name indicated
References
[B82] Berlese, A. 1882. Acari, Myriopoda et Scorpiones hucusque in Italia reperta. Fascicle 2. Typis Fratelli Salmin: Patavii.
[CF77] Canestrini, G., & F. Fanzago. 1877. Intorno agli Acari Italiani. Atti del Reale Istituto Veneto di Scienze, Lettere ed Arti, Serie 5, 4: 69–208, pls 2–7.
[E12] Evenhuis, N. L. 2012. Publication and dating of the Exploration Scientifique de l’Algérie: Histoire Naturelle des Animaux Articulés (1846–1849) by Pierre Hippolyte Lucas. Zootaxa 3448: 1–61.
[H98] Halliday, R. B. 1998. Mites of Australia: A checklist and bibliography. CSIRO Publishing: Collingwood.
[O99] Otto, J. C. 1999. Revision of the genus Erythracarus Berlese (Acarina: Anystidae: Erythracarinae). Journal of Natural History 33: 825–909.
[O00] Otto, J. C. 2000. A cladistic analysis of Erythracarinae (Acarina: Prostigmata: Anystidae), with the description of a new genus. Systematic Entomology 25: 447–484.