Ameronothridae, Norton & Franklin, 2018

Norton, Roy A. & Franklin, Elizabeth, 2018, Paraquanothrus n. gen. from freshwater rock pools in the USA, with new diagnoses of Aquanothrus, Aquanothrinae, and Ameronothridae (Acari, Oribatida), Acarologia 58 (3), pp. 557-627 : 603

What constitutes Ameronothridae ?

In this confused context, we follow Pfingstl (2017) in recognizing the separate family Podacaridae (diagnosed by Grandjean 1955 and Wallwork 1964), thereby leaving Aquanothrus , Paraquanothrus , Ameronothrus and Chudalupia in Ameronothridae . A new diagnosis of this family concept—which is supported largely by the shared regression of pedotecta—is offered below. An excellent diagnosis of Ameronothrus can be found in Schubart (1975) and a brief one for Chudalupia in Wallwork (1981), but it should be corrected and emended by material in many of the following Remarks. In some respects, Chudalupia seems the most similar of these genera to Scapheremaeus : it has the deeply black, globular bothridial seta characteristic of most Scapheremaeus , and a strong tibia I apophysis, typical of Cymbaeremaeidae and Scutoverticidae but not found in other Ameronothridae . It has the acm -tubercle and apobasic setae but lacks the ascleritic notogastral band and the various leg setal regressions that link Scapheremaeus with Aquanothrus and Paraquanothrus .

We also resurrect Engelbrecht’s (1975) family-group, originally proposed as Aquanothridae , but recognize it as the ameronothrid subfamily Aquanothrinae , which includes Aquanothrus and Paraquanothrus . In part, its resurrection highlights a distinct clade within a family that is not otherwise well-supported. But it is justified also by new knowledge of diversity, including our discovery of two North American species of Paraquanothrus and two unnamed African species of Aquanothrus , with probably others of each genus yet to be discovered. In a practical sense, recognition of the taxon will help prevent this small, but interesting group from being overlooked or subsumed when the evolution and systematics of ‘ameronothroid’ mites are discussed.

Engelbrecht’s (1975) diagnosis of Aquanothridae was short and based on only A. montanus , the description of which had important errors and omissions, so we provide a new one for the subfamily. In both diagnoses, traits considered synapomorphies in the context of the respective taxon are underlined.