Abstract
The oribatid mite genus Caleremaeus (Caleremaeidae) is widely distributed in the northern hemisphere but has been represented by only three extant and one fossil species. We redescribe the North American C. retractus (Banks, 1947) based on adults and nymphs; it is distinguishable from the European type species, C. monilipes (Michael, 1882) by its smaller adult size and minor differences in cuticular structure, and by the elongated, tapered form of seta h1 in nymphs. Two new species are proposed: C. nasutus n. sp. from forest soil in Alabama is unique in having adults with a large anterior rostral lobe (juveniles unknown) bearing lamellar setae; the arboreal C. arboricolus n. sp. from eastern USA and Canada is unique among described extant species in having adults with femoral saccules, a transverse ridge bearing lamellar setae and relatively large notogastral setae, and juveniles with a bothridial seta similar to that of the adult. Based on all available data, Caleremaeus is redescribed and considered the sole genus in Caleremaeidae. The higher classification of the family is reviewed, and past placement in Ameroidea is rejected in favor of the monofamilial Caleremaeoidea.
Highlights
Caleremaeus Berlese, 1910 (Caleremaeidae) is a distinctive genus of middle-derivative, brachypyline oribatid mites with adult traits that make identification rather easy, even at modest magnification: enlarged first tibiae and a notogaster with a T-shaped pattern of two conspicuous dorsal bulges separated by a foveate sulcus
Little is known of the other extant species, both of which are similar in many respects to C. monilipes
Juveniles were associated with adults from the same sample using criteria explained by Norton and Ermilov (2014): size and body-leg proportions were consistent with adults; features of the gnathosoma were identical, except for size; a single Caleremaeus species was represented by adults in each sample; and adults of no other oribatid mite species with similar size, proportions or gnathosoma were represented
Summary
Caleremaeus Berlese, 1910 (Caleremaeidae) is a distinctive genus of middle-derivative, brachypyline oribatid mites with adult traits that make identification rather easy, even at modest magnification: enlarged first tibiae (see epigram) and a notogaster with a T-shaped pattern of two conspicuous dorsal bulges separated by a foveate sulcus. Caleremaeus divisus Mihelčič, 1952 is known only from the original collection (arboricolous moss in Tirol, Austria) and the incomplete, poorly illustrated original description It differs from C. monilipes in features of prodorsal sculpturing and the size of the notogastral humeral projection, but it has been considered a species inquirendum (Schatz and Schuster 2009; Krisper et al 2017). Personal communication, 2017) indicated that what authors have considered C. monilipes is instead a species-complex This seems consistent with some rather striking differences in size and form, as reported and illustrated in the various published descriptions (cf Michael 1882, 1888; Sellnick 1928; Willmann 1931; Kunst 1971; Bulanova-Zachvatkina 1975; Miko and Travé 1996; Subías and Arillo 2001; Weigmann 2006; Seniczak and Seniczak 2019). Both the composition of Caleremaeidae and their position among eupheredermous superfamilies are discussed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
