Morphological and ecological differentiation of Eupelops and Propelops (Acari, Oribatida, Phenopelopidae)

Abstract

In this study, the morphological and ecological differentiation of Eupelops Ewing, 1917 and Propelops Jacot, 1937 were investigated in the light of Eupelops strenzkei and Propelops canadensis. The juveniles of these species have plicate integument and a dorsoventrally flattened hysterosoma, with short and thin setae c 1 , c 3 and of d-series on the gastronotum, whereas the shape of marginal gastronotal setae differs in these species. The juveniles of P. canadensis have all these setae short and thin, except for setae lp and of h-series in the tritonymph, which are usually longer and thicker than other setae, whereas those of E. strenzkei have most marginal setae on the gastronotum longer and thicker than other setae, especially lp and h 1 in the larva and h 3 in the nymphs. Moreover, P. canadensis has short seta h 3 in the larva, whereas in E. strenzkei only a vestige of this seta remains, as in other Eupelops species, and this morphological character has generic value. The deutonymph, tritonymph and adult of P. canadensis have solenidion φ on tibia IV, but lack seta d, whereas those of E. strenzkei have thick seta d on this segment, but lack solenidion φ, as in other Eupelops species, which have also generic value. The adults of both species have 10 pairs of notogastral setae, including c 2 , but in P. canadensis setae lp and h 3 are inserted close to each other, with porose area A1 between them, as in some species of Eupelops, whereas in E. strenzkei these setae are separated, with porose area A1 adjacent to seta lp, as in other species of Eupelops. The adults of both species have ventrodistal apophysis on genu I, as in other species of Eupelops and Propelops. All instars of E. strenzkei have secondarily anarthric subcapitulum, as other Eupelops species, which are used to remove dead parenchymous tissue, whereas those of P. canadensis have diarthric subcapitulum and normal chelicerae, which crumble the litter.

Morphology, distribution and certain population parameters of the Arctic miteOribatella arctica(Acari: Oribatida: Oribatellidae)

“…The systematic value of the presence of this seta depends on family. In the Oribatellidae studied here and by Behan-Pelletier (2011), Behan-Pelletier and Walter (2012) and Seniczak and Seniczak (2013), Damaeidae investigated by Seniczak and Seniczak (2011b) and Galumnidae investigated by Seniczak et al (2012b) seta h 3 has specific diagnostic value, whereas in Scheloribatidae (Grandjean 1958;Seniczak 1980Seniczak , 1990Seniczak et al 2013a) and Phenopelopidae (Seniczak et al 2014c(Seniczak et al , 2015a(Seniczak et al , 2015b this seta differentiates genera.…”

“…These scalps, and all protruding setae, also enlarge the body size of nymphs and protect them to a certain degree against small predators (Seniczak and Seniczak 2013). In the juveniles of Phenopelopidae the thick, long and outstanding setae have also a defensive importance (Seniczak et al 2014c(Seniczak et al , 2015a(Seniczak et al , 2015b. However, some central setae which are under the scalps of previous instars lack interaction with the environment, and are reduced in size, lost or displaced to the peripheral parts of the gastronotum.…”