Morphology of juvenile stages and ontogeny of three species and genera of Eremaeidae (Acari, Oribatida)

Abstract

The morphology of juvenile stages of Eremaeus cordiformis Grandjean, 1934 is redescribed and illustrated, and those of Eueremaeus laticostulatus Bayartogtokh, 2003 and Proteremaeus punctulatus Bayartogtokh, 2000 are described and illustrated for the first time. The juveniles of these species differ from each other mainly by the presence of distinct prodorsal ridges in the central part of the prodorsum, shape and distribution of some setae, and number of adanal and anal setae. The larva of Er. cordiformis has these ridges, whereas other species lack them. Eueremaeus laticostulatus has relatively long and barbed prodorsal seta in in the larva and most gastronotal setae similarly ornamented in all juveniles, whereas other species have these setae short and smooth. The nymphs of Er. cordiformis and Eu. laticostulatus have three pairs of posterior gastronotal setae (p 1 , h 1 , h 2 ), which are inserted close to each other in transverse row, whereas those of P. punctulatus have only two pairs (p 1 , h 1 ) there, and seta h 2 is inserted far from seta h 1 and closer to seta p 2 . The nymphs of all species lose dorsal gastronotal setae of d-series and carry the exuvial scalps of previous instars directly on the glabrous gastronotum mainly due to lateral folds. The nymphs and adult of P. punctulatus have three pairs of adanal setae and two pairs of anal setae, whereas those of other species have at least five pairs of each series. The adult of Er. cordiformis has 11 pairs of notogastral setae, whereas other species investigated here have 10 pairs. The adults of all species have lamellar costulae on the prodorsum, but in P. punctulatus they are more widely separated than in other species. At present the systematic position of Proteremaeus is controversial in the literature, but the morphology of juveniles and adult of P. punctulatus investigated here confirms the membership of this genus in the Eremaeidae. A number of morphological characters support the separation of Er. hepaticus and Er. cordiformis and we provisionally reject their synonymy, until the type or topotypic material is compared.

<p><strong>Morphological ontogeny of <em>Proteremaeus oralensis </em>sp. nov. (Acari: Oribatida: Eremaeidae) from Kazakhstan, and comments on <em>Proteremaeus </em>Piffl</strong></p>

“…The morphological ontogeny of P. oralensis is similar to that of P. punctulatus investigated by Seniczak et al (2013). The larva of both species differs slightly from each other in the length of seta h 1 , but the tritonymph of P. oralensis differs clearly from that of P. punctulatus by the location of setae h 1 , h 2 and p 1 on the posterior part of gastronotum (Table 4).…”

“…By contrast, the morphology of P. oralensis and P. punctulatus differs clearly from that of Eueremaeus laticostulatus Bayartogtokh, 2003, which has six pairs of adanal setae in the deutonymph, tritonymph and adult and 5-6 pairs of anal setae in the tritonymph and adult. Similar number of adanal and anal setae as E. laticostulatus have other species of Eueremaeus Mihelčič, 1963and Eremaeus C.L Koch, 1835(Behan-Pelletier 1993, Seniczak et al 2013, and in species with known ontogeny, the location of setae h 1 , h 2 , p 1 and p 2 on the gastronotum has diagnostic value, as in Proteremaeus species. The adults of Proteremaeus have 10 or 11 pairs of notogastral setae, depending on seta c 1 , which in P. oralensis and P. macleani is present, and in other species is absent.…”

“…According toSeniczak et al (2013), 2 Dn -deutonymph, Tn -tritonymph, Ad -adult, 3 unpaired seta also occurs, 4 seta h 2 reaches insertion of seta h 1 .…”

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

“…A similar way of fastening the exuvial scalps to the gastronotum occurs in some species of Gymnodamaeiade, like Arthrodamaeus reticulatus (Berlese, 1910), Aleurodamaeus setosus (Berlese, 1883) and Jacotella neonominata Subías, 2004, but these species use a long and barbed seta c 3 to protect the exuvial scalps against loss (Seniczak and Seniczak 2011a). The nymphs of some species of Eremaeidae use medially curved setae of l-series and h 3 to prevent loss of the exuvial scalps (Seniczak et al 2013b(Seniczak et al , 2014a.…”