Morphological analysis of the oribatid mite species Scutovertex pannonicus Schuster and description of its juvenile stages (Acari: Oribatida: Scutoverticidae)

Abstract

This paper provides a detailed redescription of the adult as well as the first morphological description of all juvenile instars (inclusive egg, prelarva and earlier larval stages) of Scutovertex pannonicus. The adults are characterized by their relatively large size (692-892 μm), their well developed sharply bordered foveae which are regularly distributed on the whole notogaster, except in the central field and the posterior notogastral brush-like setae ps 1 , h 1 -h 3 . The exochorion of the eggs shows the typical structures for the genus Scutovertex like 'mushrooms' and granules with the species-specific expression of the 'mushrooms' and its substructures. The exochorion is covered with an extra thin layer which is typical for this species. The larva and the nymphs can be distinguished from those of S. sculptus and S. minutus mainly by their lateral setae l' and l'' on tibia I which are strongly serrated and slightly broadened.

Use of Quantitative Morphological Analysis Combined with a Large Sample Size for Estimating Morphological Variability in a Case Study of Armoured Mite Carabodes subarcticus Trägårdh, 1902 (Acari: Oribatida: Carabodidae) / Carabodes Subarcticus Trägårdh, 1902 (Acari: Oribatida: Carabodidae) Bruòçrèu Taksonomijâ Plaðâk Pielietoto Pazîmju Morfoloìijas Mainîbas Kvantitatîva Un Kvalitatîva Analîze Relatîvi Lielâ Paraugkopâ

“…The very first description of a species is often limited by few specimens available at that time, and hence a low range of values for traits due to relatively small sample sizes (n < 25) examined (Michael, 1882;Trägårdh, 1902;Grandjean, 1931;Zakhvatkin, 1945;Grandjean, 1956;Woolley, 1957;Wallwork, 1972;Reeves, 1987;Salomone et al, 2003;Fernandez et al,. 2013;McCullough and Krisper, 2013; see also Table 1 and Fig. 5).…”

“…Qualitative traits so far have been used mostly in the study of morphology of armoured mites (Ramsay and Luxton, 1967;Mahunka, 1987;Norton and Kethley, 1989;Caballero et al,. 1999;McCullough and Krisper, 2013).…”

“…Regarding morphometrical studies of Oribatida, from which species descriptions dominate in numbers, 25 or fewer specimens on average have been used to describe or redescribe traits of species quantitatively (Grandjean, 1931;Eglitis, 1943;Zakhvatkin, 1945;Sellnick and Forsslund, 1952;Grandjean, 1956;Reeves and Norton, 1990;Behan-Pelletier, 1993;Salomone et al, 2003;McCullough and Krisper, 2013). Oribatid determination keys and species descriptions may be considered as the most important research elements dealing with morphological observations, yet quantitative morphometrical data mostly in these contributions are presented even without any indication of the number of observed specimens (Michael, 1882;Trägårdh, 1902;Woolley, 1957;Wallwork, 1972;Gilyarov and Krivolutskii, 1975;Reeves, 1987;Weigmann and Miko, 2002;Weigmann, 2006;Murvanidze, 2008;Ermilov, 2011;Fernandez et al, 2013).…”

“…Among many published morphometrical studies, for example, species descriptions, redescriptions or determination keys, it has not been considered that use of a small sample size might lead to lower morphological variability compared to natural populations and decrease comparability of morphological data (Michael, 1882;Trägårdh, 1902;Grandjean, 1931;Zakhvatkin, 1945;Grandjean, 1956;Woolley, 1957;Wallwork, 1972;Reeves, 1987;Salomone et al, 2003;Fernandez et al, 2013;McCullough and Krisper, 2013).…”

“…2011). Populations with geographically separate distribution have rarely been compared in species descriptions or determination keys (Haarlov, 1952;Schubart, 1975;Norton, 1978;Behan-Pelletier, 1993;Murvanidze, 2008;McCullough and Krisper, 2013; see also Table 1). Even those oribatid mites that inhabit geographically and biologically closely related habitats can show high morphological variability (Kagainis, 2014).…”