Oribatella superbula ( Berlese, 1904 )

Seniczak, Stanisław & Seniczak, Anna, 2013, Differentiation of external morphology of Oribatella Banks, 1895 (Acari: Oribatida: Oribatellidae), in light of the ontogeny of three species, Journal of Natural History 47 (23 - 24), pp. 1569-1611 : 1584-1589

Oribatella superbula ( Berlese, 1904)

( Figures 2D , 3B , 10B , 11–14 )

Oribates superbulus Berlese, 1904 .

Oribatella meridionalis Berlese, 1908 .

Oribatella superbula: Bernini 1975 ; Subías 2004; Weigmann 2006; Schatz 2008.

Diagnosis

Adult rather small (290–350 µm), and dark brown, sexual dimorphism weakly expressed. Lamellae with lateral dens, outer lamellar cusp distinctly longer than inner cusp ( Figure 11 ). Seta le thicker than in, apical end of seta in not reaching that of seta le in dorsal aspect; all protruding beyond rostrum. Notogastral setae relatively short ( Table 1), and curved ventrally, including h 1, but coxisternal setae relatively long, especially hypertrophied seta 4c ( Figure 3B ). Formula of setae and solenidia of legs as in O. quadricornuta . Seta l” on tibia I relatively thin, solenidia ω 1 and ω 2 on tarsus I approximately of similar size, famulus ε short ( Figure 2D ). Tarsi tridactylous.

Juveniles light brown, and smaller than those of O. quadricornuta , but sensillus longer than seta ex. In nymphs seta dm approximately as long as seta lm, seta dp distinctly shorter; all barbed. Nymphs carry exuvial scalps of previous instars.

Description of larva and tritonymph

Shape and colouration of larva and its setae, bothridium and sensillus similar to that in O. quadricornuta , but larva smaller than that of O. quadricornuta , and sensillus longer than seta ex ( Figure 12 ). Gastronotum with 12 pairs of setae, including seta h 3 ( Figure 13A ) positioned lateral to medial part of anal opening. Shape, location and ontogeny of gastronotal setae, gland opening gla and cupules ia, im, ip and ih as in O. quadricornuta .

Tritonymph more stocky, and with relatively shorter prodorsum than in larva, and with long ( Table 1), rather thick, curved and barbed prodorsal and gastronotal setae ( Figures 13B , 14 ), except shorter setae c 1 and dp; pairs dm and dp inserted wider than pair da. Bothridium and sensillus as in larva. Location of gland opening gla and cupules ia, im, iad, ips and ih as in O. quadricornuta . Shape and location of setae and solenidia on tibia I and tarsus I of tritonymph similar as in O. quadricornuta , but seta l” and solenidia ϕ 2, ω 1 and ω 2 relatively shorter ( Figure 10B ) than in O. quadricornuta .

Summary of ontogenetic transformations

The number, shape, location and ontogeny of setae in O. superbula are similar to those in O. quadricornuta , but the sensillus is longer than seta ex, and in the nymphs pair dp gets distinctly shorter than pair dm. The notogastral setae of adult (10 pairs) are relatively shorter than in O. quadricornuta , and seta h 1 is curved posteroventrally. The formulae of gastronotal, coxisternal, genital, aggenital setae and segments PS–AN are as in O. quadricornuta ( Table 2), and all are consistent with those of Grandjean (1949).

Distribution and ecology

Oribatella superbula is considered a Palaearctic species ( Weigmann 2006). According to Schatz (2008) this species is a muscicol and xerobiont, more abundant in soil under Holm oak ( Quercus ilex L.) trees, shrubs, strawberry tree ( Arbutus unedo L.), grasses and mosses ( Bernini 1974, 1983). It dominated in oribatid mite community in yew litter in Caserta park ( Italy, 41 ◦ 06.35’ N, 14 ◦ 19.22’ E; 35 m above sea level), achieving a mean density of 159 individuals per 500 cm 3 ( Seniczak and Seniczak 2012a), and a high dominance index (D = 52.7), whereas in nearby cypress ( Cupressus sp. ) litter this species was not abundant. In the population of O. superbula the adults dominated (56.6% of population).

Figures

Figure 2. Adult, female. (A) Oribatella quadricornuta, lateral aspect, legs partially drawn, scale bar 100 µm; (B) O. quadricornuta, part of tibia I and tarsus I, scale bar 20 µm; (C) O. quadricornuta, region of solenidion ω1; (D) Oribatella superbula, part of tibia I and tarsus I, scale bar 20 µm.

Figure 3. Adult, female, anogenital region, legs partially drawn, scale bars 50 µm. (A) Oribatella quadricornuta; (B) Oribatella superbula.

Figure 10. Part of tibia I and tarsus I of tritonymph, antiaxial aspect, some setae are not illustrated, scale bars 20 µm. (A) Oribatella quadricornuta; (B) Oribatella superbula.

Figure 11. Oribatella superbula, adult, female, dorsal aspect, legs partially drawn, scale bar 50 µm.

Figure 12. Oribatella superbula, larva, dorsal aspect, legs partially drawn, scale bar 50 µm.

Figure 13. Oribatella superbula, legs partially drawn, scale bars 50 µm. (A) Larva; (B) tritonymph.

Figure 14. Oribatella superbula, tritonymph, dorsal aspect, legs partially drawn, scale bar 100 µm.