Oribatella similesuperbula Weigmann, 2001

Seniczak, Stanisław, Ivan, Otilia, Marquardt, Tomasz & Seniczak, Anna, 2021, Morphological ontogeny of Oribatella similesuperbula (Acari: Oribatida: Oribatellidae), Zootaxa 5086 (1), pp. 90-110 : 91-105

publication ID	https://doi.org/ 10.11646/zootaxa.5086.1.8
publication LSID	lsid:zoobank.org:pub:09DEF5BF-650B-4E58-9F2A-ACAE882AA72B
DOI	https://doi.org/10.5281/zenodo.5817461
persistent identifier	https://treatment.plazi.org/id/03B7EB61-FFB9-FFD8-8EB7-F9B8FD83F8BA
treatment provided by	Plazi
scientific name	Oribatella similesuperbula Weigmann, 2001
status

Treatment

Oribatella similesuperbula Weigmann, 2001 View in CoL

( Figs. 1–15 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 View FIGURE 15 )

Morphology of adult

Adults studied here ( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3a View FIGURE 3 , 4 View FIGURE 4 , 5a View FIGURE 5 ) similar to those investigated by Weigmann (2001), but see Remarks. Mean length (and range) of females—374.2±8.5 (361–391, N= 30) and males—350.3±6.6 (range 343–361, N= 10); mean width of females—245.9±7.7 (235–259) and males—231.7±3.2 (229–235). Subcapitular setae h, m and a short and smooth ( Fig. 2 View FIGURE 2 ). Chelicera chelate, seta cha longer than chb, both barbed ( Fig. 3b View FIGURE 3 ). Palp relatively short, palpal setae smooth, except for slightly barbed l” on tibia ( Fig. 3c View FIGURE 3 ). Formula of palp setae [trochanter to tarsus (+ solenidion ω)]: 0-2-1-3-9(1). Most epimeral setae short and smooth, except for longer and barbed 3b, 3c, 4a and 4b and clearly longer, thicker and barbed 4c ( Fig. 2 View FIGURE 2 ). Most leg setae barbed, l” on genua and tibiae I and II, and l’ on genu and tibia IV longer and thicker than other setae ( Fig. 6 View FIGURE 6 ). Formulae of leg setae [trochanter to tarsus (+ solenidia)]: I—1-5-3(1)-4(2)-20(2); II—1-5-3(1)-4(1)-15(2); III—2-2-1(1)-3(1)-15; IV—1-2-2-3(1)-12. Legs heterotridactylous.

Remarks: Females and males of O. similesuperbula investigated here are slightly longer than those investigated by Weigmann (2001) —length of females 340–380, and males 320–340. In our adults, the lamellar complex is located more anterior than depicted by Weigmann (2001), and rostrum is not visible in dorsal aspect (versus visible). Other characters of adults are similar as in Weigmann (2001).

Diagnosis of juveniles

Juveniles light-brown and nymphs apopheredermous, i.e. they carry exuvial scalps of previous instars away from dorsal integument, using modified setal pair da. Prodorsal and most gastronotal setae of juveniles long and barbed, except for medium sized h 2 and minute h 3 in larva, and medium sized c 1, p 2 and p 3 in nymphs. Larva with 12 pairs of gastronotal setae, and central setae thicker than other setae, nymphs with 15 pairs, and long d -series. In all juveniles, humeral organ present. In nymphs, seta d on femora I and II, l” on genu and tibia I and genu II, and l’ on genu III clearly thicker than other leg setae.

Description of juvenile stages

Larva oval in dorsal aspect ( Figs. 5b–d View FIGURE 5 , 7 View FIGURE 7 ) and light brown. Prodorsum subtriangular, all prodorsal setae long and barbed, in longest, ro shortest ( Table 1 View TABLE 1 ). Mutual distance between setal pairs le slightly longer than between pair ro, and between pair in about two times longer than between pair ro. Seta le inserted midway between pairs ro and in. Bothridium rounded, bothridial seta narrowly clavate and barbed.

Gastronotum of larva with 12 pairs of setae, including minute h 3 inserted laterally to medial part of anal valves ( Figs. 7 View FIGURE 7 , 8a View FIGURE 8 , 9a View FIGURE 9 ). Most gastronotal setae long and thick, with clear barbs, except for medium sized h 2 and minute h 3 ( Table 1 View TABLE 1 ), central setae thicker than lateral and posterior setae ( Figs. 5b–d View FIGURE 5 , 7 View FIGURE 7 , 9a View FIGURE 9 ). Anal valves (segment P) glabrous. Cupule ih lateral to anterior part of anal valves, cupules ia, im, and ip not observed, gland opening lateroventral to seta lp, humeral organ anterior to seta c 3 ( Figs. 8a View FIGURE 8 , 9a View FIGURE 9 ). Most leg setae barbed, l” on genu and tibia I and genu II, and l’ on genu III thicker than other leg setae ( Fig. 10 View FIGURE 10 ). Seta ft’ on tarsus I and ft on tarsi II and III slightly thicker than other tarsal setae.

Nymphs more stocky than larva, with setiform bothridial seta. Gastronotum of protonymph with 15 pairs of setae because setae of p -series appearing ( Fig. 8b View FIGURE 8 ), and remaining in deutonymph and tritonymph ( Figs. 9b View FIGURE 9 , 11–13a, 13d View FIGURE 11 View FIGURE 12 View FIGURE 13 , 14 View FIGURE 14 ). In all nymphs, most gastronotal setae long and barbed, except for medium sized and slightly barbed c 1, p 2 and p 3, p 1 shorter than other posterior setae. Setal pair da long, barbed, inserted close to each other, with apical end adapted for bearing exuvial scalps of previous instars. Mutual distance between setal pair c 1 about two times longer than between setal pair da, mutual distance between setal pair dm and dp about 5.5, and 5 times longer than between setal pair da, respectively. Setae c 3, lm, lp, h -series and p 1 in marginal position on gastronotum. Protonymph, deutonymph and tritonymph carry exuvial scalps of previous instars ( Fig. 9b View FIGURE 9 ), using long setal pair da. In protonymph, one pair of setae appearing on genital valves, and two pairs added in deutonymph and tritonymph each ( Figs. 8b View FIGURE 8 , 11 View FIGURE 11 ); all short and smooth. In deutonymph, one pair of aggenital setae and three pairs of adanal setae appearing, and present in tritonymph; all short and smooth. Anal valves of protonymph (segment AD) and deutonymph (segment AN) glabrous, but in tritonymph two pairs of setae present, all short and smooth. In all nymphs, humeral organ placed as in larva. In deutonymph and tritonymph, cupule iad lateral to anterior part of anal valves, cupules ia, im, ip, ih and ips not observed, opisthonotal gland opening as in larva ( Figs. 9b View FIGURE 9 , 11 View FIGURE 11 ). In deutonymph and tritonymph, leg setae d on femora I and II, l” on genua I and II and tibia I, and l’ on genu III clearly thicker than other setae ( Figs. 13a, 13b View FIGURE 13 , 14 View FIGURE 14 , 15 View FIGURE 15 ).

Summary of ontogenetic transformations

In all instars of O. similesuperbula , the prodorsal setae are long, and le is as thick as ro and in, but in the adult le is clearly thicker than other setae. In all juveniles, seta ex is long, whereas in the adult it is short. The opening of bothridium is rounded in all instars, but in the adult it gains small scales. In the larva, the bothridial seta is narrowly clavate, in the nymphs it is setiform, whereas in the adult it is fusiform. The larva has 12 pairs of gastronotal setae, including minute h 3, the nymphs have 15 pairs (p -series appear), whereas the notogaster of adult loses setae c 2, c 3 and of d -series, such that 10 pairs of setae remain. The formula of gastronotal setae is 12-15-15-15-10 (from larva to adult), and formulae of epimeral setae are 3-1-2 (larva, including scaliform 1c), 3-1-3-1 (protonymph), 3-1-3- 2 (deutonymph) and 3-1-3-3 (tritonymph and adult). Formula of genital setae is 1-3-5-6 (protonymph to adult), aggenital setae is 1-1-1 (deutonymph to adult), and formula of segments PS−AN is 03333-0333-022. The ontogeny of leg setae and solenidia of O. similesuperbula is given in Table 2 View TABLE 2 .

Distribution, ecology, and biology

Oribatella similesuperbula View in CoL has Central European distribution ( Subías (2004, update 2021). It was recorded from Germany (Weigmann 2006) and Romania ( Călugăr & Ivan 2013). Weigmann (2001, 2006) noted the preference of O. similesuperbula View in CoL to moss and decaying wood. In Romania this species was first recorded from a forest plantation, with dominant Robinia pseudoacacia L. ( Călugăr & Ivan 2013) View in CoL , but was more abundant in bryophyte covering calcareous cliffs, which suggests its preference to such a habitat.

In this study, O. similesuperbula View in CoL was distinctly more abundant in Horia (42 individuals per 500 cm 3) than in Dâmbovicioara Gorges (2 individuals per 500 cm 3). In both habitats, the adults dominated the juveniles, which constituted 49% and 20% of sample populations, respectively. In the samples in Horia, the stage structure of this species was the following: 25 larvae, 45 protonymphs, 33 deutonymphs, one tritonymph and 107 adults. Among 40 investigated adults, the sex ratio (females: males) of O. similesuperbula View in CoL was 1:0.25, and 16% of females were gravid. The gravid females carried 1–2 relatively large eggs, each 152 x 104, which constitutes about 41% of the total body length of females. In all habitats, females of O. similesuperbula View in CoL were significantly longer and wider than males.

Note: structures are indicated where they are first added and are present through the rest of ontogeny; pairs of setae in parentheses, dash indicates no additions.