Differentiation of external morphology of Oribatulidae (Acari: Oribatida) in light of the ontogeny of three species Author Seniczak, Stanisław Author Seniczak, Anna text Zootaxa 2012 3184 1 34 journal article 45499 10.5281/zenodo.208456 7f4288f8-f0c3-423f-9f26-2415f0039141 1175-5326 208456 Lucoppia burrowsi ( Michael, 1890 ) ( Figs. 2 B, 3B, 4C, D, 9B, 10C, 11–14) Lucoppia burrowsi : Grandjean 1948 , 1950 ; Sellnick 1960 ; Marshall et al . 1987 ; Subías 2004 , 2011; Weigmann 2006 . Notaspis burrowsii Michael, 1890 . Notaspis burrowsi : Michael 1898 . Zygoribatula spinosissima Mihelčič, 1956 . Diagnosis. Adult rather large (620–750 µm), drop-shaped ( Fig. 11 ), brown. Males usually smaller than females. Most prodorsal and notogastral setae long, curved, and barbed. Sensillus rather short, clavate, with barbed head. Notogaster arched in lateral aspect ( Fig. 2 B), and with 14 pairs of rather long setae, seta c 3 lost, as in adult Ph . lucorum . Notogastral porose areas oval, porose areas also on all segments of legs, including tarsus I ( Figs. 4 C, D), except trochanters I and II. Five pairs of genital setae, three pairs in anterior part, and two pairs in posterior part of genital plates ( Fig. 3 B). Seta ad 3 small and smooth, setae ad 1 and ad 2 distinctly longer, thicker, and barbed; ad 3 located anterolateral from anal opening, far from ad 2. Solenidia and setae on tibia I and tarsus I similar as in Ph . lucorum ( Figs. 4 B, C), as well as porose areas on legs. Formulae of leg setae (and solenidia): I – 1-6 -4(1)-4(2)- 20(2); II – 1-5 -2(1)-4(2)-16(2); III – 2-3 -1(1)-3(1)-14; III – 1-2 -2-3(1)-11. Tarsi tridactylous. TABLE 1. Measurements of some morphological characters of juvenile stages of Phauloppia lucorum , Lucoppia burrowsi , and Oribatula tibialis (mean measurements of 10 specimens in μm): larva (L), protonymph (PN), deutonymph (DN), tritonymph (TN) and adult (AD). Nd—not developed. Species Morphological characters L PN DN TN AD Ph . lucorum Body length 287 429 494 546 683 Body width 178 280 297 346 416 Length of:seta le 31 51 88 122 117 seta in 52 84 112 152 133 seta c 1 21 56 102 128 154 seta c 3 56 70 95 136 Lost seta dp 55 75 101 130 168 genital opening Nd 43 58 82 72 anal opening 57 75 99 130 120 L . burrowsi Body length 231 248 277 410 618 Body width 123 132 146 182 403 Length of:seta le 21 23 40 57 120 seta in 23 25 43 54 102 seta c 1 17 18 29 37 102 seta c 3 21 23 41 51 Lost seta dp 22 27 30 47 106 genital opening Nd 30 44 50 70 anal opening 54 44 55 77 104 O . tibialis Body length 188 234 274 358 429 Body width 82 102 144 175 281 Length of:seta le 13 18 33 41 71 seta in 10 22 23 33 50 seta c 1 7 18 18 24 10 seta c 3 15 20 38 35 Lost seta dp 13 14 10 8 10 genital opening Nd 25 37 44 45 anal opening 35 50 67 80 75 Juveniles oval in dorsal aspect, light-brown, with slightly darker legs, and rather long, almost straight, and barbed setae. Most prodorsal setae longer than gastronotal setae, sensillus short, clavate, with barbed head. Gastronotum slightly arched, with 12 pairs of setae in larva, and 15 pairs in nymphs. Some gastronotal setae with excentrosclerites ( c 2, l -series and h 1 in larva, c 2, l -, h -series and p 1 in nymphs), small excentrosclerites also at nymphal setae c 1 and d -series. Description of larva and tritonymph. Larva oval in dorsal aspect ( Fig. 12 ), body light-brown, with slightly darker legs. Seta ro rather long, setae le and in shorter; pair ro inserted closest, pair in widest; all setae slightly curved and barbed; seta ex almost as long as in , but thin and smooth. Bothridium rounded, sensillus rather short, clavate, with barbed head. FIGURE 10. Tarsus I and part of tibia I of tritonymph, antiaxial aspect, scale bar 10 µm. (A) Phauloppia lucorum ; (B) Ph. lucorum , part of tarsus, dorsal aspect; (C) Lucoppia burrowsi ; (D) Oribatula tibialis ; some setae are not illustrated. FIGURE 11. Lucoppia burrowsi , adult, female. (A) Dorsal aspect, legs partially drawn, scale bar 100 µm; (B) apical part of seta le . FIGURE 12. Lucoppia burrowsi , larva, legs partially drawn, scale bar 100 µm. FIGURE 13. Lucoppia burrowsi , legs partially drawn, scale bar 100 µm. (A) Anal region of larva; (B) anogenital region of tritonymph. FIGURE 14. Lucoppia burrowsi , tritonymph, legs partially drawn, scale bar 100 µm. TABLE 2. Chosen morphological characters of Phauloppia lucorum , Lucoppia burrowsi , Oribatula tibialis , Liebstadia similis and Scheloribates latipes . Morphological Ph. lucorum L . burrowsi O . tibialis L. similis 1 S . latipes 2 characters

Formula of gastronotal setae	12-15-15-15-14	12-15-15-15-14	11-14-14-14-13	12-15-15-15-10	11-15-15-15-10
Formula of setae PS −AN	23333-0333-022	23333-0333-022	22222-0333-022	0333-0333-022	0333-0333-022
Adult
Presence of translamella	Absent	Present	Absent	Absent	Absent
Shape of Aa	Elongated	Rounded	Rounded	Rounded	Absent
Pairs of genital setae	4	5	4	4	4
Juveniles
Eexcentrosclerite at seta lm	Present	Present	Absent	Absent	Absent
Nymphs
Gastronotum in dorsal aspect	Arched	Slightly arched	Arched	Arched	Arched
Length of seta le	Longer than ro	Longer than ro	As long as ro	As long as ro	Longer than ro
Length of seta in	Longer than le	As long as le	Longer than le	Longer than le	Longer than le
Excentrosclerites at d -series setae	Small	Small	Not observed	Not observed	Not observed
Shape of seta c 1	Long, barbed	Rather short, barbed	Rather short, barbed	Short, smooth	Rather short, barbed
Shape of seta dm	Long, barbed	Rather long, barbed	Short, smooth	Short, smooth	Short, barbed
Larva
Length of seta le	Shorter than ro	Shorter than ro	Shorter than ro	Shorter than ro	As long as ro
Length of seta in	Longer than le	As short as le	Shorter than le	Longer than le	As long as le
Length of seta c 1 Length of seta dp	Longer than c 2 Longer than da	As long as c 2 Longer than da	Shorter than c 2 As short as da	Longer than c 2 As short as da	As short as c 2 As short as da

1 – according to Seniczak (1990); 2 – according to Seniczak (1980) . Gastronotum with 12 pairs of setae, including seta h 3, located lateral to medial part of anal opening ( Fig. 13 A). Setae c 3, lp , dp , h 1 and h 2 approximately as long as seta in ( Table 1 ), other setae shorter. Setae of d -, l - and h -series increasing in length from anterior to posterior, seta c 1 approximately as long as da , seta c 2 shorter, seta h 3 small; all setae barbed except smooth seta h 3. Excentrosclerites at similar setae as in larva of Ph . lucorum . Cupule ia posterior to seta c 3, cupule im posterior to seta lm , cupule ip between setae h 1 and lp , cupule ih lateral to anterior part of anal opening. Paraproctal valves (segment PS) with two pairs of small setae. Anal region with few folds. Ontogeny of setae generally similar as in Ph . lucorum , except genital setae. Tritonymph light-brown, with slightly darker legs. Prodorsal setae ( Fig. 14 ) relatively longer than in larva, especially setae le and in , these setae longer than seta ro ; all setae slightly curved and barbed, seta ex rather short and smooth. Bothridium of nymphs rounded, sensillus clavate, with barbed head, slimmer than in larva. Gastronotal setae rather long, almost straight, and barbed, except shorter seta c 2. Excentrosclerites at similar setae as in tritonymph of Ph . lucorum . Setae of p -series slightly shorter than setae of h -series, and barbed, setae ad , an -series, ag and genital setae short ( Fig. 13 B). Cupules ia and im as in larva, cupule ip between setae p 1 and p 2, cupule iad lateral to anterior part of paraproctal valves, cupule ips pushing posterolateral, and cupule ih pushing anterolateral to cupule iad . Gland opening gla lateroventral to seta lm . Anogenital region smooth or with few folds. Setation of tibia I and tarsus I of tritonymph ( Fig. 10 C) similar to that o Ph . lucorum , but seta ft ” more curved. Summary of ontogenetic transformations. In the larva seta ro is longer than setae le and in , but in the nymphs and adult the two latter pairs are longer than the former pair. The bothridium is rounded in all instars, and the sensillus has clavate head, which is more slender in the nymphs and adult than in the larva. The ontogeny of setae in L . burrowsi is generally similar to Ph . lucorum , and lyrifissure ia is located as in Ph . lucorum . The formulae of gastronotal, segments PS −AN, coxisternal, and aggenital setae are as in Ph . lucorum ( Table 2 ), but five pairs of genital setae are present in adult; all formulae are consistent with those described by Grandjean (1949) . Distribution and ecology. Lucoppia burrowsi is a Holarctic species ( Subías 2004 , 2011), but in Southern Europe and North Africa rare ( Weigmann 2006 ). This species is considered to be xerophilous ( Starý 2005 ), and rather abundant in initial stages of succession of meadows. It was rather abundant in mosses and grasses ( Seniczak et al. 2009a ) in open steppe vegetation of cape Tarkhankut in Crimea ( Ukraine , N45o13, E 32o 39, 25 m a. s. l), but was not abundant in bushy patches of this steppe ( Seniczak et al. 2011a ), which supports its preference to dry habitat. In Crimean populations of L . burrowsi the adults dominated, with a small fraction of juveniles, except the mosses, where the juveniles constituted 21% of population.