Morphological ontogeny of Minunthozetes semirufus (Acari: Oribatida: Punctoribatidae) Author Seniczak, Stanisław Author Seniczak, Anna text Zootaxa 2018 2018-12-28 4540 1 73 92 journal article 27718 10.11646/zootaxa.4540.1.8 39bea7a7-47a1-45bf-a83b-254ae95ed2cc 1175-5326 2616243 2B0486C3-6F4F-4A45-8CF6-DF24E1ED65E1 Minunthozetes semirufus ( C.L. Koch, 1841 ) ( Figs. 1–10 ) Zetes semirufus C.L. Koch, 1841 . Punctoribates bicornis Berlese, 1908 : Subías 2004 , 2018 . Oribata fusigera Michael, 1884 : Marshall et al . 1987 . Minunthozetes major Mihelčič, 1957 : Subías 2004 , 2018 . Minunthozetes semirufus : Karppinen and Krivolutsky 1982 ; Schatz 1983 ; Tarman 1983 ; Karppinen et al . 1986 , 1987 ; Flogaitis 1992; Bernini et al . 1995 ; Olszanowski et al . 1996 ; Subías 2004 , 2018 ; Weigmann 2006 ; Erman et al . 2007 ; Siepel et al . 2009; Miko 2016 ; Murvanidze and Mumladze 2016 . Morphology of adult Diagnosis of adult as given by Bayartogtokh et al . (2002) . Adults investigated herein ( Figs. 1–3a ) similar to that investigated by Bayartogtokh et al . (2002) , but see Remarks below. Mean length and maximum width (and range) of females 279.4 (271–294, n= 61) and 184.7 (175–191); those of males 269.6 (257–287, n= 59), and 172.5 (165–178), respectively. Genal tooth triangular, rostral seta alveolar ( Fig. 3b ). Cheliceral seta cha longer and thicker than chb , both barbed ( Fig. 3b ), palp setae sup , inf and l” on tibia finely barbed, other setae smooth ( Fig. 3c ). Trochanters III and IV and all femora flattened, porose areas present on dorsal parts of these segments. Tibiae and tarsi I, II and IV with strongly thickened dorsal integument ( Figs. 4a, 4b, 4d ), dorsal integument on tibia and tarsus III not thickened ( Fig. 4c ). Solenidion ω 2 on tarsus I in posterior position to ω 1 and longer than ω 1 . 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. Leg tarsi monodactylous. Remarks . Our individuals are slightly larger than those investigated by Bayartogtokh et al . (2002) – their measurements: mean length 270 (260–280), maximum width 173 (163–178), n= 6, sex not investigated. The shape and distribution of porose areas are generally similar, except for smaller porose areas Aa and A1 on the notogaster and slightly longer notogastral setae ( Table 1 , Figs. 1a , 2 , 3a ). Other differences include the seta ad 3 which is located anterior to lyrifissure iad (versus posterior to iad in Bayartogtokh et al . (2002 )), and the distal part of tutorium which is pointed (versus with three small teeth). All differences may express variability of these characters in different geographic regions. In the adult of M. semirufus illustrated by Weigmann (2006) , the lyrifissure im is placed midway between porose area Aa and gland opening gla , whereas in our individuals and those studied by Bayartogtokh et al . (2002) im is located closer to gla . Weigmann (2006) also illustrated porose areas A2 asymmetrically located, indicating variability of this character in M. semirufus . FIGURE 1. Minunthozetes semirufus , adult, female. (a) Dorsal aspect, legs partially drawn, scale bar 50 μm, (b) shape of seta la (enlarged). FIGURE 2. Minunthozetes semirufus , adult, female, ventral aspect, legs partially drawn, scale bar 50 μm. FIGURE 3. Minunthozetes semirufus . (a) Female, lateral aspect, legs partially drawn, scale bar 50 μm; (b) shape of tutorium and genal tooth (enlarged); mouthparts, right side, antiaxial view, scale bars 20 μm; (c) chelicera, (d) palp. Diagnosis of juveniles Juveniles with humeral organ and gastronotal shield, latter bearing four pairs of setae in larva ( dm , dp , lp , h 1 ), and 10 pairs in nymphs ( d -, l -, h -series, p 1 ). In larva, anterior part of gastronotal shield (pygidium) reaching insertions of setal pair dm . Larva with 12 pairs of gastronotal setae, including h 3 , nymphs with 15 pairs. In nymphs, setae of c -series inserted on separate microsclerites, and solenidion ω 2 on tarsus I located anterolateral to solenidion ω 1 . In tritonymph, seta l” on femora I and II absent. Description of juveniles Larva oval in dorsal view ( Fig. 5 ), body light-gray, pygidium gray. Prodorsum subtriangular, prodorsal setae of me- dium size ( Table 1 ) and barbed, seta ex short and smooth; in slightly longer than ro and le . Mutual distance between setal pairs le and in about four times longer than between setae ro , pair le inserted approximately midway between pairs ro and in . Opening of bothridium small and rounded, bothridial seta clavate, with barbed head. FIGURE 4. Minunthozetes semirufus , leg segments of adult (part of femur to tarsus), right side, setae on the opposite side not illustrated, in the legend, scale bar 20 μm. (a) Leg I, genu ( l’ ), tibia ( l’ ), tarsus ( pl’ ); (b) leg II; (c) leg III); (d) leg IV. FIGURE 5. Minunthozetes semirufus , larva, dorsal aspect, legs partially drawn, scale bar 20 μm. TABLE 1. Measurements of some morphological characters of juvenile stages and adult of Minunthozetes semirufus (mean measurements of 10 specimens in μm).

Morphological characters	Larva	Protonymph	Deutonymph	Tritonymph	Adult
Body length	152	215	224	264	277
Body width	93	98	123	142	182
Length of: seta le	9	12	13	14	21
seta in	10	15	17	19	21
seta bs	26	28	32	34	58
seta c 1	10	7	8	9	Lost
seta c 2	9	6	7	8	15
seta c 3	14	13	16	18	Lost
seta da	10	6	7	8	Lost
seta dp	12	7	8	9	Lost
seta la	10	6	7	8	15
seta lp	13	8	9	9	15
seta h 1	12	8	8	8	14
seta h 3	3	7	7	8	14
seta p 1	Not developed	6	6	7	13
Genital opening	Not developed	19	22	29	33
Anal opening	35	45	59	71	42

Gastronotum of larva ( Figs. 5 , 6a , 7a ) with 12 pairs of setae, including h 3 inserted lateral to medial part of anal valves; most setae of medium size and barbed, except for smooth and short h 3 . Humeral organ small, placed anterior to seta c 3 ( Fig. 7a ). Anterior and medial parts of gastronotum with transverse folds, posterior part with gastronotal shield bearing four pairs of setae ( dm , dp , lp , h 1 ), other gastronotal setae on unsclerotized cuticle. Seta dm inserted on anterior part of pygidium, pygidium porose. Cupule ia posterior to seta c 3 , cupule im posterior to seta lm , cupule ip between setae h 1 and h 2 , cupule ih lateral to anterior end of anal opening. Opisthonotal gland opening anterolateral to seta lp . Paraproctal valves (segment PS) glabrous. Shape and colour of protonymph as in larva, but gastronotum with 15 pairs of setae ( p -series added) ( Fig. 6b ), which are retained in subsequent nymphs ( Figs. 8a, 8b ). Most gastronotal setae on gastronotal shield ( d -, l -, h -series, p 1 ), setae p 2 and p 3 on unsclerotized integument; all short. In protonymph, most gastronotal setae with short and rare barbs, in other nymphs all setae smooth. Seta of c -series on separate microsclerites, gastronotal shield punctate. In protonymph, one pair of genital setae appearing on genital valves, and two pairs added in deutonymph and tritonymph each ( Figs. 8a, 8b ). In deutonymph, one pair of aggenital setae and three pairs of adanal setae ap- pearing, and remaining in subsequent instars; all short and smooth, in some individuals additional seta ad present. Tritonymph with two pairs of anal setae on anal valves ( Figs. 7b , 8b ). In tritonymph, all gastronotal setae short ( Fig. 9 ), setae of c -series on microsclerites. Cupules ia and im as in larva, cupule ip between setae h 2 and p 1 , cupule iad lateral to anterior part of anal valves, cupules ips and ih displaced lateral to iad . Opisthonotal gland opening anteroventral to seta lp , humeral organ located anterior to seta c 3 . Legs of tritonymph more stocky ( Fig. 10 ) than in adult, but location and shape of most setae and solenidia as in adult, except for solenidion ω 2 on tarsus I, located anterolateral to solenidion ω 1 ; in adult this solenidion located posterior to ω 1 . In tritonymph, setal pair v on tibia and pv and s on tarsi with shorter barbs than in adult, and some setae lacking ( l” and v’’ on femora I and II and v’ and l” on tarsus I, 30 randomly chosen tritonymphs investigated) compared to adult. FIGURE 6. Minunthozetes semirufus , ventral aspect of hysterosoma, legs partially drawn, scale bar 20 μm. (a) Larva, (b) protonymph. FIGURE 7. Minunthozetes semirufus , lateral aspect, legs partially drawn, scale bars 50 μm. (a) Larva, (b) tritonymph. Summary of ontogenetic transformations In the juveniles, the prodorsal setae ro , le and in are of medium size and remain so in the adult, except for seta ro which is alveolar in the adult. Seta ex is short in all instars. In all juveniles, the bothridium is small, rounded, and occupies the dorsal position, whereas in the adult it is covered by anterior tectum of the notogaster and is in antero- medial position. In all juveniles, the bothridial seta is clavate, with barbed head, whereas in the adult it is fusiform, with thin, long and pointed apical end. The larva has 12 pairs of gastronotal setae, including h 3 , the nymphs have 15 pairs. The notogaster of adult loses five pairs of setae ( c 1 , c 3 and d -series), such that 10 pairs of notogastral setae remain. The formula of gastronotal, epimeral, genital and aggenital setae and setal formula of segments PS̅AN are as in M . pseudofusiger (Seniczak et al. 2018b) . The ontogeny of leg setae and solenidia is generally similar to that of M . pseudofusiger (Seniczak et al. 2018b) , except for l” on femora I and II that is added in the adult, whereas in M . pseudofusiger this seta is added in the tritonymph. In the nymphs of M . semirufus , solenidion ω 2 on tarsus I is located anterolateral to ω 1 , whereas in the adult it is located posterior to ω 1 .