Minunthozetes semirufus ( C.L. Koch, 1841 )

Seniczak, Stanisław & Seniczak, Anna, 2018, Morphological ontogeny of Minunthozetes semirufus (Acari: Oribatida: Punctoribatidae), Zootaxa 4540 (1), pp. 73-92 : 74-82

publication ID	https://doi.org/ 10.11646/zootaxa.4540.1.8
publication LSID	lsid:zoobank.org:pub:2B0486C3-6F4F-4A45-8CF6-DF24E1ED65E1
DOI	https://doi.org/10.5281/zenodo.5997567
persistent identifier	https://treatment.plazi.org/id/037487B3-AC1D-ED0F-FAE1-FCE4FC0EF1EB
treatment provided by	Plazi
scientific name	Minunthozetes semirufus ( C.L. Koch, 1841 )
status

Treatment

Minunthozetes semirufus ( C.L. Koch, 1841)

( Figs. 1–10 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 )

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 View FIGURE 1 View FIGURE 2 View FIGURE 3 ) 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 View FIGURE 3 ). Cheliceral seta cha longer and thicker than chb, both barbed ( Fig. 3b View FIGURE 3 ), palp setae sup, inf and l” on tibia finely barbed, other setae smooth ( Fig. 3c View FIGURE 3 ). 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 View FIGURE 4 ), dorsal integument on tibia and tarsus III not thickened ( Fig. 4c View FIGURE 4 ). 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 View FIGURE 1 , 2 View FIGURE 2 , 3a View FIGURE 3 ). 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 .

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 View FIGURE 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.

(mean measurements of 10 specimens in μm).

Gastronotum of larva ( Figs. 5 View FIGURE 5 , 6a View FIGURE 6 , 7a View FIGURE 7 ) 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 View FIGURE 7 ). 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 View FIGURE 6 ), which are retained in subsequent nymphs ( Figs. 8a, 8b View FIGURE 8 ). 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 View FIGURE 8 ). 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 View FIGURE 7 , 8b View FIGURE 8 ). In tritonymph, all gastronotal setae short ( Fig. 9 View FIGURE 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 View FIGURE 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.

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.