Conoppia palmicincta (Michael, 1880)

Seniczak, Stanisław & Seniczak, Anna, 2024, Morphological ontogeny of Conoppia palmicincta (Acari, Oribatida, Cepheusidae), Zootaxa 5485 (1), pp. 130-154 : 131-145

Conoppia palmicincta (Michael, 1880)

( Figs 1 –18)

Leiosoma palmicinctum Michael, 1880 .

Oppia microptera Berlese, 1885 .

Conoppia microptera ( Berlese, 1885) : Willmann 1931; Balogh 1963; Karppinen and Krivolutsky 1982; Golosova et al. 1983; Schatz 1983; Tarman 1983; Karppinen et al. 1986, 1987, 1992; Marshall et al. 1987; Olszanowski et al. 1996; Niemi et al. 1997; Pankov et al. 1997; Ryabinin and Pankov 2002; Niedbała and Olszanowski 2008; Behan-Pelletier and Lindo 2019.

Conoppia palmicincta : Grandjean 1936; Pérez-Iñigo 1972; Subías and Iturrondobeitia 1978; Alberti and Błaszak 1985; Luxton 1990; Bernini et al. 1995; Shtanchaeva 2001; Schatz 2018, 2020; Miko 2016; Murvanidze and Mumladze 2016.

Phyllotegeus palmicinctum : Berlese 1913, Willmann 1927.

Diagnosis. Adult large (length 900–1250), with spherical hysterosoma, brown to dark brown. Prodorsal seta in long, le and ro of medium size, and ex short. Lamellae long, translamella present. Bothridium large, rounded, bothridial seta fusiform, with smooth head. Notogaster spherical, with nine pairs of setae (short h 1, p 1 and p 2, and alveolar l - series, h 2, h 3 and p 3).

Juveniles roundish, flattened, with most prodorsal setae setiform (short ro, le and ex; long bs), and phylliform and reticulate in. Larva with 11 pairs of gastronotal setae, including h 2, nymphs with 12 pairs. Most gastronotal setae wide, phylliform and reticulate, located in marginal positions on gastronotum, except for five pairs of setiform setae in larva (very long c 3 and h 1, medium sized h 2 and short da and dm), and four pairs of setiform setae in nymphs (very long c 3 and h 2, long p 2 and shorter p 3). Nymphs belong to eupheredermous, i.e. they lose their dorsal setae of d -series and carry exuvial scalps of previous instars on gastronotum. Most leg setae of juveniles setiform, except for three wide, phylliform setae on leg I of larva, from which l’’ on genu is reticulate, while l’ on genu and tibia has longitudinal lines. Seta l’’ on tibia I of larva, and l’’ on tibiae I and II of nymphs relatively long. Seta d accompanies solenidion σ on genua I–III and φ on tibiae II–IV.

Morphology of adult. Adults large, with spherical hysterosoma ( Figs 1 , 2 , 3a , 4a, 4b ) and brown to dark brown, similar to that redescribed by Subías and Iturrondobeitia (1978), Luxton (1990), and Baran and Bilici (2017), but see Remarks. Mean measurements (with standard deviation and range): length of females 1057.2±23.9 (1011–1092, n= 7) and males 975.3±16.0 (945–994, n= 6), width of females 801.0±42.5 (782–897) and males 726.6±35.1 (712– 799). Prodorsal seta in long and finely barbed, le and in of medium size, and ex short, all smooth ( Figs 1 , 2 , 3a , 4 , 5a, 5b ). Lamellae long, translamella present. Bothridium large, rounded, bothridial seta fusiform, with smooth head. Hysterosoma spherical, notogaster with nine pairs of setae; short h 1, p 1 and p 2 ( Figs 1 , 2 , 3a, 3d , 4a, 4b ), and alveolar l -series, h 2, h 3 and p 3. Lyrifissure ia anterolateral to vestige of seta la, im posterolateral to vestige of seta lm, ip anterolateral to seta p 1, iad lateral to anterior part of anal plate, ips and ih anteromedial and anterior to seta h 1, respectively ( Figs 1 , 2 , 3a ). Opisthonotal gland opening gla posterolateral to vestige of seta h 3. Subcapitular seta h, m and a short and smooth, a slightly shorter than other setae, small porose areas present on basal part of subcapitular plate ( Figs 2 , 3e , 5a ). Chelicera chelate-dentate (264 × 99), cha slightly longer than chb, cha finely barbed, chb smooth ( Figs 3b , 5a ). Palp relatively short (158), with setae of medium size and smooth ( Fig. 3c , 5a ), formula of palp setae (trochanter to tarsus + solenidion ω): 0-2-1-3-9(1).

All epimeral setae short and smooth ( Figs 2 , 4b , 5a ), formula of epimeral setae 3-1-3-3. Genital setae (6 pairs) short and smooth, g 5 and g 6 inserted wider than other genital setae. Aggenital (1 pair), adanal setae (3 pairs) and anal setae (2 pairs) short and smooth.

Trochanter III and IV and all femora flattened, with ventral carina, most leg setae with short barbs, setae l on tibiae I and II relatively long ( Figs. 4 , 5a, 5b , 6 ), and seta d at solenidia lost. Formulae of leg setae (and solenidia), trochanter to tarsus: I—1-5-(3+1)-(4+2)-(20+2); II—1-5-(3+1)-(4+1)-(15+2); III—2-3-(2+1)-(3+1)-15; IV—1-2-3- (3+1)-12 ( Table 2 ). Leg tarsi heterotridactylous.

Remarks. The adults of C. palmicincta investigated here are smaller than those studied by Luxton (1990) — mean length 1107 (1000–1250, n= 9), mean width 937 (800–1080), and similar as the adults investigated by Pérez-Iñigo (1972) —length 990–1040 (n= 9), width 780–884, and Subías and Iturrondobeitia (1978) —length 805–1105, but larger than those studied by Willmann (1931) —length 900, width 675, and Baran and Bilici (2017) —length 800–840, width 635–680; Luxton (1990) noticed significant differences in size between males and females, while Subías and Iturrondobeitia (1978) have not observed such differences, in other papers sex was not investigated.

Luxton (1990) observed on the posterior part of notogaster of this species two pairs of setae, and in the lectotype of C. palmicincta he found two pairs of possible insertions of setae and six pores, some with fine, short setae. Baran and Bilici (2017) also found in this species two pairs of notogastral setae. By contrast, Subías and Iturrondobeitia (1978) observed three pairs of setae on posterior part of notogaster, as in our individuals, and several pairs of alveoli, but these authors did not label them. In our C. palmicincta , the genital setae g 5 and g 6 are inserted wider than other genital setae, as in the adults drawn by Grandjean (1962, 1969), Subías and Iturrondobeitia (1978), and Baran and Bilici (2017). In the adult drawn by Luxton (1990), only g 5 is inserted wider than other genital setae.

Description of juvenile stages. Larva oval in dorsal and ventral view ( Figs 7 , 8a , 5c, 5d ), flattened in lateral aspect ( Fig. 9a ), and light-yellow. Prodorsal setae ro, le, and ex short and smooth, whereas seta in phylliform, reticulate and of medium size ( Figs 7 , 9a , 5c , 10a, 10b , Table 1 ). Mutual distance between setal pair le about 1.5 times longer than that between setal pair ro, and between setal pair in about 2.5 times longer than that between setal pair ro. Seta le inserted closer to ro than to in ( Figs 7 , 9a ). Bothridium rounded, covered by wide, phylliform, reticulate gastronotal seta c 1 in dorsal view, bothridial seta long, setiform and barbed ( Figs 7 , 9a , 5c , 10a ). Prodorsal shield well-developed, with transverse and slanting wrinkles, and covered with granular cerotegument.

Gastronotum of larva with 11 pairs of setae, including h 2 located posterior to anal valves. Most setae wide, phylliform and reticulate, in marginal position on gastronotum, except for setiform and very long c 3 and h 1 ( Figs 7 , 8a , 9a , 5c, 5d , 10 , 11c, 11d ), medium sized h 2 and short da and dm ( Table 1 ), located in central part of gastronotum. Central part of gastronotum with transverse and slanting wrinkles, and covered with granular cerotegument. Setae c 3 and h 1 finely barbed in basal part and directed anteriorly and posteriorly, respectively, but its apical ends directed posteriorly and anteriorly, respectively; other setae smooth. Long setae on large apophyses, small setae on small apophyses. Opisthonotal gland opening gla and most cupules not observed under wide, phylliform and reticulate setae, except for ih located laterally to anterior part of anal valves. Paraproctal valves (segment PS) glabrous. Most leg setae of medium size, except for relatively long l’’ on tibia I, and three wide, phylliform setae on leg I of larva (l on genu and l’ on tibia), from which l’’ on genu is reticulate, while l’ on genu and tibia has longitudinal lines ( Figs 5c, 5d , 10a–c , 12 , 13 ). Seta d accompanies solenidion σ on genua I–III and φ on tibiae II and III.

Prodorsum and prodorsal setae of protonymph as in larva, but gastronotum with 12 pairs of setae because setae h 3 and setae of p -series appearing and present in other nymphs, and setae of d -series lost and absent in other nymphs. Most gastronotal setae long, wide, phylliform, reticulate and inserted in marginal positions on gastronotum ( Figs 8b , 9b , 14 , 15 , 16 , 17a, 17b, 17d ), except for setiform and very long c 3 and h 2, long p 2 and shorter p 3. In protonymph p 3 short, in other nymphs of medium size; all smooth. Long setae on large apophyses, small setae on small apophyses, but apophyses of wide, phylliform and reticulate setae with thorns. In protonymph, one pair of genital setae present, and two pairs added both, in deutonymph and tritonymph. In deutonymph one pair of aggenital setae and three pairs of adanal setae appearing and present in tritonymph, all short and smooth ( Figs 8b , 14 ). Paraproctal valves of protonymph and deutonymph glabrous, those of tritonymph with two pairs of small and smooth setae. Opisthonotal gland opening gla and most cupules not observed under wide, phylliform setae, except for ips and ih located laterally to anterior and middle part of anal valves of protonymph, respectively, and iad located laterally to anterior part of anal valves of deutonymph and tritonymph ( Figs 8b , 14 ). In deutonymph and tritonymph, cupules ih and ips pushed posterolaterally to iad. Nymphs flattened in lateral aspect and carry exuvial scalps of previous instars ( Figs 9b , 15 , 16 ). After removing exuvial scalps central part of gastronotum with transverse and slanting wrinkles, and covered with granular cerotegument. Legs of nymphs with setiform setae, and covered with granular cerotegument ( Figs 17 , 18). Seta l’’ on tibia I and II relatively long, seta d accompanies solenidion σ on genua I–III and φ on tibiae II–IV.

Summary of ontogenetic transformations. In all juveniles of C. palmicincta the prodorsal setae ro, le and ex are short and setiform, whereas in is of medium size, phylliform and reticulate, while in the adult all these setae are setiform; in is long, ro and le are of medium size, and ex is short. In all juveniles, the bothridial seta is setiform and barbed, whereas in the adult it is fusiform, with smooth head. The larva has 11 pairs of gastronotal setae, including h 2, the nymphs have 12 pairs (h 3 and p -series are added, and d -series is lost in protonymph, and is absent in other instars), while the notogaster of adult loses setae of c -series, and only three pairs of setae (h 1, p 1 and p 2) and six pairs of alveolar vestiges (l -series, h 2, h 3 and p 3) remain. The formula of gastronotal setae (including alveolar setae) is 11-12-12-12-9 (larva to adult), and those of epimeral setae are: 3-1-2 (larva), 3-1-2-1 (protonymph), 3-1-2- 3 (deutonymph) and 3-1-3-3 (tritonymph and adult). The formula of genital setae is 1-3-5-6 (protonymph to adult), and that of aggenital setae is 1-1-1 (deutonymph to adult). The formula of segments PS–AN is 3333-0333-022. Ontogeny of leg setae and solenidia is given in Table 2 .

Distribution, ecology and biology. Conoppia palmicincta has a Holarctic distribution ( Subías 2004, updated 2024). Ivan et al. (2003) considered this species mountainous and silvicolous. This species was found in the shrub litter of Erica scoparia L. ( Pérez-Iñigo 1972), in moss on rock ( Baran & Bilici 2017), and in forest soil and on tree trunks ( Murvanidze & Mumladze 2016). In Austria it inhabits many habitats, such as colline to montane forests, colline meadows, low montane wetlands, and xeric to wet subalpine pastures at altitude 490–1610 m a. s. l. ( Schatz 2020). Conoppia palmicincta was found in several plant associations, like Piceeto-Abieto-Fagetum- Oxalidosum ( Călugăr & Vasiliu 1980), Pino mugo-Sphagnetum ( Borcard 1992) and Sphagnum mosses with Carex rostrata Stokes ( Borcard et al. 1995) . It prefers the upper soil layer ( Vasiliu & Călugăr 1985). In Grandjean’s (1941) investigations, the sex ratio of C. palmicincta (females to males) was 1:0.9. The time of development of this species in the laboratory lasted 375 days at 25 oC ( Michael 1884, Pfingstl & Schatz 2021).

In this study, C. palmicincta was collected from mosses on Scots pine trees in Saldropo National Park (Bilbao, northern Spain), and its mean density was 15 individuals per 500 cm 3. In population of this species the juveniles dominated, comprising 57% of all mites, and the stage structure was: 6 larvae, 2 protonymphs, 7 deutonymphs, 4 tritonymphs and 13 adults. The sex ratio (females to males) was 1:0.9. Most females (71%) were gravid carrying 2–8 (usually 4) large eggs, each 338 ×169, constituting 40% of body length of females .

Figures

FIGURE 1. Conoppia palmicincta, adult, dorsal aspect, legs I and II partially drawn, scale bar 100 μm.

FIGURE 2. Conoppia palmicincta, adult, ventral aspect, legs partially drawn, scale bar 100 μm.

FIGURE 3. Conoppia palmicincta, adult. (a) Lateral aspect, legs partially drawn; mouthparts, right side, antiaxial aspect, (b) chelicera; (c) palp; (d) part of posterior part of notogaster, posterior aspect; (e) subcapitular plates, ventral aspect. Scale bars 100 μm (a, d), and 50 μm (b, c, e).

FIGURE 4. Conoppia palmicincta, adult, SEM micrographs. (a) Dorsal view; (b) ventral view; (c), (d) anterior part of body, dorsal view.

FIGURE 5. Conoppia palmicincta, SEM micrographs. Adult, (a) anterior part of body, ventral view; (b) leg I, dorsal view; larva, (c) dorsal view, (d) ventral view.

FIGURE 6. Conoppia palmicincta, leg segments of adult (part of femur to tarsus), right side, antiaxial aspect, scale bar 50 μm. (a) Leg I, tarsus (pl’ not illustrated); (b) leg II; (c) leg III; (d) leg IV.

FIGURE 7. Conoppia palmicincta, larva, dorsal aspect, legs I partially drawn, scale bar 20 μm.

FIGURE 8. Conoppia palmicincta, ventral part of hysterosoma, legs III and IV partially drawn, scale bar 50 μm. (a) Larva, (b) protonymph.

FIGURE 9. Conoppia palmicincta, lateral aspect, legs partially drawn, scale bars 100 μm. (a) Larva, (b) protonymph with the exuvial scalp of larva (L).

FIGURE 10. Conoppia palmicincta, larva, SEM micrographs. Anterior part of body, (a), (b) dorsal view, (c) ventral view; (d) posterior part of body, dorsal view.

FIGURE 11. Conoppia palmicincta, larva, SEM micrographs. Ventral view, (a) anterior part of body; (b), (c), (d) posterior part of body.

FIGURE 12. Conoppia palmicincta, larva, SEM micrographs. Ventral view, (a), (b) leg I; (c) leg III; (d) leg II.

FIGURE 13. Conoppia palmicincta, leg segments of larva, right side, antiaxial aspect, scale bar 50 μm. (a) Leg I, tarsus (pl’ not illustrated); leg II; (c) leg III.

FIGURE 14. Conoppia palmicincta, ventral part of hysterosoma, legs IV partially drawn, scale bar 100 μm. (a) Deutonymph, (b) tritonymph.

FIGURE 15. Conoppia palmicincta, tritonymph, dorsal aspect, leg I partially drawn, scale bar 100 μm; right side with the exuvial scalps of larva to deutonymph.

FIGURE 16. Conoppia palmicincta, tritonymph, SEM micrographs. Dorsal view, (a), (b) habitus; (c) medial and posterior part of body; (d) anterior and medial part of body.

FIGURE 17. Conoppia palmicincta, tritonymph, SEM micrographs. Ventral view, (a) habitus; (b) anterior and medial part of body; (c) anterior part of body; (d) leg II and III.

Tables

TABLE 1. Measurements of some morphological characters of instars of Conoppia palmicincta (mean measurements of 2–10 specimens in μm); nd—not developed.

Morphological characters		Larva	Protonymph	Deutonymph	Tritonymph	Adult
Body length		390	520	618	880	1065
Body width		273	325	501	717	809
Length of prodorsum		83	118	135	158	325
Length of:	seta ro	17	23	28	77	99
	seta le	12	16	19	43	116
	seta in	46	51	57	62	215
	seta bs	110	150	160	165	66
	seta c 1	125	145	182	231	lost
	seta c 2	86	138	158	172	lost
	seta c 3	462	364	435	650	lost
	seta da	10	lost	lost	lost	lost
	seta dp	109	lost	lost	lost	lost
	seta la	90	114	121	152	lost
	seta lp	91	115	122	150	lost
	seta h 1	413	114	112	155	56
	seta h 2	66	533	631	683	lost
	seta h 3	nd	104	132	149	lost
	seta p 1	nd	88	125	132	54
	seta p 2	nd	84	101	115	53
	seta p 3	nd	22	25	61	lost
genital opening		nd	45	53	97	120
anal opening		77	93	128	198	221