Perlohmannia nasuta Schuster 1958
Creators: name: Seniczak, Stanisław
name: Ivan, Otilia
name: Marquardt, Tomasz
name: Seniczak, Anna
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Sarcoptiformes
Perlohmanniidae
Perlohmannia
Perlohmannia nasuta

description: Perlohmannia nasuta Schuster, 1958
(Figs. 1–15)
Diagnosis
Adult large (length 626–999). Rostrum with medial tooth, rostral setae usually inserted one behind another, but sometimes in transverse row. Bothridial seta with 8–9 anterior spines, exobothridial seta exa setiform, exp alveolar. Notogastral seta c 1 as short as d 1.
Juveniles elongated and unpigmented, except for light brown prodorsum, posterior part of gastronotum, epimeres and legs. Rostrum with medial tooth, rostral setae inserted one behind another. Bothridial seta with 7–8 anterior spines, exobothridial seta exa setiform, seta exp alveolar. Gastronotal seta e 2 longer than f 2. Hypertrichy occurs on tarsi, especially on tarsus I. Claparède’s organ of larva long, cudgel-shaped.
Morphology of adult
Adult (Figs. 1, 2, 3a, 4–6, 7a) similar to that described by Schuster (1960, 1965), but see Remarks. Mean length (and range) of females 954.8±29.9 (873–999, n= 22) and males 863.5±41.3 (795–933, n= 8), mean width (and range) of females 374.6±10.8 (361–403) and males 360.5±5.9 (349–367). Exobothridial seta exa setiform, exp alveolar (Figs. 1, 3a, 5, 6a, 6b). Most notogastral setae of medium size (Table 1). Lyrifissure ia posterolateral to seta cp, im anterolateral to seta e 2, ip lateroventral to seta h 3, ian anterior to seta an 3, iad anteromedial to seta ad 3, and ips and ih pushed anterolateral to seta ad 3, opisthonotal gland opening anterior to seta h 3 (Figs. 1, 2, 3a). Chelicera chelate, seta cha clearly longer than chb, cha finely barbed, chb smooth (Fig. 3b). Most palpal setae relatively short and smooth (Fig. 3c), solenidium ω and eupathidia ul relatively long, eupathidium su short, formula of setae (trochanter to tarsus + solenidion ω): 2-0-3-8(1). Ovipositor with relatively long apical setae τ 1 and ψ 1 (Fig. 3a). Trochanters III and IV and all femora oval in cross section, with porose areas on paraxial side. Most leg setae smooth, some of them (pv, ft) finely barbed. On all genua and tibiae seta d present, separated from proper solenidion (Fig. 4). In all tarsi, hypertrichy occurs (Fig. 4, Table 2), especially on tarsus I (38–40 setae). Formulae of leg setae (and solenidia), trochanter to tarsus: I – 1-7-5(2)-5(3)-(39-41)(3); II – 1-7-5(1)-5(1)-17(2); III – 2-3-4(1)-5(1)-17; IV – 2-3-4(1)-4(1)-14. Leg tarsi monodactylous.
Remarks. Our individuals are clearly larger than those described by Schuster (1960, 1965, body length 626–740 and width 218–232) and investigated by Miko (1989, body length 626–782 and width 218–308) and Bernini (1970, length of female 870 and male 760, width of female 340 and male 320). In our individuals, the second exobothridial seta (exp) is alveolar, not mentioned by these authors. The other characters of P. nasuta are similar as in Schuster (1960, 1965).
Description of juvenile stages
Larva elongated (Fig. 8) and unpigmented, except for light brown prodorsum, posterior part of gastronotum, epimeres and legs. Prodorsum trapezoid, porose, rostrum with middle tooth. Prodorsal setae ro of medium size (Table 1) and smooth, inserted after middle tooth one behind another. Pair le short, inserted closer to posterior seta ro than to pair in. Pair in long, inserted close to inner part of bothridium, mutual distance between pair in slightly longer than between pair le, pair exa short and smooth, pair exp alveolar; all prodorsal setae smooth. Opening of bothridium rounded, bothridial seta pectinate, with 7–8 anterior spines, located on its distal half.
Gastronotum of larva with 14 pairs of setae, including alveolar f 1 and inguinal h 4, inserted anterolateral to anterior part of anal valves. Most setae short and smooth, except for longer e 1, e 2, f 2, h 1, and h 2 (Table 1, Figs. 8, 9a, 10a). Posterior part of gastronotum with foveae. Cupule ia posterior to seta cp, im anterior to seta e 2, ip not found between foveae, ih posterior to seta h 4 (Figs. 9a, 10a). Opisthonotal gland opening gla anterior to seta h 1. Paraproctal valves (segment PS) with one pair of small setae. Chelicera strong, extending beyond rostrum in lateral aspect, Claparède’s organ long, cudgel-shaped (Fig. 10b). All femora oval in cross section, leg I thicker than other legs (Figs. 11a–c). All leg setae of medium size or short, genu I with two solenidia, solenidia φ 1 on tibia I and ω 1 on tarsi I and II thicker than other solenidia, curved ventrally and directed anterior, φ 1 longest, ω 1 on tarsus II shortest. Seta d on all genua and tibiae present, d on genu I alveolar. Seta l’ present on all tarsi (Fig. 11, Table 2).
Prodorsal setae, bothridium and bothridial seta of protonymph as in larva, but prodorsum slimmer, and seta ro relatively shorter than in larva. Gastronotum elongated, with 16 pairs of setae, including alveolar f 1 because inguinal seta h 4 lost and three pairs of setae of p -series appearing in protonymph, and remaining in deutonymph and tritonymph (Figs. 9b, 12a, 12b). Genital valves of protonymph with one pair of genital setae, and three pairs added in deutonymph and two pairs in tritonymph; all short and smooth. In deutonymph, one pair of aggenital setae appearing, and one pair added in tritonymph, all short and smooth. In deutonymph, three pairs of adanal setae appearing, and remaining in tritonymph; ad 1 of medium size, and length decreasing from ad 1 to ad 3. Anal valves of protonymph and deutonymph glabrous, in tritonymph with two pairs of short and smooth setae. In all nymphs, bothridial seta pectinate, with 7–9 anterior spines, located in its medial and distal parts (Figs. 7 b-d, 13). In tritonymph, gastronotum punctate and chelicera strong (Figs. 14a, 14c). Cupules ia and im placed as in larva, ip not observed between foveae, iad lateral to anterior part of anal valves, ips and ih pushed lateral and anterolateral to iad, respectively (Figs. 10c, 12b, 13). Gland opening gla anterior to seta p 2.All femora of nymphs oval in cross section, and leg I thicker than other legs (Figs. 11d–g, 14c, 15). In protonymph, most leg setae of medium size and smooth, and all setae added on femur I (Figs. 11d–g, Table 2). On all genua and tibiae seta d present, d on genu I setiform. Hypertrichy present on tarsi, especially on tarsus I, which increases during ontogeny [19-(27–28)-(32–34) setae, from protonymph to tritonymph, Figs. 11, 15].
Summary of ontogenetic transformations
The number of prodorsal setae is constant during the ontogeny of P. nasuta. In all instars, pair ro is of medium size, inserted one behind other, except for some adults, in which these setae are inserted either one behind another or in transverse row. In these stages, setal pair exp is alveolar, the location of other prodorsal setae is similar as in the larva, and length increases during the ontogeny. In all instars, the opening of bothridium is rounded, and the bothridial seta is pectinate, with 7–9 anterior spines. The larva has 14 pairs of gastronotal setae, including alveolar f 1, the nymphs have 16 pairs (inguinal seta h 4 lost, p -series appears in protonymph, and present in other instars). The formula of gastronotal setae in P. nasuta is 14-16-16-16-16 (larva to adult, including alveolar f 1), genital setae is 1-4-6-8 (protonymph to adult) and aggenital setae is 1-2-2 (deutonymph to adult). In the adult, the genital plate is divided in two parts, with six and two pairs of setae in anterior and posterior parts, respectively. Formulae of epimeral setae are 3-1-2 (larva, including scaliform 1c), 3-1-3-2 (protonymph), 3-1-3-3 (deutonymph) and 3-1-3-4 (tritonymph and adult). The ontogeny of leg setae and solenidia is given in Table 2.
Distribution, ecology and biology
Perlohmannia nasuta is known from centromeridional Europe (Subías 2004, unpublished electronic update 2021), and belongs to xerothermophilous and macrophytophagous (Schatz 1983). It was recorded from Austria (Schuster 1960), Hungary (Mahunka & Mahunka-Papp 2004), Slovakia and Czechia (Miko 1989, 2016), Italy (Bernini et al. 1995), Slovenia (Tarman 1983), Romania (Vasiliu et al. 1993), Germany (Weigmann 2006), and Caucasus (Shtanchaeva & Subías 2010). Perlohmannia nasuta was recorded from forest, meadow and arable soils (Schuster 1960, Weigmann 2006). In Romania it was recorded mainly from forests (Vasiliu et al. 1993, Ivan & Vasiliu 2000), but was neither frequent nor abundant.
In this study, P. nasuta was more abundant in the soil of forest steppe hayfield (14.6 individuals per 500 cm 3), than in that of moist habitat, with grassy cover (10.4 individuals per 500 cm 3), dominated by horsetail. In the former soil, the adults of this species dominated (36% of all individuals), whereas in the latter soil the juveniles were more abundant (62% of all individuals). In the forest steppe hayfield, the stage structure of P. nasuta was the following: 1 larva, 5 protonymphs, 12 deutonymphs, 8 tritonymphs and 47 adults, whereas in the moist habitat the number of these instars was 1, 6, 22, 3 and 20, respectively. In population of P. nasuta, females dominated (sex ratio, females to males, was 1:0.36), but no female was gravid and carried egg. Females were significantly larger than males.
description: Published as part of Seniczak, Stanisław, Ivan, Otilia, Marquardt, Tomasz & Seniczak, Anna, 2021, Morphological ontogeny of Perlohmannia nasuta (Acari, Oribatida, Perlohmanniidae), with comments on Perlohmannia Berlese, pp. 29-48 in Zootaxa 5086 (1) on pages 30-36, DOI: 10.11646/zootaxa.5086.1.5, http://zenodo.org/record/5814445