Contributions to the knowledge of oribatid mites of Indonesia. 2. The genus Pergalumna (Galumnidae) with description of a new species and key to known species in the Oriental region (Acari, Oribatida)

Sergey Ermilov; Dorotee Sandmann; Bernhard Klarner; Rahaju Widyastuti; Stefan Scheu

doi:10.3897/zookeys.529.6421

Research Article

Contributions to the knowledge of oribatid mites of Indonesia. 2. The genus Pergalumna (Galumnidae) with description of a new species and key to known species in the Oriental region (Acari, Oribatida)

Sergey G. Ermilov^‡, Dorotee Sandmann^§, Bernhard Klarner^§, Rahaju Widyastuti^|, Stefan Scheu^§

‡ Tyumen State University, Tyumen, Russia

§ Georg-August-University Göttingen, Göttingen, Germany

| Institut Pertanian Bogor, Bogor, Indonesia

Corresponding author: Sergey Ermilov ( ermilovacari@yandex.ru )

Academic editor: Vladimir Pesic

This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation: Ermilov SG, Sandmann D, Klarner B, Widyastuti R, Scheu S (2015) Contributions to the knowledge of oribatid mites of Indonesia. 2. The genus Pergalumna (Galumnidae) with description of a new species and key to known species in the Oriental region (Acari, Oribatida). ZooKeys 529: 87-103. https://doi.org/10.3897/zookeys.529.6421

ZooBank: urn:lsid:zoobank.org:pub:6C38D7A7-63BC-4314-8E4C-5BD45EBCC89A

Abstract

A new species of oribatid mite of the genus Pergalumna (Oribatida, Galumnidae) is described from litter and soil materials in Sumatra, Indonesia. Pergalumna paraindistincta sp. n. is morphologically most similar to P. indistincta Ermilov & Anichkin, 2011, P. pertrichosa Mahunka, 1995 and P. sura Balogh, 1997; however, the new species differs from P. indistincta by the smaller body size, presence of long adanal setae ad₁, and large, single median pore in females and males; from P. pertrichosa by the smaller body size, presence of three pairs of notogastral porose areas, elongated A1 and minute anal setae; from P. sura by the presence of strong adanal setae ad₁, large, single median pore in females and males, and shorter bothridial setae. Furthermore, Pergalumna hawaiiensis hawaiiensis (Jacot, 1934) and P. panayensis Ermilov & Corpuz-Raros, 2015 are recorded for the first time in the Indonesian fauna. An identification key to the known species of Pergalumna in the Oriental region is given.

Keywords

Oribatid mites, Pergalumna , new species, new record, key, Indonesia, Oriental region

Introduction

This work is a part of a continuing study on the Indonesian fauna of oribatid mites, and it includes the data on the genus Pergalumna Grandjean, 1936 (Oribatida, Galumnidae). During taxonomic identification, four species were identified, including one new to science. The primary goal of the paper is to present data on the specific localities, notes on new records and overall known distributions of registered taxa and to describe the new species.

Pergalumna is a genus that was proposed by Grandjean (1936) with Oribata nervosa Berlese, 1914 as type species. Based on an updated generic diagnosis (Ermilov et al. 2013b), it comprises more than 140 species (Subías 2004, updated 2015; Ermilov and Bayartogtokh 2015; Ermilov and Corpuz-Raros 2015) having collectively a cosmopolitan distribution (Subías 2004, updated 2015). The identification keys to selected species were given by Shaldybina (1975), Balogh and Balogh (1990, 2002), Weigmann (2006), and Ermilov et al. (2014b). The secondary goal of the paper is to provide an identification key to known species of Pergalumna in the Oriental region.

Materials and methods

Exact collection locality and habitat are given in the respective “Material examined” section for each species.

Specimens were mounted in lactic acid on temporary cavity slides for measurement and illustration. The body length was measured in lateral view, from the tip of the rostrum to the posterior edge of the ventral plate. Notogastral width refers to the maximum width in dorsal aspect. Lengths of body setae were measured in lateral aspect. All body measurements are presented in micrometers. Formulas for leg setation are given in parentheses according to the sequence trochanter–femur–genu–tibia–tarsus (famulus included). Formulas for leg solenidia are given in square brackets according to the sequence genu–tibia–tarsus.

General terminology used in this paper follows that of Grandjean (summarized by Norton and Behan-Pelletier 2009).

Drawings were made with a camera lucida using a Carl Zeiss transmission light microscope “Axioskop-2 Plus”.

Description

Pergalumna paraindistincta sp. n.

http://zoobank.org/F1F876B8-867F-4EA9-851D-FB4186C05342

Figs 1, 2, 3–4, 5–9

Diagnosis

Body size: 415–481 × 298–365. Rostral, lamellar and interlamellar setae well developed, barbed. Bothridial setae long, setiform, ciliate. Anterior notogastral margin not developed. Three pairs of elongate oval porose areas on notogaster, Aa transversally oriented, located between la and lm, A1 longitudinally oriented. Median pore single, large. Adanal setae ad₁ of medium size, straight, heavily barbed. Postanal porose area absent.

Description

Measurements. Body length: 431 (holotype: male), 415–481 (10 paratypes: three females and seven males); notogaster width: 298 (holotype), 298–365 (10 paratypes). Without sexual dimorphism.

Integument. Body color brown. Body surface microgranulate, visible under high magnification, ×1000 (diameter of granules less than 1).

Prodorsum (Figs 1, 3, 5). Rostrum broadly rounded. Lamellar (L) and sublamellar (S) lines distinct, parallel, curving backwards. Rostral (ro, 41–49), lamellar (le, 69–77) and interlamellar (in, 86–90) setae setiform, barbed. Bothridial setae (bs, 114–127) setiform, densely ciliate in medio-distal parts. Exobothridial setae and their alveoli absent. Porose areas Ad narrowly elongate oval, transversally oriented (16–20 × 4).

Figure 1.

Pergalumna paraindistincta sp. n., adult: dorsal view. Scale bar 100 μm.

Figure 2.

Pergalumna paraindistincta sp. n., adult: ventral view (gnathosoma and legs not shown). Scale bar 100 μm.

Figures 3–4.

Pergalumna paraindistincta sp. n., adult: 3 anterior part of body, lateral view (gnathosoma and leg I not shown) 4 posterior view. Scale bar 100 μm.

Figures 5–9.

Pergalumna paraindistincta sp. n., adult: 5 bothridial seta 6 anterior part of left half of subcapitulum, ventral view 7 genital plate, right 8 anal plate, left, and adanal setae 9 tibia of leg IV, right, antiaxial view. Scale bar 20 μm.

Notogaster (Figs 1, 3, 4). Anterior notogastral margin not developed. Dorsophragmata (D) of medium size, elongated longitudinally. Notogastral setae represented by 10 pairs of alveoli. Three pairs of porose areas: Aa clearly bordered, elongate oval, transversally oriented (28–32 × 8–12), A1 distinctly bordered only in anterior part, elongate oval to slightly elongate triangular, longitudinally oriented (57–68 × 12–16), A3 without clear borders, elongate oval (24–28 × 8–12). Areas Aa located between setal alveoli la and lm, equal distanced from them. Median pore present in males and females, comparatively large (diameter 10–16). All lyrifissures (ia, im, ip, ih, ips) distinct, im located antero-laterally to A1. Opisthonotal gland openings (gla) located laterally to A1.

Gnathosoma (Fig. 6). Morphology of subcapitulum, palps and chelicerae typical for Pergalumna (see Engelbrecht 1972; Ermilov and Anichkin 2011a, b). Subcapitulum size: 102–106 × 102–106. Subcapitular setae setiform, slightly barbed, m (14–16) shorter than a and h (both pairs 18–20); a thickest, m thinnest. Two pairs of adoral setae (or₁, or₂, 12–14) setiform, hook-like distally, barbed. Palps (90–94) with typical setation: 0–2–1–3–9(+ω). Axillary sacculi (sac) distinct. Chelicerae (164) with two setiform, barbed setae; cha (41) longer than chb (24). Trägårdh’s organ long, tapered.

Epimeral and lateral podosomal regions (Fig. 2). Anterior tectum of epimere I smooth. Apodemes 1, 2, sejugal and 3 well visible. Six pairs of setae, setal formula: 1–0–2–3. Setae thin, slightly barbed, 1a, 3c and 4c (24) longer than 3b (10–14) and 4a and 4b (4); 1a thicker than others. Pedotecta II (Pd II) scale-like in lateral view, rounded distally in ventral view. Discidia (dis) sharply triangular. Circumpedal carinae (cp) slightly developed.

Anogenital region (Figs 2, 4, 7, 8). Six pairs of genital (g₁, g₂, 12; g₂–g₆, 8), one pair of aggenital (ag, 8), two pairs of anal (an₁, an₂, 8) and two pairs of adanal setae (ad₂, ad₃, 8) thin, indistinctly barbed. One pair of adanal setae (ad₁, 24–36) thickened, straight, heavily barbed, however, in three paratypes one seta of the ad₁ pair is short, as ad₂ and ad₃ in morphology. Adanal setae ad₃inserted laterally to adanal lyrifissures (iad). Genital plates with two or three setae on anterior edge of each plate. Postanal porose area absent.

Legs (Fig. 9). Morphology of leg segments, setae and solenidia typical for Pergalumna (see Engelbrecht 1972; Ermilov and Anichkin 2011a, b). Claws smooth. Formulas of leg setation and solenidia: I (1–4–3–4–20) [1–2–2], II (1–4–3–4–15) [1–1–2], III (1–2–1–3–15) [1–1–0], IV (1–2–2–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1. Solenidion φ of tibiae IV inserted dorsally in posterior part of segments.

Table 1.

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Leg setation and solenidia of adult Pergalumna paraindistincta sp. n.

Leg	Tr	Fe	Ge	Ti	Ta
I	v’	d, (l), bv’’	(l), v’, σ	(l), (v), φ₁, φ₂	(ft), (tc), (it), (p), (u), (a), s, (pv), v’, (pl), l’’, ε, ω₁, ω₂
II	v’	d, (l), bv’’	(l), v’, σ	(l), (v), φ	(ft), (tc), (it), (p), (u), (a), s, (pv), ω₁, ω₂
III	v’	d, ev’	l’, σ	l’, (v), φ	(ft), (tc), (it), (p), (u), (a), s, (pv)
IV	v’	d, ev’	d, l’	l’, (v), φ	ft’’, (tc), (p), (u), (a), s, (pv)

Material examined

Holotype (male): Indonesia, Sumatra, Harapan landscape, secondary rainforest, research site HF1, 02°09'09.9"S, 103°21'43.2"E, 76 m a.s.l., from forest floor litter material. Six paratypes (two females and four males): Indonesia, Sumatra, Harapan landscape, rubber plantation, research site HR2, 01°52'44.5"S, 103°16'28.4"E, 59 m a.s.l., from forest floor litter material. Four paratypes (one female and three males): Sumatra, Indonesia, Harapan landscape, jungle rubber agroforest, research site HJ1, 01°55'40.0"S, 103°15'33.8"E, 51 m a.s.l., from forest floor litter material. All specimens were collected by Bernhard Klarner (15.XI.2013) and identified and collected to morphospecies level by Dorothee Sandmann.

Type deposition

The holotype is deposited in LIPI (Indonesian Institute of Science) Cibinong, Indonesia; three paratypes are in the collection of the Senckenberg Museum, Görlitz, Germany; seven paratypes are in the collection of the Tyumen State UniversityMuseum of Zoology, Tyumen, Russia.

Etymology

The specific name paraindistincta refers to the morphological similarity of the new species to Pergalumna indistincta Ermilov & Anichkin, 2011.

Remarks

Pergalumna paraindistincta sp. n. is morphologically most similar to P. indistincta Ermilov & Anichkin, 2011 from Vietnam (see Ermilov and Anichkin 2011b) and P. sura Balogh, 1997 from the Neotropical region (see Balogh 1997; Ermilov et al. 2014a) in having rounded rostrum, well-developed prodorsal setae, setiform and ciliate of bothridial setae, three pairs of notogastral porose areas, transversally oriented Aa and strongly elongated, longitudinally oriented A1, and the absence of anterior notogastral margin as well as postanal porose area. However, the new species differs from both by the presence of strong adanal setae ad₁ (vs. minute in P. indistincta and P. sura) and large, single median pore in females and males (vs. median pore absent in males and represented by several foveae in females in P. indistincta, and absent in females and males in P. sura). Additionally, the new species is smaller than P. indistincta (415–481 × 298–365 vs. 547–614 × 381–415) and has shorter bothridial setae than P. sura.

Furthermore, P. paraindistincta sp. n. is morphologically similar to P. pertrichosa Mahunka, 1995 from Borneo (see Mahunka 1995) in having a rounded rostrum, well developed prodorsal setae, setiform and ciliate bothridial setae, strong adanal setae ad₁, a single median pore, and the absence of an anterior notogastral margin. However, the new species differs from the latter by the smaller body size (415–481 × 298–365 vs. 550–608 × 413–454 in P. pertrichosa), presence of three pairs of notogastral porose areas with elongated A1 (vs. four pairs of porose areas with A1 rounded in P. pertrichosa) and minute anal setae (vs. well developed in P. pertrichosa).

Records

Pergalumna hawaiiensis hawaiiensis (Jacot, 1934) (see Jacot 1934a). Distribution: Pacific Islands. New record for Indonesia.

Material examined. One specimen: Indonesia, Sumatra, Harapan landscape, Jungle rubber agroforest, research site HJ1, 01°55'40.0"S, 103°15'33.8"E, 51 m a.s.l., from upper soil layer (0–5 cm), 15.XI.2013 (B. Klarner). Three specimens: Indonesia, Sumatra, Bukit Duabelas landscape, rubber plantation, research site BR2, 02°05'06.8"S, 102°47'20.7"E, 95 m a.s.l., from upper soil layer (0–5 cm), 15.XI.2013 (B. Klarner). One specimen: Indonesia, Sumatra, Bukit Duabelas landscape, oil palm plantation, research site BO3, 02°04'15.2"S, 102°47'30.6"E, 71 m a.s.l., from upper soil layer (0–5 cm), 15.XI.2013 (B. Klarner).

Pergalumna panayensis Ermilov & Corpuz-Raros, 2015 (see Ermilov and Corpuz-Raros 2015). Distribution: Philippines. New record for Indonesia.

Material examined. One specimen: Indonesia, Sumatra, Harapan landscape, rubber plantation, research site HR2, 01°52'44.5"S, 103°16'28.4"E, 59 m a.s.l., from forest floor litter material, 15.XI.2013 (B. Klarner). One specimen: same data, but in upper soil layer (0–5 cm). One specimen: Indonesia, Sumatra, Bukit Duabelas landscape, jungle rubber agroforest, research site BJ4, 02°00'57.3"S, 102°45'12.3"E, 60 m a.s.l., from upper soil layer (0–5 cm), 15.XI.2013 (B. Klarner).

Pergalumna pterinervis (Canestrini, 1898) (see Mahunka 1992). Distribution: Oriental region. New record for Indonesia.

Material examined. One specimen: Indonesia, Sumatra, Harapan landscape, jungle rubber agroforest, research site HJ2, 01°49'31.9’S’, 103°17'39.2"E, 84 m a.s.l., from forest floor litter material, 15.XI.2013 (B. Klarner). One specimen: Indonesia, Sumatra, Harapan landscape, jungle rubber, research site HJ4, 01°47'07.3"S, 103°16'36.9"E, 57 m a.s.l., from upper soil layer (0–5 cm), 15.XI.2013 (B. Klarner). One specimen: Indonesia, Sumatra, Bukit Duabelas landscape, secondary rainforest, research site BF2, 01° 58'55.1"S, 102°45'02.7"E, 77 m a.s.l., from upper soil layer (0–5 cm), 15.11.2013 (B. Klarner). Three specimens: Indonesia, Sumatra, Harapan landscape, jungle rubber agroforest, research site HJ2, 01°49'31.9"S, 03°17'39.2"E, 84 m a.s.l., from forest floor litter material, 15.XI.2013 (B. Klarner).

Key to known species of Pergalumna in the Oriental region

At present, 45 species/subspecies of Pergalumna are known in the Oriental region (Subías 2004, updated 2015; including present and personal data of the first author).

Pergalumna heroica (Willmann, 1931) from Java (see Willmann 1931), P. medialis (Sellnick, 1925) from Sumatra (see Sellnick 1925) and P. obsessa Subías, 2004 from Taiwan (see Tseng 1984 as Galumna pallida Tseng, 1984) are excluded from the key because these species have been poorly described.

Pergalumna curva curva (Ewing, 1907) from the Holarctic and Oriental regions (see Ewing 1907; Jacot 1934b), P. curva ventralis (Willmann, 1931) from the Holarctic, Neotropical and Oriental regions and Polynesia (see Willmann 1931; Jacot 1934b; Hammer 1958, 1961, 1972), P. obvia obvia (Berlese, 1914) from the Ethiopian, Neotropical, Oriental and Palaearctic regions, and Hawaii and U.S.A. (see Weigmann 2006; Ermilov et al. 2013c), P. operata Tseng, 1984 from Taiwan (see Tseng 1984) and P. pyramidalis (Tseng, 1984) from Taiwan (see Tseng 1984) were not included because systematic placement of these species is not clear. We consider P. obvia obvia as a representative of the genus Galumna Heyden, 1826 (see Ermilov et al. 2013c). Pergalumna curva curva, P. curva ventralis and P. operata Tseng, 1984 have distinct notogastral setae, which are not traits for Pergalumna (see generic diagnosis in Ermilov et al. 2013b); these species are poorly described and redescribed; however, based on available data they should be considered as representatives of the genus Allogalumna Grandjean, 1936 or Trichogalumna Balogh, 1960 (depending on presence or absence of lamellar lines). Pergalumna pyramidalis has 14 pairs of notogastral setal alveoli, developed lamellae directed to insertions of lamellar setae and pteromorphs without setae (Tseng 1984); most likely this species is a representative of the subgenus Neoribates (Neoribates) Berlese, 1914 (Oripodoidea, Parakalummidae), and it is morphologically most similar to N. (N.) paratuberculatus Ermilov, Shtanchaeva & Subías, 2014 from Vietnam (see Ermilov et al. 2014d) and N. (N.) tuberculatus Willmann, 1956 from “Czechoslovakia” (see Willmann 1956) in having tubercles on pteromorphs and some other characters.

1	Anterior margin of notogaster of specific structure, tuberculate	2
–	Anterior margin of notogaster simple, smooth or not developed	3
2	Genital plates with several striae; notogastral porose areas of medium size, larger than diameter of bothridia; body size: 451–490 × 328–366	P. margaritata Mahunka, 1989 (Mahunka 1989). Distribution: Vietnam
–	Genital plates with one pair of striae; notogastral porose areas small, similar to diameter of bothridia; body size: 402–447 × 281–315	P. pseudomargaritata Mahunka, 1994 (see Mahunka 1994). Distribution: Thailand
3	Anterior margin of notogaster distinctly developed, complete	4
–	Anterior margin of notogaster not developed	12
4	Rostrum pointed	5
–	Rostrum rounded	7
5	Four pairs of notogastral porose areas; Aa elongate triangular, transversally oriented; lateral parts of pteromorphs with strong ridges forming slightly visible reticulate pattern; body size: 517–670 × 397–525	P. altera (Oudemans, 1915) (see Aoki 1961 as P. harunaensis Aoki 1961, 1975; Engelbrecht 1972; Weigmann 2006). Distribution: Semicosmopolitan
–	Three pairs of notogastral porose areas; Aa rounded; pteromorphs without strong ridges and reticulate pattern	6
6	Interlamellar setae long; posterior part of notogaster without furrows; body size: 664–830 × 498–630	P. yurtaevi Ermilov & Anichkin, 2011 (see Ermilov and Anichkin 2011a; Ermilov et al. 2012a). Distribution: Vietnam
–	Interlamellar setae represented by alveoli; posterior part of notogaster with two parallel, longitudinal furrows; body size: 664–830 × 498–630	P. asetosa Ermilov, Shtanchaeva, Kalúz & Subías, 2013 (see Ermilov et al. 2013a). Distribution: India
7	Bothridial setae setiform; body size: 520–676 × 502	P. foveolata Hammer, 1973 (see Hammer 1973; Bayartogtokh and Chatterjee 2010). Distribution: Australian, Neotropical and Oriental region
–	Bothridial setae with developed head	8
8	Interlamellar setae minute; body surface foveolate; body size: 222–235 × 177–190	P. annulata Mahunka, 1995 (see Mahunka 1995). Distribution: Borneo
–	Interlamellar setae long; body surface not foveolate	9
9	Three pairs of notogastral porose areas; Aa rounded; body length: 820	P. corniculata (Berlese, 1905) (see Berlese 1905; Mahunka 1992). Distribution: Java
–	Four pairs of notogastral porose areas; Aa elongated, transversally oriented	10
10	Notogastral porose areas Aa triangular; median pore present; body size: 623 × 533	P. taprobanica Balogh, 1988 (see Balogh 1988). Distribution: Oriental region
–	Notogastral porose areas Aa elongate oval to boot-shaped	11
11	Bothridial setae fusiform, with well-developed head rounded distally; postanal porose area present; body size: 672 × 528	P. andhraense Raju, Appalanaidu & Rao, 1981 (see Raju et al. 1981). Distribution: India
–	Bothridial setae lanceolate, with slightly developed head pointed distally; postanal porose area absent; body size: 830–898 × 630–680	P. paraelongata Ermilov & Anichkin, 2012 (see Ermilov et al. 2012b). Distribution: Vietnam
12	Rostrum trapezoid; anal setae comparatively long, longer than width of anal plate; body size: 1278–1311 × 976–1045	P. paraclericata Ermilov, Chatterjee, Das & Bordoloi, 2014 (see Ermilov et al. 2014c). Distribution: India
–	Rostrum not trapezoid; anal setae comparatively short, shorter than width of anal plate	13
13	Rostrum pointed	14
–	Rostrum rounded	18
14	Four pairs of notogastral porose areas; Aa located nearer to setal alveoli la than lm; body size: 730–780 × 564–597	P. cattienica Ermilov & Anichkin, 2011 (see Ermilov and Anichkin 2011a). Distribution: Vietnam
–	Three pairs of notogastral porose areas; Aa located nearer to setal alveoli lm or distanced equal from la and lm	15
15	Interlamellar setae represented by alveoli; anterior part of prodorsum with two longitudinal ridges; notogastral porose areas Aa located nearer to setal alveoli lm than la; body size: 1162–1278 × 898–1012	P. minipora Ermilov, Chatterjee, Das & Bordoloi, 2014 (see Ermilov et al. 2014c). Distribution: India
–	Interlamellar setae of medium size or long; prodorsum without ridges; notogastral porose areas Aa distanced equal from la and lm	16
16	Notogastral porose areas A1 elongated, longitudinally oriented; body surface foveolate; genital plates not striate; body size: 365–415 × 265–332	P. paratsurusakii Ermilov, Shtanchaeva, Kalúz & Subías, 2013 (see Ermilov et al. 2013a). Distribution: India
–	Notogastral porose areas A1 rounded; body surface not foveolate; genital plates striate	17
17	Adanal setae ad₁ and ad₂ comparatively long, not shorter than width of anal plate; median pore absent; interlamellar setae longer than bothridial setae; body size: 597–680 × 431–498	P. paracattienica Ermilov, Chatterjee, Das & Bordoloi, 2014 (see Ermilov et al. 2014c). Distribution: India
–	Adanal setae ad₁ and ad₂ minute; median pore present; interlamellar setae shorter than bothridial setae; body size: 498–531 × 381–398	P. mahunkai Ermilov, Shtanchaeva, Kalúz & Subías, 2013 (see Ermilov et al. 2013a). Distribution: India
18	Four pairs of notogastral porose areas	19
–	Three pairs of notogastral porose areas	22
19	Interlamellar setae represented by alveoli; notogastral porose areas Aa located anteriorly to setal alveoli la; body length: 730	P. corolevuensis Hammer, 1973 (see Hammer 1973). Distribution: Fiji and India
–	Interlamellar setae of medium size or long; notogastral porose areas Aa located between setal alveoli la and lm	20
20	Notogastral porose areas A1 located antero-medially to A2; interlamellar setae of medium size; body size: 745–842 × 567–640	P. hauseri Mahunka, 1995 (see Mahunka 1995). Distribution: Borneo
–	Notogastral porose areas A1 located anteriorly to A2; interlamellar setae long	21
21	Adanal setae ad₁ and ad₂ similar in length; median pore absent; body size: 510–630 × 410–481	P. pterinervis (Canestrini, 1898) (see Canestrini 1898; Berlese 1905, 1914; Mahunka 1992; including our data). Distribution: Oriental region
–	Adanal setae ad₁ longer than ad₂; median pore present; body size: 550–608 × 413–454	P. pertrichosa Mahunka, 1995 (see Mahunka 1995). Distribution: Borneo
22	Notogastral porose areas Aa located nearer to setal alveoli la than lm; bothridial setae clavate	23
–	Notogastral porose areas Aa located nearer to setal alveoli lm than la or distanced equal from them; bothridial setae setiform or with slightly dilated, elongate head	24
23	Interlamellar setae minute, shorter than diameter of bothridia; body surface not foveolate; median pore represented by several foveae; body size: 262–282 × 192–209	P. pseudosejugalis Ermilov & Anichkin, 2012 (see Ermilov and Anichkin 2012). Distribution: Vietnam
–	Interlamellar setae short, but longer than diameter of bothridia; body surface foveolate; median pore absent; body size: 246–275 × 186–212	P. crassipora Mahunka, 1995 (see Mahunka 1995). Distribution: Borneo
24	Notogastral porose areas Aa located nearer to setal alveoli lm than la	25
–	Notogastral porose areas Aa distanced equal from la and lm	30
25	Notogastral porose areas minute, smaller than diameter of bothridia; body size: 527–612 × 390–428	P. imadatei Aoki & Hu, 1993 (see Aoki and Hu 1993). Distribution: Oriental region
–	Notogastral porose areas well developed, larger than diameter of bothridia	26
26	Body surface slightly striate; median pore represented by several foveae; body size: 610–715 × 475–545	Pergalumna hawaiiensis hawaiiensis (Jacot, 1934) (see Jacot 1934a; including our data)
–	Body surface not striate; median pore single or absent	27
27	Interlamellar setae minute, shorter than diameter of bothridia; body length: 720	P. bimaculata Hammer, 1973 (see Hammer 1973). Distribution: Polynesia and Philippines
–	Interlamellar setae of medium size, longer than diameter of bothridia	28
28	Median pore present, large; body length: 720	P. remota (Hammer, 1968) (see Hammer 1968). Distribution: New Zealand and India
–	Median pore absent	29
29	Bothridial setae densely ciliate; body size: 451–490 × 300–334	P. kotschyi Mahunka, 1989 (see Mahunka 1989). Distribution: Vietnam
–	Bothridial setae smooth; body size: 398–453 × 275–340	P. indivisa Mahunka, 1995 (see Mahunka 1995). Distribution: Borneo
30	Bothridial setae with slightly dilated, elongated head	31
–	Bothridial setae setiform	33
31	Body surface heavily tuberculate; body size: 385–425 × 285–331	P. granulata Balogh & Mahunka, 1967 (see Balogh and Mahunka 1967). Distribution: Vietnam and Japan
–	Body surface not tuberculate	32
32	Body surface heavily granulate; body size: 302–356 × 237–262	P. punctulata Balogh & Mahunka, 1967 (see Balogh and Mahunka 1967). Distribution: Vietnam
–	Body surface smooth; body size: 437–465 × 310–324	P. intermedia intermedia Aoki, 1963 (see Aoki 1963, 1966). Distribution: Palaearctic and Oriental regions
33	Notogastral porose areas A1 elongated, longitudinally oriented	34
–	Notogastral porose areas A1 rounded to oval	36
34	Adanal setae ad₁ long, not shorter than width of anal plate; median pore single; body size: 415–481 × 298–365	P. paraindistincta sp. n. Distribution: Indonesia
–	Adanal setae ad₁ minute; median pore absent or represented by several foveae	35
35	Postanal porose area absent; median more present in females; body size: 547–614 × 381–415	P. indistincta Ermilov & Anichkin, 2011 (see Ermilov and Anichkin 2011b). Distribution: Vietnam
–	Postanal porose area present; median more absent in females; body size: 576 × 426	P. magnipora capensis Engelbrecht, 1972 (see Engelbrecht 1972). Distribution: Southern Africa and India
36	Body surface striate and short ridges; posterior part of notogaster with longitudinal concavity; body size: 408–485 × 298–352	P. menglunensis Aoki & Hu, 1993 (see Aoki and Hu 1993). Distribution: southern China
–	Body not striate and without short ridges; posterior part of notogaster without concavity	37
37	Adanal setae ad₁ and ad₂ comparatively long, not shorter than width of anal plate; setae c developed on pteromorphs; body size: 514–597 × 365–431	P. minituberculata Ermilov & Martens, 2014 (see Ermilov and Martens 2014). Distribution: Nepal
–	Adanal setae ad₁ and ad₂ shorter than width of anal plate; setae c represented by alveoli on pteromorphs	38
38	Interlamellar setae represented by alveoli; median pore present; body size: 863–1145 × 639–970	P. panayensis Ermilov & Corpuz-Raros, 2015 (see Ermilov and Corpuz-Raros 2015)
–	Interlamellar setae of medium size or long; median pore absent	39
39	Bothridial setae densely ciliate	40
–	Bothridial setae densely smooth	41
40	Notogastral porose areas amorphous, without distinct borders; genital plates not striate; body size: 332–377 × 245–276	P. amorpha Mahunka, 2008 (see Mahunka 2008). Distribution: Thailand
–	Notogastral porose areas with distinct borders; genital plates striate; body size: 390–435 × 282–315	P. intermedia retroversa Aoki & Hu, 1993 (see Aoki and Hu 1993). Distribution: southern China
41	Interlamellar setae comparatively short, about 1/3 as long as their mutual distance; genital plates smooth; body size: 742–845 × 589–653	P. magnipora capillaris Aoki, 1961 (see Aoki 1961). Distribution: Palaearctic and Oriental regions
–	Interlamellar setae of medium size, about 1/2 as long as their mutual distance; genital plates striate; body size: 822–840 × 618–650	P. magnipora xishuangbanna Aoki & Hu, 1993 (see Aoki and Hu 1993). Distribution: southern China

Acknowledgements

We cordially thank Prof. Dr. Badamdorj Bayartogtokh (National University of Mongolia, Ulaanbaatar, Mongolia) and Prof. Dr. Gerd Weigmann (Free University of Berlin, Institute of Zoology, Berlin, Germany) for their valuable comments, Kristina Richter (Georg August University Göttingen, Göttingen, Germany) for assistance in building up the Indonesian oribatid mite morphospecies collection, the State Ministry of Research and Technology of Indonesia (RISTEK) for the research permit and the Indonesian Institute of Sciences (LIPI) and Ministry of Forestry (PHKA) for the collection permit, the village heads, local site owners, PT REKI and Bukit Duabelas National Park for granting access to their properties and the many colleagues and helpers for support in the ﬁeld.

Financial support was provided by the German Research Foundation (DFG) in the framework of the collaborative German – Indonesian research project CRC990 (EFForTS). The taxonomic study on Galumnoidea was supported by the Russian Foundation for Basic Research (project: 15-04-02706 A).

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