The genus Galumna in Nepalese oribatid mite fauna, with notes on systematic placement of some species (Acari, Oribatida, Galumnidae).

The oribatid mite genus Galumna (Oribatida, Galumnidae) is recorded for the first time in Nepal. A new species, Galumna tetraporosa sp. n., is described from soil of secondary mixed broadleaved forest. It is most similar morphologically to G. tokyoensis Aoki, 1966 and G. valida Aoki, 1994, however, it differs from both by the absence of interlamellar setae and the presence of two pairs of notogastral porose areas Aa. Galumna granalata Aoki, 1984 is redescribed on the basis of specimens from Nepal. Galumna floridae (Jacot, 1929) and G. hexagona Balogh, 1960 are transferred to the genus Notogalumna; G. mauritii Mahunka, 1978 is transferred to the genus Dimidiogalumna.

Introduction

is a genus that was proposed by Heyden (1826) with Hermann, 1804 as type species. Currently, it comprises more than 170 species having a cosmopolitan distribution (for example, Subías 2004, online version 2014). The main generic characters are summarized by Ermilov et al. (2013). An identification key to many species of has been presented by Balogh and Balogh (2002).

In the course of taxonomic identification of Nepalese , we discovered two species: Aoki, 1984 and a new one. This genus is recorded for the first time in Nepal. The primary goal of this paper is to describe and illustrate a new species. The secondary goal is to make a supplementary description of based on the Nepalese material. This species was described Aoki (1984) and is distributed in Japan and Taiwan (Subías 2004, online version 2014). The original description of is incomplete (lacking information about the length of morphological structures, leg setation and solenidia, gnathosoma; only figures of the pteromorph and the dorsal side of the body present).

Additionally, the systematic placement of three species of the genus , (Jacot, 1929), Balogh, 1960 and Mahunka, 1978, are discussed.

Material and methods

Three specimens (holotype: male; two paratypes: one male and one female) of sp. n. are from: Nepal, 2450–2720 m a.s.l., Terhathum District, ridge Tinjura Dara, broadleaved forest, soil, 17.IX.1983, collected by J. Martens and B. Daams.

Eight specimens of are from: Nepal, 1650–1800 m a.s.l., Taplejung District, valley of the Kabeli River, below village Yamputhin, secondary mixed broadleaved forest with bamboo, soil, 03–04.IX.1983, collected by J. Martens and B. Daams.

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 fig. The 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. Formulae for leg setation are given in parentheses according to the sequence trochanter–femur–genu–tibia–tarsus (famulus included). Formulae 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).

Taxonomy

sp. n.

http://zoobank.org/58AC6AB0-8289-46C9-8BA0-2CADF9DE6029

Figs 1 – 5

Figure 1.

sp. n., adult: dorsal view. Scale bar 200 μm.

Figure 2.

sp. n., adult: ventral view (gnathosoma and legs not illustrated). Scale bar 200 μm.

Figures 3–5.

sp. n., adult: 3 dorso-lateral view of prodorsum and anterior part of notogaster and pteromorph 4 pteromorph 5 posterior view of notogaster. Scale bars 200 μm (3, 5), 100 μm (4).

Diagnosis.

Body size: 913–979 × 730–763. Rostrum pointed. Rostral and lamellar setae of medium size. Interlamellar setae represented by alveolus. Bothridial setae long, clavate, barbed. Lamellar and sublamellar lines divergent in medio-distal part. Anterior notogastral margin not developed. Notogaster with five pairs of small, rounded porose areas, Aa divided into two parts. Median pore absent. Aggenital and ano-adanal setae minute. Postanal porose area present, elongated.

Description.

Measurements. Body length: 962 (holotype), 913–979 (two paratypes); notogaster width: 730 (holotype), 730–763 (two paratypes).

Integument. Body color black to dark brown. Body surface smooth. Pteromorphs with poorly visible radiate wrinkles.

Prodorsum. Rostrum with strong tooth (12–20). Rostral setae (ro, 53–65) setiform, barbed. Lamellar setae (le, 65–77) setiform, little thicker and less barbed than rostral setae. Interlamellar setae absent, represented alveolus. Bothridial setae (ss, 114–123) with long stalk and shorter, barbed clavate head. Exobothridial setae absent. Porose areas Ad present, elongate oval (24–32 × 12–16), but visible only in dissected specimen. Lamellar lines (L) curving backwards; sublamellar lines (S) parallel in basal part and divergent in medio-distal part to lamellar lines.

Notogaster. Anterior notogastral margin not developed. Dorsophragmata (D) of medium size, elongated. Notogastral setae represented by 10 pairs of alveoli. Five pairs of small, rounded porose areas with distinct borders: Aa divided into two porose areas – smaller lateral (8–16) and larger medial (20–28); A1 (12–16) and A2 (16–28) located close to each other; A3 (24–36) usually largest. Alveoli la inserted posteriorly to Aa. Lyrifissures im located anteriorly or antero-laterally to A1. Opisthonotal gland openings (gla) located antero-laterally to A2. Median pore absent.

Gnathosoma. Generally, morphology of subcapitulum, palps and chelicerae typical for most Galumnidae (for example, see Ermilov and Anichkin 2010, 2011; Ermilov et al. 2011). Subcapitulum little longer than wide (196 × 192). Subcapitular setae setiform, slightly barbed; a (32–36) longer, more barbed and thicker than m (24) and h (16–20). Two pairs of adoral setae (or1, or2, 20) setiform, barbed. Palps (143) with setation 0–2–1–3–9(+ω). Solenidion straight, thickened, blunt-ended, attached to eupathidium. Chelicerae (246) with two barbed setae; cha (94) longer than chb (53). Trägårdh’s organ distinct.

Epimeral and lateral podosomal regions. Apodemes (1, 2, sejugal, 3) well visible. Four pairs of epimeral setae (1b, 3b, 4a, 4b) observed ventrally, all setiform, thin, smooth, similar in length (24–32). Discidia (dis) triangular, circumpedal carinae (cp) distinct.

Anogenital region. Six pairs of genital setae (g1–g6, 24–28) setiform, thin, smooth. Anterior edge of genital figs with three setae. One pair of aggenital (ag), two pairs of anal (an1, an2) and three pairs of adanal (ad1–ad3) setae minute, similar in length (4). Adanal setae ad3 inserted laterally to adanal lyrifissures iad. Postanal porose area (Ap) elongated (36–49 × 8–12).

Legs. Generally, morphology of leg segments, setae and solenidia typical for most Galumnidae (for example, see Ermilov and Anichkin 2010, 2011; Ermilov et al. 2011). Formulae 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.

Table 1.

Leg setation and solenidia of adult sp. n. (same data for Aoki, 1984).

Leg	Trochanter	Femur	Genu	Tibia	Tarsus
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)

Roman letters refer to normal setae (ε to famulus), Greek letters to solenidia. Single prime (’) marks setae on anterior and double prime (’’) setae on posterior side of the given leg segment. Parentheses refer to a pair of setae.

Type deposition.

The holotype and one paratype are deposited in the collection of the Senckenberg Institution Frankfurt, Germany; one paratype is deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.

Etymology.

The specific name “tetraporosa” refers to the four notogastral porose areas Aa.

Remarks.

In having the pointed rostrum and bothridial setae with well developed head, sp. n. is most similar to Aoki, 1966 from the eastern Palaearctic region and Aoki, 1994 from the Pacific Islands. However, it clearly differs from both by the absence of interlamellar setae (versus long in and ) and the presence of two pairs of notogastral porose areas Aa (versus one pair in and ).

Aoki, 1984

Figs 6 – 10

Figure 6.

Aoki, 1984, adult: dorsal view. Scale bar 100 μm.

Figure 7.

Aoki, 1984, adult: ventral view (gnathosoma and legs not illustrated). Scale bar 100 μm.

Figures 8–10.

Aoki, 1984, adult: 8 dorso-lateral view of prodorsum and anterior part of notogaster and pteromorph 9 pteromorph 10 posterior view of notogaster. Scale bar 100 μm.

Measurements. Body length: 431–464 (eight specimens); notogaster width: 332–356 (eight specimens).

Integument. Body color light brown. Body surface smooth. Pteromorphs with radiate wrinkles and small (length up to 12), elongate, grain-shaped tubercles. Wrinkles and tubercles very poorly visible in some specimens.

Prodorsum. Rostrum rounded. Rostral (28–32) and lamellar (16–20) setae setiform, thin, smooth, often not visible in dorsal view. Interlamellar setae minute (4). Bothridial setae (57–65) with long stalk and shorter, barbed, clavate head. Exobothridial setae absent. Porose areas Ad present, elongate oval (10–16 × 4–6). Lamellar and sublamellar lines parallel, curving backwards.

Notogaster. Anterior notogastral margin well developed, convex. Dorsophragmata of medium size, triangular. Notogastral setae represented by 10 pairs of alveoli. Four pairs of rounded porose areas with distinct borders: Aa (16–20) larger than A1 (12–16), A2 (8–10) and A3 (10–16). Alveoli la inserted posteriorly to Aa. Lyrifissures im located between lm and lp. Opisthonotal gland openings located laterally to A1. Median pore present, located little posterior to the virtual line connecting porose areas A1.

Gnathosoma. Generally, morphology of subcapitulum, palps and chelicerae typical for most Galumnidae (for example, see Ermilov and Anichkin 2010, 2011; Ermilov et al. 2011). Subcapitulum little longer than wide (106 × 98). Subcapitular setae setiform, smooth; a (24) longer and little thicker than m (12) and h (16). Two pairs of adoral setae (10) setiform, slightly barbed. Palps (86) with setation 0–2–1–3–9(+ω). Solenidion straight, thickened, blunt-ended, attached to eupathidium. Chelicerae (131) with two barbed setae; cha (49) longer than chb (28). Trägårdh’s organ distinct.

Epimeral and lateral podosomal regions. Apodemes (1, 2, sejugal, 3) well visible. Three pairs of epimeral setae (1a, 3b, 4a) observed ventrally, all setiform, thin, smooth; 1a and 3b (12–16) longer than 4a (8). Discidia triangular, circumpedal carinae distinct.

Anogenital region. Six pairs of genital setae (12–16) setiform, thin, smooth. Anterior edge of genital figs with three setae. One pair of aggenital (8), two pairs of anal (4) and three pairs of adanal (4) setae minute. Adanal setae ad3 inserted laterally to adanal lyrifissures iad. Postanal porose area (Ap) very small, rounded (6–12). Ovipositor of typical morphology for Galumnidae (Ermilov 2010): elongate, narrow (183 × 41). Length of lobes 77, length of cylindrical distal part 106. Setae setiform, smooth, ψ1 ≈ τ1 (36–41) longer than ψ2 ≈ τa ≈ τb ≈ τc (16–20). Six setae k short (6).

Legs. Generally, morphology of leg segments, setae and solenidia typical for most Galumnidae (for example, see Ermilov and Anichkin 2010, 2011; Ermilov et al. 2011). Formulae 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.

distinctly differs from other species of the genus by the presence of grain-shaped tubercles (granules in opinion of Aoki) on pteromorphs. The present Nepalese specimens of this species are morphologically and in general appearance similar to the Japanese specimens (Aoki 1984). Only one difference is that the body body size larger (431–464 × 332–356 versus 310–330 × 250–260 in Japanese specimens). We believe these differences represent intraspecific (e.g. geographical) variability.

Notes on systematic placement of some

The analysis of literature on the -species has revealed an incorrect systematic placement of three species: (Jacot, 1929), Balogh, 1960 and Mahunka, 1978.

and were described by Jacot (1929, see also 1935; from U.S.A.) and Balogh (1960; from Angola), respectively. However, both species have a specific morphology of the notogaster (almost hexagonal, truncated posteriorly unlike other species of with well rounded notogaster posteriorly). Hexagonal and truncated posteriorly notogaster is a generic character of the genus . It was proposed by Sellnick (1959) with Sellnick, 1959 as type species, and includes five species, which are distributed in the Oriental region, Tanzania, Polynesia and Seychelles (Subías 2004, online version 2014). Representatives of differ from and also by the setiform bothridial setae (clavate in and ), fused porose areas A1 and A2 (versus not fused in and ) and localization of porose areas Aa dorsally (versus lateral localization close to hinge in and ). However, all listed characters are known in the other species in Galumnidae. For example, the large genera and Grandjean, 1936 include species with numerous variations of morphology of bothridial setae and localization of notogastral porose areas. Hence, in our opinion, inclusion of and in the genus is incorrect. We suggest these species should be transferred to : (Jacot, 1929) comb. n. and (Balogh, 1960), comb. n.

was described by Mahunka (1978) from Mauritius. However, this species has very short sublamellar lines; they are almost absent – see Fig. 59 in the original description (versus all species of with long, well developed sublamellar lines). Absence of sublamellar lines and localization of lamellar setae laterally to lamellar setae are the generic characters of the genus . This genus was proposed by Engelbrecht (1972) with Engelbrecht, 1972 as type species, and includes four species, which are distributed in the Ethiopian region, Comoro Islands, Vietnam, central China and Japan (Subías 2004, online version 2014; Ermilov and Anichkin 2014). Hence, in our opinion, inclusion of in the genus is incorrect. We suggest this species should be transferred to : (Mahunka, 1978), comb. n.