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

Abstract 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
Galumna is a genus that was proposed by Heyden (1826) with Notaspis alatus Hermann, 1804 as type species. Currently, it comprises more than 170 species having a cosmopolitan distribution (for example, Subías 2004Subías , online version 2014. The main generic characters are summarized by Ermilov et al. (2013). An identification key to many species of Galumna has been presented by Balogh and Balogh (2002).
In the course of taxonomic identification of Nepalese Galumna, we discovered two species: G. granalata 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 G. granalata based on the Nepalese material. This species was described Aoki (1984) and is distributed in Japan and Taiwan (Subías 2004(Subías , online version 2014. The original description of G. granalata 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).
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. 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  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.
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.

ft), (tc), (it), (p), (u), (a), s, (pv
eastern Palaearctic region and G. valida Aoki, 1994 from the Pacific Islands. However, it clearly differs from both by the absence of interlamellar setae (versus long in G. tokyoensis and G. valida) and the presence of two pairs of notogastral porose areas Aa (versus one pair in G. tokyoensis and G. valida).

Remarks.
Galumna granalata distinctly differs from other species of the genus Galumna 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.
Galumna floridae and G. hexagona were described by Jacot (1929Jacot ( , 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 Galumna with well rounded notogaster posteriorly). Hexagonal and truncated posteriorly notogaster is a generic character of the genus Notogalumna. It was proposed by Sellnick (1959) with Notogalumna praetiosa Sellnick, 1959 as type species, and includes five species, which are distributed in the Oriental region, Tanzania, Polynesia and Seychelles (Subías 2004(Subías , online version 2014. Representatives of Notogalumna differ from Galumna floridae and G. hexagona also by the setiform bothridial setae (clavate in G. floridae and G. hexagona), fused porose areas A1 and A2 (versus not fused in G. floridae and G. hexagona) and localization of porose areas Aa dorsally (versus lateral localization close to hinge in G. floridae and G. hexagona). However, all listed characters are known in the other species in Galumnidae. For example, the large genera Galumna and Pergalumna Grandjean, 1936 include species with numerous variations of morphology of bothridial setae and localization of notogastral porose areas. Hence, in our opinion, inclusion of Galumna floridae and G. hexagona in the genus Galumna is incorrect. We suggest these species should be transferred to Notogalumna: N. floridae (Jacot, 1929) comb. n. and N. hexagona (Balogh, 1960), comb. n.
Galumna mauritii 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 Galumna 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 Dimidiogalumna. This genus was proposed by Engelbrecht (1972) with Dimidiogalumna villiersensis 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(Subías , online version 2014Ermilov and Anichkin 2014). Hence, in our opinion, inclusion of Galumna mauritii in the genus Galumna is incorrect. We suggest this species should be transferred to Dimidiogalumna: D. mauritii (Mahunka, 1978), comb. n.