Eremaeus hepaticus C. L. Koch

Badamdorj, 2003, The soil mite family Eremaeidae (Acari: Oribatida) in Mongolia, with remarks on distribution and diversity of known genera, Journal of Natural History 37, pp. 1571-1610 : 1573-1578

Eremaeus hepaticus C. L. Koch

(figures 1–4)

Eremaeus hepaticus C. L. Koch, 1835 : Vol. 3(23).

Notaspis hepatica (C. L. Koch) : Michael, 1898: 47.

Notaspis dentilamellatus Štorkán, 1925: 24 ; Winkler, 1956: 205.

Eremaeus hepaticus acruciata Mihelčič, 1952: 102 ; Mihelčič, 1963: 596.

Eremaeus setiger Mihelečič, 1957: 60 ; Mihelečič, 1963: 596.

Eremaeus hepaticus: Berlese, 1884 : fasc. 15, No. 9, tav. 48; Sellnick, 1928: 37, figure 85; Willmann, 1931: 135, figure 158; Balogh, 1943: 55, pl. 10, figures 11, 12; Strenzke, 1955: 42, figure 9; Schweizer, 1956: 273, figure 191; Mihelčič, 1963: 577, figure 1; Bulanova- Zachvatkina, 1967: 173, pl. 11, figure 164; 1975: 160; Rajski, 1967: 152; Pérez-Iñigo, 1970: 298, figures 49–51; Aoki, 1974: 235; Subias, 1977: 125; Marshall et al., 1987: 159.

Diagnosis. Relatively large (608–640 m m) species with typical characters of Eremaeus . Costulae medium long, diverging anteriorly, transcostular ridge present, minimum distance between costulae about half the costular length; sensilli long, thin, almost setiform, very slightly expanded distally in its barbed portion; interlamellar setae relatively long, attenuate, barbed; tubercles La large, situated posterolaterad of each bothridium; four to five pairs of small tubercles present posteromediad of bothridia; 11 pairs of thin, smooth or weakly barbed notogastral setae, seta c 2 situated at level slightly posterior to that of c; five or six pairs of anal setae; genu 1

III with seta d coupled with solenidion s.

Measurements. Body length 608–640 (625) m m; length of notogaster 408–448 (427) m m; width of notogaster 320–344 (330) m m. In total 28 specimens were measured.

Integument. Body colour reddish to yellowish brown. Surface of body and legs with relatively thin granular cerotegument. Notogaster and ventral plate weakly foveate, lateral part of prodorsum and pedotecta I and II more distinctly foveate.

Prodorsum. Rostrum rounded in dorsal view, but distinctly projecting anteroventrally in lateral view. Rostral seta (ro) thin, medium long (46–54 m m), barbed. Lamellar seta (le) thin, long (64–70 m m), barbed. Costula about 48–60 m m long, pair diverging anteriorly, transcostular ridge present, minimum distance between costulae about half costular length. Shape of costula and width of transcostular ridge somewhat variable (figures 1A, 2E). Interlamellar seta 55–62 m m long, barbed, attenuate. Distance between bases of in–in slightly greater than that of ro–ro. Exobothridial seta (ex) 34–38 m m long, smooth, directed anteroventrad. Sensillus long (120– 140 m m), thin, barbed, except smooth proximal portion, almost setiform along its length or very slightly expanded in its barbed portion. Tubercle La relatively large, situated posterolaterad of bothridium. Four to five pairs of small tubercles present posteromediad of bothridia (figures 1A, C, 4A, C, D).

Notogaster. Oval, about 1.2–1.3 times as long as wide; flat in lateral view and slightly flattened anteriorly (figure 1C). Anterior margin nearly straight, posterior margin broadly rounded in dorsal view. Eleven pairs of relatively long (68–86 m m), thin, smooth or weakly barbed notogastral setae; setae of ps series slightly shorter (52–58 m m) than others. Level of seta c slightly posterior to that of c; h postero- 2 1 3

laterad of lyrifissure im. Opisthosomal gland opening (gla) and lyrifissures ia, im, ih and ips well developed; ip visible only in posterior view (figures 1, 4).

Gnathosoma . Infracapitular mentum wider than long, without noticeable microtubercles. Hypostomal setae h, m and a medium long, thin, smooth (figure 1B). Chelicera relatively large, 112–124 m m long; fixed and movable digits with few blunt teeth. Trägårdh’s organ narrow, but conspicuous; setae cha and chb conspicuously barbed; porose area present (figure 2C). Palp 78–84 m m long; setae on palp femur, genu and tibia distinctly barbed; tarsal setae smooth; tarsal solenidion v lying parallel to lateral margin of palp (figure 2D). Palpal setation: 0-2-1-3-9(1).

Epimeral region. With many muscle sigillae. Sejugal and II apodemes well developed, aligned obliquely and nearly parallel; apodeme III not evident. Epimeral setal formula 3-2-3-3, all setae smooth. Discidium rounded distally. Pedotecta I and II well developed; pedotectum I slightly projecting, pedotectum II seems bifurcate distally in dorso-ventral view (figure 1B).

Ano-genital region. Genital aperture almost round; anal aperture distinctly widened posteriorly, nearly trapezoid in shape. Six pairs of genital, one pair of aggenital, five or six pairs of anal and five pairs of adanal setae (figures 1B, 2A). About 35% of examined specimens have six pairs of anal setae; one specimen has five setae on the right genital plate and another bears seven setae on one anal plate (figures 2B, F).

Legs. Measurements of leg segments given in table 1. Femora I and II with very large porose areas; trochanters III and IV with medium sized porose areas dorsally. Femora III and IV with small porose areas. Tarsi and tibiae I–IV with small porose areas ventrally. Trochanters III and IV with very strongly developed dorsodistal projections; ventrodistal part of trochanter III with deep incision. Seta d present on genu III coupled with solenidion s; genua I, II and tibiae I–IV without setae d. Formula of leg setation (including famulus) I (1-5-3-4-19), II (1-5-3-4-17), III (2- 3-3-3-15); IV (1-2-2-3-12); formula of solenidia: I (1-2-2); II (1-1-2); III (1-1-0); IV (0-1-0). Structure and setation of legs I–IV as shown in figures 2G, H, 3A, B.

Material examined. Fifty-four specimens (31 females and 23 males): Mt Bogd Khan, Central Province , 6 km south of Ulaanbaatar, litter of larch forest ( Larix sibiricus Ledebour, 1833 ), 47°55∞N, 106°30∞E, elevation 1780 m, 4 June 1990 ; two specimens (males): Mt Orog Yamaat, Nature Reserve ‘ Gorhi Terelj’ , District Erdene , Central Province , decaying wood in birch forest ( Betula platyphylla Sukatchev, 1911 ), 48°10∞N, 107°30∞E, elevation 1750 m, 21 July 1998 ; seven specimens (three females and four males): Mt Zaan Terelj, Nature Reserve ‘ Gorhi Terelj’ , District Erdene , Central Province , litter of larch forest ( Larix sibiricus Ledebour, 1833 ), 48°10∞N, 107°40∞E, elevation 1950 m, 23 June 1990 ; two specimens (females): Mt Khangai, District Bulgan, Province Arkhangai, litter of larch forest ( Larix sibiricus Ledebour, 1833 ), 47°10∞N, 100°40∞E, elevation 2300 m, 24 June 1990 ; one specimen (female): Mt Bulgan, District Erdenebulgan, Province Arkhangai, litter of birch forest ( Betula platyphylla Sukatchev, 1911 ), 48°20∞N, 101°25∞E, elevation 1850 m, 18 May 1996 ; Leg. B. Bayartogtokh .

Remarks. The character states of Mongolian specimens are well in accord with those of the European material redescribed by Berlese (1884), Sellnick (1928), Willmann (1931), Balogh (1943), Schweizer (1956), Mihelčič (1963), Bulanova- Zachvatkina (1967, 1975), Pérez-Iñigo (1970), and some supplementary characters are provided in the present redescription. The shape of costulae and the number of anal setae are variable in this species.

Distribution. This is a very widely distributed species in the Palaearctic region. Sengbusch (1979) recorded this species from North America, but Behan-Pelletier (1993) considered that this record might be based on a misidentification.