Epidamaeus aokii, Bayartogtokh, 2001

Bayartogtokh, Badamdorj, 2001, Three new soil mites of the genus Epidamaeus (Acari, Oribatida, Damaeidae) from Mongolia, Zoosystema 23 (1), pp. 29-49 : 32-37

Epidamaeus aokii n. sp.

( Figs 1-3 )

TYPE MATERIAL. — Holotype () and 13 paratypes (9 and 4), Mont Khustai, District Altanbulag, Central Province, litter of birch forest ( Betula plataphylla ), 47°42’N, 106°25’E, 1680 m above sea level, 11.IV.1996, leg. B. Bayartogtokh, the holotype and nine paratypes are deposited in the collection of the Department of Zoology , National University of Mongolia, Ulaanbaatar, Mongolia ( NUM DZ Ac 0035- 0044); two paratypes in the collection of the Muséum national d’Histoire naturelle, Paris, France ( MNHN Acariens 1073), and two paratypes in the collection of the National Science Museum, Tokyo, Japan NSMT Ac 11182, 11183).

ETYMOLOGY. — The specific name is dedicated to Dr Jun-ichi Aoki, professor of Yokohama National University, Yokohama, Japan, who very kindly guides and encourages me in the field of study on systematics of oribatid mites.

DIAGNOSIS. — Large species with general characters of Epidamaeus ; propodolateral apophysis absent; postbothridial tubercle Ba present, tubercles Bp, Da and Dp absent; interlamellar and notogastral setae very thick, densely barbed, darkly pigmented; spinae adnatae large; enantiophyses E2, V and S developed; hypostomal setae h and m very long, thin; epimeral regions III and IV with four setae each; tarsus II with 17, III with 16 setae; leg I (1.2 time), III (1.2 time) and IV (1.4 time) longer than body length; solenidion σ of genu I equal in length to its associated seta d; solenidia σ of genua II and III half length of associated setae d.

DESCRIPTION

Measurements

Body length 732-742 (734.7) µm; length of proterosoma 305-336 (315.3) µm; width of proterosoma 305-315 (307.5) µm; length of hysterosoma 447-498 (472.9) µm; length of notogaster 508-544 (530.5) µm; width of notogaster 437-473 (453.8) µm.

Integument

Reddish-brown to dark brown in colour. Surface of body and basal part of leg segments with rather thick cerotegument. Conspicuously microtuberculate on all enantiophyses and tubercles, lateral part of podosoma and around leg acetabula. Very fine punctations present on the lateral part of prodorsum and ventral plate. Adherent debris or exuvial scalps absent.

Prodorsum

Rostrum rounded in dorsal view, but slightly projected in lateral view. Rostral seta (ro) long (132-147 [137.1] µm), finely barbed throughout. Lamellar seta (le) long (152-173 [162.6] µm), slightly longer than ro. Interlamellar seta (in) shorter, but much thicker than ro or le (102-127 [115.5] µm), densely barbed throughout, very dark. Exobothridial seta (ex) short (41-55 [48.2] µm), thin, smooth. Sensillus (ss) thin, but long (239-254 [249.1] µm), finely barbed. Bothridium irregular funnel-shaped, directed posterolateral. Tubercles Bp, Da and Dp absent; postbothridial tubercles Ba relatively large, widely spaced, situated posterolateral to the insertions of interlamellar setae. In the place of tubercles Bp integument slightly thickened and dark-coloured. Propodolateral apophysis P absent ( Fig. 1A ).

Notogaster

Slightly ovate viewed perpendicular to circumgastric scissure; about 1.1 time as long as wide. Dorso-ventral thickness of hysterosoma 488 µm; thickness of notogaster 295 µm. Spinae adnatae (sa) large (76-101 [89.2] µm), curved ventral, with broad base and distally tapered to fine tip; distance between their bases shorter than that of tubercles Ba and almost equal to that between insertions of interlamellar setae. Posterior three pairs of notogastral setae ps 1, ps 2 and ps 3 very thin and smooth, slightly shorter (60-66 µm) than the others ( Figs 1 ; 2 ); remaining notogastral setae very thick, very darkly pigmented and densely barbed throughout their length; setae c 2, la, lm and lp scarcely longer (76-91 µm) and thicker than c 1, h 1, h 2 and h 3 (66-74 µm). Lyrifissures ia, im, ih, ips and ip and latero-opisthosomal gland opening gla well-developed, visible in lateral view, but all small ( Fig. 1A, C ).

Gnathosoma

Infracapitular mentum slightly wider than long, without noticeable microtubercles. Hypostomal setae h and m very long, but thin and smooth; setae a smooth, half length of h and m ( Fig. 1B ). Chelicerae elongate, fixed and movable digits with a few blunt teeth. Trägårdh’s organ narrow; setae cha and chb conspicuously barbed; porose area present ( Fig. 2A ). Palp normal, palpal setation: 0-2-1-3-8 including solenidion ω ( Fig. 2B ).

Epimeral region

Anterior tectum of podocephalic fossa not projected, but slightly curved inward under trochanter I. Epimeral enantiophysis E2 present, but not well-visible in ventral view, more conspicuous in lateral aspect. Parastigmatic enantiophysis S, ventrosejugal enantiophysis V strongly developed, broadly rounded to subtriangular; tubercle Vp bearing epimeral seta 3b. Discidium (di) well-developed, nearly triangular. Epimeral setae smooth, long, approximately equal in length. Epimeral setal formula: 3-1-4-4 ( Fig. 1B, C ).

Ano-genital region

Structure normal for genus; ano-genital setae long and smooth. Adanal lyrifissures iad situated obliquely, at level slightly anterior to anal setae an 2 ( Fig. 1B ).

Legs

Length measurements of leg segments are shown in Table 1. Seta d on genu I just same length as solenidion σ, but on legs II and III setae d twice longer than σ. Porose areas of femora I-IV and trochanters III and IV inconspicuous. Formula of leg setation (including famulus): I (1-7-4-4-20); II (1-6-4-4-17) III (2-4-3-3-16); IV (1-4-3-3- 14); 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 Figs 2 C-F; 3.

REMARKS

Only the following known species, E. bituberculatus ( Kulczynski, 1902) , E. pavlovskii Bulanova- Zachvatkina, 1957, E. kodiakensis Hammer, 1967 and E. bakeri ( Hammer, 1952) resemble E. aokii n. sp. However, E. bituberculatus described from Poland and later reported from Europe is distinguishable from the present new species by 1) the much longer and smooth notogastral setae; 2) the widely spaced tubercles Ba and spinae adnatae sa; 3) the smooth prodorsal setae (ro, le, in); 4) the longer and more strongly barbed sensilli; 5) the longer and stronger apophysis Sp, which is larger than Sa (in E. aokii n. sp. Sa slightly stronger and longer than Sp); 6) the much longer seta l’ on tibia IV, which is 1.5 time as long as other setae (seta l’ of new species is less than 1.2 time as long as other setae); 7) the short solenidia σ of genua I- III which are always shorter than their associated setae d (solenidion σ on genu I of new species is just same in length as seta d). The original description and redescription of the compared species by Kulczynski (1902) and Bulanova-Zachvatkina (1957c, 1967, 1975), respectively, were inadequate, and only very short characterization and illustration of the dorsal view and part of leg IV are available. Therefore, it is impossible to compare the other features such as characters of leg setation, ventral and lateral aspects, which are now regarded as being important for the definition of Epidamaeus species.

The second species, E. pavlovskii described from central Asian part of Russia ( Kirghizia) can be differentiated from the new species by 1) the very small and widely spaced spinae adnatae; 2) the very long and strongly barbed (only in median part) sensilli; 3) the short, but strongly barbed interlamellar and exobothridial setae; 4) the smooth rostral setae, which are situated just on the anterior margin of rostrum (seta ro of the new species bilaterally barbed and situated laterally); 5) the same length of the solenidia σ and associated setae d of genua I-III (in the new species solenidion σ and seta d are of same length only in genu I, but in genua II and III σ about half as long as d); 6) more lateral situation of notogastral setae c 2, la, lm and lp.

E. kodiakensis described and redescribed by Hammer (1967) and Behan-Pelletier & Norton (1983) from Alaska and Russia, respectively, can be distinguished from the new species by 1) the small and widely spaced spinae adnatae; 2) the short and distally barbed sensilli; 3) the smooth rostral and interlamellar setae; 4) the smooth or very weakly barbed notogastral setae c, l and h series; 5) the absence of the enantiophysis E2; 6) the strong and distinctly pointed tubercle Sa; 7) the number of setae on the epimeral region (setal formula of epimerata: 3-1-3-4); 8) the number of setae on femur III and tarsus III.

Another North American species, E. bakeri described by Hammer (1952) and redescribed by Behan-Pelletier & Norton (1983) is distinguished from E. aokii n. sp. by 1) the presence of the strongly developed propodolateral apophysis P; 2) the small spinae adnatae; 3) the smooth rostral, lamellar, notogastral setae and sensilli; 4) the absence of the enantiophysis E2; 5) the strong and long tubercle Sa; 6) the number of setae on femur III and tarsus III.

Figures

FIG. 1. — Holotype Epidamaeus aokii n. sp.; A, dorsal aspect; B, ventral aspect; C, lateral aspect. Abbreviations: 1a, 1b, 1c, 2a, 3a, 3b, 3c, 3d, 4a, 4b, 4c, 4d, epimeral setae; a, m, h, hypostosomal setae; ad1, ad2, ad3, adanal setae; ag, aggenital setae; an1, an2, anal setae; Ba, anterior postbothridial tubercle; bo, bothridium; c1, c2, la, lm, lp, h1, h2, h3, notogastral setae; di, discidium; E2a, E2p, epimeral tubercles; ex, exobothridial seta; g1-g6, genital setae; gla, latero-opisthosomal gland opening; ia, im, ih, ips, ip, notogastral lyrifissures; iad, adanal lyrifissure; in, interlamellar seta; le, lamellar seta; ps1, ps2, ps3, posterior notogastral setae; ro, rostral seta; sa, spinae adnatae; Sa, Sp, parastigmatic tubercles; ss, sensillus; Va, Vp, ventrosejugal tubercles. Scale bar: 100 µm.

FIG. 2. — Paratype Epidamaeus aokii n. sp.; A, chelicera (left, antiaxial aspect); B, palp (left, antiaxial aspect); C, tibia and tarsus of leg I (left, antiaxial aspect); D, trochanter, femur and genu of leg I (left, antiaxial aspect); E, genu, tibia and tarsus of leg II (left, antiaxial aspect); F, trochanter and femur of leg II (left, antiaxial aspect). Abbreviations: ω, ω1, ω2, tarsal solenidion; σ, solenidion of genu; ϕ1, ϕ2, solenidia of tibia; a’, a”, anterolateral setae; bv, basiventral setae; cha, chb, cheliceral setae; d, dorsal seta of genu; d, dorsal seta; f, ft’, ft”, fastigal setae; inf, inferior seta of femur; it’, it”, iteral setae; l, l’, l”, lateral leg setae; l, l’, l”, ds, lateral and dorsal setae of tibiae; p’, p”, proral setae.; pl’, pl”, posterolateral setae; pv, pv’, pv”, primiventral setae; s, subunguinal seta; sul, ul, eupathidia of tarsus; sup, superior seta of femur; tc, tc’, tc”, tectal setae; u’, u”, unguinal setae; v, v’, v”, ventral setae; vt, it’, it”, ventral and iteral setae of tarsus. Scale bar: 100 µm.

FIG. 3. — Paratype Epidamaeus aokii n. sp.; A, tibia and tarsus of leg III (left, antiaxial aspect); B, trochanter, femur and genu of leg III (left, trochanter twisted); C, tarsus of leg IV (right, antiaxial aspect); D, genu and tibia of leg IV (right, antiaxial aspect); E, trochanter and femur of leg IV (right, antiaxial aspect). Abbreviations: ϕ, solenidia of tibia; σ, solenidion of genu; a, anterolateral setae; d, dorsal seta; ft, ft”, fastigal setae; it, iteral setae; l’, lateral setae of tibiae; p, proral setae; pv, pv’, pv”, primiventral setae; s, subunguinal seta; tc, tectal setae; u, unguinal setae; v, v’, ventral setae. Scale bar: 100 µm.