Epidamaeus angustirostratus, Bayartogtokh, 2001

Bayartogtokh, Badamdorj, 2001, Three new soil mites of the genus Epidamaeus (Acari, Oribatida, Damaeidae) from Mongolia, Zoosystema 23 (1), pp. 29-49 : 37-42

Epidamaeus angustirostratus n. sp.

( Figs 4-6 )

TYPE MATERIAL. — Holotype () and 12 paratypes (6 and 7), Mont Ikh Gazryn Chuluu , District Gobi-Ugtaal, Middle Gobi Province, desert steppe ( Caragana microphylla + Stipa glareosa), organic debris accumulated behind or between rocks,

45°50’N, 107°10’E, 1700 m above sea level, 15.IX.1991, leg. B. Bayartogtokh, the holotype and eight paratypes are deposited in the collection of the Department of Zoology, National University of Mongolia, Ulaanbaatar, Mongolia ( NUM DZ Ac 0047- 0055) ; two paratypes in the collection of the Muséum national d’Histoire naturelle, Paris , France ( MNHN Acariens 1074) and two paratypes in the collection of the National Science Museum , Tokyo, Japan ( NSMT Ac 11184, 11185) .

ETYMOLOGY. — The specific epithet “ angustirostratus ” refers to the conspicuously projected rostrum, the tip of which is conspicuously pointed.

DIAGNOSIS. — Large species; propodolateral apophysis absent; tubercle Ba present, tubercles Bp, Da and Dp absent; rostrum distinctly projected and conspicuously pointed; notogastral setae relatively thin, but very long, densely barbed, darkly pigmented; spinae adnatae medium in size; enantiophyses E2, V and S well-developed; epimeral regions III and IV with three and four setae, respectively; tarsus II with 17, III with 16 setae; leg I (1.03 time), III (1.02 time) and IV (1.4 time) longer than body length; all solenidia σ of genua I-III half long as their associated setae d.

DESCRIPTION

Measurements

Body length 753-803 (772.9) µm; length of proterosoma 288-298 (294.9) µm; width of proterosoma 305-376 (340.7) µm; length of hysterosoma 519-549 (533.9) µm; length of notogaster 559-600 (579.6) µm; width of notogaster 509- 539 (525.4) µm.

Integument

Yellowish-brown to reddish-brown in colour. Surface of body and basal part of leg segments with thin 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 on the ventral plate. Notogaster and leg segments with adherent debris; exuvial scalps absent.

Prodorsum

Rostrum distinctly projected and conspicuously pointed in both dorsal and lateral views. Rostral seta long (132-147 [135.2] µm), but thin, finely barbed. Lamellar seta thick, long, longer than ro (173-183 [177.7] µm). Interlamellar seta much shorter (81-106 [94.0] µm) and thinner than ro or le, finely barbed throughout length. Exobothridial seta (ex) very thin, smooth (61-66 [63.5] µm). Sensillus (ss) very thin, but long (254-269 [261.6] µm), densely barbed throughout its length. Tubercles Bp, Da and Dp absent, postbothridial tubercles Ba relatively small, widely spaced from each other, situated posterolateral to the insertions of interlamellar setae. Propodolateral apophysis P absent ( Fig. 4A ).

Notogaster

Almost circular, viewed perpendicular to circumgastric scissure; very slightly longer than wide, ratio of length to width 1.05:1.0. Dorso-ventral thickness of hysterosoma 427-442 (434.3) µm; thickness of notogaster 244-252 (248.5) µm. Spinae adnatae medium in size (76.2 µm), but thinner and slightly shorter than that of the former species, curved ventrad; distance between their bases almost equal to that of tubercles Ba and slightly longer than that between insertions of interlamellar setae. Notogastral setae very long (193-218 [208] µm), relatively thin, densely barbed throughout their length and darkly pigmented; posterior three pairs of setae ps 1, ps 2 and ps 3 slightly shorter (140-147 [143.2] µm) than others, also conspicuously barbed ( Fig. 4A, B ). Lyrifissures ia, im, ih, ips and ip and lateroopisthosomal gland opening gla well-developed, clearly visible in lateral view ( Fig. 4A, C ).

Gnathosoma

Infracapitular mentum almost as long as wide, without noticeable microtubercles. Hypostomal setae h, m and a very thin, relatively short ( Fig. 4B ). Chelicera elongate, fixed and movable digits with three blunt teeth. Setae cha and chb conspicuously barbed; porose area present ( Fig. 5B ). Palp normal, femur, genu, tibia and tarsus slightly slender and shorter than those of the former genus. Palpal setation: 0-2-1-3-8 including solenidion ω ( Fig. 5A ).

Epimeral region

Anterior tectum of podocephalic fossa not projected, but slightly rounded under trochanter I. Enantiophyses E2, S and V well-developed; tubercle Vp bearing epimeral seta 3b. Discidium well-developed, nearly triangular. Epimeral setae smooth, thin, long; setae 1a widely spaced from each other; epimeral setal formula: 3-1-4-4 ( Fig. 4B, C ).

Ano-genital region

Normal for genus; ano-genital setae long, smooth. Adanal lyrifissures iad situated obliquely, at level slightly anterior to adanal setae ad 3 ( Fig. 4B, C ).

Legs

Length measurements of leg segments are shown in Table 2. Associated setae d on genua I-III about twice as long as their coupled solenidia 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 4 C-F; 5A-E.

REMARKS

Among the known species of Epidamaeus , E. tecticola ( Michael, 1888) described from Great Britain, E. longisetosus ( Willmann, 1953) from eastern Alps, E. tatricus ( Kulczynski, 1902) from Poland and E. kamaensis ( Sellnick, 1925) from Sweden resemble the new species. The first species, E. tecticola described by Michael (1888) and redescribed by Luxton (1989) is distinguishable from E. angustirostratus n. sp. by 1) the presence of the conspicuously developed propodolateral apophysis P; 2) the broadly rounded tip of the rostrum; 3) the smaller spinae adnatae; 4) the rostral setae inserted on the dorsal side of rostrum (in new species ro situated on lateral side); 5) the lamellar setae situated rather marginally as opposed to more central situation of le in the new species; 6) the absence of anteroventral projection on trochanter IV (anteroventral end of trochanter IV of E. angustirostratus n. sp. with distinctly pointed projection).

The second European species, E. longisetosus , described by Willmann (1953) and redescribed by Bulanova-Zachvatkina (1957c, 1967, 1975) is distinguished from E. angustirostratus n. sp. by 1) the longer and smooth sensilli and notogastral setae; 2) the short and smooth interlamellar setae; 3) the narrow basal part of the spinae adnatae; 4) the relatively short femur IV, which is shorter than tibia IV (femur IV of E. angustirostratus n. sp. is far longer than tibia IV); 5) the smaller body size. Both the original description and redescriptions are incomplete and inadequately illustrated, therefore it is possible to compare only the dorsal aspect.

The third European species, E. tatricus , described by Kulczynski (1902), can be distinguished from new species by 1) the absence of the tubercles Ba; 2) the more thick sensilli; 3) the smooth notogastral setae; 4) the very long trochanter IV, which is twice longer than femur IV (trochanter IV of E. angustirostratus n. sp. is much shorter than femur IV); 5) the broadly rounded rostrum; 6) the presence of the short seta v’ on genu IV, which is shorter than the segment (seta v’ on genu IV of E. angustirostratus n. sp. is slightly longer than segment’s length).

The last species from Europe, E. kamaensis described by Sellnick (1925), can readily be distinguished from E. angustirostratus n. sp. by 1) the presence of the tubercles Ba and Da; 2) the long and relatively narrow tubercle Sp as opposed to short and broadly rounded Sp in E. angustirostratus n. sp.; 3) the thick, but sparsely barbed sensilli; 4) the smooth interlamellar setae; 5) the presence of very long setae d’ and l’ on genu IV, which are twice as long as the segment, and short seta v’, which is shorter than genu’s length; 6) the solenidia σ on genua I-III equal in length with their associated setae d as opposed to very short solenidia σ (about twice shorter than their associated setae) on respective segments in E. angustirostratus n. sp.

Figures

FIG. 4. — Holotype Epidamaeus angustirostratus n. sp.; A, dorsal aspect; B, ventral aspect; C, lateral aspect. Scale bar: 100 µm.

FIG. 5. — Paratype Epidamaeus angustirostratus n. sp.; A, palp (left, antiaxial aspect); B, chelicera (left, antiaxial aspect); C, genu, tibia and tarsus of leg I (left, antiaxial aspect); D, trochanter and femur of leg I (left, antiaxial aspect); E, tibia and tarsus of leg II (left, antiaxial aspect); F, trochanter, femur and genu of leg II (left, antiaxial aspect). Scale bar: 100 µm.

FIG. 6. — Paratype Epidamaeus angustirostratus n. sp.; A, tibia and tarsus of leg III (right, antiaxial aspect); B, trochanter, femur and genu of leg III (left, trochanter twisted); C, tibia and tarsus of leg IV (left, antiaxial aspect); D, femur and genu of leg IV (left, antiaxial aspect); E, trochanter of leg IV (left, twisted). Scale bar: 100 µm.