Damaeus (Tectodamaeus) cordatus, Xie, Lixia & Yang, Maofa, 2010

Xie, Lixia & Yang, Maofa, 2010, Notes on the subgenus Tectodamaeus (Acari: Oribatida: Damaeidae), with the description of a new species from China, Zootaxa 2727, pp. 56-62 : 60-61

Damaeus (Tectodamaeus) cordatus sp. nov.

( Fig.1 )

Material examined: Holotype (male in Oudemans fluid), China: Ji An city, Mt. Jinggang (26°34′25.04′′N, 114°10′38.05′′E), Jiangxi province, from litter under Pteridophytes, 950 m a.s.l., 6, July, 2008, coll. LiXia Xie. Paratype: Four paratypes (2 males, 2 females), with same data as holotype.

Etymology. The new specific name “ cordatus ” is from Latin, and refers to the heart-shaped anal aperture.

Diagnosis. Propodolateral apophysis (P) well developed. Setae of in and ex short, lanciform. Notogaster with latticed exuvial scalps. Sensillus relatively long, finely barbed. Spinae adnatae large and hooked. Setae of notogaster thick, darkly pigmented with barbs. Anal aperture wrapped by numerous cycloidal grain, heart-shaped. Leg IV extremely long, 3 times body length. Femur IV very long, proximal stalk 4.3 times length of bulb. Solenidion on genu I–III coupled with a respective seta d. Seta d on femur I sturdy, slightly barbed, inserted to the base of bulb.

Dimensions. Mean body length 442 μm (range 431–453); Mean notogastral length 318μm (296–332); Mean notogastral width: 256 μm (range 224–283).

Integument. Body color brown. Surface of body and leg segments with filamentous cerotegument. Conspicuous microtubercles present on prodorsum and around leg acetabula, legs with dense fungal mycelia.

Prodorsum. Rostrum rounded in dorsal view, but slightly projected in lateral view. Seta ro long (59 μm), finely barbed. Seta le (98 μm) longer than ro. Distance between ro slightly less than that of le. Seta in (30 μm) and ex (49 μm) smooth, short, dark brown and lanciform. Sensillus (ss) (167 μm) long, attenuate, with small barbs. Comparative length: in <ex <ro <le <ss. Propodolateral apophysis (P) well developed. Tubercles Da, Ba and Bp all present. Tubercles Da relatively large.

Notogaster. Ovate viewed perpendicular to circumgastric scissure, about 1.3 times longer than wide. Spinae adnatae large and hooked, directed into sejugal groove, pointed distally, with mutual distance equal to that between prodorsal tubercles Bp and less than that of setal pair c 2. Notogastral setae of c -series brown, sturdy and straight. l - and h -series smooth, attenuate and tip curving. Comparative length of notogastral setae: h 1 <h 2 <c 1 = c 2 <la = lm = lp <h 3, and their respective lengths: 34 μm, 39 μm, 44 μm, 49 μm and 54 μm. Setae of c -series directed anteriad, distance between c 2 1.73 times that of c 1. Pseudanal setae short, attenuate with small barbs, directed laterad, 30 μm long.

Ventral region. Epimere I with medial pit (cp) tapering anteriad as groove. Enantiophyses E2 and V present. E2a small, curved tubercle, represented by low, broadly curved ridge; E2p represented by broad ridge. Tubercle Va, triangular with pointed tip; Vp represented by low, broadly curved ridge. Tubercle Sa broadly cylindrical with hook tip, Sp subtriangular. Discidium (di) subtriangular with rounded tip, directed posterolaterad. Epimeral setae smooth, short except for 3 b. Epimeral setal formula: 3-1-3-4. Anogenital region normal, seta ad 3 far from seta ad 1 and ad 2. Fissure ian minute, represented by small, inconspicuous pore in anterolateral corner of valve. Anal aperture is wrapped by numerous cycloidal sculpturing, heart-shaped. Anal aperture appreciably narrower than genital one.

Gnathosoma. Normal for family. Mentum and gena smooth, without carinae or depressions.

Legs. Relative lengths (I–IV) 1: 0.76: 0.86: 1.29. Leg IV very long, 3 times ventral body length; Femur IV 4 times length of trochanter IV, proximal stalk of femur IV 4.3 times length of bulb. Leg setation (famulus included, solenidia in parenthesis) as shown in Table 1. Solenidion on genu I–III coupled with a respective seta d. Seta d on femur I sturdy, with minute barbs, inserted to the base of bulb. Seta d of genua I–III longer than respective coupled solenidion δ. Tibial solenidion flagelliform. Solenidion φ1 on tibial of leg I very long, 3.2 times as long as φ2. Famulus emergent, simple, short. Femoral setal formula: 5-3-3-3. Two femoral setae (v 1 ʹ, v 1 ʺ) of leg I are absent, as are two femoral setae (v 1 ʹ, v 2 ʺ) of leg II–IV. Seta vb present on tibia of leg I, IV and the seta v 1 ʹ is missing on tibia of leg IV. Only three eupathidial setae on tarsus I (p ʹ, p ʺ, s).

Legs Trochanter Femur Genu Tibia Tarsus I 1 5 4 (1) 5 (2) 18 (2) II 1 3 4 (0) 4 (1) 16 (2) III 2 3 3 (0) 3 (1) 17 (0) IV 1 3 2 (0) 4 (1) 15 (0) Remarks. The new species can be readily distinguished from all other known species in this genus by: the anal aperture wrapped by much cycloidal sculpturing and heart-shaped; spinae adnatae large and hooked; notogastral setae of c -series brown, sturdy and straight, and l - and h -series smooth, attenuate with curved tips; Leg IV extremely long, 3 times ventral body length.

Figures

FIGURE 1. Damaeus (Tectodamaeus) cordatus sp. nov. A. adult, dorsal view (100 μm); B. adult, ventral view (100 μm); C. femur and genu of leg I (100 μm); D. tibia and tarsus of leg I (100 μm); E. trochanter, femur and genu of leg IV; F. tibia and tarsus of leg IV (100 μm).