Abacarus longilobus, Skoracka, Anna, 2002

Skoracka, Anna, 2002, Two new species of eriophyoid mites (Acari: Eriophyoidea) from grasses in Poland, Zootaxa 54, pp. 1-15 : 6-13

Abacarus longilobus n. sp.

Description: Female ( Figs 3­4 ) (holotype and 9 paratypes): body length 238 (185­296), width 62 (57­67), body spindleform. Dorsomedian ridge narrow, ending near 16th dorsal annulus from end, dorsal furrow and lateral ridges ending near 6­7th annulus from end. Gnathosoma 25 (22­30) long; dorsal pedipalpal genual setae d 11 (10­12) long; v setae (sensory peg) 3 (2­3) long; ep setae 2 (2­3) long, chelicerae 22 (19­23) long, almost straight. Prodorsal shield elongate­triangular, 53 (47­57), long; 47 (44­52) wide, with pronounced, elongated frontal lobe over gnathosoma, 17 long. Sculpture of prodorsal shield: median line absent; admedian lines present only on posterior half of shield, parallel to each other; submedian lines entire only on anterior 1/3 and posterior 1/6 part of shield, parallel to lateral margins of shield. Distinct, conical microtubercles present on surface near shield. Tubercles of setae sc located on rear margin of shield, 2 (2­3) long, 3 (3­4) wide, 31 (27­ 31) apart; setae sc 13 (8­12) long, projecting to rear.

Leg I 40 (36­46) long; femur 10 (10­11) long, with seta bv 15 (12­15) long; position of seta bv 4 (4) from ventral, proximal margin of femur; genu 6 (6­7) long, with seta l’’ 26 (22­30) long, position of seta l’’ 4 (4) from dorsal, proximal margin of genu; tibia 8 (8­9) long, with seta l’ 10 (10­11) long; position of seta l’ 5 (4­5) from ventral, proximal margin of tibia. Tarsus 8 (8­9) long, with three setae: ft’’ 30 (25­30) long; ft’ 28 (21­27) long, u’ 7 (5­7) long; tarsal solenidion 10 (9­10) long; tarsal empodium simple, 8 (8­9)­rayed, symmetrical, 10 (10­12) long.

Leg II 40 (36­41) long; femur 11 (10­12) long, with seta bv 21 (17­20) long; position of seta bv 5 (4­5) from ventral, proximal margin of femur; genu 5 (5­6) long, with seta l’’ 12 (12­17) long; position of seta l’’ 3 (3­4) from dorsal, proximal margin of genu; tibia 7 (6­7) long. Tarsus 8 (8­9) long, with three setae: ft’’ 28 (22­27) long, ft’ 12 (10­14) long, u’ 6 (6­7) long; tarsal solenidion 10 (10­11) long; tarsal empodium 8 (8­9)­rayed, symmetrical, 10 (10­12) long.

Coxae with a pattern of numerous lines and dashes, some lines with microtubercles; slender sternal line present. Setae 1b 10 (10­12) apart, 11 (11­13) long; setae 1a 9 (7­9) apart, 29 (24­28) long; setae 2a 25 (22­27) apart, 53 (46­52) long; distance between setae 1b and 1a 7 (7­8), distance between setae 1a and 2a 9 (8­10).

Opisthosoma with 73 (66­74) dorsal annuli, 78 (68­81) ventral annuli, 6 (5­7) coxogenital annuli. Annuli with microtubercles; ventral microtubercles minute, conical and pointed, from level of setae f elongated; microtuberles on dorsal annuli bead­like, present only on ridges.

Setae c2 47 (38­48) long, located on 10th (8th–10th) ventral annulus from coxae II; tubercles c2 63 (48­64) apart; ventral setae d 67 (43­67) long, located on 26th (21st–28th) ventral annulus; tubercles d 36 (33­40) apart; setae e 48 (30­46) long, located on 47th (40th–48th) ventral annulus; tubercles e 13 (11­16) apart; setae f 40 (25­38) long, located on 74th (64th–77th) ventral annulus, 5th (5th) annulus from rear; tubercles f 25 (23­25) apart. Setae h1 5 (5­6) long, 8 (6­8) apart; setae h2 83 (72­98) long, 13 (11­13) apart; distance between h1 and h2 – 2 (2­3).

Genital parts 17 (16­19) long, 24 (23­27) wide, genital coverflap with 11 (10­12) longitudinal striae; setae 3a 40 (30­43) long, 14 (13­17) apart.

Male ( Fig. 5 ) (10 specimens): body length 178­221; body width 46­60, spindleform; dorsomedian ridge shorter than in female. Gnathosoma 17­26 long; dorsal pedipalpal genual seta d 8­10 long; v setae (sensory peg) 2 long; ep setae 2­3 long chelicerae 14­23 long, almost straight. Prodorsal shield elongate­triangular, 46­49 long; 38­46 wide, with pronounced, elongate frontal lobe over gnathosoma, which is shorter than those in female; pattern of shield similar to that of a female. Tubercles of setae sc located on the rear margin of shield, 2­3 long, 3 wide, 24­30 apart; setae sc 9­11 long, projecting to rear.

Leg I 32 ­37 long; femur 8­10 long, with seta bv 8­14 long; position of seta bv 3­4 from ventral, proximal margin of femur; genu 5­6 long, with seta l’’ 20­29 long; position of seta l’’ 3­4 from dorsal, proximal margin of genu; tibia 6­8 long, with seta l’ 8­10 long; position of seta l’ 3­5 from ventral, proximal margin of tibia. Tarsus 7­8 long, with three setae: ft’’ 22­29 long, ft’ 18­23 long, u’ 5­7 long; tarsal solenidion 8­10 long; tarsal empodium simple, 7­8­rayed, symmetrical, 9­11 long.

Leg II 31­35 long; femur 9­10 long, with seta bv 15­18 long; position of seta bv 3­5 from ventral proximal margin of femur; genu 4­5 long, with seta l’’ 10­15 long; position of seta l’’ 2­3 from dorsal, proximal margin of genu; tibia 5­7 long. Tarsus 7 long, with three setae: ft’’ 21­28 long, ft’ 10­12 long, u’ 5­7 long; tarsal solenidion 8­10 long; tarsal empodium 7­8­rayed, symmetrical, 9­10 long.

Coxae with a pattern of lines and microtubercles on coxae I, dashes on coxae II. Setae 1b 9­10 apart, 7­10 long; setae 1a 6­9 apart, 19­29 long; setae 2a 19­21 apart, 40­52 long; distance between setae 1b and 1a 6­8, distance between setae 1a and 2a 7­9.

Opisthosoma with 57­65 dorsal annuli, 58­69 ventral annuli, 5­7 coxogenital annuli. Annuli with microtubercles; dorsal microtubercels similar to that of female; ventral microtubercles tiny, conical, pointed.

Setae c2 36­46 long, located on 7th­9th ventral annulus from coxae II; tubercles c2 45­ 51 apart; ventral setae d 62­67 long, located on 18th­22nd ventral annulus; tubercles d 26­ 29 apart; setae e 24­40 long, located on 33rd­38th ventral annulus; tubercles e 10­14 apart; setae f 27­41 long, located on 54th­65th ventral annulus, 5th annulus from rear; tubercles f 19­24 apart. Setae h1 4­5 long, 6­7 apart; setae h2 67­81 long, 10­11 apart; distance between h1 and h2 – 2. Genital parts 14­17 long, 19­21 wide; setae 3a 26­32 long, 14­17 apart; granulated.

Nymph ( Fig. 6 ) (6 specimens): body length 162­206; body width 44­60; spindleform. Dorsomedial ridge slender, ending near 6­7th annulus from end. Gnathosoma 16­26 long; dorsal pedipalpal genual seta d 6­8 long; v setae (sensory peg) 2 long; ep setae 3 long; chelicerae 17­20. Prodorsal shield with a elongated lobe over base of chelicerae; shield triangular, its posterior margin bowed; 37­41 long, 35­44 wide. Sculpture of prodorsal shield: median line absent; admedian lines parallel to each other near; submedian lines parallel to lateral margins of shield. Conical microtubercles present on surface near shield. Tubercles of setae sc 2­3 long, 2­4 wide, located on rear margin of shield, 22­26 apart; setae sc 7­10 long.

Leg I 27­35 long; femur 6­9 long, with seta bv 7­9 long; position of seta bv 3­4 from ventral, proximal margin of femur; genu 4­5 long, with seta l’’ 18­25 long; position of seta l’’ 2­3 from dorsal, proximal margin of genu; tibia 5­6 long, with seta l’ 7­10 long; position of seta l’ 2.5­3 from ventral, proximal margin of tibia. Tarsus 5­6 long, with three setae: ft’’ 18­23 long; ft’ 14­18 long, u’ 4­6 long; tarsal solenidion 6­8 long; tarsal empodium simple, 6­7­rayed, symmetrical, 7­9 long.

Leg II 23­32 long; femur 6­8 long, with seta bv 11­13 long; position of seta bv 3­4 from ventral, proximal margin of femur; genu 4­5 long, with seta l’’ 8­10 long; position of seta l’’ 2­3 from dorsal, proximal margin of genu; tibia 3­4 long. Tarsus 5­6 long, with three setae: ft’’ 17­20 long, ft’ 7­8 long, u’ 4­6 long; tarsal solenidion 6­9 long; tarsal empodium 6­7­rayed, symmetrical, 7­9 long.

Coxae with a pattern of short, slender lines and conical microtubercles. Setae 1b 9­11 apart, 6 long; setae 1a 7­8 apart; setae 2a 20­24 apart, 30­35 long; distance between setae 1b and 1a 6­8, distance between setae 1a and 2a 7­8.

Opisthosoma with 47­64 dorsal annuli, 45­60 ventral annuli, 7­8 coxogenital annuli. Annuli with microtubercles; dorsal microtubercles sparse on ridge, bead­like, near ridge conical, pointed; ventral microtubercles conical, larger than dorsal.

Setae c 2 24­32 long, located on 6th ­9th ventral annulus from coxae II; tubercles c2 40­ 54 apart; ventral setae d 29­38 long, located on 15th–21st ventral annulus; tubercles d 25­32 apart; setae e 10­25 long, located on 26­36 ventral annulus; tubercles e 11­16 apart; setae f 19­27 long, located on 41st ­ 56th ventral annulus, 5th annulus from rear; tubercles f 18­22 apart. Setae h1 2­4 long, 5­6 apart; setae h 2 9­10 apart; distance between h1 and h2 – 2. Setae 3a 8­13 long, 8­10 apart.

Larva not seen.

Etymology: the specific designation is derived from the combination of words: longus (Latin) – long and lobus, because of the very long lobe of the prodorsal shield over the gnathosoma in this species.

Host plant: Bromus inermis Leyss. (Poaceae) .

Relation to host plant: mites are vagrants on both leaf surfaces.

Type locality: Poland, Poznañ, Cytadela (16° 56' E; 52° 25' N); scarp, southern exposition; 20.06.1999; leg. A. Skoracka.

Material examined: holotype female (ABALON248F7), 20 female partypes (ABA LON248F1­6, ABALON248F8­19), 14 males (ABALON248M1­14), 17 nymphs (ABA LON248N1­17).

Differential diagnosis: The new species is most similar to Abacarus stadelbacheri Petanovic, 1993 (from Geranium dissectum L., Geraniaceae , Italy) by the shape of the lobe over the gnathosoma, coxae ornamentation and appearance of dorsal microtubercles. Both species have similar numbers of annuli: dorsal (72 in A. stadelbacheri , 73 in A. longilobus ) and ventral (80 in A. stadelbacheri , 78 in A. longilobus ), width of genitalia (24 in both species) and distance between 3a setae (14 in both species).

A. longilobus can be distinguished from A stadelbacheri by the sculpture of the prodorsal shield and length of the dorsomedian ridge. In A. stadelbacheri on the prodorsal shield are long admedian lines and the dorsomedian ridge is ending near ½ of the opisthosoma. In A. longilobus dorsomedian ridge is longer, the admedian lines are present only on the posterior part of the shield, and the submedian lines are also present. Besides, those two species differ in the width of the prodorsal shield (56 in A. stadelbacheri , 47 in A. longilobus ), numbers of empodial rays (7 in A. stadelbacheri , 8 in A. longilobus ), length of opisthosomal setae d: (38 in A. stadelbacheri , 67 in A. longilobus ), e (16 in A. stadelbacheri , 48 in A. longilobus ), f (25 in A. stadelbacheri , 40 in A. longilobus ), 3a (19 in A. stadelbacheri , 40 in A. longilobus ).

Notice: This species was also found on three other Poaceae species: Agropyron repens (L.) P. B., Arrhenantherum elatius (L.) P. Beauv. ex J. Presl & C. and Bromus erectus Huds. The greatest intensity of its infestation was on B. inermis – 49.6 (n = 7; 95% CI: 20.7 – 101.3) and on A. elatius – 44.5 (n = 8; 18.5 – 97.0) specimens per stem. On other plants the mean number of specimens per stem was considerable lower: on A. repens – 7.3 (n = 13; 2.0 – 20.3), on B. erectus – 10.8 (n = 10; 3.6 – 28.9).

Figures

FIGURE 3. Abacarus longilobus n. sp. – female: dorsal aspect; IG – internal genitalia; DO – dorsal microtubercles; PV ­ postero­ventral view.

FIGURE 4. Abacarus longilobus n. sp. – female: CG – coxogenital region; L 1, L 2 – legs I and II.

FIGURE 5. Abacarus longilobus n. sp. – male: GM – coxogenital region.

FIGURE 6. Abacarus longilobus n. sp. – nymph: dorsal aspect; DO ­ dorsal microtubercles; VO ­ ventral microtubercles.