Aculus sayanicus, Skoracka, Anna & Pacyna, Anna, 2003

Skoracka, Anna & Pacyna, Anna, 2003, Aculus sayanicus, a new species of Eriophyidae (Acari: Eriophyoidea) from grasses in Russia, Zootaxa 149, pp. 1-10 : 2-9

Aculus sayanicus n. sp. Skoracka

DIAGNOSIS: anterior lobe of prodorsal shield with three spines, typical prodorsal shield design of distinct lines bearing conical microtubercles, 8­9­rayed empodium, long, thin and tapered solenidion.

FEMALE ( Figs 1­2 ) (holotype and 8 paratypes): Body spindleform. Body length 170 (183­235); width 60 (52­64). Gnathosoma 22 (20­23) long; dorsal pedipalpal genual seta d 14 (11­15) long; v seta (sensory peg) 2 (2) long; ep seta 3 (3); cheliceral stylets 21 (21­23) long. Prodorsal shield triangular, with rounded frontal lobe over base of chelicerae, lobe with three small spines projecting forward from under front edge. Prodorsal shield 43 (45­48) long, 46 (43­48) wide. Shield design of distinct lines, most of them bearing conical microtubercles: median line on rear ½; admedian lines entire, from anterior lobe diverging to rear margin; I submedian lines subparallel to admedian on rear ½, not reaching rear margin; II submedian lines from anterior ¼ running toward outer tubercles of sc setae, subparallel to lateral margin of shield. Tubercles of setae sc located on rear margin of shield, 4 (4­5) long, 4 (4­5) wide, 29 (28 35) apart. Setae sc 59 (48­57) long, projecting to rear.

Leg I 46 (45­47) long; femur 13 (12­13) long, with seta bv 21 (18­22) long; position of seta bv 6 (5­6) from ventral, proximal margin of femur; genu 8 (7­8) long, with seta l” 40 (33­38) long, position of seta l” 4 (4) from dorsal, proximal margin of genu; tibia 11 (11­12) long, with seta l’ 14 (14­19) long; position of seta l’ 6 (6­7) from ventral, proximal margin of tibia. Tarsus 10 (9­10) long, with three setae: ft” 30 (27­36), ft’ 30 (27­30) long, u’ 11 (8­12) long; tarsal solenidion 14 (12­14) long; tarsal empodium simple, 9 (8­9)­ rayed, symmetrical, 15 (13­15) long. Leg II 45 (42­46) long; femur 13 (13) long, with seta bv 30 (30­34) long; position of seta bv 6 (5­6) from ventral, proximal margin of femur; genu 7 (6­7) long, with seta l” 24 (19­24) long; position of seta l” 4 (3­4) from dorsal, proximal margin of genu; tibia 9 (9­10) long. Tarsus 9 (8­10) long, with three setae: ft” 32 (28 33) long, ft’ 19 (14­19), u’ 10 (10­11) long; tarsal solenidion 14 (12­14) long, thin and tapered; tarsal empodium 8 (8)­rayed, symmetrical, 15 (14­15) long.

Coxae with irregular pattern of numerous dashes and microtubercles; slender sternal line present. Setae 1b 10 (10­12) apart, (15­19) long; setae 1a 8 (8­9) apart, 44 (45) long; setae 2a 22 (23­26) apart, 67 (57) long; distance between setae 1b and 1a 10 (9­10), distance between setae 1a and 2a 8 (9).

Opisthosoma with 52 (45­64) dorsal annuli, 66 (58­74) ventral annuli, 7 (6­8) coxogenital annuli. Annuli with microtubercles; dorsal microtubercles bead­like, situated under folds of annuli and almost invisible on 2/3 anterior part of opisthosoma; ventral microtubercles rounded, located on annuli margin.

Seta c2 57 (48­51) long, located on 9th (8th­10th) ventral annulus from coxae II; tubercles c2 51 (42­54) apart; ventral seta d 72 (57­86) long, located on 21st (21st­24th) ventral annulus; tubercles d 36 (32­38) apart; seta e 45 (43­53) long, located on 38th (34th­44th) ventral annulus; tubercles e 16 (15­17) apart; seta f 42 (38­43) long, located on 62nd (58th­70th) ventral annulus, or 5th (5th) annulus from rear; tubercles f 26 (21­27) apart. Setae h1 6 (5­6) long, 6 (6­7) apart; setae h2 105 (76­86) long, 10 (10­11) apart; distance between h1 and h2 2 (2).

Genital parts 12 (11­13) long, 23 (21­24) wide, genital coverflap with 15 (10­15) longitudinal striae; setae 3a 64 (57­79) long, 17 (15­16) apart.

MALE (Fig 3) (3 specimens): body length 141­200; body width 49­57, spindleform. Gnathosoma 20­24 long; dorsal pedipalpal genual seta d 10­11 long; v seta (sensory peg) 2 long; ep seta 3 long; chelicerae 20­21 long. Prodorsal shield shape and design similar to that of a female, except the anterior lobe bearing two small spines projecting forward from under front edge. Shield 39­43 long; 40­55 wide. Tubercles of setae sc located on rear margin of shield, 4 long, 4 wide, 29­35 apart; setae sc 33­40 long, projecting to rear.

Leg I 38 ­43 long; femur 10 long, with seta bv 16­17 long; position of seta bv 5 from ventral, proximal margin of femur; genu 6 long, with seta l” 27­30 long; position of seta l” 3­4 from dorsal, proximal margin of genu; tibia 9­10 long, with seta l’ 11­12 long; position of seta l’ 5 from ventral, proximal margin of tibia. Tarsus 8­9 long, with three setae: ft” 27 long, ft’ 23 long, u’ 6­8 long; tarsal solenidion 10­11 long; tarsal empodium simple, 7 rayed, symmetrical, 11­12 long. Leg II 36 ­38 long; femur 10 long, with seta bv 25­ 28 long; position of seta bv 4­6 from ventral proximal margin of femur; genu 5­6 long, with seta l” 18 long; position of seta l” 3­4 from dorsal, proximal margin of genu; tibia 8 long. Tarsus 8­9 long, with three setae: ft” 28 long, ft’ 13 long, u’ 7 long; tarsal solenidion 11­12 long; tarsal empodium 7­rayed, symmetrical, 12­13 long.

Coxae with a pattern of dashes. Setae 1b 10­11 apart, 15 long; setae 1a 7­9 apart, 24 long; setae 2a 21­24 apart, 46 long; distance between setae 1b and 1a 7­8, distance between setae 1a and 2a 8­9.

Opisthosoma with 55­58 dorsal annuli, 60­63 ventral annuli, 5 coxogenital annuli. Annuli with microtubercles; dorsal microtubercles tiny and conical, set along annuli margins; ventral microtubercles larger than dorsal ones, conical, pointed, not ahead or slightly ahead of annuli margins.

Figure 3: Aculus sayanicus n. sp. male: TP ­ prodorsal shield; GM ­ coxigenital region; DO ­ dorsal microtubercles.

Seta c2 52­53 long, located on 9th ventral annulus from coxae II; tubercles c2 42­50 apart; ventral seta d 57­62 long, located on 18th ­20th ventral annulus; tubercles d 29­39 apart; seta e 43 long, located on 32nd­36th ventral annulus; tubercles e 14­18 apart; seta f 33­36 long, located on 56th­59th ventral annulus, or 5th annulus from rear; tubercles f 23­26 apart.

Setae h1 4­5 long, 6 apart; setae h 2 8­10 apart; distance between h1 and h2 2.

Genital parts 14­15 long, 20­23 wide; setae 3a 29­34 long, 15­19 apart; surface near the genital parts with triangular microtubercles.

NYMPH ( Fig 4 ) (2 specimens): body length 181­209; body width 48; vermiform. Gnathosoma 19 long; dorsal pedipalpal genual seta d 11 long; chelicerae 19. Shape and design of prodorsal shield similar to that of a female, with some exceptions: there are no microtubercles on shield, anterior lobe without spines. Shield 40­43 long, 44 wide. Tubercles of setae sc 3 long, 4 wide, located on rear margin of shield, 25­26 apart; seta sc 23­26 long.

Leg I 30 long; femur 7 long, with seta bv 14 long; position of seta bv 4 from ventral, proximal margin of femur; genu 5 long, with seta l ”28 long; position of seta l” 3 from dorsal, proximal margin of genu; tibia 5 long, with seta l’ 10 long; position of seta l’ 4 from ventral, proximal margin of tibia, tarsus 6 long. Tarsal solenidion 9 long; tarsal empodium simple, 7­rayed, symmetrical, 9­10 long. Leg II 27 long; femur 8 long, with seta bv 14 long; position of seta bv 4 from ventral, proximal margin of femur; genu 4 long, with seta l” 13 long; position of seta l” 3 from dorsal, proximal margin of genu; tibia 6 long. Tarsus 7 long, with three setae: ft” 21 long, ft’ 13 long, u’ 7 long; tarsal solenidion 9 long; tarsal empodium 7­rayed, symmetrical, 9 long.

Coxae with a pattern of dashes and microtubercles. Setae 1b 7­10 apart; setae 1a 9­10 apart; setae 2a 21­23 apart, 38 long; distance between setae 1b and 1a 7­8, distance between setae 1a and 2a 7­8.

Opisthosoma with 54­57 dorsal annuli, 53­54 ventral annuli, 7­8 coxogenital annuli. Annuli with microtubercles; dorsal microtubercles tiny, conical with blunt top, set along annuli margins; ventral microtubercles conical, larger than dorsal ones, slightly ahead of annuli margins.

Seta c2 37 long, located on 9th­10th ventral annulus from coxae II; tubercles c2 43 apart; ventral seta d 40 long, located on 19th21st ventral annulus; tubercles d 29 apart; seta

e located on 31­32 ventral annulus; tubercles e 11­14 apart; seta f 26 long, located on 49th­ 50th ventral annulus, or 5th annulus from rear; tubercles f 18­24 apart.

Setae h1 5 apart; setae h2 8 apart; distance between h1 and h2 2.

Setae 3a 13­14 long, 8­9 apart.

LARVA: not seen.

TYPE MATERIAL: holotype female, 10 female paratypes, 5 males, 2 nymphs collected from Poa sibirica Roshev. (Poaceae) , in Russia, south­west part of Republic of Buryatia, Eastern Sayan Mountains, Tunka Valley, 7.2 km from Arshan locality (51º59’N, 102º24’E), elevation 1800 m., taiga; 8.09.2001; leg. A. Skoracka.

This species was also found on the same host in Sayan Mountains, near Kitoy river (52º03’N, 102º23’E), elevation 864 m., taiga; 12.09.2001; leg. A. Skoracka.

RELATION TO HOST PLANT: mites are vagrants on upper leaf surfaces.

ETYMOLOGY: the specific name is derived from the name of the Mountains where this mite was found + icus, Greek, meaning pertaining to.

REMARKS: 1) A. sayanicus is the second species of the genus Aculus described from grasses. It differs from A. bambusae Kuang, 1991 (from Bambusa sp., China) by prodorsal shield design and prodorsal lobe shape. In A. sayanicus the median line is incomplete and there is no transverse line; the prodorsal lobe bears three spines. In A. bambusae the median line is complete and there is a transverse line joining admedian lines; the prodorsal lobe bears two spines. In addition, the two species differ in the number of I empodial rays (9 in A. sayanicus , 7 in A. bambusae ), number of dorsal annuli (52 in A. sayanicus , 37 in A. bambusae ) and length of setae: sc (48­57 A. sayanicus , 30 in A. bambusae ), 3a (57­79 in A. sayanicus , 22 in A. bambusae ), c2 (48­51 in A. sayanicus , 20 in A. bambusae ).

2) The other species collected in Eastern Sayan Mountains is Abacarus acutatus Sukhareva. It was found on Calamagrostis purpurea (Trin.) subsp. langsdorfii (Link) Tzvel. ( C. langsdorffi (Link) Trin. ) in Tunka Valley, 3.3 km from Arshan locality (51º57’N, 102º25’E), elevation 1100 m, taiga; 7.09.2001. This species was described from Calamagrostis epigeios (L.) Roth in Russia ( Sukhareva 1985), and was also recorded from C. arundinacea (L.) Roth in Poland ( Skoracka 2000). C. purpurea is a new host plant for this eriophyoid mite.

Figures

FIGURE 1: Aculus sayanicus n. sp. female: D ­ dorsal aspect; em empodium; DO ­ dorsal microtubercles; L 1, L 2 ­ legs I and II

FIGURE 2: Aculus sayanicus n. sp. female: CG ­ coxigenital region; IG ­ internal genitalia; PV ­ postero­ventral view.

FIGURE 4: Aculus sayanicus n. sp. nymph: D ­ dorsal aspect; CG ­ coxigenital region