Amblydromalus insolitus Nuvoloni & Lofego

Nuvoloni, Felipe Micali, Lofego, Antonio Carlos, Castro, Elizeu Barbosa & Feres, Reinaldo José Fazzio, 2015, Phytoseiidae (Acari: Mesostigmata) from rubber tree crops in the State of Bahia, Brazil, with description of two new species, Zootaxa 3964 (2), pp. 260-274 : 262-264

Amblydromalus insolitus Nuvoloni & Lofego n. sp.

( Figs 1–7 )

Diagnosis. This new species is close to others in the limonicus species group, due to the ratio between the length of Z4 and the distance between their bases ( Fig. 1 ), although this species is remarkably different from all Amblydromalus spp. due to the dorsal shield being covered mainly by roundish ornamentation, with anterolateral striae. The ornamentation is quite distinct in the central region, becoming more scattered posteriad of J2, and toward the shield borders.

Specimens examined. Holotype female and one paratype female collected from H. brasiliensis , clone FDR 5788, from Igrapiúna, Bahia, Brazil, (13°48'S, 39°10'W) 8 August 2012, E.B. Castro coll.; five female and two male paratypes collected from H. brasiliensis , clone PMB 0 1, 8 August 2012, E.B. Castro coll. All specimens are deposited at DZSJRP.

Etymology. The specific name insolitus refers to the unusual pattern of ornamentation on the dorsal shield compared with other Amblydromalus species.

Description. Female (n=7) ( Figs 1–5 ).

Dorsum. Dorsal shield covered mainly by roundish ornamentation, with a few anterolateral striae to the level of s4, 300 [304] (295–315) long and 175 [186] (175–192) wide at level of s4; five pairs of pores and seven pairs of lyrifissures visible. Setae j1 20 [20] (17–20), j3 32 [30] (30–32), j4 6 [6] (5–7), j5 5 [6] (5–7), j6 9 [9] (7–10), J2 12 [11] (9–12), J5 10 [8] (6–10), z2 10 [9] (8–10), z4 10 [8] (7–10), z5 6 [6] (6–7), Z1 12 [11] (10–12), Z4 10 [10] (10–11), Z5 60 [61] (60–65), s4 38 [36] (32–41), S2 14 [13] (11–15), S4 10 [11] (10–12), S5 9 [10] (9–10), r3 15 [13] (12–15), R1 10 [9] (8–10). Setae r3 and R1 inserted in unsclerotised cuticle. All setae smooth and pointed, except Z5 serrate.

Venter. Sternal shield smooth; with three pairs of setae and two pairs of lyrifissures. Distances between st1-st3 60 [59] (57–60), st2-st2 72 [67] (65–72). Genital shield smooth, distance between st5-st5 70 [69] (65–72). Ventrianal shield vase shaped, smooth, 100 [100] (85–107) long, 48 [52] (48–55) wide at level of ZV2, and 45 [51] (45–55) wide at median level of anus, with three pairs of pre-anal setae (JV1, JV2, ZV2) and a pair of pores in a transverse line with JV2. Opisthogastric cuticle with one pair of metapodal plates. Peritremes extending almost to j1.

Chelicera. Fixed digit 32 [30] (27–32) long, with 11 teeth; movable digit 30 [27] (25–30) long, with four teeth. Pilus dentilis not visible.

Spermatheca. Calyx saccular, 26 [24] (20–26) long, atrium distinct, blunt.

Legs. Macrosetae present on all legs: Sge I 35 [31] (20–35), Sge II 30 [31] (30–35), Sge III 35 [35] (32–40), Sti III 28 [28] (25–30), Sge IV 60 [60] (50–67), Sti IV 35 [40] (35–44) and St IV 65 [70] (65–75). All macrosetae pointed. Chaetotaxy of genu II 2 2/0 2/0 1; genu III 1 2/2 2/0 1.

Male. (n=2) ( Figs 6–7 ).

Dorsum. Dorsal shield pattern similar to female, 232–237 long and 165–175 wide. Setae j1 15, j 3 30–32, j4 6– 7, j5 7, j 6 7–10, J2 10, J5 6–8, z 2 9–10, z4 9, z5 6, Z1 10, Z 4 7–10, Z5 45–48, s4 30, S2 10, S4 10, S5 8, r 3 9–12, R1 8. All dorsal setae smooth, s4 and Z5 blunt-tipped as in female.

Venter. Sternogenital shield smooth. Ventrianal shield subtriangular ( Fig. 7 ), weakly striated, 95–102 long, 120–130 wide at anterior corners, 70 wide at anus level, with three pairs of pre-anal setae (Jv1, Jv2 and Zv2), two pairs of small circular pores, and one pair of large crescent-shaped pores. Peritreme reaching beyond level of j3.

Chelicera ( Fig. 6 ). Movable digit 20 long, fixed digit 23 long; pilus dentilis not visible. Spermatodactyl elongated, 23 long, toe and heel conspicuous.

Legs. Macrosetae with pointed tips present on all legs: Sge I 25–28 with, Sge II 25–30, Sge III 25, Sti III 22– 25, Sge IV 40 –42, Sti IV 30, and St IV 62. Chaetotaxy as in female.

Remarks. In contrast to other species of Amblydromalus , the dorsal shield of this new species is distinct reticulated, resembling many Typhlodromalus species as reported by Chant & McMurtry (2005a). However this species fits the genus Ambydromalus by having the ratio of setae s4:Z1> 3.0:1:0, j3, s4 and Z5 longer than other dorsal setae, dorsal setae smooth, Z4 not longer than distance to S4, and absence of an indentation of the dorsal shield at the level of seta S5 (such as in Typhlodromalus ). Furthermore, the length and proportions of setae seem more conservative in phytoseiid groups than dorsal reticulations, and it has been a useful feature to separate groups ( Chant & McMurtry, 2007). According to Chant & McMurtry (2005) the setal ratio s4:Z1> 3.0:1:0 is a diagnostic feature for the classification of phytoseiids in the subtribe Thyphlodromalina, and consequently as Amblydromalus . Considering these facts, we believe that the new species fits better in Amblydromalus than Typhlodromalus .

Figures

FIGURES 1 – 7. Amblydromalus insolitus n. sp. Female: 1. Dorsal idiosoma, 2. Ventral idiosoma, 3. Chelicera, 4. Spermatheca, 5. Genu, tibia and tarsus of leg IV. Male: 6. Spermatodactyl, 7. Ventrianal shield.